Case Presentation:
This is an 18‐year‐old woman diagnosed with pulmonary Langerhans cell histiocytosis (LCH) 3 months prior to becoming pregnant. She was treated at the time with etoposide and dexamethasone. She remained asymptomatic until 27 weeks of gestation, when she had worsening dyspnea with deterioration of her spirometry (20% decrease of both FVC and FEV1) and development of diffuse interstitial fibrosis on chest roentgenogram. She remained in close observation until 34 weeks of gestational age, when was admitted to the intensive care unit with worsening dyspnea, weakness, and polyuria. The patient had worsening spirometry, with an additional 15% decrease of both FVC and FEV1. Urine output was 14 mL/kg/h, urinary density 1.005, urine osmolality 303 mOsm, FeNa < 1%, and sodium 145 mEq. A diagnosis of LCH flare with pulmonary involvement and diabetes insipidus (DI) was made. The patient was started on intranasal desmopressin acetate 20 μg twice a day, and oral prednisone 1 mg/kg/day with good clinical and laboratory response. An elective C‐section was performed 2 days later, and she delivered a healthy female weighing 2150 g. Two days after delivery the patient received 2 doses of vinblastine (0.1 mg/kg) with 3 days apart between doses; prednisone was continued at the same dose. Her spirometry normalized. The patient was able to be discharged 2 weeks after delivery, with intranasal desmopressin therapy because of persistent DI.
Discussion:
Langerhans cell histiocytosis is a rare, clinically heterogeneous disease of unknown etiology characterized by the proliferation of histiocytes (cells of dendritic cell lineage that resemble Langerhans cells) and eosinophils. It occurs predominantly in children and young adults, with an incidence of in 0.5–5 per million and poor survival into adulthood. The clinical spectrum of LCH is quite varied, as any organ can be affected. Diabetes insipidus is characterized by polyuria, decreased urinary concentration, dehydration, and hypernatremia. Pregnancy itself can predispose to diabetes insipidus because of marked increase in vasopressin turnover as placental‐derived vaso‐pressinases increase throughout pregnancy, requiring q progressive increase in vasopressin production to match the rate of degradation. Because of its similar biochemical structure to oxytocin, vasopressin should be avoided in pregnancy given the theoretical risk of uterine contractions. The drug of choice to treat DI during pregnancy is desmo‐pressin, which does not seem to be teratogenic or promote uterine contractions or appear in breast milk. Its dosage must be individualized according to the urine output and osmolality.
Conclusions:
The hospitalist should be aware of the management of diabetes insipidus in pregnancy, especially in patients with predisposing conditions such as infil‐trative diseases.
Disclosures:
O. Felipe Duen˜as‐Garcia ‐ none; C. Chanana ‐ none; M. Auron ‐ none