2009 AOA Review

1. 2009 AOA Review Neurology

2. Contact Information Dominic Peters (dpeters@neoucom.edu) Jessica Nassar (jswartz@neoucom.edu) Kevin Frey (kfrey@neoucom.edu)

3. A 48-year old man comes to the physician because of a 2-day history of severe low back pain. He states that he has had periodic low back pain for years, but this is more severe than usual and radiates to the buttocks and down the right leg. His temperature is 36.8 C. Examination shows some rigidity of the lumbar spine. The pain is exacerbated by applying pressure on the paravertebral region in the lower lumbar spine and by passively raising the leg at 45 degrees while the patient lies supine. A reduced Achilles tendon reflex is noted. He has had no bowel or bladder incontinence. Which of the following is the most appropriate next step in management? • A) MRI examination of vertebral column • B) Nonsteroidaland anti-inflammatory drugs (NSAIDs) • C) Plain x-ray examination of the lumbosacral spine • D) Radionuclide bone scanning • E) Surgical consultation

4. Answer: B ,The clinical picture strongly suggests herniation of an intervertebral disc causing compression of a spinal roots (S1, considering radiation of the pain and reflex alterations). Supporting such a diagnosis is also the positive straight leg-raising test. When the history and physical examination support a diagnosis of disc herniation, conservative management is all that is needed. Current recommendations include treatment with NSAIDS and bed rest of short duration. Bed rest longer than 2 days has not been shown to provide any additional benefit

5. A 38-year-old man comes to the physician because of slowly progressive visual problems that make him “bump into objects” on both sides. He also reports that, while driving he has trouble switching lanes because he needs to turn his head all the way backward to look for other cars. Ocular examination shows bitemporal field loss with preserved visual acuity. Examination of the fundus is unremarkable. Which of the following is the most likely diagnosis? • A) Pituitary adenoma • B) Occipital lobe meningioma • C) Optic glioma • D) Optic nerve atrophy • E) Optic Neuritis • F) Retinal Detachment

6. Answer: A ,The visual deficit presenent in this patient is described as bilateral temporal hemianopia and is due to chiasmatic lesions that compromise the crossing fibers originating from the temporal retina. A large pituitary adenoma (macroadenoma) that extends beyond the sellaturcica into the suprasellar region is the most common cause of temporal hemianopia. Craniopharyngioma and meningioma are other causes.

7. A 52-year old man comes to the physician because of slowly progressive weakness in his legs. He also complains of clumsiness with his right hand, which creates difficulty with buttons or turning keys. Examination reveals mild bilateral footdrop and leg weakness. Fasiculation and mild wasting are observed in the calf muscles. There is no spasticity or impaired sensation. The speech is normal, but fasciculation of the tongue is appreciated. Respiration, pulse, and temperature are normal. A muscle biopsy shows evidence of denervation with reinnervation. Which of the following is the most likely diagnosis? • A) Amyotrophic lateral sclerosis (ALS) • B) Charcot-Marie-Tooth disease • C) Guillain-Barresyndrome • D) Myasthenia gravis • E) Spinal muscular atrophy

8. Answer: A ,Flaccid paresis involving the lower extremities, footdrop, hand clumsiness, muscle wasting, and especially fasciculation in a middle-aged person are highly suggestive of amyotrophic lateral sclerosis (ALS). This results from degeneration of the motor neurons in the spinal cord (lower motor neurons) and leads to denervation of skeletal muscle. His tongue fasisculations result from degeneration of motor neurons of cranial nerve nuclei. Continued bulbar involvement will likely eventually affect pharyngeal and facial musculature, leading to progressive dysarthria and dysphasia. Surviving neurons may reinnervatedenervatedmyofibers by sprouting of their axons. The finding of denervation/reinnervation in a muscle biopsy is confirmatory of the clinical diagnosis. The patient will later develop evidence of corticospinal and cortico-bulbar (upper motor neuron) degeneration as his disease progresses.

9. A 40-year-old man consults a physician because of dizziness. The patient reports that the dizziness starts whenever he moves his head. The dizziness is severe and lasts approximately 10-15 minutes, eventually resolving if he keeps his head still. He does not experience tinnitus or hearing changes during these episodes. Otoscopic examination is within normal limits. Which of the following is the most likely diagnosis? • A) Benign positional vertigo • B) Cholesteatoma • C) Herpes zoster oticus • D) Menieredisease • E) CerebellarStroke

10. Answer: A ,The patient has benign positional vertigo. The pathophysiology appears to involve granular masses that sit in the semicircular canals of the inner ear, stimulating hair cells, thus setting off episodes of vertigo. The primary treatment involves repositioning maneuvers (Epley Maneuver) that move the otoliths in the semicircular canals into the broader utricle and saccule. In addition, first generation antihistamines, such as meclizine, can also be effective at symptom control.

11. A 65-year-old man comes to the physician because of an increasingly severe tremor that affects the right hand. The tremor is particularly marked at rest and disappears when the limb is in movement. The man’s speech is soft but not monotonous. There is increased resistance when the arms or neck are passively flexed. Sensation and muscle strength appear intact. Short-term memory is preserved. The patient’s blood pressure is 134/82 mm Hg, temperature is 37 C, pulse is 70/min, and respirations are 10/min. The patient has a history of a previous episode of narrow-angle glaucoma. Which of the following drugs should be avoided in the treatment of his neurologic condition? • A) Amantidine • B) Benztropine • C) Bromocriptine • D) Levodopa • E) Selegiline

12. Answer: B , The clinical picture is consistent with Parkinson disease at a relatively early stage. Resting tremor may be unilateral at first. ANticholinergic drugs such as benztropine, are frequently used initially and are effective in alleviating tremor and rigidity. The key to the correct answer is the fact that the patient’s history includes narrow-angle glaucoma. Use of anticholinergic drugs may lead to an acute increase of intraocular pressure in predisposed individuals and precipitation of narrow-angle glaucoma. The other drugs listed in this question would all be appropriate for use in this patient.

13. A 45-year-old woman is involved in a head-on collision with a tree at 50 mph during which she hits her head on the windshield. In which structure is she most likely to have an intracranial hemorrhage? • A) Putamen • B) Temporal lobe • C) Thalamus • D) Occipital lobe • E) Parietal lobe

14. Answer: B , Temporal lobe. Temporal lobes and inferior frontal lobes frequently involved in traumatic brain injury. Continued forward motion of brain within cranial vault, which decelerated on impact, causes anterior brain structures to strike inside of skullcontusions. Rough cribriform plate and middle cranial fossacontribute Coup injury: reflect direct blow to brain Contrecoupinjury: reflect injury at diametrically opposed brain region (i.e., occipital lobes) where there is rebound movement of overlying skull. Expanding hematomauncalherniation

15. Quick review of traumatic brain injury: • 1) Epidural hematoma: • Rupture of middle meningeal artery from temporal bone fracture • Lucid interval before decreased LOC • CT: biconvex hemorrhage not crossing suture lines • 2) Subdural hematoma: • Rupture of bridging veins • Venous bleeding, delayed onset • Elderly, alcoholics, blunt trauma, skaen baby • CT: crescent-shaped hemorrhage that crosses suture lines

16. A 30-year-old right-handed man experiences one week of progressive ascending weakness. Examination demonstrates a lower motor neuron pattern and CSF protein is elevated. The patient reports his weakness was preceded by an episode of severe diarrhea. Which infection likely preceded this patient’s current neurological condition? • A) Mycoplasmapneumoniae • B) HIV • C) Clostridium difficile • D) Campylobacter jejuni • E) Cytomegalovirus

17. Answer: D,Campylobacter jejuni. C. jejunimost common infection preceding Guillain-Barré syndrome.Less common infections: CMV, HIV, Epstein-Barr, Lyme disease, M.Pneumoniae. Other associations: surgical procedures, exposure to thrombolytics, lymphoma, certain vaccines

18. Quick review of Guillain-Barré syndrome: • Inflammation and demyelination of peripheral nerves and motor fibers of ventral roots • Sensory effect less severe than motor • Symmetric ascending muscle weakness • Autonomic function may be affected: cardiac irregularities, hyper- or hypotension • Most survive • See increased CSF protein with normal cell count (albuminocytologic dissociation) Txt: Respiratory support, plasmapheresis, IVIG

19. A 35-year old man injured his thoracic spine in a car accident 2 years ago. Initially he had urinary urgency and a bilateral spastic paraparesis which have since improved. He still has pain and thermal sensation loss in his on part of his left body and proprioception loss in his right foot. He also still experiences paralysis of his right lower extremity. Which is the patient’s most likely spinal cord condition? • A) Brown-Séquard(hemisection) syndrome • B) SyringomyelicSyndrome • C) Complete transection • D) Tabeticsyndrome • E) Posterior column syndrome

20. Answer: A,Brown-Séquard (hemisectionsyndrome). Spinothalamicdamagecontralateral loss of pain and thermal sensation. Posterior column damageipsilateral loss of proprioception (also includes tactile and vibration sense). Destruction of corticospinal and rubrospinal tracts and motor neuronsipsilateral motor paralysis. Also causes ipsiplateral loss of all sensation at level of lesion and Horner’s syndrome if lesion above T1 (ptosis, anhidrosis, miosis)

21. Quick review of other spinal cord lesion choices: • 1) Syringomyelicsyndrome: • from lesion of central gray matter; • pain and temp fibers that cross at anterior commissure are affected bilateral loss of sensations over several dermatomes but tactile sensation is spared • 2) Complete transection of spinal cord: • bilateral spastic paralysis • no conscious appreciation of any cutaneous or deep sensation in area below transection • 3) Tabeticsyndrome: • from damage to proprioceptive and other dorsal root fibers • classically caused by syphilis • symptoms are paresthesias, pain and gait abnormalities • gait is most affected • 4) Posterior column syndrome: • bilateral loss of proprioception below lesion • preservation of pain and temperature sensation

22. A previously healthy 34-year-old man collapses while sitting at his kitchen table. The patient’s wife reports a convulsion of 2 minutes’ duration. He appeared to fully recover within 1 hour. In the ER the patient reports having new early morning headaches during the past few weeks. A brain MRI demonstrates an enhancing right frontal lesion which is likely a primary brain neoplasm. Which is the most common type of primary brain tumor? • A) Meningioma • B) Lymphosarcoma • C) Oligodendroglioma • D) Astrocytoma • E) Medulloblastoma

23. Answer: B , Astrocytoma. Most common primary brain tumors are malignant astrocytomas. Classified as grade 3 or 4. Grade 4 astrocytoma is called glioblastomamultiforme usually in adults, men>women

24. Quick review of brain neoplasm basics: • 1) Clinical presentation due to mass effect • 2) Primary brain tumors rarely metastasize • 3) Majority of adult primary tumors are supratentorial • 4) Majority of childhood primary tumors are infratentorial • 5) Half of adult brain tumors are metastases • 6) Craniopharymgiomais most common childhood supratentorial tumor

25. A 32-year-old man is involved in a motor vehicle accident. The patient has multiple injuries including a displaced fracture of the left humerus. He complains of an inability to open his left hand and loss of sensation to a portion of his left hand. Which nerve has most likely been damaged? • A) Musculocutaneous • B) Ulnar • C) Radial • D) Median • E) Axillary

26. Answer: C , Radial. Injury due to stretch or crush injury of radial nerve as it spirals around midshaft of humerus. Inability to open hand due to loss of hand and wrist extensor innervation by radial nerve radial nerve is “great extensor,” innervates brachioradialis, extensors of wrist and fingers, supinator and triceps. Likely location of sensory deficit: lateral side of dorsum of hand and dorsum of the thumb and index and middle digits

27. Quick review of upper extremity nerve injury: • 1) Median nerve: • Site of injury often supracondyle of humerus • No loss of power in arm muscles • Loss of forearm pronation, wrist flexion, finger flexion, several thumb movements • Eventual thenar atrophy • Loss of sensation over lateral palm and thumb and radial 2 ½ fingers • 2) Ulnarnerve: • Site of injury often medial epicondyle • Impaired wrist flexion and adduction • Impaired adduction of thumb and ulnar 2 fingers • “Claw hand” • Loss of sensation over medial palm and ulnar 1 ½ fingers • 3) Axillarynerve: • Site of injury surgical neck of humerus of anterior shoulder dislocation • Loss of deltoid action • 4) Musculocutaneousnerve: • Loss of function of coracobrachialis, biceps and brachialis muscles

28. A 29 y/o female suddenly develops a left hemiparesis. The patient experienced a DVT in her right leg 3 years ago. Which of the following conditions is the most likely cause of this patient's deficit?   A) NonvalvularAtrialFirbrillation B) Lupus Anticoagulant C) Mitral Valve Prolapse D) Multiple Sclerosis (MS) E) Astrocytoma

29. Answer: B , the lupus anticoagulant (an antiphospholipidantidbody) is associated with peripheral venous thrombosis and ischemic (arterial) stroke. In patients with a history of DVT, the possibility of a paradoxical embolus causing a stroke (via right-to-left cardiac shunt) should also be considered. Nonvalvularatrial fibrillation is a common cause of stroke in the elderly, but there is no reason to suspect a rhythm disturbance in this patient. Mitral valve prolapse has been associated with cardiogenic emboli and stroke. However, a search for other causes of stroke should always be made, because mitral valve prolapse is a relatively common entity, and the association with stroke in weak. Multiple sclerosis (MS) and an astrocytoma can cause neurologic deficits in young patients; however, these conditions are not associated with DVT unless the patient is immobilized. These diagnoses should be considered in the evaluation of patients with hemiparesis, but the patient's history can often serve as a clue to guide diagnostic thinking.

30. A patient with a subarachnoid hemorrhage (SAH) caused by a right anterior communicating artery aneurysm undergoes surgery 2 days after the hemorrhage. Three days later, right arm weakness develops. Which of the following diagnoses is most likely?     A) Hydrocephalus     B) Meningitis     C) Repeat Hemorrhage     D) Vasospasm     E) Hyponatremia

31. Answer: D , vasospasm can develop several days after an aneurysmal subarachnoid hemorrhage (SAH). Patients present with progressive weakness and alterations in consciousness. Early in the course, a CT scan may not reveal an ischemic infarction. Hydrocephalus can occur immediately after an SAH or weeks to months later. Symptoms are typically nonfocal and, if the hydrocephalus develops acutely, it is often accompanied by a depressed level of consciousness. Bacterial meningitis can develop after a craniotomy. Typically, there is fever and impaired arousal. Focal signs can develop but are rarely the presenting feature. Although a repeat hemorrhage can occur after clipping of an aneursym if the aneurysm is not completely isolated from the circulation, it is unusual for this to happen and present with a focal deficit, as opposed to depressed consciousness. Hyponatremia, which can develop after SAH, can cause an altered sensorium and seizures but not unilateral weakness.

32. *How would you treat vasospasm?     A) Heparin     B) Warfarin     C) Nimodipine     D) Phenytoin     E) Carbamazepine

33. Answer: C , Vasospasm is a relatively common complication of subarachnoid blood and may result in stroke. Nimodipine (Ca2+ channel blocker, primary effect is upon cerebral arteries) is used because it decreases the probability of stroke, but it does not prevent it completely. Anticoagulation with heparin or warfarin worsens the patient's prospects because it increases the risk of additional bleeding. Antiepileptic drugs, such as phenytoin and carbamazepine, may reduce the risk of seizure associated with subarachnoid blood and are sometimes given prophylactically. This patient does not have evidence of seizures, however.

34. A 62 y/o woman has a 2-month history of mild confusion. She occasionally has difficulty following a conversation. On the morning of presentation to the hospital, she developed 30 seconds of right face twitching, followed by increased confusion. Examination shows difficulties in speech comprehension and a subtle right homonymous hemianopia. A brain CT scan shows a 2 x 3 cm ill-defined region of low density in the left parietal lobe. The most likely diagnosis is:     A) Multiple Sclerosis     B) Stroke     C) Astrocytoma     D) Abscess     E) Metastsis

35. Answer: C , the patient presents with a 2 month history of progressive neurologic deficits. The CT scan shows an area of low density, and there is no mention of mass effect. The most likely diagnosis is an astrocystoma, which may not have much in the way of mass effect or enhancement on CT scan. The progressive history is against a stroke. Multiple sclerosis rarely presents in this age group and would not be expected to cause a large area of decreased density on CT scan. An abscess or metastasis would have substantial mass effect and enhancement on CT scan.

36. A 57 y/o male has a 2-month history of severe, daily headaches that involve the right frontotemporoparietal area. The headaches typically last 60-90 minutes and occur once to twice daily. Over-the-counter medications have not provided relief. Chiropractic manipulation did not help. The patient is desperate for relief because he cannot work during the headache episodes. A reasonable treatment strategy is to initiate:     A) Baclofen     B) Amitriptyline     C) Indomethacin     D) Corticosteroids     E) Sumatriptan

37. Answer: C , the patient's history is suggestive of paroxysmal hemicrania, an indomethacin-responsive disorder. In fact, a positive response to treatment with indomethacin can confirm a diagnosis of paroxysmal hemicrania. The rest of the drugs listed are not considered to be beneficial for paroxysmal hemicrania.  

38. A 79 y/o female is brushing her teeth when she has an intense sensation that the room is moving as if she were on a ship. Examination and testing reveal a cerebellar stroke. Cerebellar damage may be associated with severe vertigo if the tissue damaged is in the distribution of the:      A) Superior Cerebellar Artery     B) Posterior Inferior Cerebellar Artery (PICA)     C) Anterior Inferior Cerebellar Artery (AICA)     D) Anterior Spinal Artery     E) Posterior Cerebral Artery

39. Answer: B , the PICA has both medial and lateral branches. The medial branches supply the brainstem. With occlusion of these, vestibular nuclei in the brainstem are infarcted, and vertigo is common. Even with an occlusion limited to the lateral branches, vertigo is likely. If no brainstem damage occurs, cerebellarflocculonodular lobule injury may induce vertigo. 

40. A 25 y/o female with a history of epilepsy presents to the emergency room with impaired attention and unsteadiness of gait. Her phenytoin level is 37. She has WBCs in her urine and has a mildly elevated TSH. Examination of the eyes would be most likely to show which of the following?     A) Weakness of abduction of the left eye     B) Lateral beating movement of the eyes     C) Impaired convergence     D) Papilledema     E) Impaired upward gaze

41. Answer: B , most rhythmic to-and-fro movements of the eyes are called nystagmus. Nystagmus has a fast component in one direction and a slow component in the opposite direction. Nystagmus with a fast component to the right is called right-bearing nystagmus. Phenytoin (Dilantin) may evoke nystagmus at levels of 20 to 30 mg/dL. The eye movements typically appear as a laterally beating nystagmus on gaze to either side; this type of nystagmus is called gazed-evoked. If the patient has nystagmus on looking directly forward, he or she is said to have nystagmus in the position of primary gaze. Therapeutic levels of phenytoin are usually 10 to 20 mg/dL, and some patients develop asymptomatic nystagmus even within that range. Ataxia, dysarthria, impaired judgement, and lethargy may also occur at toxic levels of phenytoin. Many other drugs also evoke nystagmus. Weakness of abduction of the left eye, or abducens palsy, is due either to injury to the 6th cranial nerve or to increased ICP (intracranial pressure). Impaired convergence can occur normally with age or may be a sign of injury to the midbrain. Papilledema is a sign of increased ICP. Impaired upward gaze may occur in many conditions, but would not be expected to occur with toxic phenytoin level. 

42. A 56 y/o male with epilepsy is brought into the emergency room. He has been having continuous generalized tonic-clonic seizures for the past 30 minutes. He is treated with 2mg of intravenous lorazepam. Most physicians recommend using a high dose of intravenous benzodiazepine as part of the management of status epilepticus because of its:     A) Ability to suppress seizure activity for more than 24 hours after one injections     B) Lack of respiratory depressant action     C) Rapid onset of action after intravenous administration     D) Lack of hypotensiveeffects     E) Lack of dependance on hepatic function for its metabolism and clearance

43. Answer: C , until recently, the most popular benzodiazepine for use in status epilepticus was diazepam (Valium), which has a rapid onset of action but is cleared relatively quickly. Because of this property, patients needed additional medications, such as phenytoin, to protect them from recurrent seizure activity as early as 20 minutes after diazepam injection. A longer-acting benzodiazepine, lorazepam (Ativan), has the advantage of being rapid-acting like diazepam but being cleared more slowly from the body.

44. After extraction of a wisdom tooth, an 18-year old male student was diagnosed as having subacute bacterial endocarditis. He has a congenital heart disease which has been under control. Which of the following is the most likely organism causing his infection? (A) Enterococcus faecalis (B) S. aureus (C) S. epidermidis (D) S. pneumoniae (E) S. viridans

45. The patient's seizing does not stop. A second intravenous drug is given. Infusing which of the following antiepilecptic drugs at more than 50 mg/min in an adult may evoke a cardiac arrhythmia?     A) Carbamazepine     B) Diazepam     C) Phenobarbital     D) Clonazepam     E) Phenytoin

46. Answer: E , rapid infusion of phenytoin may produce a conduction block or other basis for cardiac arrhythmia. Phenytoin should not be administered at rates greater than 50 mg/min in adults or 1 mg/(kg x minutes) in children to reduce the chances of this reaction occurring. Thus, it usually requires approximately 20 minutes to administer 1000 to 1500 standard loading dose of phenytoin in an emergent setting such as status epilepticus. Fosphenytoin, a water-soluble prodrug of phenytoin that has recently become available, has the advantage of causing fewer infusion reactions. It can be given at doses of up to 150 mg/min in an adult, with risk of cardiac dysrhythmia similar to those of phenytoin. Another advantage of fosphenytoin is that it can be administered intramuscularly when IV access is problematic. Carbamazepine is not administered IV at all. Rapid infusion of phenobarbital may produce hypotension or respiratory arrest, but is much less likely to depress cardiac activity. Diazepam and clonazepam are safer than phenobarbital, but rapid infusion of excessively high doses may depress blood pressure and other autonomic functions.

47. An 18 y/o male brought into the emergency room after a diving accident. He is awake and alert, has intact cranial nerves, and is able to move his shoulders, but he cannot move his arms or legs. He is flaccid and has a sensory level at C5. Appropriate management includes:     A) Naloxonehydrocholoride     B) Intravenous methylprednisolone     C) Oral dexmethasone     D) Phenytoin 100mg TID     E) Hyperbaric oxygen therapy

48. Answer: B , high-dose intravenous methylprednisolone (30mg/kg IV bolus followed by 5.4 mg/[kg x hour] for 23 hours) has been shown to have a statistically significant, if clinically modest, benefit on the outcome after spinal cord injury when given within 8 hours of the injury. Naloxone hydrochloride and other agents, such as GM1 ganglioside, have not been shown to be of benefit. The role of surgical decompression, removal of hemorrhage, and correction of bone displacement is controversial. Most American neurosurgeons do not advocate surgery, and instead propose external spinal fixation.

49. A 41 y/o homosexual male is brought to medical attention by his partner because of headache, sluggish mentation, and impaired ambulation worsening over the previous week. The patient is known is known to be HIV-seropositive, but has done well in the past and has not sought regular medical attention. On examination, his responses are slow and he has some difficulty sustaining attention. He has a right hemiparesis with increased reflexes on the right. Routine cell counts and chemistries are normal. A contrast head CT reveals several ring-enhancing lesions. Eventually surgical aspiration of one of the lesions reveals that they are abscesses.

50. Abscesses in the brain most often develop from?     A) Hematogenous spread of infection     B) Penetrating head wounds     C) Superinfection of neoplastic foci     D) Dental trauma     E) Neurosurgical intervention