A man from Chhattisgarh presented with progressive muscle weakness and leg spasms. Pure motor paresis was seen on examination. What is the most appropriate history to be elicited in this patient?

Correct Answer: B. History of diet

The clinical presentation of progressive muscle weakness, leg spasms, and pure motor paresis in a patient from Chhattisgarh (a region with high prevalence of nutritional deficiencies) points strongly to lathyrism or nutritional neuropathy. Lathyrism is caused by consumption of Lathyrus sativus (khesari dal), which contains β-N-oxalyl-L-α,β-diaminopropionic acid (ODAP), a neurotoxin that causes irreversible motor neuron damage. This condition is endemic in parts of central India, particularly during famine or food scarcity when inferior pulses are consumed. The pure motor paresis (sparing sensory function) and spasticity are pathognomonic. Nutritional deficiencies (B12, folate, thiamine) also present similarly with motor-predominant neuropathy. Detailed dietary history—specifically asking about consumption of khesari dal, other inferior pulses, or prolonged malnutrition—is the single most discriminating and appropriate history to elicit. This directly identifies the causative agent and confirms the diagnosis, guiding management (cessation of exposure, supportive care, and rehabilitation). The geographic location and clinical phenotype make dietary history the cornerstone of diagnosis in this case.

Why the other options are wrong

A. History of vaccination — While vaccination history is relevant for polio (which also causes motor paresis), the clinical picture here—progressive weakness with spasticity and leg spasms in a Chhattisgarh resident—is far more consistent with lathyrism or nutritional neuropathy than vaccine-preventable polio. Polio typically presents with acute flaccid paralysis, not progressive spasticity. This is an NBE distractor leveraging the motor paresis feature. C. History of similar illness in the past — This would be relevant for recurrent or familial conditions (e.g., hereditary spastic paraplegia), but lathyrism and nutritional neuropathy are acquired, exposure-based disorders. A past history of identical illness would not help differentiate the cause or guide management. This option misses the acute/subacute nutritional or toxin exposure context. D. History of fever — Fever history would be pertinent for infectious causes (e.g., poliomyelitis, transverse myelitis, or Guillain-Barré syndrome), but lathyrism and nutritional deficiencies are non-inflammatory, non-infectious conditions. The absence of fever in the stem and the pure motor phenotype argue against infection. This is a common NBE trap pairing motor weakness with infection.

High-Yield Facts

Mnemonics

LATHYR for Lathyrism Features Lower limb spasticity | Acute/progressive onset | Toxin (ODAP) from khesari dal | History of diet crucial | Yield to cessation of exposure | Reversible only if caught early Motor Paresis + Spasticity = Dietary History When you see pure motor paresis with spasticity in an Indian patient from endemic region (central India), think lathyrism first, ask about khesari dal and inferior pulses immediately. This memory hook saves time in exams.

NBE Trap

NBE pairs motor paresis with vaccination (polio) and fever (infection) to distract from the nutritional/toxin exposure angle. The geographic clue (Chhattisgarh) and pure motor phenotype are the keys to recognizing this as a lathyrism/nutritional case, not an infectious one.

Clinical Pearl

In rural Chhattisgarh and central India, during drought or food scarcity, families resort to consuming khesari dal (Lathyrus sativus) as a cheap protein source. A single focused dietary history question—"Have you or your family eaten khesari dal or inferior pulses recently?"—can clinch the diagnosis and prevent further exposure, halting disease progression. This is why dietary history is the most appropriate and actionable history in this case.

_Reference: Park's Textbook of Preventive and Social Medicine (Nutritional Disorders & Lathyrism section); Harrison's Principles of Internal Medicine Ch. 379 (Nutritional Neuropathies)_