Differential Diagnosis
The patient's presentation of tremors, chills, rigidity, hyperthermia, hypertension, tachycardia, tachypnea, elevated potassium, and creatine kinase levels, along with an elevated PCO2, suggests a complex clinical picture. Here is a categorized differential diagnosis:
Single most likely diagnosis
- Malignant Hyperthermia (MH): This is a life-threatening medical emergency triggered by certain volatile anesthetics (like sevoflurane) and depolarizing muscle relaxants. The patient's symptoms, including rapid rise in temperature, muscle rigidity, and elevated creatine kinase, are classic for MH. The use of sevoflurane during the procedure strongly supports this diagnosis.
Other Likely diagnoses
- Thyrotoxic crisis: Although less likely, given the context of recent surgery and anesthesia, thyrotoxic crisis could present with similar symptoms of hyperthermia, tachycardia, and hypertension. However, the absence of other specific symptoms like exophthalmos or a known history of thyroid disease makes this less probable.
- Neuroleptic Malignant Syndrome (NMS): NMS is another condition that presents with fever, muscle rigidity, and altered mental status, often associated with the use of neuroleptic medications. While the patient has a history of depression, there's no mention of current neuroleptic use, making this diagnosis less likely.
- Sepsis: Post-operative sepsis could explain the fever, tachycardia, and elevated white blood cell count (not provided but potentially elevated). However, the specific combination of muscle rigidity, elevated creatine kinase, and the temporal relationship to anesthesia makes sepsis a less likely primary diagnosis.
Do Not Miss diagnoses
- Anaphylaxis: Although the presentation doesn't strongly suggest anaphylaxis (no mention of rash, angioedema, or significant respiratory distress beyond tachypnea), it's a potentially life-threatening condition that can occur in response to medications used during surgery. The presence of hypertension rather than hypotension makes this less likely, but it should always be considered in post-operative reactions.
- Pulmonary embolism: This is another critical condition that could present with tachypnea and tachycardia. However, the combination of hyperthermia, muscle rigidity, and elevated creatine kinase is not typical for pulmonary embolism.
Rare diagnoses
- Serotonin Syndrome: This condition, resulting from an excess of serotonin, can cause altered mental status, neuromuscular abnormalities, and autonomic dysfunction. While possible, especially with the use of certain medications, it's less likely given the specific context and symptoms presented.
- Drug-induced rhabdomyolysis: Certain medications can cause rhabdomyolysis, but this would not fully explain the acute hyperthermia and rigidity seen in this patient without a more prolonged exposure to the offending agent.