Overview
A clot blocks a vein that drains blood from the brain.
A headache that gets worse over days is the most common sign.
Symptoms
Common signs:
- Severe, worsening headache
- Seizure
- Vision changes
Less common
- Weakness
- Seizures
Look up a symptom: Blurry vision · Headache · Vomiting
When to get medical care
Causes
Clot.
Does it spread or run in families?
- It isn't contagious. You can't catch it from someone else.
Who is more likely to get it
- Pregnancy
- Estrogen
Possible complications
Diagnosis
This is diagnosed in the emergency room or hospital.
The exam
A physical exam.
Tests
Tests, if needed:
- MRI venogram:
Treatment
Emergency care is needed. While waiting for help:
Self-care
- Call 911
Prevention
To lower your risk or prevent problems:
- Ask about clot risk with birth control
Which doctor treats this
- Emergency doctors treat it first, in the ER.
- They may send you to a neurologist (brain and nerve doctor).
Living with it
Support groups and helplines
- Genetic and Rare Diseases Information Center (GARD): Free NIH information on rare diseases, including where to find experts and patient groups.
- National Organization for Rare Disorders (NORD): Patient groups, help finding care, and aid programs for rare diseases.
Back to school, work, or sports
- Recovery time varies. Ask your care team when you can drive, lift, work, and exercise.
Children, pregnancy, and older adults
- Pregnant women: Higher risk.
Pregnancy and breastfeeding
- If you're pregnant or planning to be, tell your prenatal provider about this condition.
- This condition needs closer checkups during pregnancy. Plan ahead with your doctor.
- Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
- Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
- Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.
For caregivers
- Go to visits when you can and take notes.
- Keep a list of medicines, allergies, and doctors in one place.
- Learn the warning signs that need fast care.
- Learn CPR. Many hospitals and the Red Cross offer classes.
- Take breaks and ask for help. Caregivers need care too.
Outlook
Blood thinners help most recover.
Most recover well.
Getting ready for your visit
Bring a list of your symptoms and medicines.
What to bring
- A list of your medicines and supplements
- Notes on when symptoms started and what makes them better or worse
Questions to ask
- What follow-up care do I need?
- How can I prevent this from happening again?
Research studies
Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.
Sources
Last updated 2026-11-12.