DEFINITION AND CLASSIFICATION

Anaemia is a deficiency in the number of erythrocytes (red blood cells [RBCs]), the quantity of haemoglobin and/or the volume of packed RBCs (haematocrit). It is a prevalent condition with many diverse causes, such as blood loss, impaired production of erythrocytes or increased destruction of erythrocytes (see Fig 30-1). Because RBCs transport oxygen, erythrocyte disorders can lead to tissue hypoxia. This hypoxia accounts for many of the signs and symptoms of anaemia. Anaemia is not a specific disease; it is a manifestation of a pathological process.

Figure 30-1 Causes of anaemia. RBC, red blood cell.

Anaemia is identified by a thorough history and physical examination, and then classified by laboratory review of the full blood count (FBC), reticulocyte count and peripheral blood smear. Once anaemia is identified, further investigation is done to determine its cause.^1,2

Anaemia can result from primary haematological problems or it can develop as a secondary consequence of defects in other body systems. The various types of anaemia can be grouped according to either a morphological (cellular characteristic) classification or an aetiological (underlying cause) classification. Morphological classification is based on descriptive, objective laboratory information about erythrocyte size and colour. (The terms used in this classification system are explained in Ch 29.) Aetiological classification is related to the clinical conditions causing the anaemia, such as decreased erythrocyte production, blood loss or increased erythrocyte destruction (see Box 30-1). Although the morphological system is the most accurate means of classifying anaemia, it is easier to discuss patient care by focusing on the aetiology of the anaemia. Table 30-1 relates morphological classifications to various aetiologies.

TABLE 30-1 The relationship of morphological classification and aetiologies of anaemia

CLINICAL MANIFESTATIONS

The majority of the clinical manifestations of anaemia are caused by the body’s response to tissue hypoxia. Specific manifestations can vary depending on the rate at which it has evolved, the severity of the anaemia and the presence of coexisting disease. Haemoglobin (Hb) levels are often used to determine the severity of anaemia. Mild states of anaemia (Hb 100–140 g/L) may exist without causing symptoms. If symptoms develop, it is because the patient has an underlying disease or is experiencing a compensatory response to activities such as heavy exercise. Symptoms include palpitations, dyspnoea and diaphoresis. In cases of moderate anaemia (Hb 60–100 g/L), the cardiopulmonary symptoms are increased and the patient may experience them while resting as well as with activity. The patient with severe anaemia (Hb <60 g/L) has many clinical manifestations involving multiple body systems, with fatigue and tiredness being the primary complaints (see Table 30-2).

TABLE 30-2 Clinical manifestations of anaemia

HF, heart failure; Hb, haemoglobin; MI, myocardial infarction.

* Caused by haemolysis.

NURSING MANAGEMENT: ANAEMIA

This section discusses general nursing management of anaemia. Specific care related to various types of anaemia is discussed later in this chapter.

Nursing assessment

Subjective and objective data that should be obtained from the patient with anaemia are presented in Table 30-3.

TABLE 30-3 Anaemia

NURSING ASSESSMENT

GI, gastrointestinal; Hct, haematocrit; Hb, haemoglobin; HIV, human immunodeficiency virus; LDH, lactic dehydrogenase; MCV, mean corpuscular volume; RBCs, red blood cells.

AETIOLOGY

Iron-deficiency anaemia may develop from inadequate dietary intake, malabsorption, blood loss or haemolysis (normal iron metabolism is discussed in Ch 29). Dietary iron is adequate to meet the needs of men and older women, but it may be inadequate for those individuals who have higher iron needs (e.g. menstruating or pregnant women). Table 30-4 lists nutrients needed for erythropoiesis. Dietary guidelines are available to ensure adequate intake of nutrients needed for erythropoiesis.⁷

TABLE 30-4

Nutrients needed for erythropoiesis

NUTRITIONAL THERAPY

RBC, red blood cell.

Malabsorption of iron may occur after certain types of gastrointestinal (GI) surgery and in malabsorption syndromes. Surgical procedures may involve removal or bypass of the duodenum (see Ch 42). As iron absorption occurs in the duodenum, malabsorption syndromes may involve disease of the duodenum in which the absorption surface is altered or destroyed.

Blood loss is a major cause of iron deficiency in adults. Two millilitres of whole blood contain 1 mg of iron. The major sources of chronic blood loss are from the GI and genitourinary (GU) systems. GI bleeding is often not apparent and therefore may exist for a considerable time before the problem is identified. Loss of 50–75 mL of blood from the upper GI tract is required for stools to appear black (melaena). The black colour results from the iron in the RBCs. Common causes of GI blood loss are peptic ulcer, gastritis, oesophagitis, diverticuli, haemorrhoids and neoplasia. GU blood loss occurs primarily from menstrual bleeding. The average monthly menstrual blood loss is about 45 mL and causes the loss of about 22 mg of iron. Postmenopausal bleeding can contribute to anaemia in a susceptible older woman.

Pregnancy contributes to iron deficiency because of the diversion of iron to the fetus for erythropoiesis, blood loss at delivery and lactation. In addition to anaemia of chronic renal failure, dialysis treatment may induce iron-deficiency anaemia because of the blood lost in the dialysis equipment and frequent blood sampling.

CLINICAL MANIFESTATIONS

In the early course of iron-deficiency anaemia, the patient may be free of symptoms. As the disease becomes chronic, any of the general manifestations of anaemia may develop (see Table 30-2). In addition, specific clinical symptoms may occur related to iron-deficiency anaemia. Pallor is the most common finding, and glossitis (inflammation of the tongue) is the second most common; another finding is cheilitis (inflammation of the lips). In addition, the patient may report headaches, paraesthesias and a burning sensation of the tongue, all of which are caused by lack of iron in the tissues.

DIAGNOSTIC STUDIES

Laboratory abnormalities characteristic of iron-deficiency anaemia are presented in Table 30-5. Other diagnostic studies are done to determine the cause of the iron deficiency (e.g. stool guaiac [occult blood] test). Endoscopy and colonoscopy may be used to detect GI bleeding. A bone marrow biopsy may be done if other tests are inconclusive.

TABLE 30-5 Laboratory study findings in anaemias

Hb, haemoglobin; Hct, haematocrit; MCV, mean corpuscular volume; N, normal; TIBC, total iron-binding capacity.

MULTIDISCIPLINARY CARE

The main goal of multidisciplinary care of iron-deficiency anaemia is to treat the underlying disease that is causing reduced intake (e.g. malnutrition, alcoholism) or absorption of iron. In addition, efforts are directed towards replacing iron (see Box 30-2). The patient should be taught which foods are good sources of iron (see Table 30-4). If nutrition is already adequate, increasing iron intake by dietary means may not be practical. Consequently, oral or occasionally parenteral iron supplements are used. If the iron deficiency is from acute blood loss, the patient may require a transfusion of packed RBCs and a thorough investigation of the source of blood loss.

NURSING MANAGEMENT: IRON-DEFICIENCY ANAEMIA

It is important to recognise groups of individuals who are at an increased risk for the development of iron-deficiency anaemia. These include premenopausal and pregnant women, people from low socioeconomic backgrounds, older adults and individuals experiencing blood loss. Dietary education and advice, with an emphasis on foods high in iron, is important for these groups. Supplemental iron is especially important for pregnant women. Appropriate nursing measures are presented in NCP 30-1. It is important to discuss with the patient the need for diagnostic studies to identify the cause of the anaemia. The haemoglobin and RBC counts are reassessed to evaluate the response to therapy. Compliance with dietary and drug therapy is emphasised. To replenish the body’s iron stores, the patient needs to continue to take iron therapy for 2–3 months after the haemoglobin level returns to normal. Patients who require lifelong iron supplementation should be monitored for potential liver problems related to iron storage.

AETIOLOGY

Another cause of decreased erythrocyte production is thalassaemia. Thalassaemia is a group of diseases that have an autosomal recessive genetic basis involving inadequate production of normal haemoglobin. Haemolysis also occurs in thalassaemia, but insufficient production of normal haemoglobin is the predominant problem. In contrast to iron-deficiency anaemia, in which haem synthesis is the problem, thalassaemia is due to an absent or reduced globulin protein. α-globin chains are absent or reduced in α-thalassaemia, and β-globin chains are absent or reduced in β-thalassaemia. Therefore, the basic defect of thalassaemia is abnormal haemoglobin synthesis.

Thalassaemia is commonly found in members of ethnic groups whose origins are near the Mediterranean Sea and equatorial or near-equatorial regions of Asia, the Middle East and Africa. An individual with thalassaemia may have a heterozygous or homozygous form of the disease. A person who is heterozygous has one thalassaemic gene and one normal gene and is said to have thalassaemia minor (or thalassaemic trait), which is a mild form of the disease. A homozygous person has two thalassaemic genes, causing a severe condition known as thalassaemia major.⁹ Patient information on thalassaemia is available from Thalassaemia Australia (see Resources on p 805).

CLINICAL MANIFESTATIONS

Thalassaemia major is a life-threatening disease in which growth, both physical and mental, is often retarded. The person who has thalassaemia major is pale and displays other general symptoms of anaemia (see Table 30-2). The symptoms develop in childhood by 2 years of age and can cause growth and development deficits. In addition, the person has pronounced splenomegaly and hepatomegaly. Jaundice from RBC haemolysis is prominent. As the bone marrow responds to the deficit of oxygen-carrying capacity of the blood, RBC production is stimulated and the marrow becomes packed with immature erythroid precursors that die. This stimulates further erythropoiesis, leading to chronic bone marrow hyperplasia and expansion of the marrow space. This may cause thickening of the cranium and maxillary cavity.

The patient with thalassaemia minor is frequently asymptomatic. The patient has mild-to-moderate anaemia with microcytosis (small cells) and hypochromia (pale cells).

MULTIDISCIPLINARY CARE

The laboratory abnormalities of thalassaemia major are summarised in Table 30-5. No specific drug or diet therapies are effective in treating thalassaemia. Thalassaemia minor requires no treatment because the body adapts to the reduction of normal haemoglobin. The symptoms of thalassaemia major are managed with blood transfusions or exchange transfusions in conjunction with IV deferoxamine (a chelating agent that binds to iron) to reduce the iron overloading (haemochromatosis) that occurs with chronic transfusion therapy.¹⁰ Transfusions are administered to keep the haemoglobin level at approximately 100 g/L. This level is low enough to maintain the patient’s own erythropoiesis without enlarging the spleen. Zinc supplementation may be needed (it is reduced with the chelation therapy) as well as ascorbic acid supplementation during the chelation therapy (increases urine excretion of iron; it should not be taken otherwise, as it increases the absorption of dietary iron). Iron supplements should not be given. Because RBCs are sequestered in the enlarged spleen, thalassaemia may be treated by splenectomy.

Hepatitis C is present in the majority of patients older than 25 years of age because they received blood transfusions before transfusions were screened for hepatitis C virus. Hepatitis C may result in cirrhosis and hepatocellular carcinoma. Cardiac complications from iron overload, pulmonary disease and hypertension also contribute to early death. Thus hepatic, cardiac and pulmonary organ function should be monitored and treated as appropriate. Endocrinopathies (hypogonadotrophic hypogonadism) and thrombosis may also be complications of the disease.

Although haematopoietic stem cell transplantation remains the only cure for patients with thalassaemia, the risk of this procedure may outweigh its benefits. With proper iron chelation therapy, patients are living longer.^11,12

VITAMIN B₁₂ DEFICIENCY

Normally, a protein termed intrinsic factor (IF) is secreted by the parietal cells of the gastric mucosa. IF is required for vitamin B₁₂ (extrinsic factor) absorption. Therefore, if IF is not secreted, vitamin B₁₂ will not be absorbed (vitamin B₁₂ is normally absorbed in the distal ileum). There are many causes of vitamin B₁₂ deficiency. The most common cause is pernicious anaemia, a disease in which the gastric mucosa is not secreting IF due to antibodies being directed against the gastric parietal cells and/or IF itself. Other causes of vitamin B₁₂ deficiency include gastrectomy, gastritis, nutritional deficiency, chronic alcoholism and hereditary enzymatic defects of vitamin B₁₂ utilisation (see Box 30-3).

Pernicious anaemia is a disease of insidious onset that begins in middle age or later (usually after age 40), with 60 years being the most common age at diagnosis. Pernicious anaemia occurs frequently in people of Northern European ancestry (particularly Scandinavians) and African Americans. In African Americans, the disease tends to begin early, occurs with higher frequency in women and is often severe.

AETIOLOGY

Vitamin B₁₂ deficiency can occur in patients who have had GI surgery, such as gastrectomy; patients who have had a small bowel resection involving the ileum; and patients with Crohn’s disease, ileitis, diverticuli of the small intestine and/or chronic atrophic gastritis. Long-term use of metformin can also result in vitamin B₁₂ deficiency. In these cases, the deficiency results from the loss of IF-secreting gastric mucosal cells or impaired absorption of vitamin B₁₂ in the distal ileum. Vitamin B₁₂ deficiency is also found in long-term users of histamine H₂-receptor antagonists and proton pump inhibitors, and those who are strict vegetarians.¹³

Pernicious anaemia is caused by an absence of IF, from either gastric mucosal atrophy or autoimmune destruction of parietal cells. This results in a decrease of hydrochloric acid secretion by the stomach. An acid environment in the stomach is required for the secretion of IF.

CLINICAL MANIFESTATIONS

General symptoms of anaemia related to vitamin B₁₂ deficiency develop because of tissue hypoxia (see Table 30-2). GI manifestations include a sore tongue, anorexia, nausea, vomiting and abdominal pain. Typical neuromuscular manifestations include weakness, paraesthesias of the feet and hands, reduced vibratory and position senses, ataxia, muscle weakness and impaired thought processes ranging from confusion to dementia. Because vitamin B₁₂ deficiency anaemia has an insidious onset, it may take several months for these manifestations to develop.

FOLIC ACID DEFICIENCY

Folic acid (folate) deficiency also causes megaloblastic anaemia. Folic acid is required for DNA synthesis leading to RBC formation and maturation. Common causes of folic acid deficiency include the following:

The clinical manifestations of folic acid deficiency are similar to those of vitamin B₁₂ deficiency. The disease develops insidiously and the patient’s symptoms may be attributed to other coexisting problems, such as cirrhosis or oesophageal varices. GI disturbances include dyspepsia and a smooth, beefy red tongue. The absence of neurological problems is an important diagnostic finding. This lack of neurological involvement differentiates folic acid deficiency from vitamin B₁₂ deficiency.

The diagnostic findings for folic acid deficiency are presented in Table 30-5. In addition, the serum folate level is low (normal is 7–41 nmol/L), the serum vitamin B₁₂ level is normal and the gastric analysis is positive for hydrochloric acid.

Folic acid deficiency is treated by replacement therapy. The usual dose is 1 mg per day by mouth. In malabsorption states, up to 5 mg per day may be required. The duration of treatment depends on the reason for the deficiency. The patient should be encouraged to eat foods containing large amounts of folic acid (see Table 30-4).

NURSING MANAGEMENT: MEGALOBLASTIC ANAEMIAS

Since there is a familial predisposition for pernicious anaemia, the most common type of vitamin B₁₂ deficiency, patients who have a positive family history of pernicious anaemia should be evaluated for symptoms. Although disease development cannot be prevented, early detection and treatment can lead to reversal of symptoms. Signs and symptoms of other possible megaloblastic anaemias should also be considered and brought to the attention of the primary healthcare provider.

The nursing measures presented in the nursing care plan for the patient with anaemia (see NCP 30-1) are appropriate for the patient with vitamin B₁₂ or folic acid deficiency anaemia. In addition to these measures, the nurse should ensure that injuries are not sustained because of the diminished sensations to heat and pain resulting from the neurological impairment. The patient must be protected from falling, burns and trauma. If heat therapy is required, the patient’s skin must be evaluated at frequent intervals to detect redness.

Ongoing care is focused on ensuring good patient compliance with treatment. There must also be careful follow-up to assess for neurological difficulties that were not fully corrected by adequate replacement therapy. Because the potential for cancer may be increased (e.g. gastric carcinoma is increased in patients with atrophic gastritis-related pernicious anaemia, alcohol increases the likelihood of oral and oesophageal cancers), the patient should have frequent and careful appropriate screenings.

AETIOLOGY

The incidence of aplastic anaemia is low, affecting approximately 2 out of every 1 million persons.¹⁶ There are various aetiological classifications for aplastic anaemia, but they can be divided into two major groups: congenital and acquired (see Box 30-4).

CLINICAL MANIFESTATIONS

Aplastic anaemia can present abruptly (over days) or insidiously (over weeks to months) and can vary from mild to severe. Clinically the patient may have symptoms caused by suppression of any or all bone marrow elements. General manifestations of anaemia such as fatigue and dyspnoea, as well as cardiovascular and cerebral responses, may be seen (see Table 30-2). The patient with neutropenia (low neutrophil count) is susceptible to infection and may be febrile. Thrombocytopenia is manifested by a predisposition to bleeding (e.g. petechiae, ecchymosis, epistaxis).

DIAGNOSTIC STUDIES

The diagnosis is confirmed by laboratory studies. Because all marrow elements are affected, haemoglobin, WBC and platelet values are often decreased in aplastic anaemia. Other RBC indices are generally normal (see Table 30-5). The condition is therefore classified as a normocytic, normochromic anaemia. The reticulocyte count is low. Bleeding time is prolonged.

Aplastic anaemia can be further evaluated by assessing various iron studies. The serum iron and total iron-binding capacity (TIBC) may be elevated as initial signs of erythropoiesis suppression. Bone marrow biopsy, aspiration and pathological examination may be done for any anaemic state. However, the findings are especially important in aplastic anaemia because the marrow is hypocellular with increased yellow marrow (fat content).

NURSING AND COLLABORATIVE MANAGEMENT: APLASTIC ANAEMIA

Management of aplastic anaemia is based on identifying and removing the causative agent (when possible) and providing supportive care until the pancytopenia reverses. Nursing interventions appropriate for the patient with pancytopenia from aplastic anaemia are presented in the nursing care plan for the patient with anaemia (see NCP 30-1) and the nursing care plans for thrombocytopenia (see NCP 30-2) and neutropenia (see NCP 30-3). Nursing actions are directed at preventing complications from infection and haemorrhage.

NURSING CARE PLAN 30-2 The patient with thrombocytopenia

NURSING CARE PLAN 30-3 The patient with neutropenia

The prognosis of severe untreated aplastic anaemia is poor (approximately 75% fatal). However, advances in medical management, including haematopoietic stem cell transplant (HSCT) and immunosuppressive therapy with antithymocyte globulin (ATG) and cyclosporin or high-dose cyclophosphamide, have improved outcomes significantly. ATG is a horse serum that contains polyclonal antibodies against human T cells. It can cause anaphylaxis and a serum sickness. The rationale for this therapy is that idiopathic aplastic anaemia is considered a disorder resulting from upregulated cytotoxic T-cell subset actively targeting and destroying the patient’s own haematopoietic stem cells.¹⁸ (ATG and cyclosporine are discussed in Ch 13.)

The treatment of choice for adults less than 45 years of age who do not respond to the immunosuppressive therapy and who have a human leucocyte antigen (HLA)-matched donor is a HSCT. The best results occur in younger patients who have not had previous blood transfusions, as prior transfusions increase the risk of graft rejection. HSCT is discussed in Chapter 15.

For older adults or patients without an HLA-matched donor, the treatment of choice is immunosuppression with ATG or cyclosporin or high-dose cyclophosphamide. Although this therapy may be only partially beneficial, transfusions usually can be avoided.

CLINICAL MANIFESTATIONS

The clinical manifestations of anaemia from acute blood loss are caused by the body’s attempts to maintain an adequate blood volume and meet oxygen requirements. Table 30-6 summarises the clinical manifestations of patients with varying degrees of blood volume loss. It is essential to understand that the clinical signs and symptoms the patient is experiencing are more important than the laboratory values. For example, an adult with a bleeding peptic ulcer who had a 750 mL haematemesis (15% of a normal total blood volume) within the past 30 minutes may have postural hypotension, but have normal values for haemoglobin and haematocrit. Over the ensuing 36–48 hours, most of the volume deficit will be repaired by the movement of fluid from the extravascular space into the intravascular space. Only at these later times will the haemoglobin and haematocrit reflect the blood loss.

TABLE 30-6 Clinical manifestations of acute blood loss

The nurse should be alert to the patient’s expression of pain. Internal haemorrhage may cause pain because of tissue distension, organ displacement and nerve compression. Pain may be localised or referred. In the case of retroperitoneal bleeding, the patient may not experience abdominal pain. Instead, they may have numbness and pain in a lower extremity secondary to compression of the lateral cutaneous nerve, which is located in the region of the first to third lumbar vertebrae. The major complication of acute blood loss is shock (see Ch 66). Any change in the level of consciousness or signs of agitation or confusion requires further immediate investigation.

DIAGNOSTIC STUDIES

When blood volume loss is sudden, plasma volume has not yet had a chance to increase, the loss of RBCs is not reflected in laboratory data and values may seem normal or high for 2–3 days. However, once the plasma is replaced by endogenous and exogenous means, the RBC mass is less concentrated. At this time, RBC, haemoglobin and haematocrit levels are low and reflect the blood loss.

MULTIDISCIPLINARY CARE

Multidisciplinary care is initially concerned with: (1) replacing blood volume to prevent shock; and (2) identifying the source of the haemorrhage and stopping the blood loss. IV fluids used in emergencies include solutions such as Hartmann’s. The amount of infusion varies with the solution used.

Once volume replacement is established, attention can be directed to correcting the RBC loss. The body needs 2–5 days to manufacture more RBCs in response to increased EPO. Consequently, blood transfusions (packed RBCs) may be needed if the blood loss is significant. In addition, if the bleeding is related to a platelet or clotting disorder, replacement of that deficiency should be addressed.

The patient may also need supplemental iron because the availability of iron affects the marrow production of erythrocytes. When anaemia results from acute blood loss, dietary sources of iron will probably not be adequate to maintain iron stores. Therefore, oral or parenteral iron preparations may be administered.

NURSING MANAGEMENT: ACUTE BLOOD LOSS

In the case of trauma, it may be impossible to prevent the situation leading to the blood loss. For the postoperative patient, the nurse carefully monitors the blood loss from various drainage tubes and dressings, monitors haemodynamic status and urine output and implements appropriate actions. The nursing care plan for the patient with anaemia resulting from acute blood loss will most likely include the administration of blood products (see p 797).

Once the source of haemorrhage is identified, blood loss is controlled, and fluid and blood volumes are replaced, the anaemia should begin to correct itself. There should be no need for long-term treatment of this type of anaemia.

AETIOLOGY AND PATHOPHYSIOLOGY

Sickling episodes

The major pathophysiological event of SCD is the sickling of RBCs. Sickling episodes are most commonly triggered by low oxygen tension in the blood. Hypoxia or deoxygenation of the RBCs can be caused by viral or bacterial infection, high altitude, emotional or physical stress, surgery and blood loss. Infection is the most common precipitating factor. Other events that can trigger or sustain a sickling episode include dehydration, increased hydrogen ion concentration (acidosis), increased plasma osmolality, decreased plasma volume and low body temperature. A sickling episode can also occur without an obvious cause.

Sickled RBCs become rigid and take on an elongated, crescent shape (see Fig 30-3). Sickled cells cannot easily pass through capillaries or other small vessels and can cause vascular occlusion, leading to acute or chronic tissue injury. The resulting haemostasis promotes a self-perpetuating cycle of local hypoxia, deoxygenation of more erythrocytes and more sickling. Circulating sickled cells are haemolysed by the spleen, leading to anaemia. Initially the sickling of cells is reversible with reoxygenation, but it eventually becomes irreversible due to cell membrane damage from recurrent sickling. Thus vaso-occlusive phenomena and haemolysis are the clinical hallmark of sickle cell disease.

Figure 30-3 Sickle cell haemoglobin aggregates into long chains and alters the shape of the red blood cell.

Sickle cell crisis is a severe, painful, acute exacerbation of RBC sickling causing a vaso-occlusive crisis. As blood flow is impaired by sickled cells, vasospasm occurs, further restricting blood flow. Severe capillary hypoxia causes changes in membrane permeability, leading to plasma loss, haemoconcentration, the development of thrombi and further circulatory stagnation. Tissue ischaemia, infarction and necrosis eventually occur from lack of oxygen. Shock is a possible life-threatening consequence of sickle cell crisis due to severe oxygen depletion of the tissues and a reduction of the circulating fluid volume. Sickle cell crisis can begin suddenly and persist for days to weeks.

The frequency, extent and severity of sickling episodes are highly variable and unpredictable but are largely dependent on the percentage of HbS present. Individuals with sickle cell anaemia have the most severe form because the erythrocytes contain a high percentage of HbS.

CLINICAL MANIFESTATIONS

The effects of SCD vary greatly from person to person. Many people with sickle cell anaemia are in reasonably good health the majority of the time. However, they may have chronic health problems and pain due to organ tissue hypoxia and damage (e.g. involving the kidneys and/or liver). The typical patient is anaemic but asymptomatic except during sickling episodes. Clinical manifestations of chronic anaemia include pallor of mucous membranes, fatigue and decreased exercise tolerance. Since most individuals with sickle cell anaemia have dark skin, pallor is more readily detected by examining the mucous membranes. The skin may have a greyish cast. Because of the haemolysis, jaundice is common and patients are prone to gallstones (cholelithiasis).

The primary symptom associated with sickling is pain. During sickle cell crisis the pain is severe due to ischaemia of tissue. The episodes can affect any area of the body or several sites simultaneously, with the back, chest, extremities and abdomen being most commonly affected. The pain severity can range from trivial to excruciating. The pain can be described as deep gnawing or throbbing. Approximately half of pain episodes are accompanied by objective clinical signs such as fever, swelling, tenderness, tachypnoea, hypertension, nausea and vomiting.

COMPLICATIONS

With repeated episodes of sickling there is gradual involvement of all body systems, especially the spleen, lungs, kidneys and brain. Organs that have a high need for oxygen are most often affected and form the basis for many of the complications of SCD (see Fig 30-4). Infection is a major cause of morbidity and mortality in patients with SCD. One reason for this is the failure of the spleen to phagocytise foreign substances as it becomes infarcted and dysfunctional (usually by 2–4 years of age) from the sickled red cells. The spleen becomes small because of repeated scarring, a phenomenon termed autosplenectomy. Pneumonia is the most common infection and is often of pneumococcal origin. Infections can be so severe that they can cause an aplastic and haemolytic crisis and gallstones. Acute chest syndrome is a term used to describe acute pulmonary complications that include pneumonia, tissue infarction and fat embolism. It is characterised by fever, chest pain, cough, pulmonary infiltrates and dyspnoea. Pulmonary infarctions may cause pulmonary hypertension, MI, heart failure and ultimately cor pulmonale. The heart may become ischaemic and enlarged, leading to heart failure. Retinal vessel obstruction may result in haemorrhage, scarring, retinal detachment and blindness. The kidneys may be injured due to the increased blood viscosity and the lack of oxygen and this can lead to renal failure. Stroke can result from thrombosis and infarction of cerebral blood vessels. Bone changes may include osteoporosis and osteosclerosis after infarction. Chronic leg ulcers can result from the hypoxia and are especially prevalent around the ankles. Priapism (persistent penile erection) may occur if penile veins become occluded.

Figure 30-4 Clinical manifestations and complications of sickle cell disease.

DIAGNOSTIC STUDIES

A peripheral blood smear may reveal sickled cells and abnormal reticulocytes. The presence of sickle haemoglobin can be diagnosed by the sickling test, which uses RBCs (in vitro) and exposes them to a deoxygenation agent. Electrophoresis of haemoglobin readily identifies the presence of abnormal haemoglobin. DNA testing can be done, but is costly.

As a result of the accelerated RBC breakdown, the patient has characteristic clinical findings of haemolysis (jaundice, elevated serum bilirubin levels) and abnormal laboratory test results (see Table 30-5). Skeletal X-rays will demonstrate bone and joint deformities and flattening. Magnetic resonance imaging may be used to diagnose a stroke caused by blocked cerebral vessels from sickled cells. Doppler studies may be used to assess for deep vein thromboses. Other tests may be indicated, such as a chest X-ray, to diagnose infection or an enlarged heart.

NURSING AND COLLABORATIVE MANAGEMENT: SICKLE CELL DISEASE

Multidisciplinary care for the patient with SCD is directed towards alleviating the symptoms from the complications of the disease, minimising end-organ damage and promptly treating serious sequelae, such as acute chest syndrome, which can lead to immediate death.²² There is no specific treatment for the disease. Patients with SCD should be taught to avoid high altitudes, maintain adequate fluid intake and treat infections promptly. Pneumovax, Haemophilus influenzae, influenza and hepatitis immunisations should be administered. Chronic leg ulcers may be treated with bed rest, antibiotics, warm saline soaks, mechanical or enzyme debridement and grafting if necessary. Priapism is managed with pain medication and drugs such as nifedipine.

Sickle cell crises may require hospitalisation. Oxygen may be administered to treat hypoxia and control sickling. Rest is instituted to reduce metabolic requirements. Fluids and electrolytes are administered to reduce blood viscosity and maintain renal function. Transfusion therapy is indicated when an aplastic crisis occurs. These patients, like those with thalassaemia major, may require chelation therapy to reduce transfusion-produced iron overload.

Undertreatment of sickle cell pain is a major problem. Lack of understanding can lead healthcare professionals to underestimate how much pain these patients suffer. Some patients feel their reports of pain are not taken seriously.²³ During an acute crisis, optimal pain control usually includes large doses of continuous (rather than as-needed) opioid analgesics along with breakthrough analgesia, often in the form of patient-controlled analgesia (PCA). (PCA is discussed in Ch 8.) Morphine is the drug of choice. As patients may be experiencing different types and sites of pain, a multimodal and multidisciplinary approach is often needed.²⁴ Adjunctive measures, such as non-steroidal anti-inflammatory agents, antineuropathic pain medications (e.g. tricyclic antidepressants, antiseizure medications), local anaesthetics, nerve blocks, transcutaneous electrical nerve stimulation (TENS) and/or acupuncture may be used. After discharge, patients will often continue on oral opioid analgesics.

Infection is a frequent complication and must be treated. Pain is the most common symptom of patients with SCD seeking medical care. Patients with acute chest syndrome are treated with broad-spectrum antibiotics, oxygen therapy and fluid therapy. Because these patients have an increased need for folic acid, it is important for them to obtain daily supplementation. Blood transfusions should be used judiciously to treat a crisis. They have little, if any, role in treatment between crises. In general, iron therapy is not indicated.

Although many antisickling agents have been tried, hydroxyurea is the only one that has been shown to be clinically beneficial. However, the indication as to when to start it has yet to be determined.²⁵ This drug increases the production of haemoglobin F (fetal haemoglobin), decreases the reactive neutrophil count, increases erythrocyte volume and hydration and alters the adhesion of sickle erythrocytes to the endothelium. The increase in Hb F is accompanied by a reduction in haemolysis, an increase in haemoglobin concentration and a decrease in sickled cells and painful crises.²⁶

Haematopoietic stem cell transplantation (HSCT) is the only available treatment that can cure some patients with SCD. However, the selection of appropriate recipients, the scarcity of appropriate donors, the risk and its cost-effectiveness limit its use. (HSCT is discussed in Ch 15.) Recent advances in gene therapy technology provide some promise for the future treatment of SCD.²⁷ (Gene therapy is discussed in Ch 13.)

Patient teaching and support are important in the long-term care of the patient with SCD. The patient and family must understand the basis of the disease and the reasons for supportive care. One source of information available to patients is Thalassaemia Australia (see Resources on p 805). The patient must be taught ways to avoid crises, which include taking steps to avoid dehydration and to reduce the chance of developing hypoxia—for example, by avoiding high altitudes and seeking medical attention quickly to counteract problems such as upper respiratory tract infections. Education on pain control is also needed because the pain during a crisis may be severe and often requires considerable analgesia. Minor pain episodes that are not associated with infection or other symptoms warranting medical attention can sometimes be managed at home.

Recurrent episodes of severe acute pain and unrelenting chronic pain can be profoundly disabling and depressing. Occupational therapists and physiotherapists can help the patient achieve optimum physical functioning and independence; a psychologist may be able to use cognitive behavioural therapy to help patients with SCD to cope with anxiety and depression. Because there are often these additional quality-of-life issues, the nurse can play an important role in ensuring that these needs are met through appropriate referrals. Clinical practice guidelines are available from the website of the Royal Children’s Hospital, Melbourne (see Resources on p 805).

AETIOLOGY AND PATHOPHYSIOLOGY

The two types of polycythaemia are primary polycythaemia, or polycythaemia vera, and secondary polycythaemia (see Fig 30-5). Their aetiologies and pathogenesis differ, although their complications and clinical manifestations are similar.

Figure 30-5 Differentiating between primary and secondary polycythaemia. EPO, erythropoietin; N, normal.

Polycythaemia vera is considered a chronic myeloproliferative disorder arising from a chromosomal mutation in a single pluripotent stem cell. Therefore, not only are RBCs involved but also WBCs and platelets, leading to increased production of each of these cell types. The disease develops insidiously and follows a chronic, vacillating course. The median age at diagnosis is 60 years old with a slightly male predominance. No strong evidence supports disease association with environmental exposure, although some links have been suggested. With this myeloproliferative disorder the patient has enhanced blood viscosity and blood volume and congestion of organs and tissues with blood. These patients have hypercoagulopathies that predispose them to clotting. Splenomegaly and hepatomegaly are common.

Secondary polycythaemia can be either hypoxia-driven or hypoxia-independent. In the former, hypoxia stimulates EPO production in the kidneys, which in turn stimulates erythrocyte production. The need for oxygen may be due to high altitude, pulmonary disease, cardiovascular disease, alveolar hypoventilation, defective oxygen transport or tissue hypoxia. EPO levels may return to normal once the haemoglobin is stabilised at a higher level. In this situation, secondary polycythaemia is a physiological response in which the body tries to compensate for a problem rather than a pathological response. (Hypoxia-driven secondary polycythaemia is discussed in the section on chronic obstructive pulmonary disease in Ch 28.) In hypoxia-independent secondary polycythaemia, EPO is produced by a malignant or benign tumour tissue. Serum EPO levels often remain elevated in these situations.

CLINICAL MANIFESTATIONS AND COMPLICATIONS

Circulatory manifestations of polycythaemia vera occur because of the hypertension caused by hypervolaemia and hyperviscosity. They are often the first symptoms and include subjective complaints of headache, vertigo, dizziness, tinnitus and visual disturbances. Generalised pruritus (often exacerbated by a hot bath) may be a striking symptom and is related to histamine release from an increased number of basophils. Paraesthesias and erythromelalgia (painful burning and redness of the hands and feet) may also be present. In addition, the patient may experience angina, heart failure, intermittent claudication and thrombophlebitis, which may be complicated by embolisation. These manifestations are caused by blood vessel distension, impaired blood flow, circulatory stasis, thrombosis and tissue hypoxia caused by the hypervolaemia and hyperviscosity. The most common serious acute complication is stroke secondary to thrombosis.³⁰

Haemorrhagic phenomena caused by either vessel rupture from overdistension or inadequate platelet function may result in petechiae, ecchymoses, epistaxis or GI bleeding. Haemorrhage can be acute and catastrophic. Hepatomegaly and splenomegaly from organ engorgement may contribute to patient complaints of satiety and fullness. The patient may also experience pain from a peptic ulcer caused by either increased gastric secretions or liver and spleen engorgement. A ruddy complexion (plethora) may also be present. Hyperuricaemia is caused by the increase in RBC destruction that accompanies excessive RBC production. Uric acid is one of the products of cell destruction. As RBC destruction increases, uric acid production also increases, thus leading to hyperuricaemia. This problem may cause a form of gout.

DIAGNOSTIC STUDIES

The following laboratory manifestations are seen in the patient with polycythaemia vera: (1) elevated haemoglobin and RBC count with microcytosis; (2) low to normal EPO level (secondary polycythaemia will have a high level); (3) elevated WBC count with basophilia; (4) elevated platelets (thrombocytosis) and platelet dysfunction; (5) elevated leucocyte alkaline phosphatase, uric acid and vitamin B₁₂ levels; and (6) elevated histamine levels. Bone marrow examination in polycythaemia vera shows hypercellularity of RBCs, WBCs and platelets. Splenomegaly is found in 90% of patients with polycythaemia vera but does not accompany secondary polycythaemia.

MULTIDISCIPLINARY CARE

Once the diagnosis of polycythaemia vera is made, treatment is directed towards reducing blood volume and viscosity and bone marrow activity. Phlebotomy is the mainstay of treatment. The aim of phlebotomy is to reduce the haematocrit and to keep it less than 0.45–0.48. Generally, at the time of diagnosis 300–500 mL of blood may be removed every other day until the haematocrit is reduced to normal levels. An individual managed with repeated phlebotomies eventually becomes deficient in iron, although this effect is rarely symptomatic. Iron supplementation should be avoided. Hydration therapy is used to reduce the blood’s viscosity. Myelosuppressive agents such as busulfan, hydroxyurea, melphalan and radioactive phosphorus may be given to inhibit bone marrow activity. However, due to their side effects, these treatments are usually reserved for patients at high risk for complications (e.g. thromboses). Newer, targeted therapies (targeting the JAK2 mutation) are being studied.³⁰ Paroxetine or low-dose aspirin may be used adjunctively to alleviate symptoms of erythromelalgia. Interferon-α is of particular use in women of childbearing age or those with intractable pruritus. Allopurinol may reduce the number of acute gouty attacks.³¹

NURSING MANAGEMENT: POLYCYTHAEMIA

Polycythaemia vera is not preventable. However, because secondary polycythaemia is generated by any source of hypoxia, maintaining adequate oxygenation may prevent problems. Therefore, controlling chronic pulmonary disease, stopping smoking and avoiding high altitudes may be important.

When acute exacerbations of polycythaemia vera develop, the nurse has several responsibilities. Depending on the institution’s policies, the nurse may either assist with or perform the phlebotomy. Fluid intake and output must be evaluated during hydration therapy to avoid fluid overload (which further complicates the circulatory congestion) and underhydration (which can cause the blood to become even more viscous). If myelosuppressive agents are used, the nurse must administer the drugs as ordered, observe the patient and teach the patient about medication side effects.

Assessment of the patient’s nutritional status in collaboration with the dietician may be necessary to offset the inadequate food intake that can result from GI symptoms of fullness, pain and dyspepsia. Activities must be instituted to decrease thrombus formation. The relative immobility normally imposed by hospitalisation puts the patient at risk of thrombus formation. Active or passive leg exercises and ambulation when possible should be initiated.

Because of its chronic nature, polycythaemia vera requires ongoing evaluation. Phlebotomy may need to be done every 2–3 months, reducing the blood volume by about 500 mL each time. The nurse must evaluate the patient for the development of complications.

Although the incidence is low, myelofibrosis and leukaemia develop in some patients with polycythaemia vera (10% and 5%, respectively). These may be caused by the chemotherapeutic drugs used to treat the disease, or they may be secondary to a disorder in the stem cells that progresses to erythroleukaemia. The major cause of morbidity and mortality from polycythaemia vera is related to thrombosis (e.g. stroke).

AETIOLOGY AND PATHOPHYSIOLOGY

Thrombocytopenia is a reduction of platelets below 150 × 10⁹/L. Acute, severe or prolonged decreases from this normal range can result in abnormal haemostasis that manifests as prolonged bleeding from minor trauma to spontaneous bleeding without injury.

Platelet disorders can be inherited (e.g. Wiskott-Aldrich syndrome), but the vast majority are acquired. The causes of acquired disorders include autoimmune diseases, increased platelet consumption, splenomegaly, marrow suppression (infectious or drug-mediated) and bone marrow failure (see Box 30-5). Most acquired abnormalities occur following ingestion of certain foods, herbs or drugs (see Box 30-6). Although some agents are directly myelosuppressive (e.g. chemotherapy, ganciclovir), the usual mechanism of thrombocytopenia caused by foods, herbs or drugs is accelerated platelet destruction caused by drug-dependent antibodies. Antibodies attack the platelets when the offending agent binds to a platelet surface glycoprotein. A careful review of the patient’s history helps distinguish these causes from one of the causes mentioned below. For example, quinine is in tonic water and in many herbal preparations. In addition, some drugs can affect platelet aggregation. Aspirin doses as low as 81 mg (a baby aspirin) can alter platelet aggregation. Normal function is restored with the generation of newly formed platelets.

CLINICAL MANIFESTATIONS

Many patients with thrombocytopenia are usually asymptomatic. The most common symptom is bleeding, usually mucosal or cutaneous. Mucosal bleeding may be manifest as epistaxis and gingival bleeding, and large bullous haemorrhages may appear on the buccal mucosa due to the lack of vessel protection by the submucosal tissue. Bleeding into the skin is manifested as petechiae, purpura or superficial ecchymoses (see Fig 30-6). Petechiae are small, flat, pinpoint red or reddish brown micro-haemorrhages. When the platelet count is low, RBCs may leak out of the blood vessels and into the skin to cause petechiae. When petechiae are numerous, the resulting reddish skin bruise is called purpura. Larger purplish lesions caused by haemorrhage are termed ecchymoses. Ecchymoses may be flat or raised; pain and tenderness are sometimes present.

Figure 30-6 Acute idiopathic thrombocytopenic purpura commonly manifests with purpuric lesions of this kind, although they may often be more widespread by the time medical attention is sought.

Source: Forbes CD, Jackson WF. Color atlas and text of clinical medicine. 3rd edn. London: Mosby; 2003.

Prolonged bleeding after routine procedures such as venipuncture or IM injection may also indicate thrombocytopenia. Because the bleeding may be internal, the nurse must also be aware of manifestations that reflect this type of blood loss, including weakness, fainting, dizziness, tachycardia, abdominal pain and hypotension.

The major complication of thrombocytopenia is haemorrhage. The haemorrhage may be insidious or acute, and internal or external. It may occur in any area of the body, including the joints, retina and brain. Cerebral haemorrhage may be fatal in persons with ITP. Insidious haemorrhage may be first detected by discovering the anaemia that accompanies blood loss.

Because thrombocytopenia can be accompanied by vascular thromboses in some of these disorders, signs and symptoms of vascular ischaemic problems can manifest (see Ch 37). For example, subtle confusion, headache or even serious manifestations such as seizures and coma due to TTP-related thrombosis may be seen. Signs and symptoms may be subtle, so astute and thorough assessment of the patient is essential.

DIAGNOSTIC STUDIES

The platelet count is decreased in cases of thrombocytopenia. Any reduction below 150 × 10⁹/L may be termed thrombocytopenia. However, prolonged bleeding from trauma or injury does not usually occur until the platelet count is less than 50 × 10⁹/L. When the count drops below 20 × 10⁹/L, spontaneous, life-threatening haemorrhages (e.g. intracranial bleeding) can occur. Platelet transfusions are generally not recommended until the count is below 20 × 10⁹/L unless the patient is actively bleeding. Examination of the peripheral blood smear may assist in distinguishing acquired disorders such as ITP and TTP from congenital disorders, the latter of which may be indicated by abnormally sized platelets.

Laboratory tests that assess secondary haemostasis or coagulation, such as the prothrombin time (PT) and activated partial thromboplastin time (APTT), can be normal even in severe thrombocytopenia. If they are elevated, this may point towards disseminated intravascular coagulation. Bone marrow examination is done to rule out production problems as the cause of thrombocytopenia (e.g. leukaemia, aplastic anaemia, other myeloproliferative disorders). Specific assays, such as ITP-positive antigen specific assay or 14C-serotonin release assay for HIT, can be done to assist with the diagnosis. In TTP, testing for deficiency of ADAMTS13 is not widely clinically available, so an increase of lactate dehydrogenase (LDH) is used to help establish the diagnosis. Bone marrow analysis is done if other tests are inconclusive, especially in older patients due to a higher suspicion of an underlying bone marrow disorder. When destruction of circulating platelets is the aetiology, bone marrow analysis shows megakaryocytes (precursors of platelets) to be normal or increased, even though circulating platelets are reduced. The absence or decreased numbers of megakaryocytes on bone marrow biopsy is consistent with thrombocytopenia due to decreased bone marrow production (e.g. aplastic anaemia). Special blood analyses using flow cytometry and other techniques can detect antiplatelet antibodies as the source of destruction.

The nurse needs to closely monitor the platelet count and other coagulation studies. In addition, the nurse should monitor the patient’s haemoglobin and haematocrit levels and observe the patient for cardiopulmonary distress and other manifestations of anaemia. When thrombocytopenia occurs with anaemia characterised by altered RBC morphology, including spherocytes (small, globular, completely haemoglobinated erythrocytes), fragmented cells (schistocytes) and pronounced reticulocytosis, a diagnosis of TTP should be suspected. These findings are partially a result of intravascular fibrin deposition causing a ‘slicing’ of RBCs. In TTP, thrombocytopenia may be severe, but coagulation studies are normal.

MULTIDISCIPLINARY CARE

Multidisciplinary care of thrombocytopenia varies depending on the aetiology of the thrombocytopenia. Discussion of management strategies for these different aetiologies follows (see Box 30-7).

NURSING MANAGEMENT: THROMBOCYTOPENIA

Nursing assessment

Subjective and objective data that should be obtained from a patient with thrombocytopenia are presented in Table 30-7.

TABLE 30-7 Thrombocytopenia

NURSING ASSESSMENT

HIV, human immunodeficiency virus.

CLINICAL MANIFESTATIONS AND COMPLICATIONS

Clinical manifestations and complications related to haemophilia include: (1) slow, persistent, prolonged bleeding from minor trauma and small cuts (see Figs 30-7 and 30-8); (2) delayed bleeding after minor injuries (the delay may be several hours or days); (3) uncontrollable haemorrhage after dental extractions or irritation of the gingiva with a hard-bristle toothbrush; (4) epistaxis, especially after a blow to the face; (5) GI bleeding from ulcers and gastritis; (6) haematuria from GU trauma and splenic rupture resulting from falls or abdominal trauma; (7) ecchymoses and subcutaneous haematomas; (8) neurological signs, such as pain, anaesthesia and paralysis, which may develop from nerve compression caused by haematoma formation; and (9) haemarthrosis (bleeding into the joints) (see Fig 30-9), which may lead to joint injury and deformity severe enough to cause crippling (most commonly in the knees, elbows, shoulders, hips and ankles).

Figure 30-7 Severe ecchymosis of the left hand in a person with haemophilia following a minor cut.

Figure 30-8 Haematoma that developed in a person with haemophilia after trauma to the ear.

Figure 30-9 Acute haemarthrosis of the knee is a common complication of haemophilia.

In children these symptoms may lead to the diagnosis. In adults, these developments may be the first sign of a newly diagnosed mild form of the disease that escaped detection through a childhood free of major injuries, dental procedures or surgeries. All clinical manifestations relate to bleeding, and any bleeding episode in persons with haemophilia may lead to a life-threatening haemorrhage.

Historically, haemophilia was a disease of childhood because of early death from complications. In the early 1900s the average life expectancy was 11 years. By the 1970s, advances in treatment enabled persons with haemophilia to have an average life expectancy of 68 years. Unfortunately, the acquired immunodeficiency syndrome (AIDS) epidemic and the HIV contamination of blood products in the 1980s caused the majority of haemophilia deaths in the late 1980s. However, longer-term survival (up to 72 years old) is now being observed because of improved preparation of replacement products, improved screening of blood donor populations and use of recombinant replacement factors.³⁹

DIAGNOSTIC STUDIES

Laboratory studies are used to determine the type of haemophilia present. Any factor deficiency within the intrinsic system (factors VIII, IX, XI or XII or vWF) will yield the laboratory results presented in Table 30-9.

TABLE 30-9 Laboratory results in haemophilia

VWF, von Willebrand factor.

MULTIDISCIPLINARY CARE

The goals of multidisciplinary care are to prevent and treat bleeding. Multidisciplinary care for persons with haemophilia or von Willebrand’s disease requires the provision of preventative care, the use of replacement therapy during acute bleeding episodes and as prophylaxis, and the treatment of the complications of the disease and its therapy.

Replacement of deficient clotting factors is the primary means of supporting the patient with haemophilia. In addition to treating acute crises, replacement therapy may be given before surgery and dental care as a prophylactic measure. Examples of replacement therapy are listed in Table 30-10. Fresh frozen plasma, once commonly used for replacement therapy, is rarely used today.

For mild haemophilia A and certain subtypes of von Willebrand’s disease, desmopressin acetate (also known as DDAVP), a synthetic analogue of vasopressin, may be used to stimulate an increase in factor VIII and vWF. This drug acts on endothelial cells to cause the release of vWF, which subsequently binds with factor VIII, thus increasing their concentration. It can be administered intravenously, subcutaneously or by intranasal spray. Beneficial effects (e.g. decreased bleeding time) of DDAVP, when administered IV, are seen within 30 minutes and can last for more than 12 hours. Because the effect of DDAVP is relatively short-lived, the patient must be closely monitored and repeated doses may be necessary. It is an appropriate therapy for minor bleeding episodes and dental procedures. The intranasal form may be indicated for home therapy for some patients with mild-to-moderate forms of the disease.⁴⁰

Antifibrinolytic therapy (tranexamic acid) inhibits fibrinolysis by inhibiting plasminogen activation in the fibrin clot, thereby enhancing clot stability. These agents are useful therapeutic adjuncts to stabilise clots in areas of increased fibrinolysis, such as the oral cavity, and in patients with difficult episodes of epistaxis and menorrhagia. They are contraindicated in patients with haematuria as lack of fibrinolysis in the kidneys could lead to renal failure.

Complications of treatment of haemophilia include the development of inhibitors to factors VIII or IX, transfusion-transmitted infectious disorders, allergic reactions and thrombotic complications with the use of factor IX because it contains activated coagulation factors. Patients with vWF may also develop alloantibody against vWF, the infusion of which could cause life-threatening anaphylaxis; thus replacement factors for these patients should be devoid of vWF. Because of the improved virus-detecting processes and donor screening practices, the risk of HIV and hepatitis B and C transmission is greatly reduced.

The most common difficulties with acute management are starting factor replacement therapy too late and stopping it too soon. Generally, minor bleeding episodes should be treated for at least 72 hours. Surgery and traumatic injuries may need support for 10–14 days. Because of the short half-life of the factors, regular intermittent or continuous infusions have been used to manage bleeding episodes or expected traumatic procedures. With chronic use, development of inhibitors to the factor products has occurred and requires individualised expert patient management by the healthcare team.

Designated treatment centres have been established in Australia, New Zealand and many other countries to provide multidisciplinary care of haemophilia and related disorders. The multidisciplinary team provides optimal chronic disease management.

Gene therapy has been used on an experimental basis to treat haemophilia. These clinical trials have involved: (1) removing cells from the patient and genetically modifying them to secrete factor VIII or IX; and (2) injecting vectors with the genes for factors VIII and IX.⁴⁰ (Gene therapy is discussed in Ch 13.)

NURSING MANAGEMENT: HAEMOPHILIA

AETIOLOGY AND PATHOPHYSIOLOGY

DIC is not a disease; it is an abnormal response of the normal clotting cascade stimulated by a disease process or disorder. The diseases and disorders known to predispose a patient to DIC are listed in Box 30-9. DIC can occur as an acute, catastrophic condition, or it may exist at a subacute or chronic level. Each condition may have one or multiple triggering mechanisms to start the clotting cascade. For example, tumours and traumatised or necrotic tissue release tissue factors into circulation. Endotoxin from Gram-negative bacteria activates several steps in the coagulation cascade.