Organic neuropsychiatry: a treatable cause of suicidal behaviour

The case

A previously well 29-year-old man, on holiday in Portugal, developed myalgias, drenching night sweats, overwhelming fatigue and an umbilical rash. Two weeks later, he developed worsening anxiety, agitation and obsessive behaviours, progressing over 3 weeks, together with memory difficulty, hyperphagia, paraesthesiae in limb extremities and de novo vivid nightmares. On examination, there were generalised fine jerky movements in all limbs, consistent with myoclonus. He had bilateral papilloedema. Mini-mental state examination score was 25/30, with points dropped on short-term recall and serial sevens. Additional testing (three stage Luria) demonstrated frontal dysexecutive impairment.

Question 1

How would you summarise the salient features of the case and formulate a balanced differential diagnosis?

Comment

The case can be summarised as a subacute history of progressive cognitive deterioration culminating in a suicide attempt in a high-functioning young man, with prominent psychiatric features including agitation and obsessions, and a florid paranoid delusional system (on the background of possible obsessional-compulsive disorder as a child), amnesia, myoclonus and papilloedema. There was no history of substance abuse and no seizures.

The differential diagnosis is wide and includes infective and postinfective aetiologies, inflammatory and metabolic conditions (summarised in the table 1 ).

Table 1

Variant CJD	HIV	TB/other chronic meningitis	Lupus	NMDAR-antibody encephalitis	VGKC complex/LGI1-antibody encephalitis	Wilson's
4-week history	x	[checkmark]	[checkmark]	[checkmark]	[checkmark]	[checkmark]	[checkmark]
Rash	x	[checkmark]	[checkmark]	[checkmark]	x	x	x
Myoclonus	[checkmark]	[checkmark]	x	[checkmark]	[checkmark]	[checkmark]	[checkmark]
Prodromal infection	x	[checkmark]	x	[checkmark]	[checkmark]	[checkmark]	x
Psychiatric features	[checkmark]	[checkmark]	[checkmark]	[checkmark]	[checkmark]	[checkmark]	[checkmark]
Papilloedema	x	[checkmark]	[checkmark]	[checkmark]	x	x	x
Suggestive features absent in this case	Painful dysaesthesia, cerebellar features	Risk factors	Headache, persistent fever	Arthralgia or characteristic rash	Autonomic dysfunction, dyskinesia, seizures, reduced consciousness	Faciobrachial dystonic seizures	Kayser-Fleischer rings

x , absent; [checkmark], present; CJD, Creutzfeldt-Jakob disease; LGI1, leucine-rich glioma inactivated-1; NMDAR, N-methyl D-aspartate receptor; TB, tuberculosis; VGKC, voltage-gated potassium channel.

Variant Creutzfeldt-Jakob disease (vCJD) could, in this age group, present with these psychiatric features, with new onset of sleep disturbance and myoclonus. However, vCJD sensory symptoms are often painful; the suicide attempt and short illness duration would be unusual. 1 To our knowledge, there are no reports of papilloedema in vCJD.

Papilloedema, night sweats and fatigue could suggest an infiltrative systemic process,...