Differential Diagnosis for Seizure Activity, Tongue Myoclonus, and Hyperreflexia

Single Most Likely Diagnosis

• Serotonin Syndrome: This condition is characterized by a combination of symptoms including seizure activity, myoclonus (which could involve the tongue), and hyperreflexia, often due to the use of serotonergic medications. The presence of these specific symptoms together makes serotonin syndrome a highly plausible diagnosis.

Other Likely Diagnoses

• Neuroleptic Malignant Syndrome (NMS): Although less common, NMS can present with altered mental status, muscle rigidity, and autonomic dysfunction, which might include hyperreflexia and potentially myoclonus. Seizures can also occur in NMS, making it a consideration.
• Anticholinergic Toxicity: This condition can cause seizures, altered mental status, and sometimes myoclonus. Hyperreflexia might be less commonly associated but could be seen in the context of severe toxicity.
• Lithium Toxicity: Lithium can cause a range of neurological symptoms including seizures, ataxia, and myoclonus. Hyperreflexia might also be observed, especially in more severe cases of toxicity.

Do Not Miss Diagnoses

• Meningitis/Encephalitis: Infections of the central nervous system can present with seizures, altered mental status, and sometimes focal neurological signs like myoclonus. Hyperreflexia could be seen, especially if there is involvement of the spinal cord or brainstem. Missing this diagnosis could be fatal.
• Status Epilepticus: Prolonged or recurrent seizure activity without full recovery between seizures. This is a medical emergency that requires immediate attention.
• Subarachnoid Hemorrhage: Although less directly linked to myoclonus, a subarachnoid hemorrhage can cause sudden onset of seizures and altered mental status. Hyperreflexia might not be a primary symptom but could be present.

Rare Diagnoses

• Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can cause myoclonus, seizures, and a variety of other neurological symptoms. Hyperreflexia might be seen in some cases.
• Hashimoto's Encephalopathy: A rare condition associated with Hashimoto's thyroiditis, characterized by altered mental status, seizures, and myoclonus. Hyperreflexia could be a feature, though it's less commonly highlighted.
• Tetanus: Characterized by muscle stiffness and spasms, tetanus can cause myoclonus-like symptoms and seizures in severe cases. Hyperreflexia is also a feature of tetanus.