Differential Diagnosis for Post-Anesthesia Reaction with Unremitting Headache and Tremor

Single Most Likely Diagnosis

• Serotonin Syndrome: This condition can occur after the use of certain medications, including some anesthetics, and is characterized by symptoms such as headache, tremor, and can follow an anaphylactic or angioedema reaction if the patient was given medications that affect serotonin levels during the reaction. The unremitting nature of the headache and the presence of tremor, in the absence of focal neurological deficits, support this diagnosis.

Other Likely Diagnoses

• Migraine or Tension Headache: These are common causes of headache and could be exacerbated by the stress of surgery or an anaphylactic reaction. The tremor could be related to anxiety or stress.
• Anxiety or Stress Reaction: The experience of an anaphylactic reaction and subsequent surgery could lead to significant psychological distress, manifesting as tremor and headache.
• Medication Overuse Headache: If the patient has been taking pain medications frequently for the headache, this could lead to a cycle of medication overuse headache.

Do Not Miss Diagnoses

• Cerebral Vasculitis: Although rare, this condition could present with headache and tremor, especially if there was an autoimmune response triggered by the anaphylaxis or the anesthetic.
• Subarachnoid Hemorrhage or Other Intracranial Bleed: Although the CT head was reportedly normal, the possibility of a small bleed or one that occurred after the CT was done cannot be entirely ruled out without further investigation if symptoms worsen or change.
• Infection (e.g., Meningitis, Encephalitis): Post-surgical infections can present with non-specific symptoms including headache and tremor, especially if the infection involves the central nervous system.

Rare Diagnoses

• Wilson's Disease: A genetic disorder that can cause tremor and neurological symptoms, but it would be unusual for it to present for the first time in this context.
• Pheochromocytoma: A rare tumor that could cause episodic hypertension, headache, and tremor, potentially exacerbated by anesthesia.
• Hashimoto's Encephalopathy: A rare condition associated with Hashimoto's thyroiditis, presenting with neurological symptoms including headache and tremor, which could be triggered by the stress of surgery or an anaphylactic reaction.