Table 1.

Japan Thyroid Association Definition and Diagnostic Criteria for Thyroid Storm

Definition of TS

TS or crisis is a life-threatening condition requiring emergency treatment. It is often triggered by severe physical or mental stress in thyrotoxic patients. Patients have multiple organ failure as a result of the breakdown of compensatory mechanisms.

Prerequisite for diagnosis

Presence of thyrotoxicosis with elevated levels of free triiodothyronine (fT3) or free thyroxine (fT4).

Symptoms

1. Central nervous system (CNS) manifestations: Restlessness, delirium, mental aberration or psychosis, somnolence or lethargy, coma ( ≥1 on the Japan Coma Scale or ≤14 on the Glasgow Coma Scale).

2. Fever: ≥38°C.

3. Tachycardia: ≥130 beats per minute or heart rate ≥130 in atrial fibrillation.

4. Congestive heart failure (CHF): pulmonary edema, moist rales over more than half of the lung field, cardiogenic shock, or New York Heart Association Class IV status or ≥Class III status in the Killip classification.

5. Gastrointestinal (GI)/hepatic manifestations: nausea, vomiting, diarrhea, or a total bilirubin level ≥3.0 mg/dL.

Diagnosis

Grade of TS

Combinations of features

Requirements for diagnosis

TS1

First combination

Thyrotoxicosis plus at least one CNS manifestation and one of the following: fever, tachycardia, CHF, or GI/hepatic manifestation.

TS1

Alternate combination

Thyrotoxicosis and at least three of the following: fever, tachycardia, CHF, or GI/hepatic manifestations.

TS2

First combination

Thyrotoxicosis and a combination of two of the following: fever, tachycardia, CHF, or GI/hepatic manifestations.

TS2

Alternate combination

Meets the diagnostic criteria for TS1, except that serum fT3 or fT4 level are not available.

Exclusion and provisions

Cases are excluded if other underlying diseases clearly causing any of the following symptoms: fever (e.g., pneumonia and malignant hyperthermia), impaired consciousness (e.g., psychiatric disorders and cerebrovascular disease), heart failure (e.g., acute myocardial infarction), and liver disorders (e.g., viral hepatitis and acute liver failure). Therefore, it is difficult to determine whether the symptom is caused by TS or is simply a manifestation of an underlying disease; the symptom should be regarded as being due to TS that is caused by these precipitating factors. Clinical judgment in this matter is required.

TS, thyroid storm; TS1, “definite” TS; TS2, “suspected” TS.