Subarachnoid Hemorrhage

What is Subarachnoid Hemorrhage

Subarachnoid hemorrhage is bleeding between the brain and the layer that covers the brain.

The bleeding puts pressure on the brain, and it stops blood from going to some areas of the brain. If this bleeding is not treated, it may cause brain damage, stroke, or death. This is an emergency. You must be treated in the hospital right away.

13 Interesting Facts of Subarachnoid Hemorrhage

  1. May be suggested by patient reporting “worst headache of my life”
  2. Lumbar puncture and cerebrospinal fluid analysis are indicated when CT or MRI excludes presence of a space-occupying lesion or other diagnosis
  3. Lumbar puncture and cerebrospinal fluid analysis will reveal presence of blood
    • Xanthochromia, a yellow discoloration indicating presence of bilirubin in cerebrospinal fluid, may be used to distinguish in vivo hemorrhage from traumatic lumbar puncture
  4. Differentiated based on history and results of lumbar puncture and cerebrospinal fluid analysis
  5. Patient must be stabilized and immediately transferred to a critical care center
  6. Bleeding in the subarachnoid space is usually due to ruptured aneurysm (85%); less common causes include arteriovenous malformations, trauma, and dural sinus thromboses 
  7. Similar to moyamoya disease, headache is a frequent presenting symptom Headache is described as “sudden in onset” and “more intense than ever experienced”
  8. Similar to moyamoya that presents with stroke, many patients with subarachnoid hemorrhage have reduced level of consciousness, and a small percentage have seizures
  9. On examination, neck stiffness is common, due to meningeal irritation from blood in the subarachnoid space, which would be an atypical physical finding for moyamoya disease
  10. Subarachnoid hemorrhage usually can be identified on CT, which is highly sensitive for depicting blood (an area of abnormal hyperdensity) in the subarachnoid space; subarachnoid hemorrhage is not common in moyamoya disease 
  11. MRI is very sensitive for detection of subarachnoid hemorrhage Hyperintense signal abnormality overlying cerebral sulci on fluid inversion attenuation recovery sequences
  12. Hypointense susceptibility blooming on gradient echo or susceptibility-weighted imaging sequences
  13. Lumbar puncture to show hemoglobin metabolites is an additional diagnostic procedure that can provide confirmation of subarachnoid hemorrhage when uncertainty remains

You are more likely to get this condition if you:

  • Smoke.
  • Have high blood pressure.
  • Drink too much alcohol.
  • Are older than age 50.
  • Are female, especially if you have stopped getting your period for a year or longer (menopause).
  • Have a family history of burst blood vessels (aneurysms).
  • Have a certain syndrome that leads to one of these:
    • Kidney disease.
    • Disease of tissues like bones, blood, and fat (connective tissues).

Signs of this bleeding condition include:

  • Sudden, very bad headache. It may feel like the worst headache you have ever had.
  • Feeling sick to your stomach (nausea) or throwing up (vomiting), especially if you have other signs such as a headache.
  • Sudden weakness or loss of feeling (numbness) in your face, arm, or leg, especially on one side of the body.
  • Sudden trouble with any of these:
    • Walking.
    • Moving an arm or leg.
    • Talking.
    • Understanding what people say.
    • Swallowing.
    • Seeing out of one eye or both eyes.
  • Sudden confusion.
  • Seeing double.
  • Loss of balance.
  • Sensitivity to light.
  • Stiff neck.
  • Trouble staying awake.
  • Passing out (fainting).

Follow these instructions at home:


  • Take over-the-counter and prescription medicines only as told by your doctor.
  • Do not take any medicines that contain aspirin or NSAIDs (like ibuprofen) unless your doctor says that it is safe to take them.


  • Do not use any products that have nicotine or tobacco. These include cigarettes and e-cigarettes. If you need help quitting, ask your doctor.
  • Limit alcohol to 1 drink a day for nonpregnant women and 2 drinks a day for men. One drink is equal to:
    • 12 oz of beer.
    • 5 oz of wine.
    • 1½ oz of hard liquor.

Eating and drinking

  • Ask your doctor if it is safe for you to eat and drink. You may need tests to make sure that you can swallow safely (swallow studies).


  • Do not drive until your doctor says that it is safe to drive.
  • Do not drive or use heavy machinery while taking prescription pain medicine.

General instructions

  • Do therapy as recommended. This may include:
    • Physical therapy (PT).
    • Occupational therapy (OT).
    • Speech-language therapy.
  • Rest and limit activity as told by your doctor. Rest helps your brain to heal. Make sure you:
    • Get plenty of sleep.
    • Avoid activities that cause stress to your body or mind.
  • Check your blood pressure as told by your doctor. Write down your blood pressure.
  • Keep all follow-up visits as told by your doctors. This is important.

Contact a doctor if:

  • You have a stiff neck.
  • You have a cough.
  • You have a fever.

Get help right away if:

  • You have any signs of a stroke. “BE FAST” is an easy way to remember the main warning signs:
    • B – Balance. Signs are dizziness, sudden trouble walking, or loss of balance.
    • E – Eyes. Signs are trouble seeing or a sudden change in how you see.
    • F – Face. Signs are sudden weakness or loss of feeling of the face, or the face or eyelid drooping on one side.
    • A – Arms. Signs are weakness or loss of feeling in an arm. This happens suddenly and usually on one side of the body.
    • S – Speech. Signs are sudden trouble speaking, slurred speech, or trouble understanding what people say.
    • T – Time. Time to call emergency services. Write down what time symptoms started.
  • You have other signs of a stroke, such as:
    • A sudden, very bad headache with no known cause.
    • Feeling sick to your stomach.
    • Throwing up.
    • Jerky movements you cannot control (seizure).

These symptoms may be an emergency. Do not wait to see if the symptoms will go away. Get medical help right away. Call your local emergency services (911 in the U.S.). Do not drive yourself to the hospital.


  • Subarachnoid hemorrhage is bleeding in the brain. It is an emergency. You must be treated in the hospital right away.
  • Follow instructions from your doctor about eating, resting, and taking medicines.
  • Do not take any medicines that contain aspirin or NSAIDs (like ibuprofen) unless your doctor says that it is safe to take them.

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