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Symptoms and Signs of Brain Aneurysm Symptoms and Signs

Doctor's Notes on Brain Aneurysm

A brain aneurysm is an abnormal bulge or ballooning of a blood vessel in the brain; the walls of an aneurysm are not as stable as normal blood vessel walls. Aneurysms often are found incidentally or when they either leak blood or burst (rupture). Signs and symptoms are variable and are related to the area where the aneurysm is located. However, a common sign of most aneurysms is a headache described as “the worst headache of my life.” Other signs and symptoms possibly encountered are visual defects, photophobia, face pain, nose bleeds, dilated pupils, focal neurological problems, confusion, nausea and vomiting, cardiac dysrhythmias, seizures, stroke symptoms, neck pain or stiffness, difficulty breathing and, in some patients, death. The signs and symptoms are mainly due to the blood that leaks or pours into the brain tissue, compromising brain cells and other brain components with inflammatory reactions and/or by putting pressure on them (for example, an expanding hematoma).

The cause of brain aneurysms is controversial; currently, genetic and environmental factors together is a favored theory but it may change. Medical conditions that increase risk for them include polycystic kidney disease, lupus, sickle cell anemia, endocarditis, fungal infections, hypertension, cancers, smoking, alcohol use, connective tissue disorders, head trauma and others.

Medical Author:
Medically Reviewed on 3/11/2019

Brain Aneurysm Symptoms

Most brain aneurysms do not cause any signs or symptoms and are discovered during tests for another condition. Symptoms develop rapidly when an aneurysm ruptures, and in some cases symptoms can be caused by pressure from an unruptured anuerysm. The signs and symptoms of a brain aneurysm are variable and occasionally relate to the area of the brain that is affected. However, the most common symptom of a ruptured brain aneurysm is headache and is characterized by the patient describing the headache as “the worst headache of my life.” However, some patients don't report headache as a symptom. The following is a list of possible symptoms that are seen in patients with a brain aneurysm:

  • visual defects
  • facial pain
  • focal neurological complaints
  • seizures
  • passing out or fainting
  • confusion or mental impairment
  • nausea and/or vomiting
  • cardiac dysrhythmias
  • neck pain or stiffness
  • photophobia
  • trouble breathing
  • nosebleeds
  • dilated pupils
  • stroke-like symptoms (loss of speech, loss of sense of smell, paralysis of muscles on one side of the body, or other movement defects)

Brain Aneurysm Causes

The development of brain aneurysms is considered a controversial topic. Currently, most researchers think that a combination of factors, both genetic and environmental, lead to the development of brain aneurysms. For example, some aneurysms may have a strong genetic component that is inherited (for example, individuals with polycystic kidney disease and arteriovenous malformations are more likely to develop aneurysms). However, environmental pressures such as hypertension are also associated with brain aneurysm development. In addition, some aneurysms are associated with environmental factors like infections or trauma.

Concussions & Brain Injuries Symptoms, Tests, Treatment Slideshow

Concussions & Brain Injuries Symptoms, Tests, Treatment Slideshow

Although the brain is protected by tough bone (skull) and padding (membranes), it can still be injured. Head injuries that are severe enough to affect brain function are termed traumatic brain injuries (TBIs). Damage can range from mild to severe as the brain can affect everything you do.


Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.