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Difficulty: MediumPharmacologic Interventions

A 45-year-old woman is brought to the emergency department due to altered mental status, high fever, and severe agitation. Her husband reports she has a history of Graves disease but stopped taking her medications three months ago. On physical examination, her temperature is 39.8°C (103.6°F), blood pressure is 160/70 mmHg, and heart rate is 145/min and irregular. She is visibly tremulous, diaphoretic, and delirious. An electrocardiogram confirms atrial fibrillation with a rapid ventricular response. A diagnosis of thyroid storm is suspected.

Which of the following pharmacologic interventions are appropriate components of the immediate management of this patient? (Select all that apply)

  1. Intravenous propranololAnswer
  2. Oral propylthiouracilAnswer
  3. Intravenous hydrocortisoneAnswer
  4. D
    Oral aspirin
  5. E
    Intravenous amiodarone

Answer

The appropriate components of immediate management are intravenous propranolol, oral propylthiouracil, and intravenous hydrocortisone.
The correct interventions directly address the multiple pathophysiologic derangements of thyroid storm. Propranolol controls adrenergic hyperactivity and blocks T4 to T3 conversion. Propylthiouracil halts de novo thyroid hormone synthesis and also blocks peripheral conversion. Hydrocortisone protects against relative adrenal insufficiency and further decreases peripheral T4 to T3 conversion.

Step-by-Step Solution

1
Diagnose the acute condition based on the clinical presentation.
The patient is experiencing thyroid storm, characterized by hyperpyrexia, cardiovascular dysfunction (atrial fibrillation), and severe central nervous system manifestations (delirium) in the setting of untreated Graves disease.
Establishing the correct diagnosis dictates the emergent multi-step pharmacologic protocol required to stabilize the patient.
2
Select an agent to control the severe adrenergic symptoms and heart rate.
Intravenous propranolol is selected.
Propranolol controls the heart rate in atrial fibrillation and manages tremor and agitation. It also blocks the peripheral conversion of T4 to T3.
3
Select agents to halt the synthesis of new thyroid hormone.
Oral propylthiouracil (PTU) is selected.
PTU blocks de novo hormone synthesis via thyroid peroxidase inhibition and effectively blocks peripheral conversion of T4 to T3.
4
Select an agent to prevent relative adrenal insufficiency and further reduce active hormone levels.
Intravenous hydrocortisone is selected.
High metabolic demand accelerates cortisol clearance, risking adrenal crisis. Glucocorticoids also further inhibit peripheral T4 to T3 conversion.
5
Identify and exclude contraindicated medications for symptom management.
Aspirin (for fever) and amiodarone (for atrial fibrillation) are excluded.
Aspirin displaces thyroid hormone from binding proteins, and amiodarone contains a large iodine load, both of which would acutely worsen thyrotoxicosis.

Key Concept

The acute pharmacologic management of thyroid storm requires a multi-drug regimen to block adrenergic tone (propranolol), inhibit new thyroid hormone synthesis (propylthiouracil), and block peripheral conversion of T4 to T3 (propranolol, PTU, and glucocorticoids), while strictly avoiding medications that can increase free hormone levels (salicylates) or provide excess iodine load (amiodarone).
Estimated Time:1m 30s
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Pharmacologic Interventions

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