Differential Diagnosis for Right Leg Weakness Only
Single Most Likely Diagnosis
- Lacunar stroke: A lacunar stroke, specifically a pure motor stroke, is the most likely diagnosis for right leg weakness only. This type of stroke occurs due to occlusion of small penetrating arteries that supply the internal capsule, corona radiata, or pons, resulting in isolated motor deficits.
Other Likely Diagnoses
- Cortical stroke: A stroke affecting the motor cortex, particularly the area responsible for lower limb function, can cause right leg weakness. This could be due to occlusion of a larger artery, such as the middle cerebral artery, affecting a specific area of the brain.
- Subcortical stroke: A stroke in the subcortical white matter, such as the corona radiata or centrum semiovale, can also cause isolated leg weakness.
Do Not Miss Diagnoses
- Spinal cord infarction: Although less common, spinal cord infarction can cause acute leg weakness and must be considered to avoid delayed diagnosis and potential permanent damage.
- Hemorrhagic stroke: A hemorrhagic stroke, either intracerebral or subarachnoid, can present with focal deficits, including leg weakness, and requires prompt recognition and management.
Rare Diagnoses
- Anterior cerebral artery (ACA) stroke: An ACA stroke can cause leg weakness, but it often presents with additional symptoms, such as urinary incontinence or cognitive changes. Isolated leg weakness due to an ACA stroke is less common.
- Moyamoya disease: This rare condition, characterized by stenosis or occlusion of the internal carotid artery and its branches, can cause stroke-like symptoms, including leg weakness. However, it is a rare diagnosis and typically presents with more complex or recurrent symptoms.
- Cerebral vasculitis: Inflammation of the blood vessels in the brain can cause stroke-like symptoms, including leg weakness. However, this diagnosis is rare and often associated with systemic symptoms or other neurological deficits.