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Difficulty: MediumFormulating a Differential Diagnosis

Evaluate the clinical vignettes below, which describe patients presenting with peripheral neurologic deficits and systemic symptoms. Match each patient's presentation to the most likely underlying diagnosis.

  • A 42-year-old man presents with 4 weeks of right wrist drop and left foot drop. He has experienced a 4.5-kg (10-lb) weight loss, postprandial abdominal pain, and myalgias. Labs show elevated creatinine and positive hepatitis B surface antigen, but negative antineutrophil cytoplasmic antibodies (ANCA).Polyarteritis nodosa
  • A 35-year-old woman presents with progressive difficulty climbing stairs over the past 3 days, now involving her upper extremities. Examination shows generalized flaccid weakness and absent deep tendon reflexes. She had an episode of self-resolving, bloody gastroenteritis three weeks prior.Guillain-Barré syndrome
  • A 58-year-old man who frequently hikes in the northeastern United States is evaluated for bilateral facial palsy. An ECG shows first-degree atrioventricular block. He mentions a transient, erythematous annular skin lesion with central clearing on his thigh last month.Lyme disease
  • A 48-year-old woman with adult-onset asthma and recurrent nasal polyposis presents with asymmetric numbness in her right hand and left foot. Labs reveal 18% eosinophils. Chest radiograph demonstrates patchy, transient bilateral infiltrates.Eosinophilic granulomatosis with polyangiitis

Answer

The 42-year-old man with Hepatitis B matches Polyarteritis nodosa; the 35-year-old woman with ascending paralysis matches Guillain-Barré syndrome; the 58-year-old hiker matches Lyme disease; the 48-year-old woman with asthma matches Eosinophilic granulomatosis with polyangiitis.
Each presentation requires synthesizing the neurologic deficit (mononeuritis multiplex, ascending paralysis, or cranial neuropathy) with systemic findings (Hepatitis B, antecedent diarrhea, erythema migrans, or asthma/eosinophilia) to reach the most accurate diagnosis.

Step-by-Step Solution

1
Analyze the pattern of neuropathy and associated systemic symptoms for the 42-year-old man.
The patient has mononeuritis multiplex, weight loss, intestinal angina, and Hepatitis B infection, matching the classic presentation for polyarteritis nodosa.
Identifying the medium-vessel vasculitis pattern helps rule out purely neurologic or demyelinating conditions.
2
Evaluate the acute weakness progression for the 35-year-old woman.
Ascending flaccid paralysis with absent reflexes preceded by a diarrheal illness strongly suggests Guillain-Barré syndrome.
Campylobacter jejuni is a classic trigger for acute inflammatory demyelinating polyneuropathy due to molecular mimicry.
3
Assess the neurologic and cardiac findings in the 58-year-old hiker.
Bilateral facial palsy and AV block, following an erythema migrans rash, indicate early disseminated Lyme disease.
Tick-borne illnesses have specific geographic and systemic manifestations crucial for accurate diagnosis.
4
Examine the respiratory and neurologic findings in the 48-year-old woman.
Asthma, nasal polyposis, eosinophilia, and mononeuritis multiplex confirm eosinophilic granulomatosis with polyangiitis.
Differentiating small-vessel vasculitides requires recognizing unique symptom clusters like eosinophilia and atopic history.

Key Concept

Formulating a differential diagnosis for peripheral neuropathy requires synthesizing systemic clues, chronicity, and preceding exposures.
Estimated Time:2m 0s
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Formulating a Differential Diagnosis

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