Differential Diagnosis for Acute Onset Generalized Weakness with Preserved Awareness
- Single most likely diagnosis:
- Guillain-Barré Syndrome: An autoimmune disorder that leads to rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. It often follows a minor infection and can progress to respiratory failure, making prompt recognition crucial.
- Other Likely diagnoses:
- Myasthenia Gravis: An autoimmune disease characterized by weakness and rapid fatigue of the muscles under voluntary control. It typically affects the muscles of the face, eyes, and swallowing, but can generalize.
- Electrolyte Imbalance (e.g., Hypokalemia, Hyperkalemia): Severe imbalances in potassium levels can lead to muscle weakness. Hypokalemia can cause weakness due to decreased muscle excitability, while hyperkalemia can lead to muscle weakness by affecting the resting membrane potential.
- Acute Myopathies (e.g., Polymyositis, Dermatomyositis): Inflammatory muscle diseases that can present with acute onset of muscle weakness, though typically without sensory involvement.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed):
- Botulism: A rare but potentially life-threatening illness caused by a toxin produced by the bacteria Clostridium botulinum. It leads to muscle weakness, starting with the face and neck, and can progress to respiratory failure.
- Tick Paralysis: A rare condition caused by a toxin in the saliva of certain ticks, leading to ascending paralysis that can mimic Guillain-Barré Syndrome.
- Organophosphate Poisoning: Exposure to organophosphate pesticides can cause a cholinergic crisis, leading to muscle weakness among other symptoms, due to the inhibition of acetylcholinesterase.
- Rare diagnoses:
- Periodic Paralysis: A group of rare genetic disorders that lead to episodic muscle weakness or paralysis, often associated with fluctuations in potassium levels.
- Mitochondrial Myopathies: A group of disorders caused by mitochondrial dysfunction, leading to muscle weakness and other systemic symptoms, though these typically have a more gradual onset.
- Critical Illness Myopathy/Neuropathy: Conditions that occur in critically ill patients, leading to muscle weakness, which can be severe and prolonged.