Childhood Disintegrative Disorder as a Complication of Chicken Pox.

Childhood disintegrative disorder (CDD) is characterized by late onset (>3 years of age) of developmental delays in language, social function and motor skills. Commonly there is no antecedent physical disorder leading to childhood disintegrative disorder. The present case report describes a child who developed childhood disintegrative disorder at the age of 6 years after an episode of chicken pox.

INTRODUCTION

CDD, also known as Heller's syndrome or disintegrative psychosis, is a rare condition (1.7 cases per 100,000)[1] characterised by late onset (>3 years of age) of developmental delays in language, social function and motor skills. It is grouped with the pervasive developmental disorders (PDDs) and is related to the better known and more common disorder of autism. Although recognised for many years, research on this condition is less advanced than that in autism. Commonly there is no antecedent physical disorder leading to CDD. The present case report describes a child who developed CDD at the age of 6 years after an episode of chicken pox.

CASE REPORT

Master D, 8 years and 1 month old child, was admitted with chief complaints of hyperactivity, increased talkativeness and no social reciprocity since last 2 years. It was first continuous episode of illness precipitating after an episode of chicken pox. History of present illness revealed an episode of fever with rash, diagnosed to be chicken pox for a period of 15 days about 2 years ago. After 15 days of asymptomatic period, the patient developed fearfulness, decreased social interaction and decreased speech production for next 2 months. After this, gradually patient developed new symptoms — continuous irrelevant speech, verbal stereotypy, markedly increased motor activity, no social and emotional reciprocity, no eye to eye contact, decreased performance in activities of self help. Sleep of patient was normal. The above mentioned symptoms developed within a period of 1 month and were stable after that. Antenatal, natal, postnatal and period of infancy revealed no abnormality. Developmental history revealed normal development of child till the onset of chicken pox. He was average in studies. He had normal interaction with his family member and peer group. He had no history of any physical or psychiatric illness in the past. There was no family history of any neuropsychiatric illness. On physical examination, no abnormality, including any neurological sign was detected. MRI of brain showed no abnormality. Electroencephalogram (EEG) showed occasional bursts of spike and sharp wave discharges, though clinically there was no evidence of seizure disorder.

In the ward, child would remain hyperactive most of the time and would run here and there without any purpose. He had to be restrained in the lap of parents to be controlled. He would not show any interest in the surrounding and people around. He would not show any regard to presence or absence of his parents. When someone would try to talk to him, he would not make eye to eye contact and would continuously utter irrelevant things. He would repeat some phrase multiple times without any meaning.

To confirm the diagnosis, Autism Diagnostic Interview — Revised (ADI-R)[2] was applied and a diagnosis of CDD was made on the basis of following items — onset of symptoms after the age of 3 years, normal development of language before illness, loss of language and loss of purposive hand movement, loss of motor skills and loss of self help skills.

Vineland Adaptive Behaviour Scales (VABS), 2nd edition (Vineland II)[3] was applied to actuate the age of the skills before and after the illness and it also showed significant loss of skills in each sub-domains of communication, daily living and social skills.

DISCUSSION

In our patient CDD developed after an episode of chicken pox. Various viral infections have been known as the first event leading to the development of CDD. To the author's knowledge CDD has not been mentioned as a complication of chicken pox in literature. This case represents a rare and interesting complication of chicken pox in a boy of age 6 years with normal development, developing CDD within short span of time.

The typical age of onset of CDD is 3-4 years. Though case reports have mentioned age of onset between 1 and 9 years.[4] In our patient, age of onset was 6 years. Such late age of onset has been reported in few cases.[5]

In childhood disintegrative disorder, there significant loss of previously acquired skills in at least two of the following areas — expressive or receptive language, social skills, bowel or bladder control, play behaviour or motor skills. In our patient also, there was marked loss of most of the above mentioned skills. The core features of CDD are loss of communication skills, marked regression of reciprocal interactions and the onset of stereotyped movements and compulsive behavior. In our patient, these features were present.

In most cases the intellectual deficit becomes static or shows some amount of recovery. In our patient this was seen. The patient showed significant regression of milestones within short span of time and non-progressive course after that.

The present case report aims to alert the clinicians about the possibility of developing CDD, when seeing a case of chicken pox, especially when there is presence of regression of developmental milestones.