Differential Diagnosis for Sudden Onset Left Leg Complete Paresis
Single Most Likely Diagnosis
- Contralateral stroke (left hemisphere): Given the patient's history of a remote right-sided CVA, it is likely that the sudden onset of left leg complete paresis is due to a new stroke in the left hemisphere of the brain, affecting the motor pathways that control the left leg.
Other Likely Diagnoses
- Progressive vascular disease: The patient's history of a previous CVA increases the risk of progressive vascular disease, which could lead to further ischemic events or vascular occlusions causing the sudden onset of left leg paresis.
- Seizure: A seizure, particularly a postictal state, could present with sudden onset weakness, although the absence of pain and intact sensation makes this less likely.
- Spinal cord lesion: A lesion in the spinal cord, such as a tumor or abscess, could cause sudden onset weakness, but the lack of pain and sensory changes makes this less likely.
Do Not Miss Diagnoses
- Spinal epidural hematoma: Although rare, a spinal epidural hematoma could cause sudden onset paralysis and is a medical emergency that requires prompt diagnosis and treatment.
- Aortic dissection: An aortic dissection could cause sudden onset leg weakness, especially if the dissection involves the iliac or femoral arteries, and is a potentially life-threatening condition.
- Cauda equina syndrome: This is a rare but serious condition that requires urgent medical attention, characterized by compression of the nerve roots in the lumbar spine, which could cause sudden onset leg weakness.
Rare Diagnoses
- Multiple sclerosis: Although multiple sclerosis could cause sudden onset weakness, it is less likely in this case given the patient's age and the absence of other neurological symptoms.
- Neuromuscular junction disorder (e.g., myasthenia gravis): These disorders could cause sudden onset weakness, but are relatively rare and would typically be associated with other symptoms such as muscle fatigue or fluctuating weakness.
- Inflammatory or infectious myelitis: Inflammation or infection of the spinal cord could cause sudden onset weakness, but these conditions are rare and would typically be associated with other symptoms such as fever, pain, or sensory changes.