HYDRANENCEPHALY

ALTERNATE NAMES

Hydroanencephaly

DESCRIPTION

Hydranencephaly is a rare brain malformation in which the brain’s cerebral hemispheres do not develop, and are replaced by sacs filled with cerebrospinal fluid. Hydranencephaly is considered an extreme form of porencephaly (a disorder characterized by a cyst or cavity in the cerebral hemispheres), and may be caused by intrauterine strokes or infections, or maternal trauma. Infants with hydrancephaly appear normal at birth, but within a few weeks, they show irritability, abnormal breathing patterns, and increased muscle tone. Other features developing over time may include seizures, abnormal head growth, deafness, blindness, spastic quadriparesis (paralysis), and cognitive deficits. Shunting may be needed to divert build-up of cerebrospinal fluid. (Hydranencephaly should not be confused with hydrocephalus, which is an increased accumulation of cerebrospinal fluid within the ventricles.)

DIAGNOSTIC TESTING, PHYSICAL FINDINGS, AND ICD-9-CM CODING

Diagnostic testing: The diagnosis is established by imaging such as MRI, CT, after ruling out conditions that are amenable to treatment. Preliminary diagnosis can be made in utero by ultrasound, but must be confirmed after birth.

ICD-9: 742.3

ONSET AND PROGRESSION

Hydranencephaly develops after the 12^th week of pregnancy. The prognosis is generally poor, and many children die before the age of 1 year.

TREATMENT

There is no definitive treatment for hydraencephaly. Treatment is symptom-specific and supportive.

SUGGESTED PROGRAMMATIC ASSESSMENT*

Suggested MER for evaluation:

• Clinical history and examination that describes the diagnostic features of the impairment

• Cranial MRI or CT scan

• Developmental assessment

Suggested Listings for Evaluation:

DETERMINATION

LISTING

REMARKS

Meets Listing

110.08 A

Medical Equals