Neurology

150591010

NeurologyAll New Content, Including 96 Multiple-Choice Questions

14 AMA PRA Category 1 Credits™

available until July 31, 2015.

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Medical Knowledge Self -Assessment Program®

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Table of Contents

Status Epilepticus . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22Generalized Convulsive Status Epilepticus . . . . . . 22Nonconvulsive Status Epilepticus. . . . . . . . . . . . . 22

StrokeEpidemiology and Definition of Stroke. . . . . . . . . . . . 24Diagnosis of Stroke. . . . . . . . . . . . . . . . . . . . . . . . . . . 24Stroke Subtypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Transient Ischemic Attack . . . . . . . . . . . . . . . . . . 24Ischemic Stroke . . . . . . . . . . . . . . . . . . . . . . . . . . 26Hemorrhagic Stroke . . . . . . . . . . . . . . . . . . . . . . 27

Acute Ischemic Stroke . . . . . . . . . . . . . . . . . . . . . . . . 28Clinical Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . 28Imaging Techniques . . . . . . . . . . . . . . . . . . . . . . 29Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Acute Hemorrhagic Stroke . . . . . . . . . . . . . . . . . . . . . 32Intracerebral Hemorrhage . . . . . . . . . . . . . . . . . . 32Subarachnoid Hemorrhage . . . . . . . . . . . . . . . . . 33

Other Types of Stroke . . . . . . . . . . . . . . . . . . . . . . . . 33Dural Sinus Venous Thrombosis . . . . . . . . . . . . . 33Carotid and Vertebral Artery Dissection. . . . . . . . 36Asymptomatic Aneurysm. . . . . . . . . . . . . . . . . . . 36

Admission to Stroke Units and Stroke Centers . . . . . . 36Secondary Stroke Prevention . . . . . . . . . . . . . . . . . . . 36

Hypertension. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Dyslipidemia . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36Antithrombotic Treatment. . . . . . . . . . . . . . . . . . 37Surgery for Secondary Stroke. . . . . . . . . . . . . . . . 38

Prevention of Stroke Complications . . . . . . . . . . . . . . 38Neurologic Worsening. . . . . . . . . . . . . . . . . . . . . 38Medical Complications . . . . . . . . . . . . . . . . . . . . 39Perioperative Stroke. . . . . . . . . . . . . . . . . . . . . . . 39

Primary Prevention of Stroke . . . . . . . . . . . . . . . . . . . 40Asymptomatic Carotid Stenosis . . . . . . . . . . . . . . 40

Stroke Recovery and Long-Term Prognosis . . . . . . . . 40

DementiaGeneral Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Definition and Description . . . . . . . . . . . . . . . . . 40Evaluation of the Patient with Suspected Dementia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41Differential Diagnosis of Dementia . . . . . . . . . . . 42Diagnosis of Alzheimer Diseaseand Other Dementias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Headache and Facial PainApproach to the Patient with Headache . . . . . . . . . . . . 1Secondary Headaches . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Common Features and Evaluation. . . . . . . . . . . . . 1Thunderclap Headache . . . . . . . . . . . . . . . . . . . . . 3Idiopathic Intracranial Hypertension (Pseudotumor Cerebri) . . . . . . . . . . . . . . . . . . . . . 4Trigeminal Neuralgia (Tic Douloureux). . . . . . . . . 4

Primary Headaches. . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Migraine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5Tension-Type Headache . . . . . . . . . . . . . . . . . . . . 9Cluster Headache . . . . . . . . . . . . . . . . . . . . . . . . 10Related Primary Headache Syndromes. . . . . . . . . 10

Head InjuryTraumatic Brain Injury . . . . . . . . . . . . . . . . . . . . . . . . 10Concussive Head Injury . . . . . . . . . . . . . . . . . . . . . . . 11Postconcussion Syndrome. . . . . . . . . . . . . . . . . . . . . . 11Epidural and Subdural Hematoma . . . . . . . . . . . . . . . 12Head Injury in a Military Population . . . . . . . . . . . . . 12

EpilepsyFeatures and Epidemiology of Epilepsy . . . . . . . . . . . . 12Initial Approach to the Patient with a First Seizure . . . 13Clinical Presentations of Seizures . . . . . . . . . . . . . . . . 14

Partial Seizures . . . . . . . . . . . . . . . . . . . . . . . . . . 14Generalized Seizures . . . . . . . . . . . . . . . . . . . . . . 14

Epilepsy Syndromes . . . . . . . . . . . . . . . . . . . . . . . . . . 15Partial (Focal) Epilepsy . . . . . . . . . . . . . . . . . . . . 15Idiopathic Generalized Epilepsy . . . . . . . . . . . . . . 15

Comorbidities and Complications of Epilepsy . . . . . . . 16Mood Disorders . . . . . . . . . . . . . . . . . . . . . . . . . 16Cognitive Problems . . . . . . . . . . . . . . . . . . . . . . . 16Osteoporosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16Sudden Unexplained Death in Epilepsy . . . . . . . . 16

Diagnostic Evaluation of Seizures and Epilepsy . . . . . . 16Imaging Studies. . . . . . . . . . . . . . . . . . . . . . . . . . 16Electroencephalography. . . . . . . . . . . . . . . . . . . . 17Clinical Evaluation and Video Electroencephalographic Monitoring . . . . . . . . . . 17

Treatment of Epilepsy. . . . . . . . . . . . . . . . . . . . . . . . . 18Antiepileptic Drug Therapy . . . . . . . . . . . . . . . . . 18Nonpharmacologic Therapy . . . . . . . . . . . . . . . . 21

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Alzheimer Disease. . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Prevalence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Pathogenesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Clinical Features . . . . . . . . . . . . . . . . . . . . . . . . . 43Pathologic Features . . . . . . . . . . . . . . . . . . . . . . . 44Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Non-Alzheimer Dementias . . . . . . . . . . . . . . . . . . . . . 45Dementia with Lewy Bodies . . . . . . . . . . . . . . . . 45Frontotemporal Dementia . . . . . . . . . . . . . . . . . . 46Vascular Dementia . . . . . . . . . . . . . . . . . . . . . . . . 46Normal Pressure Hydrocephalus . . . . . . . . . . . . . 46Dementia and Driving . . . . . . . . . . . . . . . . . . . . . 47

Movement DisordersOverview of Movement Disorders . . . . . . . . . . . . . . . 47Parkinson Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Clinical Features of Parkinson Disease . . . . . . . . . 48Diagnosis of Parkinson Disease . . . . . . . . . . . . . . 49Treatment of Parkinson Disease . . . . . . . . . . . . . . 49

Parkinson-Plus Syndromes . . . . . . . . . . . . . . . . . . . . . 51Gait Disturbance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Ataxia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Essential Tremor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Dystonia. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Chorea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53Tardive Dyskinesia . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Myoclonus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54Tic Disorders and Tourette Syndrome . . . . . . . . . . . . 55Wilson Disease . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55Neuroleptic Malignant Syndrome . . . . . . . . . . . . . . . . 56Restless Legs Syndrome . . . . . . . . . . . . . . . . . . . . . . . 56

Multiple Sclerosis and Other DemyelinatingDiseasesSpectrum, Pathophysiology, and Epidemiology. . . . . . 57Presenting Signs and Symptoms of Multiple Sclerosis . . 57Diagnosis of Multiple Sclerosis . . . . . . . . . . . . . . . . . . 58

Diagnostic Criteria and Testing . . . . . . . . . . . . . . 58Differential Diagnosis of Multiple Sclerosis . . . . . 59

Clinical Course of Multiple Sclerosis . . . . . . . . . . . . . . 59Treatment of Multiple Sclerosis. . . . . . . . . . . . . . . . . . 61

Lifestyle Modifications and General Health Care . . 61Treatment of Acute Exacerbations . . . . . . . . . . . . 61Disease-Modifying Therapies . . . . . . . . . . . . . . . . 62Symptomatic Management . . . . . . . . . . . . . . . . . 63

Disorders of the Spinal CordPresenting Symptoms and Signs of Myelopathies . . . . 64Compressive Myelopathies . . . . . . . . . . . . . . . . . . . . . 65

Clinical Presentation . . . . . . . . . . . . . . . . . . . . . . 65Diagnosis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

Noncompressive Myelopathies . . . . . . . . . . . . . . . . . . 66Clinical Presentation, Diagnosis, and Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Neuromuscular DisordersPeripheral Neuropathies . . . . . . . . . . . . . . . . . . . . . . . 68

Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68Classification, Findings, and Diagnosis . . . . . . . . . 68Mononeuropathies . . . . . . . . . . . . . . . . . . . . . . . 70Polyneuropathies . . . . . . . . . . . . . . . . . . . . . . . . . 70

Treatment of Neuropathic Pain. . . . . . . . . . . . . . . . . . 73Amyotrophic Lateral Sclerosis . . . . . . . . . . . . . . . . . . . 73Neuromuscular Junction Disorders . . . . . . . . . . . . . . . 74

Myasthenia Gravis . . . . . . . . . . . . . . . . . . . . . . . . 74Lambert-Eaton Myasthenic Syndrome. . . . . . . . . 74

Myopathies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75Overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75Inflammatory Myopathy . . . . . . . . . . . . . . . . . . . 76Endocrine-Related Myopathies . . . . . . . . . . . . . . 76

Neuro-oncologyIntracranial Tumors . . . . . . . . . . . . . . . . . . . . . . . . . . 77Primary Central Nervous System Tumors . . . . . . . . . . 78Management of Intracranial Tumors . . . . . . . . . . . . . . 79Paraneoplastic Syndromes . . . . . . . . . . . . . . . . . . . . . . 79

Brain DeathDescription and Findings . . . . . . . . . . . . . . . . . . . . . . 80Apnea Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81

Self-Assessment Test . . . . . . . . . . . . . . . . . . . . . . 85

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

Neurology

physician’s office will have migraine. An algorithmic approachto a patient with headache is presented in Figure 1.

Secondary HeadachesCommon Features and EvaluationBecause primary headaches are defined by symptom complexand secondary headaches by cause, extensive symptom over-lap is possible. The presence of a secondary headache syndromemay be signaled by the presence of one of the following redflags in the history or examination:

• First or worst headache

• Abrupt-onset or thunderclap attack

• Progression or fundamental change in headache pattern

• Abnormal physical examination findings

• Neurologic symptoms lasting longer than 1 hour

Headache and Facial PainApproach to the Patient with HeadacheHeadache is a nearly universal phenomenon, with a lifetimeprevalence greater than 90% in the general population. Aheadache is most often symptomatic of a benign recurrent dis-order but, at times, may reflect an isolated catastrophic con-dition. The second edition of the International Classificationof Headache Disorders (ICHD-2) divides headache into pri-mary (defined by symptoms) and secondary (defined bycause) disorders (Table 1). Less than 5% of headache presen-tations to emergency departments result from secondaryheadache. Once serious underlying causes of headache areexcluded, the possibility of migraine must be consideredbecause greater than 90% of patients who have recurrentheadache on presentation to an emergency department or

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TABLE 1 . International Classification of Headache Disorders

Primary Headaches

Migraine

Tension-type headache

Cluster headache and other trigeminal autonomic cephalalgias

Other primary headaches

Primary stabbing, cough, exertional, and sexual headaches

Primary thunderclap headache

Hemicrania continua

Hypnic headache

New daily persistent headache

Secondary Headaches

Headache attributed to head and neck trauma (postconcussion syndrome, subdural hematoma)

Headache attributed to a cranial or cervical vascular disorder (stroke, hemorrhage, dissection)

Headache attributed to a nonvascular intracranial disorder (brain neoplasm, arachnoid cyst)

Headache attributed to a substance or its withdrawal (nitrates, alcohol, caffeine)

Headache attributed to infection (meningitis, cerebral abscess)

Headache attributed to a disorder of homeostasis (hypercapnia, dialysis, hypertension)

Headache or facial pain attributed to a disorder of extracranial head and neck structures (eye, sinus)

Headache attributed to a psychiatric disorder (depression, anxiety disorders)

Cranial neuralgias, central and primary facial pain, and other headaches (trigeminal neuralgia)

Headache, neuralgia, and facial pain disorders not already mentioned

Source: Headache Classification Subcommittee of the International Headache Society. The International Classification of Headache Disorders: 2nd edition. Cephalalgia. 2004;24(suppl 1):16-22. [PMID: 14979299].

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• New headache in persons younger than 5 years or olderthan 50 years

• New headache in patients with cancer, immunosuppres-sion, or pregnancy

• Headache associated with alteration in or loss of con-sciousness

• Headache triggered by exertion, sexual activity, orValsalva maneuvers

Although most of these warning signs are found in thehistory, a focused neurologic examination is essential in thecomplete evaluation of a patient with headache. In additionto cognitive, sensorimotor, and reflex testing, a thorough cra-nial nerve assessment is essential, with examination of theoptic discs, visual fields, and eye movements. Further infor-mation may be gained by evaluating the cranium, cervicalspine, carotid and temporal arteries, temporomandibularjoint, and the ears and sinuses.

Further diagnostic evaluation is required when a red flagof secondary headache is identified. Neuroimaging is the mostsensitive diagnostic tool in the assessment of this type ofheadache. CT of the head is the preferred imaging modality inthe settings of skull fracture, acute subarachnoid or intracere-bral hemorrhage, and paranasal sinus disease. Although CTmay be more widely available and less expensive than MRI, an

Headache and Facial Pain

MRI of the brain is more sensitive in identifying intracranialpathology and, therefore, is the study of choice in most otherclinical settings of acute or chronic headache. Contrast admin-istration may be helpful in settings of malignant or inflamma-tory disease. The addition of CT or MR angiographic or veno-graphic studies may be useful when vascular pathology, such asvascular occlusion, aneurysm, or malformation, is considered.Cerebrospinal fluid (CSF) examination may be warranted inpatients with subarachnoid hemorrhage (SAH) with a normalCT or when meningoencephalitis, meningeal carcinomatosis,and disorders of intracranial hypertension or hypotension aresuspected. Electroencephalography, evoked potentials, or plainradiographs play no role in the routine evaluation of the patientwith headache. On occasion, serologic studies may be of value.Measurement of the erythrocyte sedimentation rate and C-reactive protein level are necessary to evaluate potential tem-poral (giant cell) arteritis, which often presents as a global non-descript headache in an older person reporting a new headacheassociated with malaise and fatigue. Temporal artery biopsymay be required to confirm the diagnosis. (For a further dis-cussion of giant cell arteritis, see MKSAP 16 Rheumatology.)Serum toxicology, carboxyhemoglobin determination, andthyroid function tests also may help identify specific secondaryexplanations for a headache presentation.

F I G U R E 1 . Algorithmic approach to a patient with headache. CRP = C-reactive protein level; CTA = CT angiography; ESR = erythrocyte sedimentation rate; GCA= temporal (giant cell) arteritis; IIH = idiopathic intracranial hypertension; LP = lumbar puncture; MRA = magnetic resonance angiography; SAH = subarachnoidhemorrhage; SUNCT = short-lasting unilateral neuralgiform headache with conjunctival injection and tearing syndrome.

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Neurology Self-Assessment TestThis self-assessment test contains one-best-answer multiple-choice questions. Please read these directions carefullybefore answering the questions. Answers, critiques, and bibliographies immediately follow these multiple-choicequestions. The American College of Physicians is accredited by the Accreditation Council for Continuing MedicalEducation (ACCME) to provide continuing medical education for physicians.

The American College of Physicians designates MKSAP 16 Neurology for a maximum of 14 AMA PRA Category 1Credits™. Physicians should claim only the credit commensurate with the extent of their participation in theactivity.

Earn “Same-Day” CME Credits OnlineFor the first time, print subscribers can enter their answers online to earn CME credits in 24 hours or less. You cansubmit your answers using online answer sheets that are provided at mksap.acponline.org, where a record of yourMKSAP 16 credits will be available. To earn CME credits, you need to answer all of the questions in a test andearn a score of at least 50% correct (number of correct answers divided by the total number of questions). Takeany of the following approaches:

➢ Use the printed answer sheet at the back of this book to record your answers. Go to mksap.acponline.org,access the appropriate online answer sheet, transcribe your answers, and submit your test for same-dayCME credits. There is no additional fee for this service.

➢ Go to mksap.acponline.org, access the appropriate online answer sheet, directly enter your answers, andsubmit your test for same-day CME credits. There is no additional fee for this service.

➢ Pay a $10 processing fee per answer sheet and submit the printed answer sheet at the back of this book bymail or fax, as instructed on the answer sheet. Make sure you calculate your score and fax the answer sheetto 215-351-2799 or mail the answer sheet to Member and Customer Service, American College of Physi-cians, 190 N. Independence Mall West, Philadelphia, PA 19106-1572, using the courtesy envelope pro-vided in your MKSAP 16 slipcase. You will need your 10-digit order number and 8-digit ACP ID number,which are printed on your packing slip. Please allow 4 to 6 weeks for your score report to be emailed backto you. Be sure to include your email address for a response.

If you do not have a 10-digit order number and 8-digit ACP ID number or if you need help creating a usernameand password to access the MKSAP 16 online answer sheets, go to mksap.acponline.org or email custserv@acponline.org.

CME credit is available from the publication date of July 31, 2012, until July 31, 2015. You may submit youranswer sheets at any time during this period.

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Item 1A 37-year-old woman is evaluated for a 1-week history ofheadache. She describes the headache as constant, worse whenshe first awakens, and characterized by a feeling of increasedpressure. She reports no other focal neurologic symptoms. Thepatient has a 10-pack-year history of tobacco use. Her onlymedication is a low-dose estrogen oral contraceptive.

On physical examination, temperature is normal, bloodpressure is 112/78 mm Hg, pulse rate is 62/min and reg-ular, and respiration rate is 16/min; BMI is 37. Bilateralpapilledema is noted. The Valsalva maneuver increases theheadache pain. All other general and neurologic examina-tion findings are unremarkable.

Results of laboratory studies show a normal leukocytecount, a platelet count of 322,000/µL (322 × 109/L), anINR of 1.1, and an activated partial thromboplastin time of36 s.

An MRI of the brain without contrast is normal.

Which of the following is the most appropriate nextdiagnostic test?

(A) Cerebral angiography(B) Lumbar puncture(C) Magnetic resonance venography(D) Measurement of serum lupus anticoagulant level

Item 2A 71-year-old man is evaluated in the intensive care unit 11days after undergoing surgery to relieve a bowel obstruction.His postoperative course has been complicated by septicshock and multiorgan failure, for which he has received intra-venous fluids, broad-spectrum antibiotics, vasopressors,corticosteroids, and insulin. He has been on mechanical ven-tilation for 10 days. For the past 72 hours, he has been hemo-dynamically stable, but attempts at weaning him from theventilator have been unsuccessful. The patient previously wasgiven muscle relaxants and neuromuscular junction–blockingagents, but these have been withheld for the past 4 days.

On physical examination, the patient is alert, followscommands, and cooperates with the examiner. Vital signsare stable. Cranial nerves are intact. Flaccid quadriparesis ofthe upper and lower extremities is noted that is greaterproximally than distally. Areflexia is present.

Results of laboratory studies show a serum creatinekinase level of 850 units/L and a plasma glucose level of200 mg/dL (11.1 mmol/L).

Results of electromyography show absent sensoryresponses in the legs and low amplitudes in the hands. Shortduration, low-amplitude motor units consistent withmyopathy are noted.

Which of the following is the most likely diagnosis?

(A) Corticosteroid myopathy(B) Critical illness myopathy(C) Guillain-Barré syndrome(D) Myasthenia gravis

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Directions

Each of the numbered items is followed by lettered answers. Select the ONE lettered answer that is BEST in each case.

Item 3A 50-year-old man is seen for a new-patient evaluation. Hereports a recent diagnosis of Parkinson disease made after a2-year history of stiffness in his right arm, a tendency to pos-ture when walking, an awkward and stiffly inverted stepwhen using the right leg, but no tremor. During this period,his voice became softer and slightly high pitched. Thepatient lost his sense of smell 10 years ago and has a 2-yearhistory of diplopia when reading, a 9-month history of uri-nary urgency and impotence, and no history of dementia,depression, or psychosis. He has been taking high-dose levo -dopa replacement therapy since diagnosis without improve-ment in symptoms.

Which of the following features in the patient’s historyis most suggestive of an atypical parkinsonism syn-drome?

(A) Absence of a tremor(B) Diplopia(C) Impotence(D) Loss of olfaction(E) Poor response to levodopa

Item 4A 50-year-old man is evaluated in the emergency depart-ment for recent onset of vomiting and a 2-week history ofheadache that has become progressively worse. His wifereports that for the past 2 months, he has been much clum-sier than usual and has otherwise “not seemed himself.”The patient has no personal or family medical history ofnote and takes no medication.

On physical examination, temperature is 37.2 °C(99.0 °F), blood pressure is 150/90 mm Hg, pulse rateis 110/min, and respiration rate is 13/min. Signs of leftneglect are noted. Fingers in the left visual field are alsonot recognized. Subtle left facial weakness, a left prona-tor drift, and decreased sensation on the left are present.Reflexes are 1+ on the right and 3+ on the left. The lefttoe is upgoing.

An MRI shows a 4- × 3- × 3-cm intraparenchymal ring-enhancing lesion in the right parietal lobe with surroundingedema and areas of central necrosis and hemorrhage. Achest radiograph shows no lesion.

Which of the following is the most likely diagnosis?

(A) Glioblastoma multiforme(B) Meningioma(C) Oligodendroglioma(D) Schwannoma

Item 5A 56-year-old man is evaluated in the emergency department6 hours after onset of left hemiplegia, right gaze deviation,

Item 1 Answer: CEducational Objective: Evaluate suspected duralsinus venous thrombosis with magnetic resonancevenography.

This patient should next undergo magnetic resonancevenography. Her headache, which is worse in the morn-ing and with performing the Valsalva maneuver, is con-sistent with one caused by elevated intracranial pressure.Given the headache characteristics, her history of tobaccoand oral contraceptive use, and the presence ofpapilledema, she most likely has dural sinus venousthrombosis. Dural sinus venous thrombosis may presentwith signs and symptoms of intracranial hypertension,such as headache, papilledema, and visual problems;focal neurologic findings or seizures; and mental statuschanges, including stupor and coma. Major risk factorsfor cerebral sinus venous thrombosis in adults includeconditions that predispose to spontaneous thromboses,such as inherited or acquired thrombophilia, pregnancy,oral contraceptive use, malignancy, sepsis, and headtrauma. Other diagnostic possibilities include pseudotu-mor cerebri and viral or bacterial meningitis.

Of all the possible imaging modalities, magnetic reso-nance venography is the most sensitive test for detecting thethrombus and the occluded dural sinus or vein and thus isthe test of choice for diagnosing dural sinus venous throm-bosis. After the diagnosis is established, the recommendedtreatment is smoking cessation, discontinuation of oral con-traceptives, and systemic anticoagulation to prevent sequel -ae related to elevated intracranial pressure for 6 months ifno hypercoagulable disorder is found.

Cerebral angiography may demonstrate absence of thedural sinuses but is an expensive and invasive test and is notroutinely indicated for diagnosing dural sinus venousthrombosis.

Lumbar puncture may ultimately be required in thispatient to confirm elevated intracranial pressure, which isalready suggested by the presence of papilledema, or todiagnose pseudotumor cerebri. This diagnosis, however,requires exclusion of a dural sinus venous thrombosis.The lack of fever or elevated leukocyte count makesmeningitis unlikely as a diagnosis and a lumbar punctureunnecessary.

Measurement of the serum lupus anticoagulant levelin this patient is inappropriate. Hypercoagulable testingwould be indicated to determine the duration of antico-agulation needed in this patient only after a dural sinusvenous thrombosis was diagnosed. The lupus anticoagu-lant is unlikely to be present if the coagulation profile isnormal.

K E Y P O I N T

• The diagnostic test of choice for diagnosingdural sinus venous thrombosis is magnetic reso-nance venography.

BibliographyStam J. Thrombosis of the cerebral veins and sinuses. N Eng J Med.

2005;352(17):1791-1798. [PMID: 15858188]

Item 2 Answer: BEducational Objective: Diagnose critical illnessmyopathy.

This patient has critical illness myopathy, which is seen inseverely ill patients after a prolonged (>7 days) stay in theintensive care unit (ICU). Inability to extubate and pre-dominantly proximal flaccid limb weakness are classicfindings. Critical illness myopathy is characterized by an ele-vated serum creatine kinase (CK) level. Predisposing factorsinclude the patient’s prolonged ICU stay, use of cortico-steroids and neuromuscular junction–blocking agents, andhyperglycemia.

Corticosteroid myopathy presents with predominantlyproximal weakness, preserved reflexes, a normal serum CKlevel, and normal or only mildly myopathic findings onelectromyography (EMG).

Guillain-Barré syndrome can share the clinical presen-tation of critical illness myopathy. The serum CK level,however, would be normal.

Patients with generalized myasthenia gravis typicallyhave limb weakness, diplopia, slurred speech, dysphagia,and dyspnea. Findings on neurologic examination includeptosis, impaired ocular motility, and limb weakness thatincreases with repeated testing (fatigable weakness). Deeptendon reflexes and sensory examination findings are nor-mal. Results of EMG in myasthenia gravis would showcharacteristic decremental motor responses on repetitivestimulation. The patient’s findings are not consistent withmyasthenia gravis.

K E Y P O I N T

• Critical illness myopathy can occur in severelyill patients after a prolonged stay in the inten-sive care unit and is characterized by an inabil-ity to extubate, flaccid limb weakness, and anelevated serum creatine kinase level.

BibliographyGriffiths RD, Hall JB. Intensive care unit-acquired weakness. Crit Care

Med. 2010;38(3):779-787. [PMID: 20048676]

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