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A 75-year-old man, known for his sharp intellect, suddenly displays aberrant behaviour, and forgetfulness concerning routine tasks, and eventually develops pronounced drowsiness, occasionally nodding off even during meals. Upon investigation, it was discovered that he had a collection of blood located around his brain. He undergoes surgery to evacuate the blood collected, which is situated outside the brain and experiences a complete recovery thereafter.
Since ancient times, dating back to the Neolithic age, there exists evidence of a practice known as trephination, involving the drilling of holes in the skull. Hippocrates detailed trephination as a procedure for head injuries linked with bone fractures. Moving into the modern era, Johannes Wepfer documented in 1657 CE the presence of blood-filled cysts beneath the brain’s covering. The successful neurosurgical management of chronic Subdural Hematoma (SDH) was initially documented by Hulke in 1883 and has since undergone further advancements.
Chronic SDH is a condition where blood collects between the skull and the surface of the brain, beneath a covering called dura. It usually occurs around 4 to 6 weeks after a minor head injury, which might be so slight that the patient does not even remember it. Surprisingly, though, about half of the patients who develop SDH do not have any history of head trauma at all.
In contrast to rapid-onset bleeding within the brain, such as in cases of uncontrolled hypertension, where patients deteriorate within seconds or minutes, chronic SDH develops slowly over days to weeks. This gradual onset occurs as the brain’s tolerance threshold is gradually surpassed by the increasing blood volume and subsequent rise in the pressure inside the brain.
Patients can present with symptoms of headache, vomiting, confusion, personality changes, feeling drowsy, and developing weakness of arms or legs often mimicking a stroke.
In young people, SDH is usually due to a significant head injury following a blow to the head or a car crash. Older people are at increased risk of SDH.
With advancing age, the inevitable shrinkage (atrophy) of the brain occurs. Secondly, while the skull bone acts as a rigid, unyielding structure, the brain’s gel-like physical composition initially adapts to the increasing pressure of the bleeding by deforming and accommodating it. However, this accommodation reaches a critical point when the brain’s threshold and reserves are finally overwhelmed. It is now that patients and their relatives typically notice clinical symptoms.
Some of the other risk factors for developing this condition are those who are on anti platelet drugs (Aspirin, Clopidogrel) or anticoagulant therapies (Warfarin, Newer anticoagulant drugs), cancer, or undergoing treatment for malignancies or
have underlying conditions that increase the bleeding tendency. For those patients who are on blood thinners like Warfarin or newer anticoagulant drugs apart from the immediate withdrawal of drugs, medications like Vitamin K and prothrombin Complex Concentrates (PCC) must be administered if the blood is too thin which increases additional risks to the bleeding.
Once diagnosed, this highly treatable and life-saving condition is typically addressed through an emergency surgical procedure. This procedure involves drilling a couple of holes into the skull directly over the area of the large hematoma. Careful evacuation of the bleeding is then performed, allowing the brain to decompress and symptoms to rapidly resolve. Remarkably, this surgery can even be conducted under local anaesthesia if the patient is considered unsuitable for general anaesthesia.
Fortunately, the prognosis for chronic SDH is very favourable. Following surgery, patients often experience a quick return to their pre-existing state of health.
(Dr Satish Sathyanarayana is a Bengaluru-based senior consultant and neuro & spinal surgeon while Dr Praveen Kumar Kaudlay is a consultant haemato-oncologist with a special interest in stem cell transplantation at Royal Wolverhampton NHS Trust, UK.)