Differential Diagnosis for the 17-year-old boy
- Single most likely diagnosis
- Heatstroke: The patient's symptoms of sudden onset confusion, bizarre behavior, high body temperature (105 °F), dry mouth and eyes, vomiting, and unsteadiness, especially during a biking trip in high humidity, strongly suggest heatstroke. The physical exertion in a hot and humid environment increases the risk of heatstroke.
- Other Likely diagnoses
- Serotonergic medication withdrawal: Although the patient stopped taking sertraline a few days ago, the symptoms presented are more indicative of an acute environmental exposure rather than withdrawal, which typically includes symptoms like dizziness, headaches, and irritability.
- Dehydration: Given the patient's dry mouth, vomiting, and the context of biking in high humidity, dehydration is a plausible contributing factor to his condition.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Meningitis or Encephalitis: Although less likely given the context, these conditions can present with sudden onset confusion, fever, and vomiting. Missing these diagnoses could be fatal.
- Severe Hyponatremia or Hypernatremia: Electrolyte imbalances can occur due to dehydration and vomiting, leading to severe neurological symptoms.
- Rare diagnoses
- Scorpion toxin effect: This is highly unlikely without a history of a scorpion sting and does not fit well with the overall clinical picture presented.
- Denaturation of heat shock protein: While heat shock proteins are involved in the body's response to heat, "denaturation of heat shock protein" as a diagnosis is not a recognized clinical entity in this context.
- Increased presynaptic norepinephrine: This is a physiological or biochemical state rather than a diagnosis and does not directly explain the patient's symptoms without further context.