History
Mr. Zaheer was a 40-year-old gentleman. He was a non-smoker and non-drinker. He was under police custody.
He does not have any known past medical history. He reported no family history of neurological diseases.
This was his second admission for headache, palpitation, and chest pain since an episode of assault with head injury 6-7 months ago. He was admitted for similar symptoms 2 months prior. His limb power was documented to be full during the previous admission.
Upon clarification of his lower limb symptoms, he reported a traumatic accident 10 years ago that resulted in right knee and femoral fractures.
He experienced intermittent electrical-shock-like pain radiating from the right mid-thigh to the right lateral knee at the site of the previous injury since 3 years ago.
His bilateral lower limb weakness began gradually 9 months ago. The weakness came on both lower limbs simultaneously. He was unable to recall any precipitating events. The progressive weakness rendered him unable to walk and made him chair-bound while under custody.
There were no upper limb, above-neck, or sphincter symptoms. He denied fever or illicit drug use.
Physical examination
Neurological examination was pertinent for marked, symmetrical bilateral lower weakness upon direct testing. He was, however, able to perform at least anti-gravity lower limb movements during goal-oriented tasks, including kicking away his blanket, performing the heel-shin test. Hoover sign was positive bilaterally.
He was able to stand and walk with minimal support during conversations, albeit with a small stepped, cautious gait.
There was no tongue or muscle wasting. Neck and upper limb power was normal, as was the tone and reflexes.
Investigations
Baseline blood tests were unremarkable. There were no parasaggital lesions on the plain CT brain.
Thought process
The lesion was mostly likely localized to the cord, bearing in mind the inconsistent physical signs, confounded by pain symptoms, and positive Hoover sign. The lack of upper motor neuron signs including ankle clonus also left doubts regarding a genuine myelopathy.
The absence of parasaggital lesions would speak against a cerebral localization. The normal reflexes were counter to that expected in neuropathies (chronic inflammatory demyelinating polyneuropathy) and neuromuscular junction disorders (Lambert-Eaton myasthenic syndrome, in which the degree of weakness is often less than the functional difficulty would lead one to expect, rather than vice versa in Mr. Zaheer’s case). The prominent pain symptoms were also in opposition with an anterior horn cell, neuromuscular junction or muscle pathology.
The inconsistent myelopathy syndrome should raise the suspicion of a functional disorder.
Next steps
An MRI of the spine was arranged to objectively exclude the possibility of a myelopathy. The goal was to end diagnostic odyssey if a functional disorder remains the top differential diagnosis.