Overview
Definition:
Thyroid storm is a rare but life-threatening exacerbation of hyperthyroidism, characterized by decompensated cardiac function, exaggerated signs and symptoms of hyperthyroidism, and altered mental status
In adolescents, it often presents as a complication of poorly controlled Graves' disease or after thyroid manipulation.
Epidemiology:
Thyroid storm is estimated to occur in 1-2% of patients with thyrotoxicosis
While more common in adults, it can occur in adolescents, particularly those with untreated or inadequately treated hyperthyroidism or precipitating factors like infection, surgery, or trauma.
Clinical Significance:
Thyroid storm represents a medical emergency requiring prompt diagnosis and aggressive management
Delays in treatment significantly increase morbidity and mortality
Understanding the specific challenges in adolescent patients, including their often more dynamic physiology and potential for non-adherence, is crucial for effective care.
Clinical Presentation
Symptoms:
High fever (often >38.5°C or 101.3°F)
Extreme tachycardia (heart rate >140 bpm)
Severe agitation, delirium, psychosis, or coma
Nausea, vomiting, diarrhea, and abdominal pain
Jaundice
Congestive heart failure with pulmonary edema
Exacerbation of ophthalmopathy.
Signs:
Profound hyperthermia
Marked tachycardia, often with arrhythmias like atrial fibrillation
Dehydration
Profound weakness
Goiter may be present
Signs of heart failure
Neurological deficits ranging from tremor to stupor or coma
Absence of fever does not exclude thyroid storm.
Diagnostic Criteria:
No single diagnostic criterion is universally accepted
The Burch-Wartofsky Point Scale is commonly used, assigning points based on temperature, heart rate, CNS dysfunction, gastrointestinal symptoms, and precipitating factors
A score of ≥45 is highly suggestive of thyroid storm.
Diagnostic Approach
History Taking:
Detailed history of recent illness, infections, surgery, or trauma
Medication history, particularly compliance with antithyroid drugs and any recent withdrawal
Family history of thyroid disease
Symptoms of hyperthyroidism (palpitations, weight loss, heat intolerance, anxiety).
Physical Examination:
Assess vital signs meticulously: temperature, heart rate, blood pressure, respiratory rate, oxygen saturation
Perform a thorough cardiovascular examination for arrhythmias and heart failure
Assess neurological status for agitation, delirium, or coma
Examine the thyroid gland for size and tenderness
Evaluate for signs of infection.
Investigations:
Thyroid function tests: TSH (suppressed), free T4 and T3 (elevated, often significantly)
Complete blood count (leukocytosis may indicate infection)
Electrolytes, liver function tests, renal function tests
Electrocardiogram (ECG) to assess for arrhythmias and signs of cardiac strain
Chest X-ray if heart failure is suspected
Blood cultures if infection is suspected.
Differential Diagnosis:
Sepsis without thyrotoxicosis
Heatstroke
Malignant hyperthermia
Pheochromocytoma crisis
Serotonin syndrome
Delirium tremens
Acute psychosis
Overdose of stimulants.
Management
Initial Management:
Aggressive supportive care is paramount
Hospitalization in an intensive care unit (ICU) setting is essential
Fluid resuscitation to correct dehydration
Antipyretics (acetaminophen is preferred
avoid aspirin as it can displace thyroid hormones)
Cooling blankets or ice baths for hyperthermia
Supplemental oxygen.
Medical Management:
Inhibition of thyroid hormone synthesis: Thionamides
Propylthiouracil (PTU) is often preferred initially due to its additional effect in blocking peripheral conversion of T4 to T3
Adolescent dosing for PTU: 150-250 mg every 6-8 hours, or 20 mg/kg/day divided every 6-8 hours
Methimazole can be used but is less effective at blocking peripheral conversion
Adolescent dosing for Methimazole: 15-20 mg every 6-8 hours, or 0.5-0.75 mg/kg/day divided every 6-8 hours
Blockade of thyroid hormone release and action: Beta-blockers
Propranolol is the drug of choice
Adolescent dosing for Propranolol: 10-40 mg every 6 hours, or 1-2 mg/kg/day divided every 6 hours
It should be initiated after thionamides have been started to prevent unopposed beta-adrenergic stimulation of T3 production
Inhibition of peripheral deiodination: Iodine
Administer iodide (e.g., potassium iodide solution, 5-10 drops orally or intravenously) 1 hour after initiating thionamides to prevent further synthesis of thyroid hormones
Corticosteroids: Hydrocortisone 100 mg IV every 6-8 hours, or dexamethasone, to reduce peripheral conversion of T4 to T3 and for potential adrenal insufficiency.
Surgical Management:
Rarely indicated as a primary treatment for thyroid storm
Thyroidectomy may be considered in selected cases with persistent, life-threatening symptoms despite maximal medical therapy, or for management of a concurrent goiter causing airway compression, after stabilization.
Supportive Care:
Continuous cardiac monitoring
Close monitoring of vital signs and neurological status
Management of complications like heart failure, arrhythmias, and electrolyte imbalances
Nutritional support, often via nasogastric tube if oral intake is compromised
Management of precipitating factors, such as aggressive antibiotic therapy for infections.
Complications
Early Complications:
Cardiovascular collapse, including cardiogenic shock and myocardial infarction
Acute respiratory distress syndrome (ARDS)
Cerebral edema and stroke
Gastrointestinal hemorrhage and perforation
Acute kidney injury
Sepsis.
Late Complications:
Permanent cardiac damage
Persistent neurological deficits
Adrenal insufficiency
Recurrence of hyperthyroidism if underlying cause is not addressed.
Prevention Strategies:
Strict adherence to antithyroid medication regimens in adolescents with hyperthyroidism
Prophylactic treatment for patients undergoing thyroid surgery or those with significant thyrotoxicosis undergoing other stressful procedures
Prompt recognition and management of infections or other precipitating factors.
Prognosis
Factors Affecting Prognosis:
Severity of hyperthyroidism
Degree of organ dysfunction at presentation
Promptness and efficacy of treatment
Presence of precipitating factors
Age of the patient.
Outcomes:
With prompt and aggressive management, mortality rates have decreased significantly
However, thyroid storm remains a serious condition
Patients who survive typically have a good prognosis if their hyperthyroidism is subsequently well-controlled.
Follow Up:
Long-term follow-up with pediatric endocrinology is essential
This includes regular monitoring of thyroid function tests, adjustment of antithyroid medication, and assessment for ophthalmopathy or other autoimmune manifestations
Education for adolescents and their families on adherence to treatment is critical.
Key Points
Exam Focus:
Thyroid storm is a hyperthyroid crisis with high fever, tachycardia, and altered mental status
Management priorities are supportive care, blocking new hormone synthesis (thionamides), blocking hormone action/release (beta-blockers, iodine), and reducing peripheral conversion (corticosteroids)
PTU is often preferred initially in adolescents due to its effect on peripheral conversion
Beta-blockers should be initiated AFTER thionamides.
Clinical Pearls:
Always consider thyroid storm in adolescents with unexplained fever, tachycardia, and altered mentation, especially if they have a history of hyperthyroidism
The Burch-Wartofsky Point Scale can be a useful, albeit imperfect, tool for diagnosis
Remember to treat the precipitating factor.
Common Mistakes:
Delaying treatment due to diagnostic uncertainty
Using aspirin, which can worsen thyrotoxicosis
Initiating beta-blockers before thionamides
Inadequate supportive care
Underestimating the severity and potential for rapid deterioration.