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USMLE Step 2 CK
l Internal Medicine
Eaton-Lambert myasthenic syndrome is characterized by increasing muscle strength on repetitive contraction. This syndrome is seen in association with malignancy, especially small-cell
carcinoma of the lung.
Botulism may cause a myasthenic-like illness, but the pupils are usually dilated and repetitive
nerve stimulation (on EMG) shows an incremental increase in muscular fiber contraction
(opposite of myasthenia gravis).
Diagnosis. The best initial test for the diagnosis of myasthenia gravis is the acetylcholine-receptor antibody test. In generalized myasthenia gravis, 80–90% of patients will have a positive test.
In the presence of fatigable muscle weakness, a positive antibody test is specific and virtually
diagnostic. Antibodies are present in only 70% of those with disease limited to the eyes.
The edrophonium (Tensilon) test is sensitive but not specific for the diagnosis. Additionally,
patients may experience nausea, diarrhea, fasciculations, syncope (rare), or bradycardia during the test, which are cholinergic symptoms.
Imaging studies of the chest such as x-rays and CT scan should be performed to detect a thymoma. Thymoma is found in 10–15% of patients. Thymic hyperplasia is found in 65%.
The most accurate test for the diagnosis of myasthenia gravis is electromyography (EMG).
The characteristic finding is a decremental decrease in muscle fiber contraction on repetitive
nerve stimulation.
Treatment. Anticholinesterase (usually pyridostigmine or neostigmine) medications are useful for the symptomatic treatment of myasthenia gravis. Pyridostigmine is longer lasting.
If treatment with anticholinesterase medications is unsuccessful in providing symptomatic
relief, the physician should consider immunosuppressive therapy.
There are numerous medications used for immunosuppressive therapy. These interventions primarily differ in the onset of therapeutic benefit. They are used if thymectomy is not effective.
Glucocorticoids are effective in improving weakness but take 1 to 3 months for you to observe
a clinical benefit. Steroids are the initial immunosuppressive of choice. If patients fail steroid
therapy, azathioprine is the most widely used medication used in combination with steroids.
The benefits of azathioprine therapy may take >3–6 months to peak. Cyclosporine and cyclophosphamide are alternatives to azothiaprine but are more toxic.
Plasmapheresis and IV immunoglobulin are immunosuppressive therapies noted for their ability to rapidly improve weakness in myasthenia gravis. They are therefore reserved for patients in
acute myasthenic crisis. These therapies are used when respiratory involvement occurs or when
patients go to the operating room.
Thymectomy is indicated in postpubertal patients and in those age <60 with generalized myasthenia gravis before initiation of immunosuppressive therapy. Thymectomy is performed in
those not controlled with anticholinesterase medications to prevent the use of potentially
toxic medication such as systemic steroids. Thymectomies are also performed when a thymoma is present to prevent the spread of malignant thymic disease.
Aminoglycoside antibiotics may exacerbate myasthenia gravis and should be avoided. In fact,
many medications may worse myasthenia gravis.
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Mycophenolate is a newer immunosuppressive drug with less adverse effects than steroids or
cyclophosphamide.
AMYOTROPHIC LATERAL SCLEROSIS
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Amyotrophic lateral sclerosis (ALS) is an idiopathic disorder of both upper and lower motor
neurons. ALS has a unique presentation of muscle weakness combined with signs of upper
motor neuron loss, cranial nerve palsies, respiratory involvement, and lower motor neuron destruction, while at the same time preserving bowel, bladder sensory, cognitive, and
sexual function. The cranial nerve, or bulbar, palsies result in dysphagia, difficulty chewing,
decreased gag reflex, dysarthria (difficulty in articulating words), and difficulty in handling
saliva. Since there is often respiratory muscle involvement, recurrent aspiration pneumonia is
the most common cause of death. A weak cough is also characteristic, and this only worsens
the respiratory problem.
There is no pain from abnormal sensory neuropathy because this is entirely a motor neuron
disease. On the other hand, the upper motor neuron involvement gives significant spasticity
that can lead to pain. Mentation, bowel, bladder, and sexual function remain intact for the
same reason. In other words, a fully mentally alert patient loses nearly all motor control while
still being able to think and perceive. The patient becomes fully aware of being trapped in a
body that does not function. Head ptosis occurs because the extensor muscles of the neck
become too weak to keep the head up.
Upper motor neuron manifestations are weakness with spasticity and hyperreflexia. Lower
motor neuron manifestations are weakness with muscle wasting, atrophy, and fasciculations; this
includes tongue atrophy. The combination of upper and lower motor neuron weakness is the
unique presentation of ALS. The most accurate confirmatory test is the electromyogram, which
will show diffuse axonal disease. CPK levels are sometimes mildly elevated, and the cerebrospinal
fluid and MRI scans are normal.
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The only treatment that may slow down the progression of the disease is riluzole, which
is thought to work by inhibiting glutamate release. Death typically results in 3–5 years.
Spasticity is treated with baclofen and tizanidine.
Many of the exam questions regarding ALS will be ethical questions on issues of the withholding of care. Since ALS has no impact on cognitive function, the patient is felt to retain the
capacity to make medical decisions. This means the patient has the right to refuse potentially
lifesaving therapy such as antibiotics, nasogastric tube placement, tracheostomy, or the use
of mechanical ventilation. The patient should not be allowed to commit suicide nor should
the physician assist with the suicide. Withholding intubation or antibiotics is not considered
assisting a suicide. Every adult patient with the capacity to understand the implications of
their choice is allowed to refuse any therapy they do not want.
MULTIPLE SCLEROSIS
A 32-year-old woman comes to the emergency department complaining of
numbness and tingling in her right hand. Her symptoms began several days ago
and have worsened over the last several hours. She states that 3 years ago she
had an episode of “seeing double” that lasted 2 days and resolved on its own.
Physical examination is significant for hyperreactive reflexes bilaterally in her
lower extremities. Increased spasticity is also noted in her lower extremities.
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l Internal Medicine
Definition. An autoimmune inflammatory disease of the CNS white matter characterized by
a relapsing or progressive course.
Etiology. The cause of multiple sclerosis (MS) is thought to be multifactorial. There is evidence
that genetic susceptibility plays an important role. The disease occurs primarily in female
populations of Northern European descent and of child-bearing age, respectively. This implies
a role for some sort of environmental trigger (infectious, dietary, climatic). Pathologically, focal
areas of demyelination are characteristic of the disease.
Clinical Presentation. Commonly, patients will present complaining of weakness, numbness,
tingling, or unsteadiness of a limb. Urinary urgency or retention, blurry vision, and double
vision are all common initial manifestations of the disease. Symptoms may persist for several
weeks or may resolve spontaneously over a few days.
There are several forms of the disease that may change the course of management and are
therefore important to recognize. Most patients will have a months-long to years-long disease-free period after their first exacerbation.
• Relapsing remitting disease: progression is characterized by relapses of active disease
with incomplete recovery during the periods of remission
• Secondary progressive disease: progression becomes more aggressive so that a consistent worsening of function occurs
• Primary progressive disease: symptoms are progressive from the onset of disease with
the early onset of disability (least common form)
It is important to understand when the diagnosis of multiple sclerosis should be suspected.
Classically, the diagnosis is made clinically when a young patient (usually age <55) presents
with a history of multiple neurologic complaints that cannot be explained by the presence of
one CNS lesion. In other words, suspect the diagnosis when a patient presents with multiple
neurologic deficits separated by time and space (anatomy).
A number of triggers are known to exacerbate the disease. Infections or trauma may
acutely worsen the disease. Pregnancy, especially the 2 to 3 months following birth, may
also exacerbate symptoms. However, there are generally fewer attacks during the pregnancy.
Uncomplicated MS typically has no adverse effects on the outcome of the pregnancy.
Diagnosis. To diagnose MS you have to rely on clinical criteria supplemented with radiologic
and laboratory confirmations. The advent of MRI scanning of the brain has dramatically
changed the methods by which multiple sclerosis is diagnosed.
MRI of the brain is the most accurate test to diagnose MS, reaching a sensitivity of 85 to 95%
in symptomatic persons. Increased T2 and decreased T1 intensity represent the increased
water content of demyelinated plaques in the cerebrum and spine. Enhancement of lesions
with gadolinium indicates active MS lesions that may enhance for up to 2 to 6 weeks after an
exacerbation. MS is an unusual disease in that the best initial test for the diagnosis is also the
most sensitive one, namely MRI of the brain and spine.
Evoked response potentials detect slow or abnormal conduction in response to visual, auditory, or somatosensory stimuli. The limitation of this test for the diagnosis of MS is that many
other neurologic diseases can give an abnormal result. The test is not specific for the diagnosis
of MS. As a result, evoked potentials are rarely used to make the diagnosis.
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Cerebrospinal fluid (CSF) analysis usually reveals a mild pleocytosis (usually <50 cells/mL)
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and a total protein that is mildly elevated. A protein level exceeding 100 mg/dL is unusual and
should be considered as evidence against the diagnosis of MS. An elevated IgG index (oligoclonal bands) is found in 70 to 90% of patients with MS. The finding is nonspecific, and as a
result, CSF for oligoclonal banding is recommended only when the MRI is nonconfirmatory
but clinical suspicion for MS remains high.
Treatment. The treatment of multiple sclerosis can be divided into disease-modifying therapy,
treatment of complications, and treatment for symptomatic relief during an acute exacerbation. The specific agents used depend on progression of the disease at the time of diagnosis.
In relapsing-remitting disease, there are 3 disease-modifying agents that have been shown to
reduce the number of clinical exacerbations and the number of MRI lesions:
• Interferon-b1a
• Interferon-b1b
• Glatiramer acetate
More importantly, these medications seem to delay the onset of significant disability.
Glatiramer is also known as copolymer I.
In secondary progressive disease, interferon-b1b and mitoxantrone have been shown to reduce
the number of exacerbations, decrease MRI activity, and delay onset of disability. In patients
who receive mitoxantrone, dose-related cardiotoxicity is a concern; mitoxantrone should be
given only to patients with a normal ejection fraction. Mitoxantrone is not a first-line agent to
prevent disease progression because of its cardiotoxicity. In patients with relapsing-remitting
disease or secondary progressive disease who cannot tolerate treatment with IFN-b1b, IFN-b1a,
or glatiramer acetate, you can consider treatment with methotrexate, mitoxantrone, cyclophosphamide, IV immunoglobulin, or azathioprine. ACTH is no longer used.
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No approved disease-modifying therapy exists at this time for primary progressive disease.
Mitoxantrone, cyclophosphamide, and natalizumab are not used for a first episode of disease.
Natalizumab is associated with progressive multifocal leukoencephalopathy (PML).
The length and intensity of an acute exacerbation is shortened by the administration of glucocorticoids. Typically, an acute exacerbation is treated with 3 days of intense IV steroids followed by
a course of oral medication tapered over 4 weeks. In patients with severe disease who are unresponsive to steroid therapy, plasma exchange can be used as an alternative treatment.
For patients with spasticity, baclofen is the most effective medication. Tizanidine and diazepam
are useful for nocturnal spasticity but are limited in their use for daytime symptoms because
they cause intense somnolence. Pain secondary to trigeminal neuralgia and dysesthesias
responds well to carbamazepine, gabapentin, phenytoin, pregabalin, or tricyclic antidepressants. Bladder hyperactivity is treated with oxybutynin, whereas urinary retention is treated
with bethanechol. Fatigue may be treated with amantadine or fluoxetine. Erectile dysfunction
can be treated with sildenafil acetate.
All disease-modifying therapies are relatively contraindicated in pregnancy. Interferon and
glatiramer should both be stopped for a pregnancy.
Fingolimod is an oral disease-modifying medication that decreases rates of MRI progression.
It prevents lymphocytes from proliferating outside of lymph nodes. Cardiac toxicity can be
severe.
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Dalfampridine is an oral disease-modifying medication that increases walking speed. It
is a unique potassium channel blocker for which the precise mechanism of action (for
improved walking speed) is not clearly known.
DEMENTIA
A 67-year-old woman is brought to the clinic complaining of forgetfulness.
She states that recently she has been forgetting common phone numbers
and the name of her mailman, whom she has known for 25 years. Her past
medical history is significant for hypertension, coronary artery disease, and high
cholesterol. Her physical examination is unremarkable.
Definition. Cognitive function is measured by various mental functions, including memory,
concentration, language, praxis, visuospatial functioning, and executive functions. “Dementia”
refers to loss of memory with impairment of any other cognitive function sufficient to interfere with social or occupational functioning.
Etiology. There are >100 identifiable causes of dementia in the elderly. Among the many
reversible causes of dementia, you should consider hypothyroidism, vitamin B12 deficiency,
hepatic or uremic encephalopathy, CNS vasculitis, syphilis, brain abscess, brain tumor (primary or metastatic), medications (especially anticholinergics), obstructive sleep apnea, central
sleep apnea, trauma, subdural hematoma, normal pressure hydrocephalus (NPH), and depression. Irreversible causes of dementia include progressive multifocal leukoencephalopathy,
Alzheimer disease, dementia with Lewy bodies, frontotemporal degeneration including Pick
disease, vascular dementia including multi-infarct dementia and Binswanger disease, and
Creutzfeldt-Jakob disease (CJD). Alzheimer disease accounts for 60 to 80% of all causes.
The prevalence of dementia is 1–5% between ages 65–69, rising to 45% by age 100. Only 5%
of Alzheimer disease is inherited.
Clinical Presentation. The most common cause of dementia is Alzheimer disease. Typically,
patients will present with problems in memory and visuospatial abilities that generally occur
early in the course of the disease. Social graces can be retained despite significant loss of cognitive
decline. Hallucinations and personality changes typically occur late in the course of the disease.
Mild cognitive impairment refers to memory loss without dysfunction of other cognitive
domains. These patients have a higher risk of developing Alzheimer disease later in life but do
not have Alzheimer disease. The rate of progression is 15–20% per year.
Alzheimer disease is, by definition, the loss of memory as well as other cognitive disturbances,
such as aphasia, agnosia (the failure to identify entities despite intact sensory function), apraxia, or the loss of the ability to make plans and execute them. There is no single diagnostic test
for Alzheimer disease.
Patients with frontotemporal dementias such as Pick disease will typically present with personality changes early in the course of their disease, with relative sparing of their visuospatial
function. Social, interpersonal, and emotional abnormalities precede memory impairment.
Frontotemporal dementia is often noted primarily by the family because the patient lacks
insight into their condition. There is no proven therapy for this condition.
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Dementia with Lewy bodies (DLB) can be confused with delirium and is characterized by fluc-
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tuating cognitive impairment.
Dementia secondary to Parkinson disease should be accompanied by clinical findings consistent with that disease. Recurrent visual hallucinations are also characteristic.
Dementia secondary to CJD is characterized by a shorter (weeks to months), more aggressive
course than Alzheimer disease. Patients with CJD will present with dementia and myoclonus.
Variant CJD is bovine spongiform encephalopathy (BSE). BSE is from the ingestion of prions
from affected cattle. The diagnosis of CJD is by rapidly progressive dementia, myoclonus,
ataxia, and the presence of 14-3-3 protein in the CSF. EEG may also help diagnose. These criteria can eliminate the need for brain biopsy.
Vascular dementia is divided into multi-infarct dementia, which typically has a stepwise progression associated with discrete cerebrovascular events, and Binswanger disease, involving the
subcortical white matter, which presents with a slowly progressive course.
Normal pressure hydrocephalus will present with prominent gait abnormalities early in the
course of the disease that usually precede the onset of cognitive impairment. There will also
be associated urinary incontinence.
Diagnosis. All patients with cognitive impairment should be assessed with a Mini Mental
Status Examination (MMSE) to identify the areas of cognitive impairment.
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Initially, the workup should focus on ruling out reversible causes of the dementia. If a reversible cause is identified, it should be treated, with the hope that cognitive function can be
recovered. Laboratory studies should include a complete blood count (CBC), electrolytes, calcium, creatinine, liver function studies, glucose, thyroid-stimulating hormone (TSH), vitamin
B12, RPR, and HIV.
Brain imaging is most useful for patients who have a focal neurologic exam, seizures, gait
abnormalities, and an acute or subacute onset of their symptoms. EEG and CSF evaluation
are not necessary except for NPH-opening pressure. No CSF marker is proven beneficial with
the exception of 14-3-3 protein in CJD.
Treatment. Treatment of dementia revolves around insuring that the family and the patient
have the proper medical and emotional support to cope with the disease. Caregivers are at an
increased risk for depression and anxiety. Their concerns and frustrations should be addressed
at frequent intervals.
Raising the level of acetylcholine in CSF benefits patients with Alzheimer disease.
Pharmacotherapy with donepezil has been shown to improve cognitive function in mild to
moderate dementia. Other anticholinesterase inhibitors (rivastigmine, galantamine) appear to
have similar efficacy.
Memantine is a disease-modifying drug used in advanced disease either alone or with a cholinesterase inhibitor. Memantine seems to be neuroprotective and reduces the rate of progression of disease.
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HUNTINGTON DISEASE
A 34-year-old man comes to the clinic for an evaluation of strange spontaneous
movements that have been occurring lately. Recently, while sitting at a family
dinner, the patient experienced uncontrolled grimacing with grunting. His father
died at the age of 41 from “dementia.”
Definition. A genetic degenerative brain disorder.
Etiology. Huntington disease is caused by the presence of the HD gene located on chromo-
some 4p. The gene contains a CAG trinucleotide repeat expansion that codes for a protein
called huntingtin. The HD mutation leads to abnormal cleavage of the huntingtin protein,
interfering with nuclear mechanisms, and causing cell death. The disease is inherited in an
autosomal dominant fashion. Successive generations tend to have the disease occuring at an
earlier age. This is called anticipation.
Clinical Presentation. The clinical hallmarks of the disease include chorea and behavioral
disturbance. Onset is usually in the fourth or fifth decade and can begin with either chorea or
behavioral change. The personality changes consist of irritability, anger, paranoia, or signs of
depression. Antisocial behavior may develop. The chorea may begin as fidgeting that progresses
to sudden movements of the trunk or limbs. Gait is poorly coordinated and has a choreic quality. Memory is usually preserved until late in the disease but lack of judgment, disinhibition,
and inattention are early manifestations. There is frequently an associated depression. Dementia
becomes severe later in the disease.
Diagnosis. Diagnosis is made by genetically testing for the presence of the CAG trinucleotide
DNA repeat expansion. There is a 50% chance of passing it on to children. CT scanning shows
cerebral atrophy. Atrophy of the caudate nucleus is severe later.
Treatment. Tetrabenazine helps the movement disorder of Huntington disease but will not
reverse or cure the underlying disease process. Death occurs 15–20 years after the diagnosis.
Haloperidol or clozapine can be used to control behavioral changes.
PARKINSON DISEASE
A 56-year-old man is brought to the office by his wife for evaluation of a resting
tremor that she noticed recently. She also states that her husband has been
moving “very slowly” as of late. When questioned, the patient states that he feels
fine and does not know why his wife is dragging him from doctor to doctor. His
past medical history is significant for mild hypertension that has been treated with
a thiazide diuretic.
Physical examination is significant for a resting tremor noted in his right hand.
When walking, the patient is stooped forward, taking small steps. You note
cogwheel rigidity in his right upper extremity with a positive Myerson sign.
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Definition. Parkinson disease is defined as a neurologic syndrome resulting from the deficiency
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of the neurotransmitter dopamine as a consequence of degenerative, vascular, or inflammatory
changes in the basal ganglia.
Etiology. There are numerous causes of Parkinsonism. Many drugs can cause Parkinsonism,
including neuroleptic agents (haloperidol, chlorpromazine), antiemetics (metoclopramide),
alpha-methyldopa, and reserpine. Poisoning from MPTP, carbon monoxide, cyanide, and
manganese are also causes of Parkinsonism. Any structural lesion around the basal ganglia
(trauma, tumor, abscess, infarct) can produce clinical Parkinson disease. Patients who have
survived an episode of encephalitis can develop postencephalitic Parkinsonism.
Clinical Presentation. The cardinal manifestations of Parkinson disease are bradykinesia
(manifested by slow movements, mask facies, reduction of automatic movements), cogwheel rigidity, postural instability, and resting tremor. A useful mnemonic is to think of Mr.
Parkinson as a fine BRITish gentleman.
Bradykinesia
Rigidity (cogwheel)
Instability (postural)
Tremor (resting)
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There are a number of “Parkinson plus” syndromes, which are characterized by their relative
lack of response to therapy with levodopa/carbidopa.
Parkinsonism + vertical gaze palsy = supranuclear palsy
Parkinsonism + prominent ataxia = olivopontocerebellar atrophy
Parkinsonism + prominent orthostatic hypotension = Shy-Drager syndrome (now called
multiple-system atrophy)
Several other diseases can imitate Parkinsonism. Severe depression can cause a paucity of
spontaneous movement that can mimic Parkinsonism. Essential tremor can be mistaken for
the tremor of Parkinson disease, but the lack of other neurologic symptoms and a positive
family history of tremor and its amelioration with alcohol distinguish the two entities. A
normal pressure hydrocephalus can present with ataxia and gait disturbances, which can also
be mistaken for Parkinson disease. The presence of dementia and urinary incontinence with
dilated ventricles on a CT scan of the head can help identify this disorder. Huntington disease
can present with akinesia and chorea. The positive family history and dementia usually suggest the correct diagnosis.
Diagnosis. The diagnosis of Parkinson disease is a clinical one. It is important to identify any
secondary causes of a patient’s Parkinsonism that are potentially reversible. There is no diagnostic test of choice that can identify patients with Parkinson disease.
Treatment. There are many medications available for the treatment of Parkinson disease. The
underlying pathophysiology that causes Parkinson disease is the imbalance of dopaminergic (too
little) and cholinergic (too much) tone on the basal ganglia. Thus, medical treatment revolves
around increasing dopaminergic tone or decreasing cholinergic tone on the basal ganglia.
Not surprisingly, the medications available for the medical treatment of Parkinson disease
directly stimulate dopamine receptors (carbidopa/levodopa, dopamine agonists), indirectly
increase the amount of dopamine available (COMT inhibitors, selegiline, amantadine), or
block acetylcholine stimulation of the basal ganglia (benztropine, trihexyphenidyl).
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Direct-acting dopamine agonists such as pramipexole or ropinirole can be used alone as initial therapy or in combination with small doses of levodopa/carbidopa. Two other dopamine
agonists are bromocriptine and cabergoline. All of them are less efficacious than levodopa.
Dopamine agonists do, however, have less dyskinetic side effects. Bromocriptine and pergolide
are ergot derivatives and can cause cardiac toxicity.
The first step when considering what medication to start with is evaluating the patient’s functional status. Patients with an intact functional status are managed differently from patients
with a compromised functional status.
Patients with intact functional status (less bradykinesia) are not generally given carbidopa/
levodopa as initial therapy. Such patients are started on anticholinergic medication when they
are age <60. This is particularly true for those in whom tremor is the predominant symptom. When age >60, the treatment of choice is amantadine. The reason why anticholinergics
are relatively contraindicated in elderly patients is because the side effects (dry mouth, urinary retention, constipation, confusion/hallucinations) occur more frequently and severely.
Anticholinergics such as benztropine and trihexyphenidyl are used mostly to relieve tremor and
rigidity. Avoid with BPH and glaucoma.
For patients with compromised functional status (more significant bradykinesia), the best
initial therapy is carbidopa/levodopa. Carbidopa inhibits extracerebral dopa-decarboxylase,
allowing more of the levodopa to reach the central nervous system, where it is needed.
Levodopa is the precursor to dopamine. Carbidopa protects the levodopa from breakdown in
the periphery, ensuring its secure delivery to the central nervous system. There are several late
complications to carbidopa/levodopa therapy: Dyskinesia (abnormal movements), akathisia
(restlessness), and “on-off” phenomena are all disconcerting to the patient. All of these late
side effects are termed “response fluctuations” and can be managed by using a sustained release
form of carbidopa/levodopa, adding a dopamine agonist, selegiline, or a COMT inhibitor, or
restricting the main protein meal to the night. COMT inhibitors are tolcapone and entacapone.
They are always used in conjunction with levodopa to help reduce the dose or modify response
fluctuations. COMT inhibitors have no effect alone; they decrease the metabolism of the
levodopa. They are an adjunct to the use of levodopa to reduce adverse effects.
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Selegiline was once thought to slow the progression of the disease. Selegiline can be used in
those with a declining or fluctuating response to levodopa. Selegiline offers mild symptomatic
benefit in early disease. Rasagiline is a newer version.
Surgery should only be considered for patients who cannot tolerate or respond adequately to
medical therapy. The procedures usually performed are pallidotomy or thalamotomy. The
placement of deep brain stimulators is also effective when placed in the globus pallidus or
subthalamic nuclei. Surgical therapy is a last resort.
BENIGN ESSENTIAL TREMOR
This is an idiopathic disorder consisting of an isolated tremor of the hands, head, or both.
The lower extremities tend to be spared. Essential tremor can be worsened by the use of caffeine or beta agonists. Examination reveals no other abnormalities. Although the level of disability tends to be limited, there can be interference with manual skills such as the ability to
write. It is characteristic of this disorder that there is an improvement with the use of alcohol.
The patient will describe shaky hands, which improve with 2–3 drinks.
There is no specific diagnostic test for this disorder. Treatment is propranolol. If propranolol
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is ineffective, alternate medications are primidone, alprazolam, and clozapine. If no medical
therapy is effective, thalamotomy is indicated.
RESTLESS LEG SYNDROME
Restless leg syndrome (RLS) is an idiopathic condition resulting in a sensation of creeping and
crawling dysesthesia within the legs, leading to involuntary movements during sleep. Often the
condition is brought to attention because of multiple bruises sustained by the sleep partner.
The condition can be familial and is exacerbated by sleep deprivation, caffeine, and pregnancy.
There is also an association with uremia, iron deficiency, and peripheral neuropathy.
There is no specific diagnostic test for this disorder. Treatment is a dopamine agonist such
as pramipexole or ropinirole, although some patients may need levodopa/carbidopa. Other
therapies are narcotics and benzodiazepines.
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