Medical Nutrition Therapy for Neurologic Disorders

1. Aspiration of water poses little risk to the patient if oral bacteria associated with the development of aspiration pneumonia can be minimized.

2. Allowing free water decreases the risk of dehydration.

3. Allowing free water increases patient compliance with swallowing precautions and improves quality of life.

4. Good oral hygiene is a key ingredient of the water protocol and offers other benefits to swallowing.

Etiology: At least three genes have been discovered that cause early-onset, familial AD; other genetic mutations have been associated with age-related, sporadic AD. Apolipoprotein-E4 (Apo-E4) is a protein located on chromosome 19; it binds β-amyloid and is involved in the transport of cholesterol. Thus, Apo-E4 has both cardiovascular and nutritional implications. Damage to key mitochondrial components (Kidd, 2005), oxidative stress, impaired insulin signaling, elevated homocysteine (Hcy), low folate, and high serum cholesterol may be causal factors.

Lead, iron, aluminum, copper and zinc have been implicated in AD pathogenesis because they catalyze the production of free radicals and induce dementia (Ramesh et al., 2010). With aging, changes occur in neurogenesis and Reelin signaling (Shetty, 2010). Inflammatory pathways have been implicated as well. Beclin 1 is a protein involved in the regulation of autophagy, a cellular degradation and maintenance pathway that is reduced in patients with AD (Jaeger and Wyss-Coray, 2010).

Pathophysiology: Alzheimer’s disease (AD) is a progressive, neurodegenerative disease characterized in the brain by abnormal clumps of amyloid beta (Aβ) peptide and neurofibrillary tangles (NIH, 2006). The early symptoms of AD, forgetfulness and loss of concentration, are often missed because they are misinterpreted as natural signs of aging (see Pathophysiology and Care Management Algorithm: Alzheimer’s Disease).

AD begins gradually; advances; and eventually leads to confusion, personality and behavior changes, and impaired judgment. Manifestations of AD result in a progressive dementia, with increasing loss of memory, intellectual function, disturbances in speech, loss of independence, disordered eating behavior, and weight change.

Persons with poor physical function seem to have a high risk for developing AD (Wang, 2006). Initially, day-to-day events are forgotten, possessions are misplaced, and appointments are missed but memories are retained. Cerebral function declines, mostly evident after pronounced memory loss. Names of objects are forgotten (anomia), words spoken by others are repeated (echolalia), and comprehension is mostly lost (agnosia). Over time, motor skills deteriorate, evidenced by changes in reflexes and a shuffling gait. When AD reaches the terminal stage, bowel and bladder controls are lost; limb weakness and contractures occur; intellectual activity ceases. The patient becomes completely incapacitated in a vegetative state as death approaches.

Medical Management: AD is diagnosed by histopathologic examination. The disease includes a preclinical disease stage, a mild cognitive impairment stage, and finally dementia. For the first time in decades, new diagnostic and treatment guidelines are being developed by the National Institute on Aging. Nonsteroidal antiinflammatory drugs (NSAIDs) or aspirin in combination with intake of food sources of vitamin E, other antioxidants, and ω-3 fatty acids are currently most effective (Shetty, 2010).

Cerebral vasodilators, stimulants, levodopa, and megadoses of vitamins remain unproven and drug treatment is experimental. Tacrine, the first cholinesterase inhibitor approved by the Food and Drug Administration (FDA) for treatment of AD, gives only modest improvement in function and cognition. Some other medications are used to suppress aberrant behavior, disturbed sleep, anxiety, or agitation. Collaborative interdisciplinary care may improve behavioral and psychological symptoms (Callahan et al., 2006). Stem cell transplantation may be tested for improving memory (Shetty, 2010). Other therapies are under development; see New Directions: Supplementation of Cell Membrane Phospholipids in Alzheimer’s Disease?

Medical Nutrition Therapy: Diets rich in saturated fatty acids and alcohol, and deficient in antioxidants and vitamins promote the onset of the disease; diets rich in unsaturated fatty acids, vitamins, antioxidants, wine, curcumin and some spices suppress its onset by scavenging free radicals and preventing oxidative damage (Ramesh et al., 2010). Proper inclusion of antioxidants and specific nutrients may protect the AD patient. A 2010 report of a 4 year prospective cohort study of 2148 community-based adults (65+ years of age) found that persons with a diet characterized by higher intakes of salad dressing, nuts, fish, tomatoes, poultry, cruciferous vegetables, fruits, and dark and green leafy vegetables were less likely to acquire AD than those eating diets of high-fat dairy products, red meat, organ meats, and butter (Gu et al., 2010). Because several dietary polyphenols are known to chelate metals, their routine use may also be protective (Ramesh et al., 2010). Garlic may be neuroprotective (Chauhan, 2005) and resveratrol prevents neuronal decline with aging (Anekonda, 2006; Ramesh et al., 2010). See also Figure 41-5.

Etiology: The cause of ALS is not clear. Genetic analysis of patients with familial, chromosome 21–linked ALS suggests that misfolding mutations in the copper-zinc superoxide dismutase (SOD1) gene may be involved (Nordlund and Oliveberg, 2006). Risk factors related to occupation, trauma, diet, or socioeconomic status are not consistent. However, it has been noted in several studies that elevated Hcy has neurotoxic effects. Because high Hcy levels induce oxidative stress and stimulate excitotoxic receptors, they damage motor neurons (Zoccolella et al., 2010).

Pathophysiology: The pathologic basis of weakness in ALS is the selective death of motor neurons in the ventral gray matter of the spinal cord, brainstem, and in the motor cortex. Clinical manifestations are characterized by generalized skeletal muscular weakness, atrophy, and hyperreflexia. The natural course for ALS is unpleasant. Decline is relentless and without remissions, relapses, or plateaus; it finally progresses to death usually in 2 to 6 years (Czaplinski, 2006).

The typical presentation is evidenced with both lower motor neuron (weakness, wasting, fasciculation) and upper motor neuron deficits (hyperactive tendon reflexes, Hoffman signs, Babinski signs, or clonus). Muscle weakness begins in the legs and hands and progresses to the proximal arms and oropharynx. As these motor nerves deteriorate, almost all of the voluntary skeletal muscles are at risk for atrophy and complete loss of function. The loss of spinal motor neurons causes the denervation of voluntary skeletal muscles of the neck, trunk, and limbs, resulting in muscle wasting, flaccid weakness, involuntary twitching (fasciculations) and loss of mobility.

Progressive loss of function in cortical motor neurons can lead to spasticity of jaw muscles, resulting in slurred speech and dysphagia. The onset of dysphagia is usually insidious. Swallowing difficulties usually follow speech difficulties. Although some weight loss is inevitable given the muscle atrophy, consistent or dramatic loss may be an indicator of chewing difficulties or dysphagia (Bulat and Orlando, 2005). Eye movement and eye blink are spared, as are the sphincter muscles of the bowel and bladder; thus incontinence is rare. Sensation remains intact and mental acuity is maintained.

Medical Management: No currently known therapy cures the disease. To lower high serum Hcy levels, short-term treatment with a high dose of methylcobalamin (B₁₂) shows promise (Zoccolella et al., 2010). Use of folate and antioxidant treatments should also be investigated. Although mechanical ventilation can extend the life of patients, most decline this option. Quality of life is poor in advanced ALS and supportive comfort measures are primarily used.

Medical Nutrition Therapy: There are decreases in body fat, lean body mass, muscle power, and nitrogen balance and an increase in resting energy expenditure as death approaches. Some of the nutritional changes during the different stages of ALS are noted in Table 41-9.

Hypermetabolic status and increased resting energy expenditure measurements have been noted. The relationship between dysphagia and respiratory status is important. As ALS progresses, a progressive loss of function in bulbar and respiratory muscles contributes to oral and pharyngeal dysphagia. In late stages, when the respiratory status is impaired, alternative tube placement besides PEG may be required.

The clinician should become familiar with common clinical findings in ALS to prevent secondary complications of malnutrition and dehydration. The functional status of each patient should be monitored closely so that timely intervention with the appropriate management techniques can be started. In particular, dysphagia should be monitored closely. Oropharyngeal weakness affects survival in ALS by placing the patient at continuous risk of aspiration, pneumonia, and sepsis and by curtailing the adequate intake of energy and protein. These problems can compound the deteriorating effects of the disease. The Amyotrophic Lateral Sclerosis Severity Scale is often used to assess the functional level of swallowing, speech, upper and lower extremities. Once the severity of deficits has been identified, appropriate interventions can be implemented (see Focus On: Dysphagia Intervention for Amyotrophic Lateral Sclerosis).

Pathophysiology: Most seizures begin in early life, but a resurgence of epileptic events occurs after age 60. The first occurrence of a seizure in adults should prompt investigation into a cause. A clinical workup usually reveals no anatomic abnormalities, and the cause of the seizure may remain unknown (idiopathic). Seizures before age 2 are usually caused by developmental defects, birth injuries, or a metabolic disease (see Chapters 44 and 45). The medical history is the key component for suggesting further avenues of diagnostic investigation and potential treatments, especially in children. An electroencephalogram can help to delineate seizure activity. It is most helpful in localizing partial complex seizures.

Medical Management: The dramatic tonic-clonic (grand mal) seizure is the most common image of a seizure (lasting 1 to 2 minutes), yet numerous classifications of seizures, each with a different and often less dramatic clinical presentation, exist. A generalized seizure involves or appears to involve the entire brain cortex from its beginning phases. The tonic-clonic seizure comes under this heading. After such a seizure the patient wakes up slowly after a time; he or she will be groggy and disoriented for minutes to hours after the event. This is termed the postictal phase and is characterized by deep sleep, headache, confusion, and muscle soreness.

The absence seizure (petit mal) is also generalized in nature. A patient with absence seizures may appear to be daydreaming during an episode, but he or she recovers consciousness within a few seconds and has no postictal fatigue or disorientation. Partial seizures occur when there is a discrete focus of epileptogenic brain tissue. A simple partial seizure involves no loss of consciousness, whereas a complex partial seizure is characterized by a change in consciousness. Failure of partial seizure control may prompt consideration of seizure surgery. A localized focus resected from nonessential brain renders a patient seizure free in 75% of cases.

Determining the seizure type is key to implementing effective therapy. Generalized seizures are ordinarily managed with valproate or phenytoin. Phenytoin metabolism has unusual kinetics; thus toxic levels may be attained with very small dosage adjustments. These drugs interact with other drugs metabolized in the liver and may cause liver damage. Liver enzymes and serum drug levels must be monitored periodically. Gabapentin is rapidly gaining popularity because of its safety and ease of use. Carbamazepine or phenytoin can usually control partial seizures. Use of just one antiseizure medication is recommended initially, resorting to combination therapies only when needed.

Medications used in anticonvulsant therapy may alter the nutrition status of the patient (see Chapter 9 and Appendix 31). Phenobarbital has been associated with decreased intelligence quotient when used in children. It is occasionally considered for use after failure of other antiepileptic drugs. Phenobarbital, phenytoin, and primidone interfere with intestinal absorption of calcium by increasing vitamin D metabolism in the liver. Long-term therapy with these drugs may lead to osteomalacia in adults or rickets in children, and vitamin D supplementation is recommended. Folic acid supplementation interferes with phenytoin metabolism; thus it contributes to difficulties in achieving therapeutic levels. If folic acid supplementation is necessary, it should be consistent, and medication adjusted accordingly.

Phenytoin and phenobarbital are bound primarily to albumin in the bloodstream. Decreased serum albumin levels in malnutrition or advanced cirrhosis limits the amount of drug that can be bound. This results in an increased free drug concentration and possible drug toxicity even with a standard dose.

Absorption of phenobarbital is delayed by the consumption of food; therefore administration of the drug must be staggered around mealtimes if it is used. Continuous enteral feeding slows the absorption of phenytoin, thus necessitating an increase in the dose to achieve a therapeutic level. Stopping the tube feeding 1 hour before and 1 hour after the phenytoin dose is generally recommended. Whenever tube feedings are stopped, the dose of phenytoin needs to be adjusted to avoid toxicity.

Medical Nutrition Therapy: A ketogenic diet can be used for treatment of all types of seizures in children with intractable epilepsy in whom drug therapies have failed. The ketogenic diet has minimal side effects, and risks of the diet are low blood sugar, upset stomach at first caused by the high amounts of fat, and constipation. The long-term risk of kidney stones is rare; elevated serum cholesterol is usually is temporary and disappears with discontinuation of the diet; and growth, which is sometimes slowed while on the diet, resumes at the child’s normal rate (Patel et al., 2010). Although the diet is very demanding and requires continued effort even after the first phase, it completely controls epilepsy in one third of the children whose seizures are otherwise uncontrollable (Groomes et al., 2011). Practical guidelines for implementing the diet have been released by the American Academy of Neurology and the American Epilepsy Society and can be retrieved from the Epilepsy Foundation website (Kossoff et al., 2009).

The diet is designed to create and maintain a state of ketosis (Bough and Rho, 2007). The beneficial effect in epilepsy may be caused by a change in neuronal metabolism; ketones may inhibit neurotransmitters, thus producing an anticonvulsant effect in the body. To begin the diet the individual usually fasts in the hospital for 24 to 72 hours until ketonemia is produced as measured by the level of beta-hydroxybutyrate in the blood. For many patients, if the diet is going to work, it usually works during this initial period with a reduction in seizures; however, sometimes the child needs to follow the subsequent ketogenic diet for 3 months before there are any reductions in seizure activity. It should also be noted that antiepileptic drugs are not stopped when administering the ketogenic diet.

In the traditional approach, once ketosis is established, caloric intake is resumed in a ratio of 3 : 1 or 4 : 1, meaning that there are 3 or 4 g of fat for every 1 g of protein and carbohydrate combined in the diet. With a 4 : 1 ratio, the diet is calculated so that at least 80% of the kilocalories are from fat. Protein is calculated to provide appropriate intake for growth (approximately 1 g/kg/day). Carbohydrates are added to make up the remaining small portion of calories.

The majority of the diet is composed of fresh meats, eggs, cheese, fish, heavy whipping cream, butter, oils, nuts, and seeds. Vegetables and fruits are added in small amounts, within the current diet prescription (Table 41-10). Ketosis is monitored by regular measurements of serum β-hydroxybutyrate. Even though goal levels are patient specific, most individuals need to be in the range of 35-60 mg/L (4-7mmol/L) for seizure control. A carbohydrate-free multiple vitamin and mineral supplement is necessary to ensure that the diet is nutritionally complete. However, additional vitamins and minerals are often necessary, including calcium, vitamin D, and selenium.

Other nonfood items such as sugar-containing toothpaste, shampoo, and lotions need to be avoided. It is important that the diet be strictly followed; the smallest amount of extra carbohydrate can cause a breakthrough seizure. The child should be monitored, because too rapid a rate of weight gain can decrease ketosis and reduce effectiveness.

A variation of the ketogenic diet is the modified Atkins diet in which calories are not restricted, but carbohydrates are drastically limited to 10 to 20 g/day. The ratio of fat to protein and carbohydrate is usually 1 : 1. It appears that the best results are achieved when the diet begins with 10 g/day of carbohydrate and is then adjusted upward, always maintaining ketosis (Porta et al., 2009; Weber et al., 2009).

Another modification of the traditional ketogenic diet is the medium-chain triglyceride (MCT) oil–based ketogenic diet, used frequently in the United Kingdom and Canada, in which some of the long-chain fats of the traditional diet are replaced with MCTs. MCT oil is an odorless, colorless, tasteless oil and was originally used as a means of improving the palatability of the diet. A greater amount of nonketogenic foods such as fruits and vegetables and small amounts of bread and other starches can be allowed because ketosis from MCT can be more readily achieved with a lower percentage of fat in the diet. MCT can be added in to the classic ketogenic diet and modified Atkins diet to increase ketosis. Coconut oil can also be used as a source of MCT to increase palatability, but it contains only 45% to 50% MCT so more may be needed. MCT oil or coconut oils are also added if the serum triglycerides are too high with the use of the traditional ketogenic diet.

Initiating the ketogenic diet is intense. Further, the diet may be unpalatable as well as complex, requiring weighing and measuring of all foods, thus making compliance difficult to achieve. To be successful, children may benefit from behavioral techniques, whereas parents most often require substantial psychosocial support. Attention required during the fine-tuning phase varies and is affected by the patient’s health status, growth, and development. For the child whose epilepsy is controlled by the diet, complying with the diet is much easier than dealing with devastating seizures and injuries.

Discontinuation of the diet can be considered after 2 to 3 years, especially if the child has been seizure free for a year, although seizure control medication may still be necessary. The person is “weaned” off the ketogenic diet over a period of several months to a year as small amounts of carbohydrates are added with observation for seizure reoccurrence.

Etiology: In 60% of cases the disorder follows an infection, surgery, or an immunization. Some of the more common organisms are Campylobacter jejuni and Mycoplasma. Several pathologic varieties exist, and the nature of the distinction is related to the segment of the immune system that is inflicting nerve damage. The clinical course of GBS is similar regardless of subtype, although GBS after a Campylobacter infection tends to be more severe.

Pathophysiology: Relatively symmetric weakness with paresthesia usually begins in the legs and progresses to the arms. The loss of function in affected nerves occurs because of demyelination. Myelin is the specialized fatty insulation that envelops the conducting part of the nerve, the axon. In GBS the immune system recognizes myelin and mounts an attack against it. Presumably myelin shares a common characteristic with the pathogen from the antecedent infection; thus the immune system cannot differentiate what is foreign (the pathogen) from what is native (myelin). When the nerve is demyelinated, its ability to conduct signals is severely impaired, resulting in neuropathy.

Medical Management: GBS reveals itself in a matter of days. The most common sequence of symptoms is areflexia (absence of reflexes), followed by proximal limb weakness, cranial nerve weakness and respiratory insufficiency. These symptoms normally peak by 2 weeks but may progress up to 1 month. Medical diagnosis is ordinarily made on clinical grounds, but nerve conduction studies are also beneficial. Before the clinical course is apparent, myelopathic disorders need to be considered.

Because of the precipitous progression of GBS, hospitalization is usually necessary. Vital capacity and swallowing function may rapidly deteriorate such that intensive care is sometimes necessary. Intubation and respiratory support should be instituted early in respiratory decline to avoid the need for resuscitation. Plasmapheresis, the exchange of the patient’s plasma for albumin, is often helpful to reduce the load of circulating antibodies. Intravenous immunoglobulin or steroids have been shown to be of benefit.

Medical Nutrition Therapy: Guillain-Barré syndrome evolves quickly; during the acute stage, the metabolic response of GBS is similar to the stress response that occurs in neurotrauma. Energy needs assessed by indirect calorimetry may be as high as 40 to 45 kcal/kg and protein needs twice the usual amount. Supportive nutritional care should be offered to attenuate muscle wasting.

For a small percentage of patients, oropharyngeal muscles may be affected, leading to dysphagia and dysarthria. In this situation, a visit by the dietitian at mealtime can be a valuable way to observe difficulties the patient may have with chewing or swallowing. Specific difficulties warrant evaluation by a swallowing specialist. The speech therapist can evaluate the degree of dysphagia and make appropriate dietary recommendations pertaining to texture. As the patient recovers, it is important to discuss safe food handling and future prevention of C. jejuni infection.

Pathophysiology: Although the cause is unknown, migraine headache is thought to be vascular in origin and follows a family history of migraines or of visual prodromata. The leading theory proposes that dural blood vessels become dilated and the pulsatile blood flow through these vessels distends and irritates the highly pain-sensitive dura mater. This would explain the throbbing quality of the headache. An inflammatory component to migraine headache is also present along with mitochondrial dysfunction (Gardner and Boles, 2010).

Medical Management: Treatment depends on the frequency of attacks and the presence of comorbid illness. A thorough history is the key to medical diagnosis. To qualify for a diagnosis of migraine headache, the headache must be throbbing, episodic, and supremely intense. A history of intercurrent nausea, vomiting, photophobia, and visual or olfactory auras should be present.

Numerous medicines are used to prevent or abort migraine, indicating a less than clear understanding of its pathophysiologic characteristics. NSAIDs are often the first line, followed by sympathomimetics and serotonin agonists such as sumatriptan. Prophylaxis can include calcium channel antagonists, β-adrenergic blockers, and serotonin antagonists.

Medical Nutrition Therapy: Migraine attacks are triggered by a variety of factors, including food, drugs, odors, and changes in sleep habits; they respond to a variety of treatments (Dowson et al., 2006). Because foods implicated in one individual may not trigger attacks in another and food intolerance thresholds vary over time, generalized recommendations about food avoidance are ill advised. There has been attention to biogenic amines such as tyramine or phenylethylamine in foods as triggers of migraine headaches. A trial of a tyramine- or phenylethylamine-restricted diet may be recommended for some clients (see Box 9-3 in Chapter 9 for biogenic amine–containing foods), but evidence is not clear on its success (Sun-Edelstein and Mauskop, 2009a). Because suspect food items or “trigger foods” can only be correctly identified if eliminated and then reintroduced into the diet, the dietitian can strategize on this approach. See Chapter 27 for a food diary form to record intake and timing of symptoms, and to determine which foods may be a problem. In some patients dehydration may be the instigator; one simple measure is to drink more water (at least 2-3 cups) to rehydrate (Blau, 2005; Spigt et al., 2005).

Many patients try herbs or botanical products or nutritional supplementation to manage their headaches. Feverfew is used by many migraine sufferers, even though a Cochrane Database Review has not proven its efficacy. Because of their roles in energy metabolism, two nutrients, riboflavin and coenzyme Q₁₀, have been suggested (Hershey et al., 2007; Schiapparelli et al., 2010). Magnesium has also been shown effective in treating migraine headaches (Sun-Edelstein and Mauskop, 2009b).

Pathophysiology: In MG the body unwittingly makes antibodies to AchR. These antibodies are the same that fight off colds and give immunity. The AchR antibodies bind to AchR and make them unresponsive to Ach. There is no disorder of nerve conduction and no intrinsic disorder of muscle. The characteristic weakness in MG occurs because the signal of the nervous system to the muscle is garbled at the neuromuscular junction. Patients with MG commonly have an overactive thymus gland. This gland resides in the anterior thorax and plays a role in the maturation of B lymphocytes, the cells that are charged with synthesizing antibodies.

Medical Management: Relapsing and remitting weakness and fatigue, varying from minutes to days, characterize MG. The most common presentation is diplopia (double vision) caused by extraocular muscle weakness, followed by dysarthria, facial muscle weakness, and dysphagia. Dysphagia or swallowing disorders (resulting from fatigue following mastication) may cause malnutrition. Less commonly, proximal limb weakness in the hips and shoulders may be present. Severe diaphragmatic weakness can result in respiratory difficulty. No involvement of sensory nerves occurs.

Anticholinesterases are medicines that inhibit acetylcholinesterase, thus serving to increase the amount of Ach in the neuromuscular junction. Corticosteroids are immunosuppressive. Removal of the thymus results in symptomatic improvement in most patients.

Medical Nutrition Therapy: Chewing and swallowing are often compromised in MG. Because this compromise occurs with fatigue, it is important to provide nutritionally dense foods at the beginning of meals before the patient tires. Small, frequent meals that are easy to chew and swallow are helpful. Difficulties holding a bolus on the tongue have also been observed, suggesting that foods that do not fall apart easily may be better tolerated. For patients treated with anticholinesterase drugs, it is crucial to time medication with feeding to facilitate optimal swallowing.

Physical activity should be limited before mealtime to ensure maximum strength to eat a meal. It is also important not to encourage food consumption once the patient begins to tire because this may contribute to aspiration. If and when respiratory crisis occurs, it is usually temporary. Nutrition support via NG tube may be implemented in the interim to assist in maintaining vital functions of the patient until the crisis subsides. Once extubated, a swallow evaluation using cinefluoroscopy is appropriate to assess the degree of deglutitory dysfunction (swallowing irregularity) or risk of aspiration associated with an oral diet.

Pathophysiology: The precise cause of MS remains undetermined. A familial predisposition to MS has been noted in a minority of cases. However, familial tendency is not well established and no consistent pattern of Mendelian inheritance has emerged (Victor and Ropper, 2005). Geographic latitude and diet are therefore implicated. Epidemiologic studies have linked the incidence of MS to geographic location and sunshine exposure. The degree of sunlight exposure catalyzes the production of vitamin D₃ in the skin. This form of vitamin D₃ is a selective immune system regulator and may inhibit MS progression (Mark and Carson, 2006). Further, in cross-sectional evaluations of MS and vitamin D, an increased prevalence of clinical vitamin D deficiency was associated with decreased bone density (Mark and Carson, 2006). Given the current evidence of the potential benefits of vitamin D, it appears to be reasonable and safe to consider vitamin D supplementation adequate to achieve normal levels in patients with MS (Solomon and Whitham, 2010).

Medical Management: Fluctuating symptoms and spontaneous remissions make treatments difficult to evaluate. Currently no proven treatment for changing the course of MS, preventing future attacks, or preventing deterioration exists. Initially recovery from relapses is nearly complete, but over time, neurologic deficits remain. Therefore measures to maximize recovery from initial attacks or exacerbations, prevent fatigue and infection, and use all of the available rehabilitative measures to postpone the bedridden stage of disease are imperative. Physical and occupational therapies are standard for weakness, spasticity, tremor, uncoordination, and other symptoms.

Drugs for spasticity can be initiated at a low dose and cautiously increased until the patient responds. Physical therapy for gait training and range-of-motion exercises helps. Steroid therapy is used in treating exacerbations; adrenocorticotropic hormone (ACTH) and prednisolone are the drugs of choice. However, treatment is not consistently effective and tends to be more useful in cases of less than 5 years’ duration. Side effects of short-term steroid treatment include increased appetite, weight gain, fluid retention, nervousness, and insomnia. Reduced cerebrospinal fluid and serum levels of vitamin B₁₂ and folate have been noted in MS patients who receive high-dose steroids. Methotrexate may also be used with ACTH, causing anorexia and nausea. Drug therapies may be a challenge (see Chapter 9 and Appendix 31).

Medical Nutrition Therapy: Several dietary regimens for managing MS have been studied, all of which have yielded equivocal results. Various diets such as allergen-free, gluten-free, pectin-free, fructose-restricted, raw food diet, megadoses of micronutrients, zinc phosphates with calcium, and other combinations have been ruled ineffective. The RD’s evaluation of the patient to maximize nutritional intake is imperative. Vitamin D status should be assessed by measuring 25-hydroxy vitamin D and supplementation may be warranted; total intake should be monitored from multivitamin and mineral supplements and fortified foods (Brown, 2006).

As the disease progresses, neurologic deficits and dysphasia may occur as the result of damaged cranial nerves. Thus diet consistency may need to be modified from solids to mechanically soft or pureed items, even progressing to thick liquids to prevent aspiration. Impaired vision, dysarthria, and poor ambulation make meal preparation into a difficult task. In this situation reliance on comfort foods or prepackaged, single-serving, or convenience foods often permits independent preparation of meals. Given the chronic nature of this debilitating disease, patients may require enteral nutrition support.

Neurogenic bladder is common, causing urinary incontinence, urgency, and frequency. To minimize these problems, distributing fluids evenly throughout the waking hours and limiting them before bed is helpful. Some patients limit fluid intake severely to decrease frequency of urination but thereby increase the risk of UTIs. UTIs are common in patients with MS, and some patients increase their intake of cranberry juice as a form of self-treatment (see Chapter 36).

Neurogenic bowel can cause either constipation or diarrhea, and incidence of fecal impaction is increased in MS. A diet that is high in fiber with additional prunes and adequate fluid can moderate both problems.

Pathophysiology: Although the cause of PD remains unclear, it is multifactorial and the pathogenesis is well described. It involves an interaction of inheritance with environmental factors. There is a marked loss of dopaminergic neurons (pigmented cells) in the substantia nigra, as well as tyrosine hydroxylase, the rate-limiting enzyme for dopamine.

In studying the brains of people with PD after they die, accumulations of protein called Lewy bodies (named after the doctor who first found them) are found. More than 10 genes causing familial PD have been identified. Genetic testing for PD is not warranted at this time, but continued investigations hold promise.

The role of endogenous toxins from cellular oxidative reactions has emerged because aging has been associated with a loss of neurons containing dopamine and an increase in monoamine oxidase. When metabolized (enzymatic oxidation and autooxidation), dopamine produces endogenous toxins (hydrogen peroxide and free radicals), causing peroxidation of membrane lipids and cell death. In the presence of an inherited or acquired predisposition, severe oxidative injury can lead to substantial loss of dopaminergic neurons similar to that observed in PD.

Several other environmental factors have also been implicated as causal factors of PD. The connection between smoking and a lowered risk for PD has been evaluated, but results are inconsistent (Zhang et al., 2006). In older patients, drug-induced PD may occur as a side effect of neuroleptics or metoclopramide (see Chapter 9 and Appendix 31).

Nutrient-related findings are biologically plausible and support the hypothesis that oxidative stress may contribute to the pathogenesis of PD (Czlonkowska et al, 2010). The relationships of folate, elevated plasma homocysteine levels, fiber and caloric deficits are being evaluated. Vitamin B₆ intake may also decrease the risk of PD (De Lau et al., 2006). The final environmental factor associated with the incidence of PD is exposure to chemicals and toxins, as in farming communities where pesticides are used. However, no one chemical toxin or heavy metal is known as the cause (Victor and Ropper, 2005).

Medical Management: The “classic triad” signs—tremor at rest, rigidity, and bradykinesia—remain the criterion for medical diagnosis. However, it was well over a century before l-dopa (a precursor to dopamine) was introduced for controlling symptoms. Exelon, a cholinesterase inhibitor, was approved by the FDA in 2006 for use in mild to moderate PD dementia. Pharmacotherapy agents, surgical interventions, and physical therapy are the best adjunctive therapies.

Medical Nutrition Therapy: The primary nutrition intervention should be to focus on drug-nutrient interactions, especially between dietary protein and l-dopa. Side effects of medications for PD include anorexia, nausea, reduced sense of smell, constipation, and dry mouth. To diminish the gastrointestinal side effects of l-dopa, it should be taken with meals. Avoid foods that contain natural l-dopa such as broad beans (fava beans). For some patients dyskinesia may be reduced by limiting dietary protein at breakfast and lunch and including it in the evening meal. Table 41-11 presents a sample menu for this diet.

Fiber and fluid adequacy lessen constipation, a common concern for persons with PD. Interactions between pyridoxine and aspartame should be considered as well. Pyridoxine has a possible interaction with l-dopa. Decarboxylase, the enzyme required to convert l-dopa to dopamine, depends on pyridoxine. If excessive amounts of the vitamin are present, l-dopa may be metabolized in the periphery and not in the CNS where its therapeutic activity occurs. Therefore vitamin preparations containing pyridoxine should not be taken with doses of l-dopa. In addition, manganese should be carefully monitored to avoid excesses above DRI levels.

The high demand for molecular oxygen, the enrichment of polyunsaturated fatty acids in membrane phospholipids, and the relatively low abundance of antioxidant defense enzymes are all relevant factors (Sun et al., 2008). Antiinflammatory and neuroprotective effects come from phenolic compounds, such as resveratrol from grapes and red wine, curcumin from turmeric, apocynin from Picrorhiza kurroa, and epigallocatechin from green tea (Sun et al., 2008). Sufficient intake of vitamin D₃ and ω-3 fatty acids can be suggested.

As the disease progresses, rigidity of the extremities can interfere with the patient’s ability to perform self-feeding. Rigidity interferes with the ability to control the position of the head and trunk, necessary for eating. Eating is slowed; mealtimes can take up to an hour. Simultaneous movements such as those required to handle both a knife and fork become difficult. Tremor in the arms and hands may make self-feeding of liquids impossible without spilling. Perception and spatial organization can become impaired.

Dysphagia is often a late complication. A large number of patients may be silent aspirators, which affects nutrition status.

Experimental treatment procedures are being tested and reported with increasing frequency. Deep brain penetration, other surgical interventions, and efforts with stem cell research continue in hopes that a “cure” is possible.