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Encephale. 2011 Feb;37(1):54-8. doi: 10.1016/j.encep.2010.03.001. [Neuropsychiatric symptoms revealing pseudohypoparathyroidism with Fahr's syndrome]. [Article in French] Otheman Y, Khalloufi H, Benhima I, Ouanass A. Hôpital psychiatrique universitaire Ar-Razi, CHU d'Avicenne, Rabat-Salé, Maroc. yothman12@yahoo.fr

Fahr's syndrome is characterized by the presence of intracerebral, bilateral and symmetrical non-arteriosclerotic calcifications, located in the central grey nuclei. One of its main etiologies is pseudohypoparathyroidism (PHP), due to a resistance to the action of parathormone (PTH) with essentially hypocalcaemia and a normal or a high rate of PTH.

CASE REPORT:  Mr B.A. is a 36-year-old man, admitted to hospital because of refractory psychotic symptoms associated with alcohol abuse and fits of convulsion, for diagnostic and therapeutic update.

Mr B.A. had presented convulsions since the age of 10, without regular medical treatment. He showed a decrease in his school performances and started using alcohol. Since the age of 17, he began expressing delusions of persecution and of enchantment fed by the persistence of the convulsions.

He was administered phenobarbital, and classic antipsychotics (haloperidol and levomepromazine) and developed serious extrapyramidal side effects, treated with an anticholinergic (trihexyphenidyl).

Evolution was rather disadvantageous: more epileptic fits, exaggeration of tremors; abuse of alcohol and persistence of psychotic symptoms.

On admission, psychiatric examination objectified paranoid delusions of being possessed and persecuted by others.

Neurological examination revealed the presence of limb tremors, with a positive Froment's sign on the right, and dysarthria. Other than this, the patient was shorter in comparison with his siblings and exhibited bad dentition. A CT brain scan found bilateral, symmetric basal ganglia calcifications, confirmed by MRI, in favour of Fahr's syndrome. Phosphocalcic investigations revealed a low concentration of serum calcium (65 mg/l) and a hyperphosphataemia (60.1mg/l).

The blood level of parathyroid hormone was in the upper limit of normal (66 ng/l), and levels of thyroid hormones and thyroid-stimulating hormone were normal. The diagnosis of Fahr's syndrome, revealing a pseudohypoparathyroidism was posed, and the patient was orientated to endocrinology after readjustment in his therapy (sodium valproate and olanzapine).

DISCUSSION:  About 40% of the patients with Fahr's syndrome are seen with primarily cognitive and other psychiatric findings. For this patient, hypocalcaemia was at the origin of his convulsions, and the use of phenobarbital, known for its hypocalcemiant action, provoked the inverse result. Alcohol drinking also aggravated hypocalcaemia, and maintained the fits. The use of classic antipsychotics and anticholinergic agents, amplified the extrapyramidal signs caused by Fahr's syndrome. Recognizing the origin of the symptoms allowed rethinking the therapeutic strategy according to all these elements.

CONCLUSION:  Psychiatrists should consider Fahr's syndrome as a differential diagnosis in the evaluation of psychosis associated with convulsions. This case, along with others in the literature, further emphasizes the importance of the role of neuro-imaging and the search for disrupted phosphocalcic metabolism in patients with atypical or refractory psychotic symptoms.

Copyright © 2010. Published by Elsevier Masson SAS.

PMID: 21349375