Une porphyrie démentielle ou manifestations psychiatriques chroniques de la porphyrie. À propos d’un cas

Abstract

Porphyrias are rare inherited disorders due to specific enzyme abnormalities of heme biosynthesis. We can classify them as hepatic or erythropoïetic, the type depends on the organ in which the enzyme is deficient. Among the hepatic forms, three of them are clinically characterised by acute abdominal pain and neuropathy, sometimes associated with psychiatric disorders. This 58-year-old woman has been hospitalized frequently since 1995 with depression, apathy, or for suicide attempts. She has a history of alcohol addiction and since 1992 suffers from non-insulin dependant diabetes. She had been treated by benzodiazepines and neuroleptic medication for several years. Psychiatric examination revealed persecution and megalomania delirium associated with a Capgras syndrome, confusion, disorientation, depression and blunted affect. Results of neurologic examination showed reduced deep tendon reflexes, and nerve conduction revealed sensitive neuropathy. Moreover, she lay down, remained non-responsive and resisted care. The whole clinical picture evoked early dementia. Coloured urine was noticed and porphyria tested. When the diagnosis of intermittent acute porphyria was made, she gradually improved by stopping the drugs not indicated for the case, and by treating her diabetes. A few months later, while hospitalized for a similar episode, she choked on her food and died, probably caused by autonomic neuropathy. Our hypothesis was that chronic and debilitating psychopathology may be due to acute intermittent porphyria. Probably, among patients treated for psychiatric illness, some of them may suffer from this enzyme abnormality. Above all, the psychopathology associated with intermittent acute porphyria is polymorphous such as atypical psychosis, schizoaffective disorder, depression, apathetic withdrawal, and in this case report dementia. In like manner, organic manifestations are numerous and varied, leading to erroneous diagnosis. We suspect that patients with porphyria are common among mentally ill subjects. Do we have to test all our psychiatric patients for porphyria? It seems that the prevalence of intermittent acute porphyria in the psychiatric patient population is 0.21%, whereas the prevalence in the normal population is from 0.001 to 0.002%. The early detection of porphyria may diminish morbidity and mortality rates, and perhaps heal some chronic atypical psychiatric illnesses.