Dandy-Walker variant associated with bipolar affective disorder.

The Dandy-Walker malformation is a congenital brain malformation, typically involving the fourth ventricle and the cerebellum. To date, the Dandy-Walker syndrome has not been described in association with bipolar disorder type I mania, and therefore we briefly report the case of a Dandy-Walker variant associated with acute mania. A 10-year-old boy was brought by his mother to the outpatient clinic of the Department of Psychiatry of a tertiary care hospital, with symptoms of mania. The MRI brain of the patient showed a posterior fossa cystic lesion, a giant cisterna magna communicating with the fourth ventricle and mild hypoplasia of the cerebellar vermis, with the rest of the structures being normal and no signs of hydrocephalus. These findings showed that the patient had a Dandy-Walker variant. He responded partially to valproate and olanzepine, which controlled the acute manic symptoms in the ward.

Introduction

The Dandy-Walker malformation is a congenital brain malformation, typically involving the fourth ventricle and the cerebellum. This syndrome has been described in association with schizophrenia,[1] obsessive-compulsive disorder,[1] and bipolar II disorder.[2] However, to date, the Dandy-Walker syndrome has not been described in association with bipolar disorder type I mania, and therefore we briefly report a case of a Dandy-Walker variant associated with acute mania.

Case Report

A 10-year-old boy, was brought by his mother to the outpatient clinic of the Department of Psychiatry of a tertiary care hospital, with excessive cheerfulness. He was disinhibited in speech and behavior, restless, talking fast and loudly, singing songs at times, disobeying parents and doctors, had poor sleep and appetite, and was difficult to manage at home. His mental status examination revealed psychomotor agitation and elated mood, but no delusional ideas or hallucinations. His manner was friendly but uncooperative and he had no insight. A complete physical examination revealed malformed teeth, pallor, poor nutritional status, and the neurological examination was unremarkable. Exploration of the patient's developmental history from the mother revealed an uneventful antenatal history, a full-term vaginal delivery, history of birth asphyxia, and all milestones were delayed. He had received all his immunizations appropriately. He had stopped going to school after the third grade, due to poor academic abilities.

There was no family history of any neurological or psychiatric illness.

Upon consent and request from his mother, he was admitted into the child psychiatry unit with his mother. He was reviewed by senior psychiatrists and a diagnosis of bipolar affective disorder, mania without psychotic symptoms, first episode, was confirmed along with possible mental subnormality, pending IQ assessment. After obtaining informed consent from his mother, routine blood tests was done. His blood hemoglobin levels were 8.0g/dl, liver and renal functions, electrocardiogram, an echocardiograph, and an abdominal ultrasound was normal. Interestingly, the MRI brain scan [Figure 1] of the patient showed a posterior fossa cystic lesion, a giant cisterna magna communicating with the fourth ventricle and mild hypoplasia of the cerebellar vermis, with the rest of the structures being normal and no signs of hydrocephalus. These findings showed that the patient had a Dandy-Walker variant.

Figure 1

Magnetic resonance imaging of the patient. Midsagittal view of the brain, note severe hypoplastic cerebellar vermis and dilatation of the fourth ventricle, with a posterior fossa cyst

He was prescribed valproate and olanzepine to control his acute manic symptoms. After two weeks of admission, the psychomotor agitation had reduced and he was less friendly than before. His sleep improved, but his appetite was still poor. In subsequent reviews, he was more manageable, however, the symptoms still persisted. He continues to receive the above medications now. Even though the incidence of associated malformations range between 50 and 70%, our case had only malformed teeth with overriding. His low hemoglobin levels were due to poor nutrition and he was prescribed iron supplements. A clinical diagnosis of mild mental retardation was made, but could not be confirmed by proper neuropsychological assessment, as the patient was highly uncooperative.

Discussion

Dandy-Walker malformation may occur as part of Mendelian disorders and chromosomal aberrations. Environmental factors including viral infections, alcohol, and diabetes have also been suggested to play a role in the genesis of Dandy-Walker malformation, but the evidence is uncertain. Clinically this syndrome can present with mental retardation, cerebellar ataxia, and symptoms of hydrocephalus. This patient had none of the direct complications as described above, except for mental retardation, which could also be explained by the history of birth asphyxia. Morphometric[34] and functional[5] neuroimaging studies have demonstrated a link between the cerebellum and mood symptoms in bipolar patients. All this suggests a possible direct causal relationship between the pathophysiology of bipolar disorder and the Dandy-Walker variant with cerebellar vermian hypoplasia. It can even be speculated that this syndrome could influence the poor response of the bipolar illness to treatment, as seen in this case.