Ischemic Stroke: The most common type of stroke, accounting for about 87% of all strokes. It occurs when a blood vessel in the brain is blocked, reducing blood flow and oxygen to the brain. The left face and left arm weakness suggest a right hemisphere stroke, which could involve the middle cerebral artery (MCA) territory, a common site for ischemic strokes.

Hemorrhagic Stroke: Although less common than ischemic strokes, hemorrhagic strokes (about 13% of all strokes) can also present with focal neurological deficits like left face and left arm weakness. This type occurs when a blood vessel in the brain ruptures, leaking blood into the surrounding tissue.
Transient Ischemic Attack (TIA): Often referred to as a "mini-stroke," TIAs are temporary periods of symptoms similar to those of a stroke. They don't cause permanent damage but are a warning sign of a future stroke. The symptoms of TIA are the same as those of a stroke but typically last less than 24 hours.

Subarachnoid Hemorrhage: Although less common, a subarachnoid hemorrhage can present with sudden onset of severe headache and sometimes focal neurological deficits. It's crucial to identify this condition promptly due to its high morbidity and mortality rates.
Brain Tumor: A tumor in the right hemisphere of the brain could cause left face and left arm weakness by compressing or invading nearby brain tissue. While less likely than vascular causes, missing a brain tumor could have significant implications for treatment and prognosis.
Meningitis or Encephalitis: Infections like meningitis or encephalitis can cause a variety of neurological symptoms, including focal weakness, although they more commonly present with fever, headache, and altered mental status.

Cerebral Venous Thrombosis: A blood clot in the brain's venous sinuses can cause stroke-like symptoms, including focal weakness. This condition is less common and often associated with specific risk factors like pregnancy, oral contraceptives, or thrombophilic conditions.
Mitochondrial Encephalomyopathy, Lactic Acidosis, and Stroke-like episodes (MELAS): A rare genetic disorder that can cause stroke-like episodes, among other symptoms. It's an important consideration in younger patients without traditional vascular risk factors.
Arteriovenous Malformation (AVM): An AVM is a tangle of blood vessels in the brain that can cause a variety of symptoms, including stroke-like episodes, due to bleeding or steal phenomenon. While rare, identifying an AVM is crucial for preventing future complications.