Thyroid Storm Clinical Presentation

Patients may have a known history of thyrotoxicosis. In the absence of previously diagnosed thyrotoxicosis, the history may include symptoms such as irritability, agitation, emotional lability, a voracious appetite with poor weight gain, excessive sweating and heat intolerance, and poor school performance caused by decreased attention span. Burch and Wartofsky have published precise criteria and a scoring system for the diagnosis of thyroid storm based on clinical features.^[2]

• General symptoms

  • Fever
  • Profuse sweating
  • Poor feeding and weight loss
  • Respiratory distress
  • Fatigue (more common in older adolescents)
• GI symptoms

  • Nausea and vomiting
  • Diarrhea
  • Abdominal pain
  • Jaundice^[3]
• Neurologic symptoms

  • Anxiety (more common in older adolescents)
  • Altered behavior
  • Seizures, coma

Physical findings include the following:

• Fever

  • Temperature consistently exceeds 38.5°C.
  • Patients may progress to hyperpyrexia.
  • Temperature frequently exceeds 41°C.
• Excessive sweating
• Cardiovascular signs

  • Hypertension with wide pulse pressure
  • Hypotension in later stages with shock
  • Tachycardia disproportionate to fever
  • Signs of high-output heart failure
  • Cardiac arrhythmia (Supraventricular arrhythmias are more common, [eg, atrial flutter and fibrillation], but ventricular tachycardia may also occur.)
• Neurologic signs

  • Agitation and confusion
  • Hyperreflexia and transient pyramidal signs
  • Tremors, seizures
  • Coma
• Signs of thyrotoxicosis

  • Orbital signs
  • Goiter

The causes of thyroid storm are as follows:

• Thyroid storm is precipitated by the following factors in individuals with thyrotoxicosis:

  • Sepsis
  • Surgery
  • Anesthesia induction^[4]
  • Radioactive iodine (RAI) therapy^[5]
  • Drugs (anticholinergic and adrenergic drugs such as pseudoephedrine; salicylates; nonsteroidal anti-inflammatory drugs [NSAIDs]; chemotherapy^[6] )
  • Excessive thyroid hormone (TH) ingestion
  • Withdrawal of or noncompliance with antithyroid medications
  • Diabetic ketoacidosis
  • Direct trauma to the thyroid gland
  • Vigorous palpation of an enlarged thyroid
  • Toxemia of pregnancy and labor in older adolescents; molar pregnancy
• Thyroid storm can occur in children with thyrotoxicosis due to any cause but is most commonly associated with Graves disease. Other reported causes of thyrotoxicosis associated with thyroid storm include the following:

  • Transplacental passage of maternal thyroid-stimulating immunoglobulins in neonates
  • McCune-Albright syndrome with autonomous thyroid function^[7]
  • Hyperfunctioning thyroid nodule
  • Hyperfunctioning multinodular goiter
  • Thyroid-stimulating hormone (TSH)–secreting tumor
• Graves disease may also occur in children with Down syndrome or Turner syndrome and in association with other autoimmune conditions, including the following:

  • Juvenile rheumatoid arthritis
  • Addison disease
  • Type I diabetes
  • Myasthenia gravis
  • Chronic lymphocytic (Hashimoto) thyroiditis
  • Systemic lupus erythematosus
  • Chronic active hepatitis
  • Nephrotic syndrome
• The pathophysiologic mechanisms of Graves disease are shown in the image below.Pathophysiologic mechanisms of Graves disease relating thyroid-stimulating immunoglobulins to hyperthyroidism and ophthalmopathy. T4 is levothyroxine. T3 is triiodothyronine.
• Although the exact pathogenesis of thyroid storm is not fully understood, the following theories have been proposed:

  • Patients with thyroid storm reportedly have relatively higher levels of free THs than patients with uncomplicated thyrotoxicosis, although total TH levels may not be increased.
  • Adrenergic receptor activation is another hypothesis. Sympathetic nerves innervate the thyroid gland, and catecholamines stimulate TH synthesis. In turn, increased THs increase the density of beta-adrenergic receptors, thereby enhancing the effect of catecholamines. The dramatic response of thyroid storm to beta-blockers and the precipitation of thyroid storm after accidental ingestion of adrenergic drugs such as pseudoephedrine support this theory. This theory also explains normal or low plasma levels and urinary excretion rates of catecholamines. However, it does not explain why beta-blockers fail to decrease TH levels in thyrotoxicosis.
  • Another theory suggests a rapid rise of hormone levels as the pathogenic source. A drop in binding protein levels, which may occur postoperatively, might cause a sudden rise in free hormone levels. In addition, hormone levels may rise rapidly when the gland is manipulated during surgery, during vigorous palpation during examination, or from damaged follicles following RAI therapy.
  • Other proposed theories include alterations in tissue tolerance to THs, the presence of a unique catecholaminelike substance in thyrotoxicosis, and a direct sympathomimetic effect of TH as a result of its structural similarity to catecholamines.