Differential Diagnosis for Painful Bilateral Lower Limb Weakness with Fever
Single Most Likely Diagnosis
- Guillain-Barré Syndrome: An autoimmune disorder that often presents with ascending paralysis, which can start as bilateral lower limb weakness, accompanied by pain and fever. The condition is typically preceded by a respiratory or gastrointestinal infection.
Other Likely Diagnoses
- Polymyositis: An inflammatory muscle disease that can cause bilateral lower limb weakness, pain, and fever. It is part of a spectrum of idiopathic inflammatory myopathies.
- Dermatomyositis: Similar to polymyositis but also includes characteristic skin manifestations. It presents with muscle weakness, pain, and fever, along with specific dermatological findings.
- Neuropathic conditions due to infections: Certain infections like Lyme disease, HIV, or viral neuropathies can cause painful bilateral lower limb weakness accompanied by fever.
Do Not Miss Diagnoses
- Spinal Epidural Abscess: A serious condition that requires immediate medical attention. It can present with fever, back pain, and progressive neurological deficits, including bilateral lower limb weakness.
- Transverse Myelitis: Inflammation of the spinal cord that can cause bilateral lower limb weakness, pain, and fever. It is a medical emergency due to the risk of rapid progression to severe neurological impairment.
- Botulism: A rare but potentially life-threatening illness caused by a toxin produced by Clostridium botulinum. It can present with muscle weakness, which may start in the lower limbs, along with fever and other systemic symptoms.
Rare Diagnoses
- Critical Illness Myopathy: A condition that occurs in critically ill patients, characterized by muscle weakness and wasting. It can present with bilateral lower limb weakness but is typically seen in the context of prolonged ICU stays.
- Tick-borne illnesses: Certain tick-borne diseases, such as tick paralysis, can cause ascending paralysis and fever. These conditions are rare and depend on geographical exposure to specific ticks.
- Vasculitic neuropathy: Conditions like polyarteritis nodosa or granulomatosis with polyangiitis can cause neuropathy, leading to painful bilateral lower limb weakness and fever, though these are less common presentations.