Persistent cognitive and motor deficits following acute hydrogen sulphide poisoning

This case study describes the long-term after-effects of hydrogen sulphide exposure in a previously health 27-year-old male. Upon hospital admission the patient had a Glasgow Coma Score (CGS) of 3; with emergency treatment including hyperbaric oxygen treatments, he progressed to a GCS of 15 on day 7. Although both CT and MRI scans were unremarkable, PET using F-18 deoxyglucose administered 3 years after the accident showed abnormally decreased metabolism bilaterally in the temporal and inferior parietal lobes as well as the left thalamus. Uptake in the striatum was heterogeneous and abnormal. A cerebral perfusion study using SPECT performed 3.5 years after the accident revealed bilaterally decreased flow in the putamen but no cortical abnormalities. Neuropsychological and neurofunctional testing revealed the following impairments: microsmia, psychomotor slowing, extrapyramidal signs and deficits in memory and executive/planning functioning. These findings are discussed in the context of hydrogen sulphide's known mechanisms of toxicity and the functions of the basal ganglia.