Differential Diagnosis for the 12-year-old girl with myasthenia
- Single most likely diagnosis
- Cholinergic crisis due to increased dose of pyridostigmine: The patient's symptoms of increased sweating, diarrhea, fever, ptosis, and dysphagia, along with hypotension (BP=90/60), are consistent with a cholinergic crisis. This condition occurs when there is an excess of acetylcholine in the neuromuscular junction, often due to overdose of cholinesterase inhibitors like pyridostigmine. The recent increase in pyridostigmine dose 7 days prior to presentation supports this diagnosis.
- Other Likely diagnoses
- Myasthenic crisis: This is a life-threatening condition characterized by an exacerbation of myasthenia gravis symptoms, which can be triggered by various factors including infection or medication changes. While the patient's increased ptosis and dysphagia could suggest a myasthenic crisis, the presence of systemic symptoms like diarrhea and fever, along with increased sweating, points more towards a cholinergic crisis.
- Infection (e.g., Rota virus infection): Although the patient has fever and diarrhea, which could suggest an infectious cause like Rota virus, the combination of these symptoms with increased sweating, ptosis, and hypotension in the context of recent pyridostigmine dose increase makes cholinergic crisis more likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Septic shock: Although less likely given the context, septic shock from any bacterial infection could present with hypotension, fever, and altered mental status. It's crucial to consider and rule out sepsis, especially in a patient with compromised immune status or those on immunosuppressive therapy.
- Neuroleptic malignant syndrome (NMS): While NMS is rare and typically associated with the use of neuroleptic drugs, it can present with fever, altered mental status, and autonomic dysfunction. Given the patient's presentation, it's essential to consider NMS, especially if there's any history of neuroleptic use.
- Rare diagnoses
- Botulism: This rare condition, caused by the toxin produced by Clostridium botulinum, can present with ptosis, dysphagia, and autonomic dysfunction. However, the presence of diarrhea and the recent increase in pyridostigmine dose make this diagnosis less likely.
- Organophosphate poisoning: Exposure to organophosphates can cause cholinergic toxicity, presenting with symptoms similar to those of the patient. However, there's no mention of exposure history, making this diagnosis less probable.