History of presenting complaint

Fig. 8.1 shows typical symptoms of diseases of the urinary system. As always, enquire deeper about the presenting complaint. Use open questions and non-verbal prompting where possible. Use the mnemonics SQITARS (Site, Quality, Intensity, Timing, Aggravating factors, Relieving factors, and associated Symptoms) or SOCRATES (Site, Onset, Character, Radiation, Associated symptoms, Timing, Exacerbating and alleviating factors, Severity) to help you to gather as much information as possible.

Fig. 8.1 Symptoms of the renal and urinary systems.

Past medical history

Find out any past or current medical illnesses, operations or trauma. Past history of any renal or urological disease is obviously important. Diabetes and hypertension are risk factors for CKD. Systemic diseases such as vasculitis can cause glomerulonephritis. CKD is related to a higher risk of cardiovascular disease. A recent streptococcal throat infection can trigger post-streptococcal glomerulonephritis.

Drug history

Find out all the medications that the patient takes. Also ask about over-the-counter medicine and homeopathic medicine. Many medications can affect renal function (Fig. 8.2). Also remember that the pharmacokinetics of drugs can be altered in renal disease.

Fig. 8.2 Drugs that can impair renal function.

Family history

Polycystic kidney disease, Alport's syndrome and Fabry's syndrome are inherited renal diseases. Many other diseases will have some genetic component. A family history of CKD stage 5 increases the risk of an individual having CKD. Some families have a tendency for IgA nephropathy. Also ask about family history of diabetes and hypertension. Ethnicity is important in the incidence of some diseases, e.g. SLE and diabetic nephropathy in South Asian populations.

Social history

A patient's social situation can be very important in deciding management. Ask about their marital status, social support network, hobbies and how they are coping at work. Other factors in the social history:

Ideas, concerns and expectations

It is important to find out patient's ideas and concerns regarding their presentation. Ask what they are hoping the doctor can do for them; this may seem obvious but different patients bring different agendas and this will affect your management later.

General inspection

Whenever you examine a patient it is important to remember the following points:

Hands

Abnormalities of the nails that indicate underlying renal disease are summarized in Fig. 8.3. To examine the hands, spread out the fingers on a flat, white surface. This will highlight any shortening of the distal phalanges; a difference of length between the fingers is often seen in severe renal osteodystrophy secondary to chronic renal failure. This is due to chronic high circulating levels of parathyroid hormone. With the patient holding their hands straight out, look for a course flapping movement called asterexis. Whilst this could be caused by severe uraemia it cannot be distinguished from asterexis caused by CO₂ retention or liver failure.

Fig. 8.3 Nail signs in renal disease.

Pinch the skin on the back of the hand to determine its elasticity or turgor. Reduced skin turgor can be caused by old age but can also indicate dehydration.

Arms

Look in the arms for an arteriovenous fistula, used for dialysis access. If you find a fistula:

Bruising can occur in uraemia as can scratch marks associated with pruritus.

Face

In the face you will want to check the general appearance, look at the conjunctivae for pallor and look in the mouth for ulcers, infections and fetor. You may want to carry out ophthalmoscopy and check the patient's hearing. The facial signs related to renal disease are listed in Fig. 8.4.

Fig. 8.4 Signs in the face related to renal disease.

Neck

Identify any central venous lines placed that may be used for dialysis access.

Measure the jugular venous pressure (JVP) which is a good indicator of fluid load. The patient should be at 45° and with the head turned to the left. Look between the two heads of the sternocleidomastoid on the left side and note any pulsations in the internal jugular vein. This can be differentiated from visible arterial pulsations because:

If a waveform is visible then measure the height from the top of the fluid level vertically down to the angle of Louis. More than 4 cm is considered raised.

Thorax

Observe the shape of the chest which can be deformed by renal osteodystrophy (a late sign).

Abdomen

The patient should be lying as flat as possible on a firm mattress with arms by the side and head supported with one or two pillows – check that the patient is comfortable. This position ensures that the abdominal muscles are relaxed, making palpation much easier.

Stand on the right-hand side of the bed, ideally with the patient exposed from ‘nipples to knees’; to maintain privacy expose the patient from the xiphisternum to the level of the symphysis pubis.

Inspection

Spend the first 20–30 s inspecting the patient from the end of the bed. Look around the patient for any clues – drips, drains and dialysis machines. Fig. 8.5 gives the signs usually seen on general inspection of the abdomen in a patient with renal disease.

Fig. 8.5 Findings on general inspection of the abdomen in renal disease.

Palpation

Before palpating, check if the patient is in pain. If the answer is yes, ask where the painful or tender area is and start palpating from the point furthest from the locus of the pain. Tell the patient to breathe normally and relax – you will be able to feel much more through relaxed abdominal muscles. It can help to kneel at the bedside so that you are at the same level as the patient – always demonstrate this in an examination.

Develop a routine for examining all the regions and organs to avoid omitting anything:

• Begin with gentle palpation of the nine regions of the abdomen; then repeat using deeper palpation – keep looking at the patient's face for any signs of discomfort

• Feel for the liver and spleen while the patient is breathing deeply in and out

• Next examine the kidneys and urinary bladder, feeling for the aorta, and then check the hernial orifices (inguinal and femoral) while the patient is coughing

• If you feel a mass, define its site, size, shape, edge, surface (regular or irregular), consistency, mobility, movement with respiration and whether it is pulsatile or resonant to percussion. Also check for associated scars and listen over the mass for a bruit.

Fig. 8.6 explains how the kidneys are examined and gives the relevant findings in various renal conditions. The differentiating features between an enlarged left kidney and splenomegaly are summarized in Fig. 8.7.

Fig. 8.6 How to examine the kidneys and relevant findings in a variety of renal conditions

Fig. 8.7 Features that distinguish between left kidney enlargement and splenomegaly.

Clinical Note

The kidneys are usually not palpable except in very thin people. When they are enlarged, however, be careful, because an enlarged kidney can easily be confused with:

• Hepatomegaly (right)

• Splenomegaly (left).

Digital rectal examination

Always obtain permission and have a chaperone. The patient should lie on the left side, with the knees drawn up to the chest.

• Inspect the perianal area for haemorrhoids, fissures, inflammation, prolapse and ulcers

• Put lubricant on the glove and insert finger into the rectum

• Assess the tone of the anal sphincter and the size and shape of the prostate (normally walnut-sized)

• After removing your finger, inspect for any blood or faeces.

Palpable changes in the prostate and their clinical significance are summarized in Fig. 8.8. A vaginal examination should also be performed in female patients. (See Crash Course: Obstetrics and Gynaecology for further details.)

Fig. 8.8 Changes of the prostate noted on digital rectal examination.

Legs

Examine the legs for rashes which might indicate vasculitis related to the kidneys, e.g. Henoch-Schönlein purpura.

If the legs are swollen confirm that it is pitting oedema by pressing for a few seconds and seeing if the indentation remains afterwards. This is associated with nephrotic syndrome and volume overload.

Haematuria

Blood in the urine can be:

The degree of haematuria does not always reflect the severity of the underlying disorder.

Diagnostic approach

Fig. 8.12 shows the common sites of lesions causing haematuria. The significance of urinalysis is summarized in Fig. 8.13. Transient causes of haematuria should first be excluded with a MSU culture. eGFR should be measured.

Fig. 8.12 Common sites of lesions causing haematuria. BPH, benign prostatic hypertrophy.

Fig. 8.13 Urine analysis – findings and their interpretations.

Macroscopic haematuria is investigated with MSU culture, urine cytology and urological imaging, e.g. ultrasound and intravenous urogram or CT urogram. Finally diagnostic flexible cystoscopy is performed.

Microscopic haematuria should be measured with dipstick tests. One + of blood or more on two dipstick tests or any symptoms requires further investigation. This would include eGFR, urine ACR and blood pressure. Then renal ultrasound would be performed if the patient was young or urological imaging and cystoscopy if old or had risk factors for urological malignancy.

Hints and Tips

Remember that painless macroscopic haematuria is bladder cancer until proven otherwise.

Proteinuria

Proteinuria is the presence of excess protein in the urine. It is usually assessed using a dipstick, which detects protein levels above 300 mg/L. ‘Microalbuminuria’ is the presence of excess urinary albumin but in amounts insufficient to cause a positive dipstick analysis. Proteinuria is best measured as the protein concentration on a ‘spot’ (early morning) urine sample corrected for urine creatinine concentration (protein to creatinine ratio or albumin to creatinine ratio). It may also be quantified on 24-h urine collections to give the amount excreted in 24 h but this is difficult to perform accurately and no longer routinely recommended. The amount of protein excreted can vary through the day and may increase with up-right posture (orthostatic proteinuria). Urine usually contains < 20 mg/L of albumin and < 200 mg/day of protein (exact values vary from laboratory to laboratory according to methods used to measure protein).

Proteinuria is seen in diabetic nephropathy. As well as being a risk factor for progressive chronic kidney disease (CKD), proteinuria is also associated with increased cardiovascular risk in hypertension and ischaemic heart disease.

The causes of proteinuria are summarized, together with relevant investigations, in Fg. 8.14.

Fig. 8.14 Causes and investigation of proteinuria.

Plain radiography

Plain radiography of the kidney, ureters and bladder (KUB) is a simple, non-invasive test that can be used before specialized imaging. It is used to detect calcification in the kidney, such as renal and urinary tract stones – uric acid stones cannot be detected, but in general 90% of stones are radio-opaque (Figs 8.15 and 8.16). It also shows the size and position of the kidneys (this is unreliable), and any secondary bony deposits (such as can be associated with prostatic cancer).

Fig. 8.15 Plain abdominal radiograph showing several calculi in the left kidney (arrows).

(Courtesy of Mr RS Cole.)

Fig. 8.16 This plain abdominal radiograph shows a large staghorn calculus (arrow) in the right kidney in a patient who presented with recurrent urinary tract infections.

(From Williams G, Mallick NP, 1994. Color atlas of renal diseases, 2nd edn. Mosby Year Book.)

Ultrasonography

Ultrasonography is a non-invasive technique that involves high-frequency sound waves. It can accurately assess the size, shape and position of the kidney, and can also distinguish solid masses and renal cysts (Figs 8.17 and 8.18). Dilatation of the pelvicalyceal system and upper ureters can also be detected – suggesting the presence of urinary tract obstruction. This is a major cause of reversible renal failure, and can be treated if detected early enough. Transrectal ultrasound (TRUS) can also assess prostate size and be used to guide a prostate biopsy (Fig. 8.19). Renal vein thrombosis can be detected with Doppler ultrasonography, and arterial Doppler studies can be used to identify renal artery stenosis. The specificity and sensitivity of ultrasound investigations are very operator-dependent.

Fig. 8.17 Ultrasound scan showing the typical appearance of polycystic kidneys. There are multiple cysts (arrows) in the parenchyma.

(From Lloyd-Davis RW et al, 1994. Color atlas of urology, 2nd edn. Mosby Year Book.)

Fig. 8.18 Hydronephrosis of the left kidney demonstrated by ultrasonography. The echolucent (black) areas within the kidney are caused by dilated calyces (A). The bipolar length (B) of the kidney is normal and the cortical thickness (C) is well preserved, suggesting that prompt relief of the obstruction will allow good functional recovery.

Fig. 8.19 A rectal ultrasound probe is used to define and stage carcinoma of the prostate. The arrow highlights an echo-poor area in the left peripheral zone of the prostate. This extends into the central part of the gland and beyond the capsule.

(Courtesy of Dr D Rickards.)

Computed tomography

Computed tomography (CT) is a quick and non-invasive technique, which can be used with or without contrast. It is used to define renal and retroperitoneal masses and is ideal for locating and staging renal tumours (Fig. 8.20). It is also used to show polycystic kidney disease and has the advantage of also highlighting non-renal pathology. Modern techniques involving spiral CT can be used to visualize the anatomy of the renal arteries, renal vein and inferior vena cava, as well as retroperitoneal studies. Increasingly, CT without contrast is the investigation of choice to diagnose obstruction to the urinary tract or renal calculi (Fig. 8.21).

Fig. 8.20 CT scan highlighting a right renal cell carcinoma that extends through the intercostal space between ribs 11 and 12 (arrow) and medially along the renal vein. The high density (white) areas (arrows) indicate calcification.

(From Williams G, Mallick NP, 1994. Color atlas of renal diseases, 2nd edn. Mosby Year Book.)

Fig. 8.21 An abdominal CT scan of a patient who presented with acute renal failure and bilateral loin pain. There is bilateral hydronephrosis secondary to bilateral ureteric stones. In the upper image a nephrostomy tube is seen in the right renal pelvis (A). The lower image demonstrates a dense opacity (calculus) lying in the ureter approximately at the level of L2 (B). Subsequent images demonstrated a similar opacity at L3 on the left.

Intravenous urography and intravenous pyelography

Intravenous urography (IVU) and pyelography (IVP) involve serial radiographs taken after intravenous injection of radio-opaque contrast medium (Figs 8.22 and 8.23). Normal kidney function is required, and the patient must not be pregnant. An IVU can assess kidney size and shape as well as the anatomy and patency of the calyces, pelvis and ureters. It can also be used to localize fistulae and highlight filling defects in the bladder.

Fig. 8.22 An intravenous urogram showing bilateral hydronephrosis in response to bladder neck obstruction caused by dense granulation and fibrous tissue in a patient with schistosomiasis of the bladder.

(From Williams G, Mallick NP, 1994. Color atlas of renal diseases, 2nd edn. Mosby Year Book.)

Fig. 8.23 An intravenous urogram showing marked calyceal clubbing in the right kidney (arrows). There is gross dilatation of the calyces, which is pronounced in all poles of the kidney. These findings are the result of unilateral reflux of urine and chronic infection.

(From Lloyd-Davis RW et al, 1994. Color atlas of urology, 2nd edn. Mosby Year Book.)

Investigations involving contrast involve the risks of allergy to the contrast medium and renal damage (especially if there is pre-existing chronic kidney disease). Allergy can range from mild (itching, nausea and vomiting) to severe life-threatening anaphylaxis. Previous reactions to contrast are a contraindication to its further use.

Renal arteriography

Conventional renal arteriography uses contrast medium to demonstrate the anatomy of the renal arteries. It is used to detect renal artery stenosis or aneurysms (Fig. 8.24). Therapeutic angioplasty may be performed at the same time. It can also be used in the diagnosis of tumours, but this is becoming less common with the increasing use of CT. A catheter is introduced into the femoral artery, through which contrast is injected into the renal artery and a series of radiographs are taken.

Fig. 8.24 Subtraction arteriogram of a right kidney. There is a single right renal artery with a significant stenosis at the ostium (arrow) with post-stenotic dilatation.

Renal artery stenosis can also be detected using magnetic resonance imaging, avoiding the use of potentially nephrotoxic contrast (Fig. 8.25).

Fig. 8.25 Magnetic resonance renal angiography demonstrating a tight stenosis at the origin of the right renal artery (arrow). The irregularity of the abdominal aorta is due to marked atheroma.

Micturating cystourethrography

Micturating cystourethrograms are used to demonstrate vesicoureteric reflux from the bladder to the ureters during emptying of the bladder (Fig. 8.26). Reflux can be classified into three grades.

Fig. 8.26 A micturating cystourethrogram showing bilateral ureteric reflux. This patient has early calyceal clubbing (A) and ureteric dilatation (B). This is grade 3 reflux.

(Courtesy of Mr RS Cole.)

This technique was used to investigate patients with recurrent urinary tract infections but has largely been replaced by other techniques because of concerns over ionizing radiation (especially in children).

Urodynamic studies

These are used to distinguish urge incontinence from genuine stress incontinence. They also detect bladder/detrusor muscle instability. The bladder is catheterized and a pressure probe is inserted to measure the bladder pressure. A rectal probe is also inserted to assess intra-abdominal pressure. The detrusor muscle pressure can be calculated by subtracting the bladder pressure from the intra-abdominal pressure. The bladder is then filled with water until the patient feels the urge to void. At this point the relative pressures are recorded. If the patient has stress incontinence, an increase in intra-abdominal pressure (e.g. coughing) leads to involuntary urine leakage, with no bladder/detrusor muscle contraction. If the patient has urge incontinence, the bladder/detrusor muscle contracts either spontaneously or with increased abdominal pressure, and the patient feels an overwhelming urge to urinate immediately (Fig. 8.27).

Fig. 8.27 Diagnosing incontinence using urodynamic studies. (A) Normal cough; (B) identifies stress incontinence, in which urine leakage is seen in response to raised intra-abdominal pressure; (C) shows urge incontinence, in which urine leakage is seen in response to detrusor muscle instability following a rise in intra-abdominal pressure.

Retrograde pyelography

Retrograde pyelography is used to define the site of an obstruction (Fig. 8.28) or lesions within the ureter. It does not require functioning kidneys. Under general anaesthesia a ureteric catheter is inserted into the ureter under cystoscopic guidance. Contrast medium is injected into the catheter to identify any lesions. It may be used therapeutically to help dislodge ureteric stones and coax them down the ureter.

Fig. 8.28 Retrograde pyelogram showing a large filling defect in the left ureter (arrow) caused by a tumour.

(From Lloyd-Davis RW et al, 1994. Color atlas of urology, 2nd edn. Mosby Year Book.)

Antegrade pyelography

This is used to define the site of obstruction in the upper urinary tract, i.e. mainly within the pelvicalyceal system. Following percutaneous catheterization of a renal calyx contrast medium is injected as described above for retrograde pyelography Percutaneous catheterization of the pelvicalyceal system (nephrostomy) is also used therapeutically to relieve obstruction.

Magnetic resonance imaging

Magnetic resonance imaging (MRI) is an imaging technique that does not involve ionizing radiation – unlike CT. Instead, it relies on the measurement of the magnetic fields of atomic nuclei. It can differentiate cystic and solid renal masses and is useful for precise staging of tumours. However, MRI cannot be used in patients with pacemakers or other metallic implants. Magnetic resonance has now been developed to provide resolution sufficient to diagnose atheromatous renal artery stenosis (see Fig. 8.25). MR urography can also allow anatomical and functional evaluation of the urinary tract withouth the need for ionizing radiation or iodine-containing contrast agents.

Radionuclide scanning

Technetium-labelled dimercaptosuccinic acid (^99mTc-DMSA) provides static images of the renal parenchyma. It highlights the localization, shape and function of each individual kidney, and highlights scarring as a result of reflux nephropathy (Fig. 8.29). Technetium-labelled pentetic acid (^99mTc-DTPA) is excreted by renal filtration and the changes in the level of ^99mTc-DTPA in the kidney over time are quantified using a gamma camera. This provides a dynamic index of blood flow to each kidney. It is used to assess transplant function (Fig. 8.30A) and can demonstrate obstruction to the upper urinary tract (by diuresis renogram; Fig. 8.30B). It can also be used to determine the relative function of each kidney. Both ^99mTc-DMSA and ^99mTc-DTPA are injected into the venous circulation. Radionuclide techniques can be used to demonstrate reflux nephropathy.

Fig. 8.29 (A) ^99mTc-DMSA scan showing a right upper pole scar (courtesy of Dr TO Nunan). (B) The graph shows a diminished uptake of 36% for the right kidney, indicating a degree of loss of function correlating with the scar.

(From Williams G, Mallick NP, 1994. Color atlas of renal diseases, 2nd edn. Mosby Year Book.)

Fig. 8.30 (A)^99mTc-DTPA diuretic renogram showing a transplanted kidney functioning normally (arrow). (From Catto GRD et al, 1994. Diagnostic picture tests in renal disease. TMIP.) (B) Diuretic isotopic renography showing tracings for normal, obstructed and dilated (without obstruction) upper urinary tract. Obstruction can be distinguished from dilatation by administering furosemide, which promotes excretion of the isotope in dilatation (without obstruction) but has no effect on excretion rates in obstruction.

(From Johnson RJ, Feehally J, 2000. Comprehensive nephrology. Mosby Year Book.)

Other imaging techniques

Other imaging techniques include scintigraphy. This may be used to investigate vesicoureteric reflux in place of conventional imaging techniques, avoiding exposure to large doses of X-rays. Scintigraphy can also demonstrate secondary deposits in the bone (Fig. 8.31).

Fig. 8.31 This bone scintigram shows areas of increased activity in the ribs, sternum and pelvis (highlighted on the scan as dark ‘hotspots’). This indicates multiple bone metastases in a patient with carcinoma of the prostate.

(Courtesy of Dr TO Nunan.)

Cystoscopy

A rigid or flexible cystoscope is inserted through the urethra to inspect the interior surface of the lower urinary tract (bladder and urethra). This technique is very useful in the diagnosis and treatment of tumours in the bladder. It can also be used to identify stones and fistulae, to take a tissue biopsy and to assess prostatic disease.

Diagnostic cystoscopy can be carried out in the outpatient clinic, and involves a flexible cystoscope examination under local anaesthesia. Therapeutic cystoscopy may require a hospital admission and uses a rigid cystoscope, with the patient under general anaesthesia.

Renal biopsy

Renal biopsy is necessary to classify glomerulonephritis, which can influence the choice of therapy in patients with nephrotic syndrome and acute nephritis. It is also used in the diagnosis and assessment of systemic diseases that affect the kidneys, e.g. sarcoidosis and systemic lupus erythematosus. It can aid the investigation of unexplained acute kidney injury, proteinuria, and haematuria and is vital in the management of patients with renal transplants. A sample of the kidney tissue can be taken by inserting a biopsy needle into the kidney under ultrasound guidance, with the patient lying in the prone position. This is then examined under a microscope, using immunochemical staining to detect complement or immunoglobulins. Relative contraindications to renal biopsy include:

The main complications are pain, bleeding (haematuria or perinephric haematoma) or infection (rare).