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Difficulty: MediumFormulating a Differential Diagnosis

Match each patient's clinical presentation with the most likely underlying neurologic diagnosis.

  • A 55-year-old man presents with progressive weakness in his right hand. Examination reveals muscle atrophy in the right intrinsic hand muscles, fasciculations in the tongue, and brisk reflexes in both lower extremities. Sensory examination is completely normal.Amyotrophic lateral sclerosis
  • A 35-year-old woman presents with leg weakness that has been worsening over three days. Examination shows symmetric lower extremity weakness and absent patellar and Achilles reflexes. She reports having a severe diarrheal illness two weeks ago.Guillain-Barré syndrome
  • A 28-year-old man presents with the inability to move his legs and urinary retention developing rapidly over 24 hours. Examination reveals flaccid paraplegia and a distinct loss of pinprick sensation below the level of the umbilicus.Transverse myelitis
  • A 72-year-old woman with a history of autoimmune gastritis presents with progressive unsteadiness. Examination shows symmetric upper motor neuron signs in the legs and markedly diminished position and vibratory sensation in the toes.Subacute combined degeneration

Answer

Patient 1 matches Amyotrophic lateral sclerosis; Patient 2 matches Guillain-Barré syndrome; Patient 3 matches Transverse myelitis; Patient 4 matches Subacute combined degeneration.
Each clinical vignette isolates a classic neurological presentation by manipulating key physical exam findings—specifically reflex tone, sensory involvement, and temporal history. The correct matching aligns the precise neuroanatomical deficits with the pathophysiology of the specific disease process.

Step-by-Step Solution

1
Analyze the first patient's symptom profile.
The patient has both upper motor neuron (brisk reflexes) and lower motor neuron (atrophy, fasciculations) signs with a normal sensory exam.
Identifying pure motor involvement with mixed upper and lower motor neuron signs narrows the differential directly to amyotrophic lateral sclerosis.
2
Analyze the second patient's symptom profile.
The patient has ascending symmetric weakness, areflexia, and a recent history of a gastrointestinal illness.
Recognizing the post-infectious (often Campylobacter jejuni) timeline combined with purely peripheral demyelination (areflexia) establishes a diagnosis of Guillain-Barré syndrome.
3
Analyze the third patient's symptom profile.
The patient has rapidly progressive paraplegia, autonomic dysfunction, and a clear sensory level at the umbilicus.
A distinct sensory level combined with sudden motor and autonomic deficits requires localization to the spinal cord, making transverse myelitis the most likely differential among the choices.
4
Analyze the fourth patient's symptom profile.
The patient has combined posterior column (vibration/proprioception) and lateral corticospinal tract (upper motor neuron) dysfunction, alongside a history of autoimmune gastritis.
Correlating the patient's risk for Vitamin B12 deficiency (due to pernicious anemia) with the classic neurological presentation solidifies the diagnosis of subacute combined degeneration.

Key Concept

Formulating a differential diagnosis for acute and subacute neurological weakness requires precise anatomical localization utilizing sensory levels, reflex status, and temporal disease progression.
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Formulating a Differential Diagnosis

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