creation date: 2025-12-08 14:13
tags: Pathologies
Thyroid Storm
Background
Definitions
Thyroid storm, also known as thyrotoxic crisis, refers to an acute, life-threatening complication of hyperthyroidism.
Etiology
Thyroid storm precipitate from superimposed factors of patients with diagnosed or undiagnosed hyperthyroidism. These include:
- Abrupt discontinuation of antithyroid medicine
- Thyroid surgery
- Non-thyroid surgery
- Trauma
- Acute illnesses (eg. infection, MI, DKA, drug reactions)
- Giving birth
- Recent use of iodinated contrast
- Radioiodine therapy (rare)
- Burns
- Stroke or traumatic brain injury
- Medication side effects (eg. amiodarone, anesthetics, salicylates)
- Hyperemesis gravidarum in pregnancy
Pathogenesis
The pathogenesis of thyroid storm is unclear. Hypotheses suggest the rapid increase in thyroid hormone results in sympathetic nervous system hyperactivity. This along with the response to catecholamines and cellular response to thyroid hormone during acute stress or infection results in cytokine releases and immunologic disturbances.
The clinical features manifest as a result of the excessive thyroid hormone response. There is an intense elevation of metabolic activity increasing oxygen and nutrition requirements. Thyroid effect also increase CNS symptoms.
Clinical Presentation
Signs & Symptoms
The typical presentation is that of an exaggerated hyperthyroid response.
Central nervous system
- Agitation
- Anxiety
- Delirium
- Psychosis
- Stupor
- Coma
Cardiovascular - Tachycardia (often >140 bpm)
- CHF
- Hypotension
- Cardiac arrhythmia
Gastrointestinal - Nausea/vomiting
- Diarrhea
- Abdominal pain
- Hepatic failure with jaundice
Others - Hyperpyrexia to ≥40 degrees C
- Goiter
- Graves’ disease: ophthalmopathy, lid lag, hand tremor, warm/moist skin
History & Physical Exam
A rapid history and physical should be performed. A history of hyperthyroidism may be elicited but suspicion should be maintained despite it. Precipitating factors should be identified if possible.
Physical exam should be rapid and assess for signs and symptoms of thyroid storm.
Risk factors
Patients at risk are those:
- With long standing untreated hyperthyroidism
- Experienced acute event that may precipitate
- Irregular use or discontinue antithyroid medication
Diagnosis
Criteria
The diagnosis of thyroid storm is made clinically with evidence of hyperthyroidism.
Evidence of hyperthyroidism is defined as:
- Elevation of free T4 and/or T3
- Suppression of TSH
Clinical evaluation of signs and symptoms should be made for diagnosis. A number of scoring systems exist but are not universally accepted nor validated.
Burch-Wartofsky Point Scale (BWPS)
| Criteria | Scoring |
|---|---|
| Temperature | Score of 0-30 based on temp from 37.2C - ≥40C |
| CNS dysfunction | 10 (agitation), 20 (delirium/psychosis/lethargy), 30 (seizure/coma) |
| Tachycardia | 5 (99-109), 10 (110-119), 15 (120-129), 20 (130-139) and 25 (greater than 140) |
| Atrial fibrillation | 10 (presence) |
| Heart failure | 5 (pedal edema), 10 (bi-basilar rales), 15 (pulmonary edema) |
| GI dysfunction | 10 (diarrhea, N/V, abdo pain), 20 (unexplained jaundice) |
| Presence of precipitating factor | 10 (presence) |
| A score of 25-45 suggests an impending storm while a score of ≥45 suggests thyroid storm. |
An alternative system is the Japanese Thyroid Association (JTA) TS1/TS2 system but can be less sensitive than the BWPS.
Work-up
Following clinical suspicion of thyroid storm, thyroid function tests should be obtained.
- TSH
- Free T4 and T3
Further assessment of etiology should be performed but should not delay management.
Differential
The most common symptoms that may be due to alternative diagnoses is fever and should be differentiated.
Other diagnoses include:
- Sepsis
- Infection
- Psychosis
- Cocaine use
- Pheochromocytoma
- Neuroleptic malignant syndrome
- Hyperthermia
Red Flags / Complications
The mortality of thyroid storm is around 8-25%.
The complications from untreated thyroid storm are:
- Arrhythmias
- High-output cardiac failure
- Seizures, delirium, coma
- Elevated liver enzymes and jaundice
- Abdominal symptoms
- Atrial fibrillation and thromboembolism
Management
Treatment of thyroid storm consist largely of clinical dogma and not based on prospective studies. Treatment is similar for patients with severe hyperthyroidism who do not meet criteria for thyroid storm.
The management of thyroid storm occurs in an ICU.
Initial Management
Immediate treatment includes:
Beta blocker (propranolol preferred):
- Control tachycardia and blood pressure
- Contraindicated in acute decompensated heart failure
- Use caution with asthma, COPD, severe peripheral vascular disease; consider cardioselective options
- Propranolol inhibits conversion of T3 to T4 at high doses
- Titrate dose to heart rate; typically 60-80mg PO q4-6h
Thionamide (propylthiouracil (PTU) preferred):
- Blocks de novo thyroid hormone synthesis within 1-2 hr of administration
- 200-250 mg q4h; consider loading dose of 500-1000 mg
Iodine (SSKI or Lugol’s solution):
- Blocks release of T4 and T3 from gland within hours
- Administer ≥1 hr after thionamide to prevent use in de novo synthesis
- Use caution if etiology is toxic adenoma or toxic MNG
- SSKI 5 drops PO q6h OR Lugol’s solution 10 drops PO TID
Hydrocortisone (only if thyroid storm):
- Reduce T4 to T3 conversion and may reduce autoimmune process
- 300 mg loading dose then 100mg IV q8h
- Dexamethasone can be used as alternative
Subsequent Management
Following evidence of clinical improvement, medications can be reduced.
- Beta-blockers: discontinue after thyroid function tests return normal
- Thionamide: switched to methimazole once T3 is declining and hospital discharge anticipated (preferred for better safety profile, compliance rates)
- Iodine: discontinued unless thyroidectomy planned within 10-14 days
- Hydrocortisone: tapered and discontinued; duration of taper depends on time on steroid