Differential Diagnoses

Question 1

Give 3 differentials for a patient with limb weakness.

Answer 1

• Motor neurone disease – progressive onset, often asymmetrical.
• Multiple sclerosis – often subacute onset.
• Stroke – acute, and may still be present following acute event.
• Peripheral neuropathy – distal weakness, often accompanied by sensory loss, seen in diabetic patients or those deficient in B12 or folate.

Question 2

Give 3 differentials for a patient with difficulty initiating or coordinating weakness.

Answer 2

• Motor neurone disease – amyotrophic lateral sclerosis. Associated sx. Inc. progressive limb weakness and difficulty with fine motor tasks.
• Parkinson’s disease.
• Apraxia – inability to perform purposeful movements despite intact strength and coordination. May be acquired following stroke or traumatic brain injury, or may be developmental.

Question 3

Give 3 differentials for a patient with upper motor neurone signs (e.g., hypertonia, hyperreflexia, clonus).

Answer 3

• Motor neurone disease – if pure UMN signs, primary lateral sclerosis subtype is most likely. Accompanying sensory loss is unlikely, and sphincter and ocular muscle dysfunction is reserved for advanced disease.
• Multiple sclerosis – accompanied by altered sensation, subacute limb weakness, and cerebellar symptoms.
• Hyperthyroidism.

Question 4

Give 3 differentials for a patient with features of parkinsonism.

Answer 4

• Parkinson’s disease.
• Multiple system atrophy (MSA) – autonomic features are often more predominant in early disease than PD. Associated sx. Inc. unsteadiness and falls.
• Drug-induced parkinsonism – bilateral symptoms often caused by medications with block dopamine or increase its breakdown (e.g., 1st gen antipsychotics, anti-emetics).
• Progressive supranuclear palsy (PSP) – unsteadiness, dysphagia, and gaze palsies are more predominant.

Question 5

Give 3 differentials for a tremor.

Answer 5

• Parkinson’s disease (resting tremor) or essential tremor (active tremor).
• Drug-induced parkinsonism.
• Hyperthyroidism.

Question 6

Give 3 differentials for seizures.

Answer 6

• Epilepsy – seizure period may have tongue biting, incontinence, or automatisms, and is followed by a post-ictal period.
• Functional seizures/functional neurological disorders – typically longer duration of seizure, quicker recover, and retained awareness with bilateral arm movements, back arching, and eye opening during events.
• Vasovagal episodes – LOC often preceded by sensation of dizziness, jerking movements less common but if seen are very brief, quick recovery.