Normal pressure hydrocephalus (NPH) consists of Hakim-Adams triad: Gait disturbances, memory decline and urinary incontinence. Ventriculo-peritoneal shunt (VP shunt) is routinely recommended to treat this condition. Acute or subacute subdural hematoma (SDH) can occur in 2-17% of patients following VP shunt.
Increased susceptibility to SDH can be attributed to the shunt decreasing intracranial pressure by decreasing ventricular volume, causing the vessels bridging the subdural space to become stretched and making them vulnerable to sheering forces and bleeding upon minor trauma.
Treatment of SDH after VP shunt depends on patient’s clinical condition. In large SDH with deterioration in patient’s alertness, emergency burr hole hematoma evacuation is needed. However, in patients with minor or no symptoms, one can increase the shunt valve pressure and surgery can be avoided.
In the above case, a 76 year old person presented with classical features of NPH. VP shunt surgery was done in August 2019, which resulted in significant improvement in gait. However, a CT scan done a few days after surgery showed right sided small SDH. As he had no symptoms, no treatment was advised. After two months, he had mild headache. Repeat CT scan done showed mild increase in the size of SDH. The neurosurgeon increased the shunt valve pressure.