Thyroid Storm (Thyrotoxic Crisis)

Introduction

Thyroid storm also known as thyrotoxic crisis is a rare but life-threatening condition of hypermetabolic state induced by excessive release of thyroid hormones (THs) in individuals with thyrotoxicosis.
Mortality rate is up to 30% even with treatment.
Causes of death include cardiac failure, arrythmias and hyperthermia
Precipitants of thyroid storm (thyrotoxic crisis) include the following:

  1. Infections
  2. Trauma & Surgery
  3. Stroke
  4. Diabetic ketoacidosis
  5. Radio iodine treatment of patients with partially treated or untreated hyperthyroidism

Clinical features of thyroid storm (thyrotoxic crisis)

  • Fever
  • Diarrhoea
  • Vomiting
  • Jaundice
  • Seizures
  • Coma

Complications of thyroid storm (thyrotoxic crisis)

The complications of thyroid storm (thyrotoxic crisis) are:

  1. Cardiac failure
  2. Arrythmias
  3. Hyperthermias

Investigations

  • Diagnosis is mainly clinical and laboratory investigations are done to identify possible precipitants-infection.
  • Level of thyroid hormones may not be markedly elevated.
  • Correlation does not exist between levels of thyroid hormones and thyroid storm.
  • FBC may show leucocytosis even in the absence of infection
  • Raised bilirubin,
  • Alkaline phosphatase

Management

  • The management of thyroid storm (thyrotoxic crisis) requires intensive monitoring
  • Supportive care
  • Identification and treatment of precipitating cause(s)

Treatment objectives

  • Reduction in T synthesis/action and
    restoration to normal values
  • Treatment of identified precipitating factors
  • Prevention of complications

Drug treatment

Propylthiouracil
Adult: 600 mg loading dose; 200 – 300 mg orally every 6 hours by nasogastric tube or per rectum
Child:

  • 5-12 years: Initially 50 mg orally 3 times daily until euthyroid then adjusted as
    necessary
  • 12 18 years. Initially 100 mg 8 hourly daily administered until euthyroid then adjusted as necessary; higher doses
    sometimes required

Saturated Solution of Potassium lodide
(SSKI)
Adult: 5 drops every 6 hours; to be
commenced 1 hour after the first dose of propylthiouracil
Child:

  • 1 month -1 year: 0.2 – 0.3 mL orally 8 hourly daily.
  • Dilute well with milk and water

Propranolol
Adult: 40-60 mg orally every 4 hours or 2 mg intravenously every 4 hours
Child:

  • Neonate, initially 250-500 μg/kg every 6 -8 hours, adjusted according to response
  • 1 month – 18 years: initially 250-500 μg/kg every 6 – 8 hours, adjusted according to response; doses up to 1 mg/kg may be required; maximum 40 mg every 8 hours

Dexamethasone

  • 2 mg intravenously every 6 hours

Intravenous Chlorpromazine 50-100mg.

  • Intramuscular route to treat agitation

Intravenous anti-arrhythmic

  • Used if arrhythmia is present; choice of drug depends on arrhythmia type.

Antibiotics

  • (if infection is present)

Supportive measures

  • Adequate hydration with intravenous fluids and cooling