Some individuals experience mild or severe CCM symptoms, while others experience none at all. Symptoms vary significantly, based on the location of the CCM lesion, the strength or weakness of the blood vessel walls, and how much bleeding occurs. Blood may pool inside the vessels or leak into surrounding brain tissue, triggering symptoms such as:
- Bleeding in the brain
- Focal neurologic symptoms, such as weakness or paralysis
A CCM lesion may shrink or grow as it bleeds and reabsorbs blood. As the size changes, the type and severity of symptoms may change. While a lesion may be present in childhood, most people with CCM do not become symptomatic until adulthood. Some asymptomatic lesions are incidentally discovered when a patient has brain imaging for an unrelated reason, such as a CT or MRI scan after a concussion or for evaluation of migraine symptoms. A cavernous angioma with symptomatic hemorrhage (CASH) is most likely to rebleed and merits urgent evaluation. The cases with CASH are also the subject of novel clinical trials, trial readiness and benchmarker research.