Following a recent boxing match with Chris Eubank Jnr, Nick Blackwell was taken to hospital and placed in an induced coma because of ‘bleeding on the brain’. Thankfully he has since awoken from his coma.
The skull is a rigid bony box which contains the brain, blood vessels and a small quantity of fluid. When injured, any organ will swell. Within the skull there is little room for the brain to expand or swell. If the brain has been injured, initial medical treatment cannot change this; it is a primary brain injury. Medical treatment aims to reduce or eliminate the effects of the brain swelling within a rigid container. The confined swelling results in increased pressure inside the skull which decreases blood perfusion; this adds to the initial injury. This is secondary brain injury.
What is ‘bleeding on the brain’? Well, medics distinguish three main types, one primarily due to disease and two related to injury. A subarachnoid haemorrhage does produce a small amount of bleeding, but is not normally due to injury.
If there is injury to the head, skull and brain, either a sub-dural or epidural (or extradural) haemorrhage may occur. These are different. An epidural haemorrhage (or extradural haematoma) is a bleed between the dura mater, the inner lining of the skull, and the bone; it is arterial, often from injury to the middle meningeal artery. Classically, this presents when a person is hit on the side of the head, looses consciousness for a very short period, appears to recover fully (the lucid interval), but is later found dead. There is usually little or no significant injury to the brain itself, rather it is the expansion of the bleeding in a closed container which causes the effects. This lucid period can be very deceptive; think of Natasha Richardson.
A subdural haemorrhage happens when there is injury to veins passing from the surface of the brain to the inside of the dura. The patient may gradually loose consciousness, but here the bleeding is a result of direct brain injury.
The initial management of either a subdural or epidural haematoma is the same; to ensure that the patient is adequately oxygenated, by giving oxygen through a face mask, preventing further injury, recognising the problem and its extent by a CT scan, and deciding whether there is sufficient bleeding for an operation to be necessary to evacuate the clot. Simultaneously, the natural process of swelling, potentially leading to secondary injury, can be counteracted by ‘shrinking’ the brain by drugs and controlled breathing (‘ventilation’); this necessitates an anaesthetic. This is a ‘medically induced coma’, part of the armamentarium of treatment.
Recovery from a significant head injury is often slow, measured in months and years rather than days and weeks. While the primary brain injury cannot be reversed, the brain has amazing ‘plasticity’. Other parts of the brain can, given encouragement and physiotherapy, take over the functions of the damaged part, often to a remarkable extent. As it is often difficult to know the extent of any patient’s eventual progress, treatment is given to all in the expectation and hope that all will recover. The recovery from what seems a significant injury can be quite remarkable.
The title is this post is from a quote by Hippocrates of Cos. And Hippocrates’ aphorism is as true today as when first formulated nearly two and a half millennia ago.