Subarachnoid hemorrhage
Subarachnoid hemorrhage refers to bleeding within the subarachnoid space; area between the arachnoid membrane and the pia mater.
Space where the CSF circulates and it’s responsible for protecting the brain by serving as a cushion. A hemorrhage in this space can cause a coma, paralysis and even death.
Etiology
- SAH can be Traumatic of Spontaneous (primary)
- Spontaneous SAH is often related to brain aneurysms; the most common being a berry aneurysm. These aneurysms swell up and weaken the walls of the arteries over time. When an aneurysm erupts, it quickly bleeds and forms a clot. This condition is responsible for most SAH cases. Aneurysmal hemorrhage may occur at any age, but it’s common between age 40 and 65. Brain aneurysms more common in women, smokers and those with high blood pressure.
- Other causes of spontaneous SAH include: bleeding from an arteriovenous malformation and rupture mycotic aneurysm
- Rare causes: herpes simplex encephalitis, neoplasm, leukemia, thrombocytopenia, hypertension, metastasis, cocaine abuse
- Most common aneurysm sites are at the terminal portion of the internal carotid artery, the junction of the anterior cerebral and anterior communicating arteries, or at the origin of the middle carotid artery.
Symptoms
- Initial misdiagnosis of SAH occurs in 15% of patients
- More than 1/3 of SAH patients give history of suspicious symptoms days or weeks earlier, including headache, stiff neck, nausea and vomiting, syncope, or disturbed vision. These prodromal symptoms often due to minor leaking of blood from the aneurysm, therefore referred to as warning leaks.
- Sudden loss of consciousness
- Unusually severe headache; headache may be the only symptom:
- Sudden onset (in a split second, like a “blow” or “explosion” on/in the head; “sentinel” headache, “the worst headache in my life”), gradual over minutes than in seconds, maximal in seconds.
- Location; diffuse and poorly localized, but may be occipital and retroorbital.
- Precipitants; uncommon, for example weight lifting.
- Duration; hours (possibly minutes) to weeks
- Nausea
- Vomiting
- Neck stiffness (meningismus) – takes about 3-12 hours after onset to develop, blood in subarachnoid space which acts as meningeal irritant
- Pain and stiffness in the back and legs, hours to days after the onset, blood irritating lumbosacral nerve roots
- Light sensitivity (photophobia)
- Epileptic seizures, transient vertigo, altered mentation – uncommon
Signs
- None (very often!)
- Meningism; absence of neck stiffness does not exclude SAH
- Focal neurological signs; III-rd nerve palsy, VI-th nerve palsy, IX-XII nerve palsy, hemiparesis, paraparesis, cerebellar ataxia, etc.
- Subhyaloid haemorrhages
- Fever
- Hypertension