Differential Diagnosis for Spontaneous Lower Extremity Weakness and Areflexia
Single Most Likely Diagnosis
- Guillain-Barré Syndrome: An autoimmune disorder that is the most common cause of acute flaccid paralysis, characterized by rapid onset of muscle weakness and areflexia, often following a minor infection. It typically starts in the lower extremities and ascends.
Other Likely Diagnoses
- Lumbar Disc Herniation: Can cause sudden onset of lower extremity weakness and areflexia, especially if the herniation compresses the cauda equina, a condition known as cauda equina syndrome.
- Spinal Cord Infarction: Although less common, spinal cord infarction can present with acute lower extremity weakness and areflexia due to the interruption of blood supply to the spinal cord.
- Peripheral Neuropathy: Certain types of peripheral neuropathy, such as those associated with diabetes or alcohol abuse, can present with weakness and areflexia, though the onset is typically more gradual.
Do Not Miss Diagnoses
- Spinal Epidural Abscess: A serious condition that requires immediate medical attention. It can cause rapid progression of neurological deficits, including lower extremity weakness and areflexia, due to compression of the spinal cord.
- Cauda Equina Syndrome: A medical emergency that occurs when the nerves in the spinal canal are compressed, leading to loss of bladder and bowel control, as well as lower extremity weakness and areflexia.
- Spinal Cord Tumor: Though less common, spinal cord tumors can compress the spinal cord, leading to neurological deficits. Early diagnosis is crucial for treatment and preservation of neurological function.
Rare Diagnoses
- Acute Transverse Myelitis: An inflammation of the spinal cord that can cause sudden onset of neurological symptoms, including lower extremity weakness and areflexia, though it is relatively rare.
- Neurosyphilis: A condition caused by the bacterium Treponema pallidum, which can lead to a variety of neurological symptoms, including lower extremity weakness, though it is less common in the modern era due to the availability of effective antibiotics.
- Vitamin Deficiency (e.g., Vitamin B12 Deficiency): Can lead to subacute combined degeneration of the spinal cord, presenting with weakness, areflexia, and other neurological symptoms, but the onset is typically gradual.