Rare diseases · Sign or symptom
Subarachnoid hemorrhage
HP:0002138
What it means
Hemorrhage occurring between the arachnoid mater and the pia mater.
Bleeding into the subarachnoid space the area between the arachnoid membrane and the pia mater surrounding the brain. Subarachnoid hemorrhage may occur spontaneously, usually from a ruptured cerebral aneurysm, or may result from head injury.
In everyday care
Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:
Rare diseases that can present with this15
Sometimes5–29%
9- Acute transverse myelitis
- Dural sinus malformation with arteriovenous shunt
- Extracranial carotid artery aneurysm
- Familial cerebral saccular aneurysm
- Familial thoracic aortic aneurysm and aortic dissection
- Hereditary hemorrhagic telangiectasia
- Parkes Weber syndrome
- Reversible cerebral vasoconstriction syndrome
and 1 more in this range
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Tracking symptoms like this for someone? Eleplan keeps symptoms, diagnoses, medications and every specialist in one plan.
Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.