Hyperammonemic Encephalopathy and Thyroid Storm Leading to Coma: A Case Report

Area of Science:

• Endocrinology
• Neurology
• Nephrology

Background:

• Hyperammonemic encephalopathy (HE) is typically associated with liver dysfunction or metabolic disorders.
• Thyroid storm, a critical endocrine emergency, causes severe metabolic disturbances.
• The connection between thyroid storm and hyperammonemia is not well-established.

Observation:

• A previously healthy 33-year-old male presented with fatigue, nausea, vomiting, and rapid neurological deterioration.
• Laboratory results revealed significant hyperammonemia (284 µmol/L) and thyrotoxicosis (fT4: 27 pmol/L, TSH: 0.007 µIU/mL) without hepatic dysfunction.
• Neurological status declined from GCS 12 to 7; brain MRI and CSF analysis were normal.

Findings:

• The patient was diagnosed with coma secondary to hyperammonemic encephalopathy and thyroid storm.
• Treatment included antithyroid drugs (propylthiouracil), iodine, beta-blockers (propranolol), steroids (hydrocortisone), and continuous renal replacement therapy (CRRT).
• Ammonia levels normalized within 48 hours, resulting in significant clinical improvement and successful extubation.

Implications:

• This case underscores the importance of considering hyperammonemia in altered mental status, even without evident liver disease.
• It highlights a potential, though unproven, link between thyroid dysfunction and ammonia metabolism.
• Early recognition and integrated management of endocrine and metabolic emergencies are crucial for patient outcomes.