Differential Diagnosis for 13-year-old Male with Possible Seizure
- Single most likely diagnosis:
- Cannabis-induced seizure: Given the presence of THC in the patient's system and a history of seizure, it's plausible that the cannabis use triggered the seizure. The acute confusion, slurred words, and the patient's bizarre statement about "ships in his head burning" could be attributed to the psychoactive effects of THC, possibly exacerbated by the seizure.
- Other Likely diagnoses:
- Idiopathic epilepsy: The patient has a history of seizures, which could indicate an underlying condition such as idiopathic epilepsy. The normal lab results do not rule out this possibility.
- Metabolic disorder: The elevated lactic acid could suggest a metabolic disorder, although the absence of other abnormal lab results makes this less likely. It could be worth exploring further, especially if there's a history of similar episodes.
- Infectious cause: Although labs show no abnormalities, an infectious cause (like meningitis or encephalitis) could present with seizures and confusion. The presence of tachycardia might support this, but the lack of fever or other specific symptoms makes it less likely.
- Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):
- Intracranial hemorrhage or stroke: Although less likely given the patient's age and lack of trauma history, these conditions can present with sudden onset of seizure and confusion. Imaging studies would be crucial to rule out these potentially fatal conditions.
- Meningitis or encephalitis: Despite the lack of specific symptoms like fever or neck stiffness, these infections can be deadly if not promptly treated. A lumbar puncture might be necessary if there's a high index of suspicion.
- Status epilepticus: If the patient had a prolonged seizure or multiple seizures in a short period, this could be a life-threatening condition requiring immediate intervention.
- Rare diagnoses:
- Mitochondrial disorders: Given the elevated lactic acid, a mitochondrial disorder could be considered, although it would be rare and might require more specific testing for diagnosis.
- Hashimoto's encephalopathy: This is a rare condition associated with autoimmune thyroiditis, which can cause seizures and confusion. It's unlikely but could be considered if other causes are ruled out and there are indications of thyroid dysfunction.