A young pregnant woman with shortness of breath
WHAT TREATMENT?
4. How would you treat this patient at this point?
- No drug therapy, just supportive care
- Propranolol (Inderal)
- Levothyroxine
- Propylthiouracil
Several types of drugs are used to manage hyperthyroidism.
Antithyroid drugs such as propylthiouracil, methimazole (Northyx, Tapazole), and carbimazole block thyroid hormone synthesis by inhibiting thyroid peroxidase. Propylthiouracil also blocks peripheral conversion of T4 to T3. Side effects of these agents include abnormal sense of taste, pruritus, urticaria, agranulocytosis, and hepatotoxicity.4
Usually, hyperthyroidism is treated with propylthiouracil at the smallest effective dose. This has been proven to be safe to the fetus and mother during pregnancy.9 Propylthiouracil and the other drugs in its class cross the placenta, but propylthiouracil crosses at one-quarter the rate of the other two.9
Beta-blockers are effective in the acute phase of thyrotoxicosis against tachycardia, hypertension, and atrial fibrillation. They also decrease conversion of T4 to T3, which is an added benefit. Beta-blockers can be tapered as thyroid hormone levels decrease.
A short course of a short-acting beta-blocker would be an option for our patient and would decrease her symptoms, although she does not have the typical markedly elevated T4 or T3 levels. In the long term, a beta-blocker would present a fetal risk, but short courses can be tolerated without incident.9
Radioactive iodine 131 is used in patients with Graves disease. 131Iodine therapy is safe for most adults, but in pregnancy its use is contraindicated. Fetal thyroid tissue is thought to be present after 10 weeks of gestation and could be damaged by the use of radioactive iodine. Another warning with the use of radioactive iodine is that patients should avoid close contact with other adults for a few days after treatment, and should avoid close contact with children and pregnant women for 2 to 3 weeks after treatment because of the risk of exposure to radiation emanating from the thyroid gland.
Levothyroxine is a treatment for hypothyroidism, not hyperthyroidism.
CASE CONTINUED
Our patient is treated with propranolol and monitored for several days in the hospital, during which her symptoms markedly improve. She is discharged without complications.
TAKE-HOME POINTS
The evaluation of shortness of breath in adult patients can be difficult, given the many possible causes. It is especially challenging in pregnant patients, since normal physiologic changes of pregnancy may produce these symptoms.
In many instances, cardiomyopathy must be suspected if a pregnant patient complains of shortness of breath. However, it is not the only possible cause.
