A 37-year-old woman comes to the emergency department due to persistent nausea and vomiting. The patient has had intermittent nausea for the past week and constant nausea and vomiting for the past 2 days. Now, she is unable to tolerate any solids or liquids. The patient has had no fever, chills, abdominal pain, diarrhea, constipation, or sick contacts. She has well-controlled chronic hypertension and hypothyroidism. The patient has had no surgeries. She is sexually active and uses condoms intermittently. The patient smokes half a pack of cigarettes daily but does not use alcohol or recreational drugs. Temperature is 36.7 C (98 F), blood pressure is 130/88 mm Hg, and pulse is 108/min. Mucous membranes are dry and capillary refill time is delayed. The thyroid is nontender and diffusely enlarged on palpation. Cardiac examination shows sinus tachycardia and no murmurs. The abdomen is nontender and nondistended. A urine pregnancy test is positive. Urinalysis is positive for ketones. Pelvic ultrasound reveals a viable, 8-week intrauterine twin gestation. Which of the following is the most significant risk factor for this patient's current symptoms?
Hyperemesis gravidarum | |
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This patient has hyperemesis gravidarum, a severe form of persistent nausea and vomiting in pregnancy that is often characterized by dehydration (eg, dry mucous membranes, delayed capillary refill, tachycardia) and hypoglycemia (as evidenced by ketonuria). Additional clinical features may include orthostatic hypotension, electrolyte abnormalities, and a >5% loss of prepregnancy weight. Hyperemesis gravidarum typically occurs during the first trimester and early portions of the second trimester.
A common risk factor for hyperemesis gravidarum is a twin (multiple) gestation; other risk factors include hyperemesis gravidarum in a prior pregnancy, a hydatidiform mole, and a history of migraines or motion sickness. Twin gestations are thought to be at an increased risk for hyperemesis gravidarum due to elevated hCG and progesterone concentrations from a larger placental volume. hCG levels (which peak at the same time as hyperemesis gravidarum symptoms) may be a cause for increased nausea. Elevated progesterone levels, which relax smooth muscle tone at the lower esophageal sphincter (ie, gastroesophageal reflux) and in the stomach (ie, delayed gastric emptying), can cause increased or persistent vomiting.
Nausea and vomiting in pregnancy typically resolve spontaneously by the second trimester and can be managed with antiemetics and dietary changes (eg, small meals). Patients with hyperemesis gravidarum typically require treatment for their electrolyte abnormalities and hypovolemia and are placed on multiple scheduled antiemetics.
(Choice A) Chronic hypertension is a risk factor for preeclampsia, fetal growth restriction, and abruptio placentae. It is not a risk factor for hyperemesis gravidarum.
(Choice B) Hyperemesis gravidarum may cause a transient hyperthyroidism because elevated hCG levels share a similar subunit to TSH and, therefore, can have some thyroid-stimulating activity. Maternal hypothyroidism does not increase the risk of hyperemesis gravidarum.
(Choice C) Hyperemesis gravidarum is more common in young women during their first pregnancy, not those of advanced (>35) maternal age.
(Choice E) Tobacco use protects against hyperemesis gravidarum, likely because it increases the metabolism of estrogen and thereby decreases serum estrogen levels.
Educational objective:
Hyperemesis gravidarum is a severe form of nausea and vomiting in pregnancy that typically occurs during the first trimester. A common risk factor is a twin gestation due to elevated hCG and progesterone levels.