Endocrine · Year 2 · from Endocrine
Case 3: Thyroid Storm
Patient Demographics
- Age: 28 years
- Sex: Female
- Occupation: Graduate student
Chief Complaint
"My daughter has high fever, is confused, and her heart is racing."
History of Present Illness
A 28-year-old woman with known Graves disease (diagnosed 1 year ago, non-adherent with methimazole) is brought to the emergency department by her mother. She developed a urinary tract infection 3 days ago and was started on antibiotics. Over the past 24 hours, she became increasingly agitated, confused, and developed high fever. She has been vomiting and having diarrhea. On arrival, she is diaphoretic, tremulous, and unable to answer questions coherently. Her mother confirms she stopped taking her methimazole 2 months ago because of side effects.
Physical Examination
- Vital Signs: BP 160/60 mmHg (widened pulse pressure), HR 168 bpm (irregular), Temp 40.2°C, RR 28/min
- General: Severely ill-appearing, agitated, diaphoretic
- Mental Status: Confused, disoriented, picking at bedsheets
- Eyes: Proptosis, lid lag
- Neck: Diffusely enlarged thyroid, thyroid bruit
- Cardiovascular: Tachycardia with irregular rhythm (atrial fibrillation), hyperdynamic precordium
- Abdomen: Hyperactive bowel sounds, mild tenderness
- Skin: Hot, flushed, diaphoretic
- Extremities: Marked tremor
Workup
- Laboratory Studies:
- TSH: <0.01 mIU/L
- Free T4: 7.8 ng/dL (markedly elevated)
- Free T3: 22.4 pg/mL (markedly elevated)
- Glucose: 156 mg/dL
- AST/ALT: Mildly elevated
- Bilirubin: 2.1 mg/dL (elevated)
- WBC: 14,000/μL
- ECG: Atrial fibrillation with rapid ventricular response
- Burch-Wartofsky Score: >45 (highly suggestive of thyroid storm)
Diagnosis
Thyroid storm precipitated by infection in uncontrolled Graves disease
Treatment
IMMEDIATE - this is a medical emergency with 10-30% mortality:
- Block thyroid hormone synthesis:
- PTU 500-1000 mg loading dose, then 250 mg every 4 hours (preferred in storm - also blocks peripheral T4→T3 conversion)
- Block thyroid hormone release (give 1 hour AFTER PTU):
- Potassium iodide (SSKI) 5 drops every 6 hours OR
- Lugol's solution 10 drops every 8 hours
- Block peripheral conversion and effects:
- Propranolol IV 1 mg slow push, repeat as needed; OR esmolol drip
- High-dose propranolol also blocks T4→T3 conversion
- Block T4→T3 conversion additionally:
- Hydrocortisone 100 mg IV every 8 hours (also treats possible relative adrenal insufficiency)
- Supportive care:
- Aggressive cooling (acetaminophen, cooling blankets - avoid aspirin as it displaces T4 from binding proteins)
- IV fluids
- Treat precipitating cause (antibiotics for UTI)
- ICU admission
- Once stable: Continue PTU, consider definitive therapy (RAI or surgery)
Clinical Pearl
Thyroid storm is a life-threatening exacerbation of hyperthyroidism with multi-organ dysfunction. The Burch-Wartofsky score helps assess probability based on temperature, CNS effects, GI/hepatic dysfunction, cardiovascular dysfunction, heart failure, and precipitant history. Treatment follows the mnemonic "PPTB" - PTU (synthesis), Potassium iodide (release), (proprano)Lol (effects), Beta-blocker. Iodide must be given at least 1 hour after antithyroid drug to prevent using the iodine as substrate for new hormone synthesis. Glucocorticoids are important because thyroid hormone increases cortisol metabolism, and these patients may have relative adrenal insufficiency.
Clinical Image
Treatment algorithm for thyroid storm showing the sequence of medications and their mechanisms of action.
Image Source: Wikimedia Commons - "Thyroid storm management" License: CC BY-SA 4.0 URL: https://commons.wikimedia.org/wiki/File:Hyperthyroidism_treatment_diagram.svg