Low-grade fever, erythematous rash in pregnant woman • Dx?

Treating pregnant patients

Doxycycline and tetracycline, which are routinely used to treat Lyme disease, are not appropriate in the obstetric population. The CDC recommends up to a 3-week course of antibiotics; the standard regimen is amoxicillin 500 mg by mouth tid. For women who are allergic to penicillin, as was the case with our patient, cefuroxime 500 mg by mouth bid is the treatment of choice.⁹

Our patient underwent a detailed ultrasound at 21 weeks, which revealed normal fetal anatomy and no evidence of cardiac malformations. The remainder of her pregnancy was uncomplicated, and she gave birth vaginally at 41 weeks to a baby boy weighing 3700 g.

THE TAKEAWAY

There is a need to increase awareness of Lyme disease in pregnancy on a national level. It is the responsibility of every practitioner caring for obstetric patients in endemic regions to address new-onset rash promptly. There have been cases of women who experienced erythema migrans and arthralgias after exposure to a tick bite, later delivering infants with cardiac anomalies such as atrial and ventricular septal defects.¹⁰ In obstetric patients acutely infected during the first trimester, a fetal echocardiogram is reasonable, given the demonstrated high potential for fetal cardiac anomalies.

Preventing adverse fetal outcomes requires early treatment with antibiotics. The CDC maintains that there have been no life-threatening adverse fetal effects from Lyme disease seen in women who are appropriately treated, as well as no transmission of Lyme disease in the breast milk of lactating mothers.⁹