Pathology of post traumatic brainstem and hypothalamic injuries.
OBJECTIVE
Several autopsy studies of head injury are available but pathology of brainstem and hypothalamic injuries are addressed in very few of them. We studied brains of 47 patients who succumbed to head injury, with special attention to topographical distribution of brainstem and hypothalamic injuries.


METHODS
Brains retrieved at autopsy of 47 patients who succumbed to head injury following road traffic accidents (32 cases) or fall from height (15 cases) were examined for brainstem and hypothalamic injuries. Brainstem lesions were grouped into Type I (in absence of raised intracranial pressure and downward herniation) and Type II (secondary to raised ICP and herniation). Lesions were mapped topographically and examined histologically for axonal and myelin changes. Anatomical location of lesions was correlated with mode of injury, site of impact, occurrence of associated lesions, prognosis and survival.


RESULTS
Brain-stem injury was noted in 36 cases (76.5%) [Type I in 7 (14.9%) and Type II in 29 cases (61.7%)]; hypothalamic injuries in 20 (42.5%), and combined hypothalamic and brainstem injuries were seen in 17 (36.1%). 11 had no brainstem/hypothalamic injuries. Brainstem hemorrhages occurred in lower midbrain and upper pons, and hypothalamic injuries involved paraventricular nuclei. In cases with combined injury to brainstem and hypothalamus, lesions involved rostral ventral mesencephalon of brainstem and paraventricular region of hypothalamus. The site of impact had no definite correlation with occurrence of brainstem or hypothalamic injuries though basal fractures and road traffic accidents were more often associated with hypothalamic injuries. Survival of cases with Type I injury was shorter than Type II (14.2 vs. 65.2 hours) due to involvement of raphe/reticular nuclei. Though cases with hypothalamic injuries did not result in early death, involvement of anterior hypothalamus resulted in shorter survival (< 6 hours) compared to posterior. Diffuse axonal injury and hypothalamic involvement were more often seen with Type II brainstem injuries. Cerebral contusions were a common accompaniment of hypothalamic injuries (80%).


CONCLUSIONS
Brainstem and hypothalamic injuries are seen in significant proportion of traumatic brain injuries and may have an important role in determining the survival and prognosis. Insight into mechanisms of injury to hypothalamo-brainstem axis is essential for evolving better therapeutic strategies and prevention of post traumatic long term sequelae.
Shukla
D
D
Department of Neurosurgery, National Institute of Mental Health & Neurosciences, Bangalore, India.
Mahadevan
A
A
Sastry
K V R
KV
Shankar
S K
SK
D000058:Accidental Falls; D000063:Accidents, Traffic; D000293:Adolescent; D000328:Adult; D000368:Aged; D001344:Autopsy; D001930:Brain Injuries / Q000209:etiology / Q000473:pathology*; D001933:Brain Stem / Q000293:injuries* / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D023261:Glasgow Outcome Scale; D006801:Humans; D007031:Hypothalamus / Q000293:injuries* / Q000473:pathology*; D007223:Infant; D008297:Male; D008875:Middle Aged; D014057:Tomography, X-Ray Computed