A 48-year-old woman with a history of Grave’s disease undergoes an urgent appendectomy. Four hours after surgery she is found to be confused and diaphoretic. Her vital signs are:
On physical examination there is no evidence of rigidity. An arterial blood gas ABG shows:
Thyroid function tests are sent. Although awaiting the results, which of the following medications would be most appropriate to give?A. Aspirin
Correct Answer: B
This patient has thyrotoxicosis (thyroid storm), an acute, life-threatening hypermetabolic state resulting from excessive thyroid hormone. It clinically manifests as altered mental status, fever, tachycardia, and hypertension, which can lead to cardiomyopathy, congestive heart failure, and cardiovascular collapse. In patients with underlying hyperthyroidism it may be precipitated by illness, surgery, or other severe stress. Management is generally supportive with cooling and administration of fluids, as well as measures to inhibit the effects of the excessive thyroid hormones, reduce thyroid hormone synthesis, and prevent further release. The underlying cause of the thyroid storm should also be treated.
Propranolol is effective at blocking the hyperadrenergic manifestations of thyrotoxicosis. Propranolol is a nonselective beta blocker that crosses the blood-brain barrier and is known to decrease the conversion of T4 to T3. Although antipyretic agents should also be administered, aspirin is generally avoided as it may displace thyroid hormone from thyroid binding globulin and exacerbate symptoms. Bromocriptine is a dopamine agonist that is used in treatment of neuroleptic malignant syndrome. Dantrolene expresses excitation-contraction coupling in skeletal muscle by acting as a receptor antagonist to the ryanodine receptor and is the treatment for malignant hyperthermia. Neuroleptic malignant syndrome and malignant hyperthermia are hypermetabolic states that can present similarly to thyrotoxicosis (tachycardia, hyperthermia, altered mental status) but also more commonly result in muscle rigidity, metabolic acidosis, and hypercarbia.