Benign post-traumatic encephalopathy syndrome in young people. Critical review of the literature

Abstract

A trivial head injury can transiently render a child lethargic or even comatose. There have been several isolated reports concerning such conditions. Critical analysis disclosed that all these reports had certain factors in common: 1) they occurred in young people, 2) after head injury, 3) with several minutes to hours of lucid period; 4) neurological signs and symptoms were transient, and 5) complete recovery was usual. On closer checking, however, these syndromes could be categorized into three groups, i.e., nonconvulsive, convulsive, and brain swelling types. A typical non-convulsive type was the juvenile head trauma syndrome (Haas et al.). Injuries were usually trivial. After a short time, nausea, vomiting, lethargy, headache, cortical blindness, hemiparesis, and/or brain stem signs occurred. Not only a similarity of the manifestations with the periodic syndrome and migraine attacks but also the presence of migraine diathesis was frequently reported. Altogether 50 cases of the convulsive type were collected from the literature. Most of them were young children with minor head injury. Some became stunned, or received skull fractures. Convulsions were mostly focal motor. The third type consisted of 23 cases of diffuse brain swelling in children with a lucid period reported by Bruce et al. Vomiting, headache, disturbed consciousness from lethargy to coma, pupillary changes, apnea, and/or convulsive seizure were noted. CT scans disclosed small ventricles and effacement of the perimesencephalic cistern. All recovered without deficits except one who died from delayed brain swelling. In the first and second types of patients, no brain swelling was documented. Two patients who, after a minor head injury, convulsed and died of severe brain swelling have been separately reported. Three cases of the first type and one case of the second type recently experienced by the authors showed normal CT scans in the acute stage. All these three types might have a common underlying mechanism and they might be collectively termed as ‘benign post-traumatic encephalopathies in young people’, modified from Guthkelch. Children and young adults must have low thresholds against external force or more specifically either to increased extracellular potassium or to cerebral vasospasm. The relationship with migraine diathesis was noted only in the first type, which probably indicates a lower threshold in such predisposed youngsters.