A 24-year-old woman presents to the ED complaining of dizzinessand numbness and tingling in her fingertips with decreased range of motion.Her initial vitals include a HR of 100 beats per minute, a RR of 30 breathsper minute with an oxygen saturation of 100% on room air. The patient deniesany other symptoms. Upon physical examination, the patient appears anxious,tachypneic with a clawed appearance to both hands which are difficult torange. An arterial blood gas is drawn that shows a pH of 7.55 with adecreased carbon dioxide level and normal bicarbonate level. Which of thefollowing underlying metabolic disturbances is responsible for this patient’ssymptoms?a. Metabolic acidosisb. Metabolic alkalosisc. Respiratory acidosisd. Respiratory alkalosise. Hyperthyroidism384
Weakness and DizzinessAnswers345. The answer is d. (Rosen, p 1435.) The patient had a TIA, whichinvolves neurologic deficits that resolve within 24 hours of onset. TIAsoften precede ischemic stroke; up to 50% of patients with a TIA will havea stroke in the next 5 years, with the highest incidence in the first month.It is important to recognize TIAs and to evaluate patients for cardiac orcarotid arterial sources of emboli. Although the symptoms often resolve,many patients with a TIA will have evidence of infarction on CT/MRI.The patient did not have a thrombotic (a) stroke. Neurologic deficits arenot transient in a cerebral vascular accident. Conversion disorder (b) is a raredisorder that is characterized by the abrupt, dramatic onset of a single symp-tom. It typically presents as some nonpainful neurologic disorder for whichthere is no objective data. It is a diagnosis of exclusion. Although migraineauras can include focal neurologic deficits ©, the patient in the vignette doesnot have a history of migraines and is not complaining of a headache. Toddparalysis (e) is a transient focal neurologic deficit that persists after a seizure.346. The answer is a. (Tintinalli et al, p 1404.) BPV is a transient positionalvertigo associated with nystagmus. The problem occurs secondary to thecreation and movement of canaliths (free-moving densities) in the semicircularcanals of the inner ear with a particular head movement. Neurologic deficitsare absent in BPV. Note that horizontal, vertical, or rotary nystagmus canoccur in BPV. It is important to pay special attention to a patient with verticalnystagmus because it may be associated with a brainstem or cerebellumlesion. BPV is treated with the Epley maneuver (a series of head and bodyturns that reposition the canalith), antiemetics, and antihistamines. Keydifferences between peripheral and central vertigo are seen in the chart.Food poisoning (b) would not cause vertigo. If it is associated withvomiting and diarrhea, it can lead to dehydration and lightheadedness butnot vertiginous symptoms. Meniere disease ©, is an inner ear disease ofunclear etiology. It presents with recurrent attacks of vertigo and tinnitus,with deafness of the involved ear between attacks. Labyrinthitis (d) presentswith hearing loss and sudden, brief positional vertigo attacks. TIAs (e) involving385
the vertebrobasilar system can present with vertigo but is an unlikely diagnosisin this case of recurrent positional vertiginous symptoms.347. The answer is a. (Rosen, p 1522.) High clinical suspicion in this caseis for myasthenia gravis, an autoimmune condition in which acetylcholinereceptor antibodies block acetylcholine binding and prevent normal neu-romuscular conduction. The disease typically affects young women and oldermen and presents with generalized weakness worsening with repetitivemuscle use that is usually relieved with rest. Ptosis and diplopia are usuallypresent. The edrophonium test is used to help diagnose myasthenia gravis. Itinvolves administering edrophonium, a short-acting anticholinesterase, whichprevents acetylcholine breakdown. With the increased acetylcholine levelsat the neuromuscular junction, the patient experiences a subjective andobjective improvement of symptoms by preventing rapid breakdown ofacetylcholine at the myoneural junction. Serologic testing (b) for antibodiesto acetylcholine receptors is useful when positive and should be obtainedin the workup of this patient. A negative test does not exclude the disorder.The electromyogram is diagnostic. © You may consider a CT scan to evalu-ate the patient for possible mass lesion or aneurysm that is causing her ptosisand diplopia. However, the clinical scenario is more consistent with myas-thenia gravis. (d) An electrolyte panel will likely be normal. (e) If the edro-phonium test is normal, a lumbar puncture should be considered.348. The answer is b. (Rosen, pp 120-122.) The patient has a progressiveascending peripheral neuropathy, also known as Guillain-Barré syndrome.Peripheral vertigo Central vertigoPathophysiology Disorder of vestibular Disorder of brain nerve (CN VIII) stem or cerebellumSeverity Intense Less intenseOnset Sudden SlowPattern Intermittent ConstantNausea and vomiting Usually present Usually absentExacerbated by position Most of the time Less of the timeHearing abnormalities May be present Usually absentFocal neurologic deficits Usually absent Usually presentFatigability of symptoms Yes NoNystagmus Horizontal, vertical, Verticalrotary
Weakness and Dizziness Answers 387Patients can usually remember a preceding viral illness, usually gastroen-teritis. Deep tendon reflexes are typically absent.Hypokalemic periodic paralysis is part of the heterogeneous group ofmuscle diseases known as periodic paralyses and is characterized by episodesof flaccid muscle weakness occurring at irregular intervals. Most of theconditions are hereditary and are more episodic than periodic. Peripheralvascular disease ©, a common complication of longstanding diabetes, causesparesthesias in the distal lower extremities and not acute paralysis. Tetanus(d) manifests as muscular rigidity caused by the Clostridium tetani toxinpreventing release of inhibitory neurotransmitters. Lockjaw is a commoncomplaint in generalized tetanus. A brain abscess (e) typically presents withfever, headache, and focal neurologic findings and is usually caused by anassociated trauma, surgery, or infectious spread from another site.349. The answer is c. (Rosen, pp 120-122.) Progressive paralysis in Guillain-Barré syndrome can rapidly ascend to the respiratory system and causerespiratory failure. Patients need to be monitored and provided ventilatorsupport as necessary.(a) Guillain-Barré syndrome is a transient, not permanent, condition.(b, d, and e) are not complications of the syndrome.350. The answer is d. (Tintinalli et al, p 172.) This patient presents withhypokalemia, secondary to increased potassium losses through vomitingand diarrhea as well as reduced oral intake. Potassium deficiency results inhyperpolarization of the cell membrane and leads to muscle weakness,hyporeflexia, intestinal ileus, and respiratory paralysis. CharacteristicECG findings include flattened T waves, U waves, and prolonged QT and PRintervals.Hyponatremia (a) and hypernatremia (b) mainly affect the central nervoussystem (CNS), resulting in headache, anorexia, lethargy, and confusion. Inmore severe cases, hyponatremia causes seizures, coma, and respiratory arrest;whereas patients with profound hypernatremia develop ataxia, tremulousness,and spasms. Hyperkalemia © can lead to cardiac dysrhythmias and typicallyexhibits distinctive ECG findings including peaked T waves, prolonged QTand PR intervals, and widened QRS complex that can progress to a sinewave pattern. Signs of hypercalcemia (e) include bony and abdominal pain,renal stones, and altered mental status (remembered by: “bones, stones, groans,and psychiatric overtones”). In addition, cardiac effects include bradycardia,heart blocks, and shortened QT interval on ECG.
- The answer is d. (Rosen, pp 1434-1435.) The CT image shows a largehypodensity in the right parietal-occipital region representing an ischemicstroke. Ischemic strokes comprise 80% of all strokes, with hemorrhagicstrokes accounting for the other 20%. Ischemic events include thrombotic(thrombus forming at the site of an ulcerated atherosclerotic plaque), embolic(thrombus embolized to a distal site), and lacunar (small terminal arteryocclusion) strokes. This patient likely had a cardioembolic secondary to atrialfibrillation. Atrial fibrillation is an important risk factor for an embolic stroke,particularly when patients are noncompliant with anticoagulation therapy,as the patient in the vignette. Intracranial bleeding secondary to a hemorrhagicevent appears hyperdense on CT scan. The diagram above illustrates thecerebral circulation.352. The answer is b. (Rosen, pp 253-254.) Consider MS as a diagnosis inpresentations of various neurologic symptoms that are difficult to explain by asingle CNS lesion, particularly those occurring in a female in her third decadeof life. MS is a multifocal demyelinating CNS disease that in 30% of cases ini-tially presents with optic neuritis (unilateral eye pain and decreased visual acuity).Ant. cerebral A.Ant. choroidal A.Post. cerebral A.Middle cerebral A.Deep branches ofmiddle cerebral A.Body ofcaudateInternalcapsulePutamenClaustrumGlobuspallidusUncusSubthalamic bodyRed nucleusThalamus(Reproduced, with permission, from Kasper DL et al. Harrison’s Principles of InternalMedicine. New York, NY. McGraw-Hill, 2005: 2381.) (Courtesy of CM Fisher, MD.)
Weakness and Dizziness Answers 389Myasthenia gravis (a) commonly presents with muscle weakness that isexacerbated by activity, sleeplessness or alcohol intake and is relieved by rest.The most frequent initial symptoms include ptosis, diplopia, and blurred vision.Vertebrobasilar insufficiency © presents with cerebellar and brainstem symp-toms, such as vertigo, dysphagia, and diplopia, none of which are present inthis patient. Encephalitis (d) is an infection of brain parenchyma and pre-sents with altered mental status that may be associated with focal neurologicdeficits. Patients might present with behavioral and personality changes,seizures, headache, photophobia, and generalized symptoms of fever, nausea,and vomiting. Guillain-Barré syndrome (e) is the most common polyneuropa-thy. It is described as an ascending paralysis that is often preceded by a viralsyndrome. Classically it is associated with the loss of deep tendon reflexes.353. The answer is e. (Rosen, pp 2553-2554.) Demyelinating MS lesions areoften well demonstrated on MRI but cannot be visualized on (d) CT scan.The edrophonium test (a) is used as an adjunct in the diagnosis ofmyasthenia gravis. A carotid artery angiogram (b) is useful when evaluatingthe carotid arteries for trauma, dissections, or thrombus. Analyzing CSF© can help aid you in the diagnosis of MS as it often reveals oligoclonal band-ing and elevated protein.354. The answer is d. (Rosen, pp 1440-1442.) The patient is a good candidatefor fibrinolytic therapy. She is having an acute ischemic stroke (in thedistribution of the middle cerebral artery), has no contraindications to thetherapy and is being evaluated within the 3-hour (180-minute) therapeuticwindow from the onset of symptoms. Exclusion criteria for the use ofthrombolytics include:• Evidence of intracranial hemorrhage on noncontrast head CT (absolute)• Minor or rapidly improving stroke symptoms• Clinical suspicion for subarachnoid hemorrhage• Active internal bleeding within last 21 days• Known bleeding diathesis• Within 3 months of serious head trauma, stroke, or intracranial surgery• Within 14 days of major surgery or serious trauma• Recent arterial puncture at noncompressible site• LP within 7 days• History of intracranial hemorrhage, A-V malformation• Witnessed seizure at stroke onset• Recent myocardial infarction, or systolic BP > 185 mm Hg or diastolic BP >110 mm Hg
The head CT may initially appear normal and starts to show the extentof injury within 6 to 12 hours after the onset of symptoms.(a) Current guidelines recommend that thrombolytics be administeredwithin 3 hours (180 minutes) of the patient’s symptom onset. Any patientwhose symptoms are present upon waking up from sleep is excludedbecause it cannot be certain when the symptoms began. (b) The generalconsensus in the neurology literature is to not treat hypertension in patientswith acute ischemic stroke unless they are candidates for thrombolysis andtheir BP is > 185 mm Hg systolic or 100 mm Hg diastolic. Labetalol is oftenrecommended over nitroprusside. Labetalol preserves normal cerebral autoreg-ulation whereas nitroprusside, a vasodilator, may divert blood from theinjured tissue and cause increased ischemia. Heparin therapy © has notbeen shown to reduce stroke-related mortality or disability in the setting ofacute stroke. If the patient is not a candidate for thrombolytics, aspirin (e)should be given in the setting of acute ischemic stroke. Maintenance therapywith daily aspirin or another antiplatelet agent has been shown to help reducestroke recurrence after a TIA.355. The answer is e. (Rosen, pp 1522-1524.) Myasthenia gravis is anautoimmune disease of the neuromuscular junction that is more commonin women in their twenties and thirties and men in their seventies andeighties. Myasthenia gravis results from autoantibodies directed against thenicotinic acetylcholine receptor at the neuromuscular junction. This leadsto destruction of acetylcholine receptors and competition with acetylcholinefor the remaining receptors. Muscular weakness and fatigability are thehallmarks of myasthenia gravis. Ocular symptoms manifest early and includeptosis, diplopia, and muscle weakness. Symptoms usually worsen as the dayprogresses. Diagnosis is usually made by the edrophonium or Tensilon test.(a) Botulism is a toxin-mediated disease that causes acute weakness bythe irreversible binding of botulinum toxin to the presynaptic membraneof nerves subsequently inhibiting the release of acetylcholine. The classicpresentation of botulism is a descending, symmetric paralysis. Unlike myas-thenia gravis, botulinum toxin decreases cholinergic output, which may leadto anticholinergic signs, such as dilated pupils, dry skin, urinary retention,constipation, and increased temperature. (b) Lambert-Eaton myasthenicsyndrome is often associated with small-cell carcinoma of the lung. Autoan-tibodies cause a decreased release of acetylcholine from presynaptic nerves.However, with repeated stimulation, the amount of acetylcholine in thesynaptic cleft increases leading to an improvement of symptoms throughout
Weakness and Dizziness Answers 391the day. © The third cranial nerve innervates many of the extraocularmuscles and the levator palpebrae. In addition, ciliary nerve fibers thatrun along the third cranial nerve function to constrict the pupil. Damageto the third cranial nerve often results in ptosis, mydriasis, and the classic“down and out” eye. However, these symptoms do not wax and wane aspresented in this scenario. (d) Guillain-Barré syndrome is an ascendingperipheral neuropathy classically presenting after a history of viral illness. It isassociated with loss of deep tendon reflexes and earlier symmetric, distalweakness.356. The answer is a. (Rosen, pp 1440-1442.) This patient’s BP of 215/118 mmHg needs to be lowered to 185/110 mm Hg to make her a good candidatefor thrombolytic therapy. Labetalol is the agent of choice in this case.Fibrinolytic administration (b) at this level of hypertension carries arisk of intracranial bleed. Daily aspirin © has been shown to reduce theincidence of strokes. However, aspirin should not be administered within24 hours of fibrinolytic use since it increases the risk of postthrombolyticbleed. Antiseizure prophylaxis with phenytoin (d) is not indicated in ischemicstrokes although a small percentage of stroke patients will seize within thefirst 24 hours. Hyperventilation and mannitol (e) are used for temporarymanagement of increased intracranial pressure owing to cerebral edema inan ischemic stroke, which peaks at 72 to 96 hours. There is no role formannitol in acute stroke in a patient without signs of elevated intracranialpressure.357. The answer is c. (Rosen, p 2169.) Patients with initial flu-like symptomsfrom the same household who were exposed to combustion products (ie,from a home generator) are at risk for carbon monoxide (CO) poisoning.CO binds to hemoglobin with greater affinity than oxygen and shifts theoxygen-hemoglobin dissociation curve to the left, thus decreasing oxy-gen release. Clinically, patients with mild CO toxicity present with flu-likesymptoms, nausea, and vomiting, which progresses to chest pain, dyspnea,confusion, seizures, dysrhythmias, and coma. CO level can be obtained bya carboxyhemoglobin level from blood. CO poisoning is treated with oxygenand, if severe, with hyperbaric oxygen therapy.An important clue to the diagnosis is the development of similar symptomsin the patient and her husband at the same time. While it is important toconsider ordering a WBC count (a), a head CT scan (b), and an LP (d) forevaluation of the symptoms, think CO poisoning when there are multiple
patients with the same symptoms in the setting of exposure to combustibleproducts. It is not appropriate to do nothing (e) since the patient is clearlyin need of medical attention.358. The answer is a. (Rosen, pp 1436-1437.) The middle cerebral arteryis the most common site of intracranial cerebral artery thrombosis. Clinicalfindings can include contralateral hemiplegia, hemianesthesia, and homony-mous hemianopsia. The upper extremity deficit is usually more severe thanthe lower extremity deficit. Aphasia occurs if the dominant hemisphere isinvolved. Gaze preference is in the direction of the lesion.Choice (b) is incorrect since the findings are ipsilateral to the area ofinjury. Choice © describes deficits in the anterior cerebral artery (ACA)distribution with greater deficits in lower extremity and altered mentationbecause of frontal lobe involvement. Crossed deficits, such as contralateralmotor and ipsilateral cranial nerve findings (d) occur in brainstem strokes,which are supplied by the posterior circulation. Pure motor (e) or sensoryloss occurs in lacunar infarcts, which involve small penetrating arteries.359. The answer is e. (Rosen, pp 1437-1438.) Do not get confused withthe multiple signs and symptoms in this case! They involve three distinctareas of the brain; the brainstem (facial droop, dysphagia, vertigo, and verticalnystagmus), cerebellum (ataxia, vertigo, and vertical nystagmus), and visualcortex (diplopia). All of these anatomical areas are supplied by the posteriorcirculation, specifically the vertebrobasilar artery. A mnemonic to helpremember the presentation of a vertebrobasilar stroke is the “three D’s”:dizziness (vertigo), dysphagia, and diplopia. There are cerebellar andcranial nerve deficits observed on both sides of the body.(a) Lacunar infarcts are small infarcts that are usually caused by ahypertensive vasculopathy but may occur in diabetics and can affect both theanterior and posterior cerebral vessels. Lacunar strokes involve penetratingcerebral arterial vessels lying deep in the grey matter (internal capsule) orbrain stem. BPV (b) is a transient positional vertigo associated with nystag-mus. Neurologic deficits are absent in BPV. Note that horizontal, vertical, orrotary nystagmus can occur in BPV; however vertical nystagmus is alwaysworrisome as it may indicate a brainstem or cerebellum lesion. Labyrinthitis©, an infection of the labyrinth, presents with hearing loss and sudden briefpositional vertigo attacks and does not involve other neurologic deficits. Theposterior cerebral artery (d) delivers blood supply to the occipital cortex andupper midbrain. Clinical findings include contralateral homonymous
Weakness and Dizziness Answers 393hemianopsia, hemiparesis, hemisensory loss, memory loss, and ipsilateralcranial nerve III palsy that is pupil sparing.360. The answer is a. (Tintinalli et al, p 1405.) You should suspect BPVin this patient. BPV is a transient positional vertigo associated with nystagmus.The problem occurs secondary to the creation and movement of canaliths(free-moving densities) in the semicircular canals of the inner ear that isassociated with a particular head movement. The Dix-Hallpike maneuveris a diagnostic test designed to reproduce transient vertiginous symptomsand nystagmus of BPV. The maneuver involves having the patient go fromsitting to a supine position with eyes open and head rotated to the affectedside. The test is positive if the maneuver reproduces vertigo and the patientexhibits latent rotary nystagmus. A negative Dix-Hallpike maneuver doesnot exclude the condition.Caloric stimulation testing (b) is performed for acoustic nerve evaluationby introducing cold or warm water or air into an ear canal and observingtransient nystagmus. It is unnecessary for BPV diagnosis. Orthostatic vital signs© should be obtained if you suspect orthostatic hypotension. The patient inthis case is symptomatic when he lies down, not when he is standing orsitting up, which is not consistent with this diagnosis. Head CT scan (d)should be ordered if you suspect central, rather than peripheral causes ofvertigo. ECG (e) is necessary if you suspect a cardiac cause of dizziness.361. The answer is b. (Rosen, p 1667.) This woman presents with iron-deficiency anemia secondary to menorrhagia. A history of chronic heavymenses and pale conjunctiva on examination should make you suspiciousof this common disorder. About 20% of women and 3% of men are irondeficient. Complete blood count provides hemoglobin and hematocritlevels to diagnose anemia. Typically, the mean corpuscular volume (MCV)is low in iron-deficiency anemia. In addition, the patient usually exhibits lowserum iron, low serum ferritin, and a high total iron-binding capacity.Electrolyte or renal function abnormalities (a) are unlikely in a younghealthy woman. Except for tachycardia, the ECG © will be normal unlessthe patient has underlying cardiac disease, which can lead to ischemia inthe setting of anemia. Chest x-ray (d) is not useful as an initial diagnostic test.It is appropriate to obtain it if you suspect a lung infiltrate, mass, congestiveheart failure, or other cardiopulmonary disease. Chest CT with contrast(e) would help to diagnose a pulmonary embolism that may present withweakness, dyspnea on exertion, and tachycardia. In this case, however, the
patient has no risk factors and has a better alternative diagnosis based onhistory and physical examination findings.362. The answer is b. (Tintinalli et al, p 176.) This common presentationof hypercalcemia is initially managed with aggressive isotonic saline IVhydration to restore volume status. Hypercalcemia impairs renal concen-trating ability, and patients typically present with polyuria, polydipsia,and dehydration and may develop kidney stones. Increased calciumlevels also cause generalized weakness, bone pain, neurologic symptoms(ataxia, altered mental status), GI dysfunction (abdominal pain, nausea, vom-iting, anorexia), and ECG abnormalities (shortened QT interval). A handymnemonic for symptoms of hypercalcemia is “bones, stones, groans, and psy-chiatric overtones.”Calcitonin (a) decreases calcium levels by reducing bony osteoclastactivity and intestinal calcium absorption. It does not produce an immediateeffect and is generally not started in the ED. Loop diuretics such as furosemide© increase renal elimination of calcium but worsen volume depletion.Patients need to be hydrated first. Obtaining a chest radiograph (d) is a goodidea while the patient is getting IV hydration. This patient has a significantsmoking history and recent weight loss which should raise your suspicionof a neoplastic lung process causing hypercalcemia. Malignancy is animportant cause of hypercalcemia; others include endocrine abnormalities(hyperparathyroidism, hyperthyroidism, pheochromocytoma, adrenal insuf-ficiency), granulomatous disease (sarcoidosis, tuberculosis), drugs (thiazides,lithium), and immobilization. The patent’s ECG (e) may show a shortenedQT interval. Very high calcium levels may cause heart block.363. The answer is c. (Tintinalli et al, p 1463.) Unilateral findings of ptosisand miosis as well as anhidrosis are seen in Horner syndrome which resultsfrom interrupted sympathetic nerve supply to the eye.Palsy of the oculomotor nerve results in a “down and out” eye becauseof the dysfunction of the extraocular muscles innervated by the oculomotornerve. In addition, the pupil appears mydriatic as a result of the loss offunction of the ciliary parasympathetic nerves. Ptosis is common becausethe oculomotor nerve innervates the levator palpebrae. Homan sign (a) refersto leg pain with dorsiflexion of the foot sometimes seen in patients with deepvenous thrombosis. This sign has poor sensitivity and specificity. Bell palsy(b) involves unilateral facial paralysis as a result of peripheral involvement ofthe facial nerve. In patients with a central facial nerve lesion the forehead is
Weakness and Dizziness Answers 395spared. Kehr sign (d) refers to left shoulder pain associated with splenicrupture. Nikolsky sign (e) is sloughing of the outer epidermal layer withrubbing of the skin seen in dermatologic diseases, such as pemphigus vulgarisand scalded skin syndrome.364. The answer is a. (Tintinalli et al, pp 1387, 1463.) This patient has aninternal carotid artery (ICA) dissection secondary to chiropractic neckmanipulation. ICA dissection can occur spontaneously or in minor necktrauma and should be considered in a young patient with acute stroke.ICA dissection should also be suspected in patients with neck pain andHorner syndrome because of the disruption of ipsilateral oculosympatheticfibers. In this scenario, it presents with ipsilateral Horner syndrome andcontralateral ischemic motor deficits. Other causes of acute Horner syndromeinclude tumors (ie, Pancoast tumor), stroke, herpes zoster infection, andtrauma.Cavernous sinus syndrome (b) presents with headache, ipsilateral eyefindings, and sensory loss in the distribution of cranial nerve V—-ophthalmicbranch. Eye findings include proptosis, chemosis, Horner syndrome, andophthalmoplegia caused by the involvement of cranial nerve III, IV, and VI. Itdoes not cause decreased strength in the extremities. MS © is an inflamma-tory demyelinating CNS disease resulting in various neurologic abnormalities,such as optic neuritis, transverse myelitis, and paresthesias. Transverse myelitis(d) is a postviral or toxic inflammation of the spinal cord that results in sensoryloss and paresis. An isolated spinous process fracture (e) typically occurs in thesetting of trauma and is considered a stable vertebral fracture. It does not resultin motor weakness.365. The answer is c. (McIntyre, 2006.) This patient presents withvertebrobasilar insufficiency (vertigo) and claudication (atypical arm painwith exercise), symptoms consistent with subclavian steal syndrome. Thisphenomenon occurs in patients with subclavian artery occlusion or steno-sis proximal to the vertebral artery branch, which causes retrograde bloodflow in the vertebral artery with ipsilateral arm exercise. Collateral arteriesarising from the subclavian artery distal to the obstruction deliver blood tothe arm. During arm exercise these vessels dilate and siphon blood from thehead, neck, and shoulder to increase perfusion of ischemic arm muscles.This results in temporary reversal of blood flow in the vertebral artery leadingto vertebrobasilar insufficiency and symptoms of vertigo, dizziness, syn-cope, dysarthria, and diplopia. Arm pain is a result of muscle ischemia.
Superior vena cava syndrome (a) is caused by an obstruction of thesuperior vena cava typically caused by the compression of a tumor. Themost common complaints include edema and venous distention of the faceand upper extremities. Facial plethora and telangiectasias are also commonlynoted. Aortic dissection (b) can cause a difference in BP in the extremities.In general, patients complain of tearing chest pain that radiates into theirback. If suspicion is high for aortic dissection, a CT scan with contrast orechocardiography should be performed to rule out the diagnosis. Anginapectoris (d) refers to myocardial ischemia caused by insufficient coronaryblood flow to meet myocardial oxygen demand. It typically presents withsymptoms of chest discomfort relieved with rest or nitroglycerin. Patientsmight complain of arm pain or radiation of pain to the arms, but the presen-tation does not involve neurologic deficits. Vestibular neuronitis (e) refersto acute self-limiting dysfunction of the peripheral vestibular system thatcauses vertigo.366. The answer is c. (Tintinalli et al, p 1418.) This patient presents withsymmetric proximal muscle weakness and characteristic heliotrope rashof dermatomyositis. It is an idiopathic inflammatory myopathy with asso-ciated dermatitis. The characteristic of the disease is progressive symmetricproximal muscle weakness with possible dysphagia, symmetric heliotrope rashin the periorbital region or neck, elevated creatinine kinase, and abnormal elec-tromyogram and muscle biopsy. There is also an associated risk of malignancy.Myasthenia gravis (a) is an autoimmune disorder of the neuromuscularjunction in which antiacetylcholine receptor antibodies compete withacetylcholine at the nicotinic postsynaptic receptors. The disease causescharacteristic progressive reduction in muscle strength with repeated muscleuse. Bulbar muscles are most commonly involved, and patients reportworsening of symptoms at night and improvement with rest or in themorning. MS (b) is an inflammatory demyelinating CNS disease resultingin various neurologic abnormalities, such as optic neuritis, transverse myelitis,and paresthesias. Rhabdomyolysis (d) refers to muscle fiber breakdownbecause of a variety of etiologies, such as trauma, burns, ischemia, seizures,excessive muscular activities, sepsis, and myopathies. Its complicationsinclude hyperkalemia, metabolic acidosis, and acute renal failure. Disseminatedgonococcal infection (e) is a systemic disease secondary to the presence ofNeisseria gonorrhoeae in the bloodstream. In the early bacteremic phasepatients present with fevers, migratory polyarthritis, and rash; this evolves
Weakness and Dizziness Answers 397from disseminated erythematous macules into hemorrhagic pustular lesions.Serious complications may include meningitis, osteomyelitis, and endocarditis.367. The answer is b. (Tintinalli et al, p 970.) This patient has Lyme disease,the most common vector-borne zoonotic infection in the United States.The spirochete, Borrelia burgdorferi, is transmitted to humans by the deertick Ixodes, and although the risk of infection after a bite is about 3% inhighly endemic areas (Northeast and Midwest); it increases to 25% if the tickis attached for longer than 72 hours. This patient presents in the second stage ofLyme disease. The first stage involves the development of erythema migrans,a spreading annular erythematous lesion with central clearing occurringcommonly at the tick bite site 2 to 20 days after the bite. The second stagetypically occurs within 6 months of the initial infection and is characterizedby fever, fatigue, arthralgias, neuropathies (ie, Bell palsy), cardiac abnormalities(ie, myocarditis presenting with conduction delay), and multiple annularlesions. Tertiary stage of Lyme disease occurs year after the infection andconsists of chronic arthritis, subacute encephalopathy, and polyneuropathy.Primary and secondary stages of the disease are treated with doxycycline.Tertiary stage is treated with IV ceftriaxone or penicillin.Some sources refer to any facial nerve palsy as Bell palsy (a), whereasmost consider Bell palsy an idiopathic facial nerve paralysis. An easy way tolook at it is that facial nerve paralysis may have an identifiable cause or maybe idiopathic, in which case it is referred to as Bell palsy. In either case,exclude Lyme disease in patients with facial nerve palsy by sending Lyme titerlevels. Ramsay Hunt syndrome © is a facial nerve palsy secondary to varicella-zoster virus (VZV). VZV causes chicken pox and may remain dormant innerve ganglia for years. In addition to cranial nerve VII paralysis, the syndromeis characterized by severe ear pain, vertigo, hearing loss, and classic shinglesin the ear. A brain tumor (d) may cause facial nerve compression centrallyand may present with partial facial paralysis with forehead sparing. Theforehead is bilaterally innervated, and the intact contralateral branch providesmotor function. RMSF (e) is a tick-borne Rickettsia rickettsii infection. Thedisease involves constitutional symptoms of high fever, myalgias, severeheadache, and a characteristic blanching erythematous macular rash whichspreads from distal extremities to the trunk.368. The answer is d. (Rosen, pp 1714-1723.) This patient is tachypneic,probably as a result of some underlying anxiety, which has resulted in
paresthesias, carpal spasm, and tetany. This occurs as a result of an alkalemicenvironment that decreases ionized calcium levels. The treatment is reas-surance, a rebreathing mask allowing for carbon dioxide retention and possi-bly sedation. The patient’s metabolic profile is consistent with a respiratoryalkalosis (elevated pH, low carbon dioxide). The blood gas indicates a purealkalosis therefore an acidosis is not seen (a and c). The bicarbonate levelis normal and therefore it is not caused by a metabolic disturbance (b).Patients with hyperthyroidism (e) may be tachycardic, hyperthermic withan elevated BP. Upon physical examination, these patients may also appearto be underweight, have bulging eyes (exophthalmos) and complain of pal-pitations, diarrhea, tremors, and generalized anxiety. Hyperthyroidism isnot a direct cause of tetany.
PediatricsQuestions369. A 6-month-old girl is brought to the ED because of persistent cryingfor the past 6 hours. Her teenage father informs you that she has beeninconsolable since awaking from her nap. No recent illness, trauma, fever,or other complaints are reported. On physical examination the patient isalert, awake, and crying. You note swelling, deformity, and tenderness ofthe left femur. When inquired about this finding, the caretaker responds,“Her leg got stuck between the rails of her crib.” Radiographs show a mini-mally displaced spiral fracture of the left femur. Which of the following isthe next best step in management?a. Genetic workup for osteogenesis imperfecta and other bone abnormalitiesb. Orthopedic consultation for closed reductionc. Serum electrolytes including calcium and phosphated. Perform skeletal survey and contact Child Protective Servicese. Placement of posterior splint and discharge home with orthopedic follow-up399
- 4-year-old boy is brought to the ED by a concerned mother after shenoticed lesions under his nose and around his mouth as seen in the imagebelow. The patient is otherwise well with no change in behavior, fever, orvomiting reported. On physical examination, you note a well nourished,well developed male in no acute distress with multiple small round, honey-colored lesions with slightly erythematous centers. What is the predomi-nant organism involved?400
a. Group B streptococcusb. Staphylococcus aureusc. Streptococcus pyogenesd. Streptococcus pneumoniaee. Salmonella spp.(Reproduced, with permission, from Wolff K, Goldsmith LA, Katz SI et al. Fitzpatrick’s Dermatol-ogy in General Medicine. 7th ed. New York, NY: McGraw-Hill; 2008: Figure 177-1.)
Pediatrics 401371. A 3-year-old African American boy with a history of sickle-cell dis-ease presents to the ED after he developed a low-grade fever, runny nose,and an erythematous discoloration of both cheeks. His vital signs are heartrate (HR) 110 beats per minute, respiratory rate (RR) of 24 breaths perminute, and pulse oximetry of 98% on room air. The patient looks well andis in no acute distress. You note a macular lesion in both cheeks. The rashis not pruritic and there is no associated cellulitis or suppuration. What isthe most serious complication to consider in this patient?a. Osteomyelitisb. Viral encephalitisc. Pneumoniad. Aplastic anemiae. Meningitis372. A 9-month-old boy is brought to the ED with a 2-day history of fever,vomiting, and fussiness. The patient has had multiple episodes of emesisthat follow intense periods of fussiness after which the patient seems to relaxand go to sleep. He has had no fever or diarrhea. In between these episodes,he has slightly decreased energy but otherwise seems well. Oral intake isdecreased and urine output has been decreased since the day of presenta-tion. Which of the following statements is true regarding this condition?a. The majority present with vomiting, colicky abdominal pain, and currant jellystools.b. Air enema is the therapeutic intervention of choice.c. Plain films of the abdomen can usually confirm the diagnosis.d. Surgical intervention is often indicated.e. Most of these have a “lead point” as the underlying pathologic cause.373. A 7-year-old girl with sickle-cell disease and a previous history ofadmissions for acute painful crises presents with a 1-day history of feverand cough. She is tachypneic on presentation with a temperature of 102°F.Auscultation of the chest reveals rales on the right. A chest radiograph con-firms the diagnosis of pneumonia. After initial treatment with antibioticsand intravenous (IV) fluids, patients with this condition are most at risk fordeveloping what complication?a. Acute chest syndromeb. Sepsis as a result of the relative immunodeficiency of patients with sickle-celldiseasec. Empyemad. Strokee. Congestive heart failure because of the anemia coupled with infection
- A 2-year-old boy is brought to the ED by his parents stating that he islimping. The mother states that he was fine yesterday but woke up todayand would not bear weight. He had a normal active day yesterday with nonotable falls. On examination, the patient is in mild distress. His vital signsare a temperature of 101°F, HR 120 beats per minute, RR 24 breaths perminute, blood pressure (BP) 90/55 mm Hg. He has mild nasal congestion.He is able to move his left lower extremity only a small amount and has dis-comfort with range of motion of his left hip. He is unable to bear weight.There is no swelling, rash, warmth, or erythema. White blood cell (WBC),C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) are allnormal. Radiograph of the hips bilaterally and left femur and knee are allnegative. After high dose ibuprofen in the ED, the patient is able to bearweight. What is the most appropriate management of this patient?a. Admit for IV antibiotics.b. Consult orthopedics after ultrasound for aspiration of hip in the operatingroom (OR).c. Bone scan to evaluate for osteomyelitis.d. Nonsteroidal anti-inflammatory drugs (NSAIDs) and reassurance to parentswith follow-up in 24 hours.e. Splint leg for treatment of occult fracture through growth plate than can not bevisualized on initial x-rays.402