Subarachnoid haemorrhage (SAH)

SAH is bleeding into the subarachnoid space, which is the area between the brain and the arachnoid membrane.


Causes:

1. Traumatic causs of SAH – Head injury, Fracture of skull

2. Non traumatic causes of SAH –

Aneurysm rupture: A common cause where a bulging blood vessel in the brain bursts.

Arteriovenous malformations: Abnormal connections b/w arteries and veins can also lead to SAH.

Other causes: Conditions like hypertension, blood disorders, or certain infections.


Symptoms:

1. Severe Headache: Often described as the worst headache of a person's life (Thunderclap headache)

2. Nausea and Vomiting: Common due to increased intracranial pressure.

3. Loss of consciousness: Can occur immediately after the bleed.

Neck Stiffness: Due to irritation of the meninges.

4. Seizures 


Diagnosis:

1. CT Scan: Often the first imaging test used to detect bleeding.

2. MRI: Can be used for more detailed imaging.

3. Lumbar Puncture: Used to detect blood in the cerebrospinal fluid if CT is inconclusive.

4. Angiography: To identify the source of bleeding, such as an aneurysm.


NOTE: Normal CSF is colorless clear fluid and in the case of subarachnoid haemorrhage CSF appears yellow.


NOTE: Xanthochromia is the yellowish discoloration of cerebrospinal fluid (CSF) that occurs when blood mixes with CSF, often due to subarachnoid hemorrhage (SAH).

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