History: A 4-year-old boy was found in a pool. He had been there for an unknown period of time. He had a Glasgow Coma Scale (GCS) score of 5 upon arrival at the hospital.
Noncontrast CT shows diffuse effacement of the sulci with “slit-like” ventricles and loss of gray-white differentiation. The presence of a “white cerebellum sign” and of early tonsillar herniation also is seen.
- Hypoxic-ischemic injury
- Toxic-metabolic disorder
- Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)
Diagnosis: Hypoxic-ischemic injury due to near drowning
In children, near drowning is a relatively common cause of hypoxic-ischemic injury. Othercauses include cardiac arrest, cerebrovascular disease, and asphyxiation.
No matter what the cause, findings include symmetric effacement of the ventricles and other CSF-containing spaces, as well as a loss of gray-white differentiation. The basal ganglia also may show decreased attenuation on CT. If MRI is performed (often not necessary), DWI is the most sensitive sequence.
When hypoxic-ischemic injury is suspected, the finding of a hyperattenuating cerebellum compared with hypoattenuating cerebral hemispheres portends a poor prognosis. In general, the diagnostic checklist should include involvement of deep gray nuclei and also excluding the presence of herniation.