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Case of the month: What is the cause of this patient’s confusion?

Case of the month: What is the cause of this patient’s confusion?

In the third of our monthly series, Dr Roger Henderson is asking readers to suggest what is the cause of this patient’s confusion and change of mood. Put your answers in the comments. Answers to be revealed on 2 July!

The case

A 38-year-old man had been experiencing anxiety, anger outbursts and some hallucinations over the previous nine months, sufficient to warrant a referral for a psychiatric opinion. He had no pre-existing medical conditions, smoked both conventional tobacco and cannabis daily, was unemployed and had a past history of homelessness 15 years earlier. He admitted to working as a sex worker during this time. There was no family history of significant illness – including dementia – and he did not drink alcohol excessively. His psychiatrist commenced him on antipsychotics but these appeared to have had little effect and his symptoms progressively worsened, including a loss of appetite and deteriorating cognitive impairment. He was kept under psychiatric review.

He then presented acutely with urinary incontinence, difficulty in speaking and confusion. Examination showed him to be alert but slow in movement, thin, tattooed, unkempt, malnourished and wary of interacting with any healthcare professional. He was obviously disorientated in both time and place, occasionally verbally aggressive, and with a degree of dysarthria and some mild bradykinesia. He had a negative Romberg test. Although examination was difficult, it appeared that his light reflexes were slightly reduced. He was admitted to hospital immediately for further investigations.

A number of blood tests were performed, including a full blood count, liver function tests, blood glucose, urea and electrolytes, inflammatory markers, thyroid function tests, HIV and hepatitis screen. These were all found to be negative. A chest X-ray and ECG were normal, and he had no obvious cardiac abnormalities on examination. His cognitive impairment rapidly worsened and further investigations were arranged including a brain MRI scan, lumbar puncture and serological testing.

What is going on? Share your ideas in the comments box below on what the explanation could be and what action you would take.

Dr Roger Henderson is a GP in south-west Scotland


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Please note, only GPs are permitted to add comments to articles

Jullien Walkley 18 June, 2024 12:28 pm

Could this be Limbic Encephalitis?

Gavin Watt 18 June, 2024 12:30 pm

This chap has a rapidly progressive dementia and organic psychosis.I wonder about Jacob creutzfeldt but i cannot see a connection with being a former sex worker. It would be useful also to do syphilis serology as neurosyphilis could be a possibility. MRI and LP would be interesting. A commoner illness would be multiple sclerosis.

Samuel wilson 18 June, 2024 2:13 pm


David Mosley 18 June, 2024 4:31 pm

ChatGPT gives neurosyphilis as no1, Wernicke’s as no2, and (rather less plausibly!) HIV seroconversion as no3.

Francis Morgan 20 June, 2024 2:29 pm

As above – tertiary syphillis.

David Church 21 June, 2024 11:00 pm

I would start with urinalysis and MSU, in case of UTI, which is probably commonest, regardless of history, and Bloods often near-normal He may also have suffered an exponential deterioratoin due to malnutrition from simply self-inflicted drug-induced cannabis psychosis with low blood sugars – this probably contributes to the picture anyway even if there is more infective cause.
Other problems indicated by the historical markers (which may be red herrings) include Syphilis, Tuberculosis, HIV directly, and HIV-related parasitic infections, Leprosy, or other opportunistic infections (including Herpes simplex) affecting brain or spinal cord/CSF flow.
MS is a possibility, but I think less likely to account for all the symptoms and then the deterioration of those symptoms in this way. I have actually seen this with HSV encephalitis, although in a well-nourished patient, and much shorter overall timescale.
Brain tumour is also possible – the link with the ‘red ehrring’ historical factors being simply the associated tendency to avoid health-care professionals interactions!

Nelly Tuneva-King 23 June, 2024 10:07 pm

Tertiary syphilis or Subacute sclerosis panencephalitis