What are the rare causes of a stroke?

There are very many rare causes of stroke. Some are described here.

Vascular disorders

Noninflammatory blood vessel disorders

Fibromuscular dysplasia
A disease that causes abnormal cell development in the artery wall. Renal (kidney) and carotid arteries are most commonly affected.

Radiation-induced vasculopathy
Radiation treatment for cancers of the head and neck may lead to delayed toxicity to the nervous system.

Moyamoya disease
A rare disease of the carotid arteries in which they progressively narrow and potentially close, resulting in ischaemic or haemorrhagic stroke.

Fabry disease
A rare genetic disease that causes lipid deposits in the inner lining of blood vessels.

Inflammatory blood vessel disorders

Isolated angiitis of the central nervous system
A rare form of inflammatory blood vessel disease that affects the brain and spinal cord; no other blood vessels appear to be affected.

Cerebral vasculitis related to autoimmune disease
Many autoimmune diseases can cause stroke, e.g. systemic lupus erythematosus (SLE). Giant cell arteritis (see below) is another example.

Antiphospholipid antibody syndrome
This is considered a variant of SLE.

Temporal (giant cell) arteritis (GCA)
A systemic inflammatory disorder of the blood vessels. The most serious complication of GCA is permanent blindness. It’s twice as common in women, but still rare.

Cerebral vasculitis related to infection
Several infectious diseases may cause inflammation of cerebral blood vessels, including meningovascular syphilis, tuberculous meningitis, other bacterial meningitis, fungal meningoencephalitides, neurocysticercosis, varicella-zoster virus encephalitis, HIV and hepatitis C virus.

Cerebral vasculitis related to toxins
Cocaine, amphetamines, heroin, LSD and glue sniffing inflame the cerebral blood vessels.

Cerebral vasculitis related to neoplasms
Diseases of the arteries may rarely complicate systemic tumours. Meningitis caused by cancer or lymphoma may affect the small and middle-sized intracranial arteries.

Haematological disorders

Hereditary and acquired blood clotting disorders
Ischaemic stroke may be associated with hereditary and acquired blood clotting disorders. These are uncommon.

Sickle cell disease (also called sickle cell anaemia)
A genetic disorder that causes abnormal haemoglobin (the substance in red blood cells that carries oxygen to all the body’s organs).

Prothrombotic (clotting) disorders
The tendency for some people to develop blood clots in certain parts of the body, such as the deep veins in the leg.

Disorders of the coagulation system
Certain gene mutations may cause blood to clot more easily. Clotting tendencies are also associated with oral contraceptives, systemic inflammatory disorders and malignancies.

Miscellaneous disorders

Migraine-related stroke
Migraine with aura is associated with an increased risk for ischaemic and haemorrhagic stroke in women, especially those under age 55 years.

Cerebral venous thrombosis (CVT)
CVT is a rare cause of stroke. In children, it’s related to infections such as sinusitis, tonsillitis or pharyngitis, and requires immediate antibiotics. In adults, most cases are related to hereditary and acquired blood clotting disorders, pregnancy, the oral contraceptive pill, severe dehydration, malignancy and conditions that cause blood cells to grow abnormally in the bone marrow. CVT is also caused by COVID-19 and vaccinations for the virus.

Summary

Those are some of the rare causes of a stroke. Don’t worry if you have not heard of most of them.