Types of Brain Bleeds
Brain bleeds are the equivalent of bleeding within the skull, known as an intracranial haemorrhage. This is a drastic, potentially fatal occurrence which can often go undetected when it shows no visible signs or symptoms. Brain bleeds can occur due to trauma to the brain, from accidents or otherwise.
There are several types of brain bleeds:
(1) Intracerebral haemorrhage
This occurs at a rate of around 40,000–67,000 cases in the United States alone. Moreover, it has a very high mortality rate of 35–52%. In general, intracerebral bleeds occur within the brain tissue or within the ventricles (i.e, the areas which produce cerebrospinal fluid that circulates within our nervous system). Causes/risk-factors include trauma, aneurysms (i.e, swollen arteries), brain tumors, high blood pressure, and the build-up of proteins called amyloid proteins. Other risk factors include high alcohol intake, high cholesterol, genetic predispositions, the use of anticoagulants and/or drugs.
(2) Subarachnoid haemorrhage
A subarachnoid haemorrhage is, essentially, bleeding between the arachnoid and the pia membrane. The arachnoid and pia membranes are two out of the three meninges, or outer coverings, of the brain: the dura mater, arachnoid mater, and pia mater. Thus, sub-arachnoid haemorrhages are essentially deeper than intra-cerebral bleeds. These are primarily caused by trauma, although aneurysms may also cause sub-arachnoid haemorrhage (SAH). One-third of SAH cases occur during sleep. Symptoms include severe headaches, which makes it hard to detect. 
(3) Epidural haemorrhage
Epidural haemorrhages, or Epidural hematomas, comprise of bleeding outside the dura mater, and below the skull. This is an internal brain bleed, but the most external compared to other brain bleeds. It comprises of approximately one-tenth of all traumatic brain injuries. Causes include trauma (falls, accidents, or attacks), infections, brain tumors, loss of ability to clot blood, or malformed blood vessels. This is more common in the early years of life (ages 20–30), and accounts for 15% of all fatal head injuries. Primary symptoms include a loss of consciousness, coma, headaches, and potential vomiting or seizures. If untreated, it can very quickly result in death.
(4) Subdural haemorrhage
A subdural haemorrhage, or a subdural hematoma, is different from an epidural hematoma because here, blood collects under the dura mater of the brain. Many subdural hematoma cases occur in children of less than 2 years of age, where trauma occurs to them during delivery. Due to this, it is also referred to as “shaken baby syndrome”, and can lead to bleeding of the retina (a layer of the eye). Causes of subdural hematomas in adults is primarily accidents or injury.