Differential Diagnosis for Acute Bilateral Lower Extremity Weakness
Single Most Likely Diagnosis
- Guillain-Barré Syndrome: An autoimmune disorder that often follows a viral infection, leading to rapid onset of muscle weakness, which can start in the lower extremities and ascend. It is a common cause of acute bilateral lower extremity weakness due to its relatively high incidence and characteristic presentation.
Other Likely Diagnoses
- Spinal Cord Compression: Conditions such as herniated discs, spinal stenosis, or tumors can compress the spinal cord, leading to bilateral lower extremity weakness. The onset can be acute, especially with traumatic injuries or rapidly expanding lesions.
- Electrolyte Imbalance (e.g., Hypokalemia, Hyperkalemia): Severe imbalances in potassium levels can lead to muscle weakness. While often more generalized, the lower extremities can be prominently affected, especially in cases of hypokalemia.
- Neuropathy (e.g., due to diabetes or alcohol abuse): Though typically more chronic, certain neuropathies can present with subacute or acute worsening of symptoms, including significant lower extremity weakness.
Do Not Miss Diagnoses
- Spinal Epidural Abscess: A serious infection that can compress the spinal cord, leading to acute neurological deficits, including bilateral lower extremity weakness. Early diagnosis is crucial for treatment and prevention of long-term damage.
- Cauda Equina Syndrome: A condition where the nerves in the spinal canal are compressed, often due to a herniated disc. It requires urgent medical attention to prevent permanent neurological damage.
- Acute Transverse Myelitis: Inflammation of the spinal cord that can cause rapid onset of symptoms, including bilateral lower extremity weakness. Prompt recognition and treatment are essential to improve outcomes.
Rare Diagnoses
- Tick Paralysis: A rare condition caused by a toxin in the saliva of certain ticks, leading to ascending paralysis that can start with lower extremity weakness.
- Botulism: A neurological disorder caused by a toxin that can lead to muscle weakness, starting with the face and descending, but can also present with generalized or localized weakness, including the lower extremities.
- Critical Illness Neuropathy/Myopathy: Conditions that occur in the context of severe illness, leading to muscle weakness, which can be prominent in the lower extremities. These are less common but should be considered in the appropriate clinical context.