Differential Diagnosis for Focal Weakness
- Single most likely diagnosis
- Stroke: This is the most common cause of focal weakness, resulting from either ischemia or hemorrhage in the brain, leading to sudden onset of weakness, often unilateral.
- Other Likely diagnoses
- Traumatic brain injury: Head injuries can cause focal weakness due to direct damage to the brain or increased intracranial pressure.
- Multiple sclerosis: An autoimmune disease that affects the central nervous system, leading to demyelination and a variety of neurological symptoms, including focal weakness.
- Spinal cord injury: Damage to the spinal cord can result in focal weakness or paralysis, depending on the level and severity of the injury.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Brain tumor: Although less common, brain tumors can present with focal weakness, and early diagnosis is crucial for treatment and prognosis.
- Cerebral vasculitis: Inflammation of the blood vessels in the brain can lead to focal weakness, among other symptoms, and requires prompt treatment to prevent further damage.
- Subdural or epidural hematoma: These conditions, often resulting from head trauma, can cause increased intracranial pressure and focal weakness, necessitating urgent medical attention.
- Rare diagnoses
- Mitochondrial myopathies: A group of genetic disorders affecting the mitochondria, leading to muscle weakness, which can sometimes present as focal.
- Inflammatory myopathies: Conditions like polymyositis or dermatomyositis can cause muscle weakness, which may initially appear focal.
- Neuromuscular junction disorders (e.g., myasthenia gravis): These conditions can cause fluctuating muscle weakness, which might be mistaken for focal weakness in some cases.