A<unk>  is a medical condition in which poor blood flow to the brain causes cell death. There are two main types of<unk> : ischemic, due to lack of blood flow, and hemorrhagic, due to bleeding. Both cause parts of the brain to<unk> op functioning properly. Signs and symptoms of a<unk>  may include an inability to move or feel on one side of the body, problems understanding or speaking, dizziness, or loss of vision to one side. Signs and symptoms often appear soon after the<unk>  has occurred. If symptoms last less than one or two hours, the<unk>  is a transient ischemic attack (TIA), also called a mini-stroke. A hemorrhagic<unk>  may also be associated with a severe headache. The symptoms of a<unk>  can be permanent. Long-term complications may include pneumonia and loss of bladder control. The main risk factor for<unk>  is high blood pressure. Other risk factors include high blood cholesterol, tobacco smoking, obesity, diabetes mellitus, a previous TIA, end-stage kidney disease, and atrial fibrillation. An ischemic<unk>  is typically caused by blockage of a blood vessel, though there are also less common causes. A hemorrhagic<unk>  is caused by either bleeding directly into the brain or into the space between the brain's membranes. Bleeding may occur due to a ruptured brain aneurysm. Diagnosis is typically based on a physical exam and supported by medical imaging such as a CT scan or MRI scan. A CT scan can rule out bleeding, but may not necessarily rule out ischemia, which early on typically does not show up on a CT scan. Other tests such as an electrocardiogram (ECG) and blood tests are done to determine risk factors and rule out other possible causes. Low blood sugar may cause similar symptoms. Prevention includes decreasing risk factors, surgery to open up the arteries to the brain in those with problematic carotid narrowing, and warfarin in people with atrial fibrillation. Aspirin or<unk> atins may be recommended by physicians for prevention. A<unk>  or TIA often requires emergency care. An ischemic<unk> , if detected within three to four and half hours, may be treatable with a medication that can break down the clot. Some hemorrhagic<unk> s benefit from surgery. Treatment to attempt recovery of lost function is called<unk>  rehabilitation, and ideally takes place in a<unk>  unit; however, these are not available in much of the world. In 2013, approximately 6.9 million people had an ischemic<unk>  and 3.4 million people had a hemorrhagic<unk> . In 2015, there were about 42.4 million people who had previously had a<unk>  and were<unk> ill alive. Between 1990 and 2010 the number of<unk> s which occurred each year decreased by approximately 10% in the developed world and increased by 10% in the developing world. In 2015,<unk>  was the second most frequent cause of death after coronary artery disease, accounting for 6.3 million deaths (11% of the total). About 3.0 million deaths resulted from ischemic<unk>  while 3.3 million deaths resulted from hemorrhagic<unk> . About half of people who have had a<unk>  live less than one year. Overall, two thirds of<unk> s occurred in those over 65 years old.
Stroke
Hypoglycemia
Epilepsy
Hypertensive encephalopathy
Subarachnoid hemorrhage
Giant cell arteritis
Migraine 
Bell's palsy