SDH and cranial pressure

 Q: Which of the following is more likely to cause subdural hematoma (SDH)? (select one)

A) Intracranial hypotension 

B) Intracranial hypertension

Answer: A

Although trauma is one of the most common etiology of SDH, intracranial hypotension i.e., low cerebrospinal fluid (CSF) pressure is the second most common reason. It can occur after lumbar puncture, ventriculostomy, lumboperitoneal shunt, or any neurosurgical procedure. 

Decrease CSF pressure reduces brain buoyancy and increases the traction on bridging veins. Moreover, decrease CSF pressure causes engorgement of cerebral veins.

#neurology

References:

1. de Noronha RJ, Sharrack B, Hadjivassiliou M, Romanowski CA. Subdural haematoma: a potentially serious consequence of spontaneous intracranial hypotension. J Neurol Neurosurg Psychiatry. 2003;74(6):752-755. doi:10.1136/jnnp.74.6.752 

2. Beck J, Gralla J, Fung C, et al. Spinal cerebrospinal fluid leak as the cause of chronic subdural hematomas in nongeriatric patients. J Neurosurg 2014; 121:1380.