Case 2: Poor development in an Infant

A 7 month old infant has been brought to the attention of the doctor because of concerns of developmental delay. He was born prematurely at 34 weeks and was delivered by normal vaginal delivery. Apgar score performed at 1 and 5 minutes were 7 and 9 respectively. He was subsequently admitted to the Special Care Baby Unit for supportive care. His mother noted that he is not achieving the normal developmental milestones at 6months.

His charts showed his growth and height were approx 75th percentile and head circumference 50th percentile. On examination, the infant was irritable and was able to visually fixate on objects. Head control was poor and Moro's reflexes are present. Tendon reflexes were brisk and plantar responses were upgoing. Muscle tone was noted to be increased and spasticity in the lower limbs are apparent.


What are the likely diagnoses?




In considering infants with global developmental delay, it is important to classify the disorder into two main groups: static encephalopathy and progressive encephalopathy. It is important to note whether there is a trend of poor development - in a patient who is deteriorating rapidly then more investigations are likely to be needed. There is a wide variety of presenting symptoms including feeding problems, falling behind developmental milestones, muscle or sensory problems, speech and swallowing difficulties.

One of the best known reasons of static encephalopathy is cerebral palsy, which is caused by early damage to the brain at or around the time of birth. Causes can be variable and include hypoxic injuries, vascular strokes and certain infections such as Toxoplasma or Herpes simplex. MRI can be performed to assess the severity of this disease. Clinically, the infant may display a certain degree of spasticity and may exhibit speech and language disorders. There are some types of cerebral palsy where spasticity does not feature, eg ataxic or athetoid types.

Progressive encephalopathy is suspected when there is a persistent decline in development, vision, hearing or irritability in an infant. Sometimes, there is concomitant seizures and movement disorders, which can be confused with cerebral palsy. Causes of this can include rare metabolic or degenerative diseases, such as Friedriech's ataxia, ataxia telangiectasia or inherited leukodystrophies. Clinical correlation depends on the region of brain affected- damage to the gray matter can lead to cognitive defects and seizures; white matter lesions lead to spasticity and motor problems.

Several types of leukodystrophies exist in infants, and these are due to defects in the myelin production that ensure good conduction in the nerves. Examples include Tay Sachs disease, Alexander disease and metachromatic leukodystrophy. Although rare, it is important to recognize these as potential causes of developmental problems. In a lot of cases, child abuse or neglect is suspected and social services are often involved.

In conclusion, cerebral palsy is one of the commonest causes of poor development and static encephalopathy. It must be separated from progressive encephalopathy where the damage to the brain is onging. Prognosis is poor and often there are no available cures for these rare disorders.