Psychiatric Symptoms as the First or Solitary Manifestation of Somatic Illnesses: Hyperammonaemia Type II.

AIM: We describe the difficulties encountered in making a diagnosis where a somatic condition manifests itself alongside psychiatric symptoms associated with possible psychiatric comorbidities.

METHODS

A case study is presented of a 15-year-old girl who was eventually diagnosed with ornithine transcarbamylase (OTC) deficiency (hyperammonaemia type II), following an initial diagnosis of pervasive developmental disorder, selective mutism, and anorexia nervosa.

RESULTS

The OTC disease is not fully expressed in females and its prevalence is lower than in males. Around 17-20% of female patients found with a defective OTC gene on an X chromosome can suffer from OTC deficiency that may result in elevated levels of ammonia in the blood; this occurs when one of the X chromosomes become inactivated. Patients typically present with nausea, migraines, and a history of dietary protein avoidance. In more severe cases, ataxia, confusion, hallucinations, and cerebral oedema can occur. The OTC deficiency can thus remain undiagnosed in women for many years.

CONCLUSION

Somatic comorbidity in psychiatric inpatients is commonly found; however, such disorders are rarely diagnosed or even treated adequately.