Subarachnoid Haemorrhage

• Subarachnoid haemorrhage involves bleeding in the subarachnoid space, where the cerebrospinal fluid is located, between the pia mater and the arachnoid membrane.
• Subarachnoid haemorrhage is usually the result of a ruptured cerebral aneurysm.
• Subarachnoid haemorrhage has a very high mortality (around 30%) and morbidity, making it essential not to miss.
• Subarachnoid haemorrhage is more common in individuals aged 45 to 70, women, and those of black ethnic origin.
• General risk factors for subarachnoid haemorrhage include hypertension, smoking, and excessive alcohol intake.
• Subarachnoid haemorrhage is particularly associated with family history, cocaine use, sickle cell anaemia, connective tissue disorders such as Marfan syndrome or Ehlers-Danlos syndrome, neurofibromatosis, autosomal dominant polycystic kidney disease, and others.
• The typical history of subarachnoid haemorrhage is a sudden-onset occipital headache during strenuous activity, such as heavy lifting or sex.
• The sudden and severe onset of a subarachnoid haemorrhage leads to the “thunderclap headache” description.
• Lumbar puncture is considered after a normal CT head for subarachnoid haemorrhage.
• CT angiography is used after confirming the diagnosis to locate the source of the bleeding for subarachnoid haemorrhage.
• CT head is the first-line investigation for subarachnoid haemorrhage.
• Seizures following a subarachnoid haemorrhage are treated with anti-epileptic drugs.
• Hydrocephalus refers to increased cerebrospinal fluid, causing expansion of the ventricles, and can be treated with lumbar puncture, external ventricular drain, or ventriculoperitoneal (VP) shunt.
• Surgical intervention may be used to treat aneurysms following a subarachnoid haemorrhage.
• Blood in the subarachnoid space causes hyper-attenuation on CT, but a normal CT head does not exclude a subarachnoid haemorrhage.
• Nimodipine is a calcium channel blocker used to prevent vasospasm, a common complication following a subarachnoid haemorrhage, resulting in brain ischaemia.
• Patients with subarachnoid haemorrhage should be managed by a specialist neurosurgical unit.
• With a subarachnoid haemorrhage, a CSF sample will show a raised red cell count, xanthochromia (a yellow colour to the CSF caused by bilirubin), and hypertonic pressure.
• The NICE guidelines (2022) recommend waiting at least 12 hours after the symptoms start before performing a lumbar puncture, as it takes time for the bilirubin to accumulate in the cerebrospinal fluid (CSF).
• Patients with reduced consciousness due to subarachnoid haemorrhage may require intubation and ventilation.
• Supportive care for subarachnoid haemorrhage involves a multi-disciplinary team during the initial stages and recovery.
• CT is less reliable more than 6 hours after the start of symptoms for subarachnoid haemorrhage.
• Neck stiffness, photophobia, vomiting, and neurological symptoms such as visual changes, dysphasia, focal weakness, seizures, and reduced consciousness are common features of subarachnoid haemorrhage.