Diagnosing Primary Hyperparathyroidism in Pregnancy: A Case of Altered Parathyroid Hormone Degradation in Pregnancy.

Diagnosing primary hyperparathyroidism in pregnancy is difficult due to pregnancy-related changes in parathyroid hormone (PTH); calcium; 1,25 vitamin D; and renal calcium excretion. Parathyroid hormone-related peptide (PTHrP) produced by the placenta adds additional complexity. Our case is the first to demonstrate an increased rate of PTH degradation within a pregnant individual who returned unexpectedly low PTH levels. We describe a 27-year-old female patient who presented at 25 weeks gestation with pancreatitis and hypercalcemia. Primary hyperparathyroidism was suspected but variable PTH results led to uncertainty and an assay error was considered. PTH samples were collected in both serum-separating tubes (SST) and EDTA tubes and compared to controls (5 nonpregnant and 5 pregnant individuals). Samples were retested every 2 hours for a period of 10 hours. A rapid decline in the measured PTH was noted in the index case, an observation which differed from controls. We postulated that internal and/or external factors influenced the PTH measurement obtained from our patient. From our observations, rapid PTH degradation in pregnancy, and individual variation in PTH stability and laboratory processes, can influence PTH results and impact on interpreting hypercalcemia in pregnancy.

Maternal Metyrapone Use During Breastfeeding: Safe for the Breastfed Infant.

CONTEXT: Metyrapone is an inhibitor of endogenous adrenal corticosteroid synthesis, which has been proven to be a viable option in controlling maternal serum cortisol concentrations during pregnancy. The infant exposure to maternally ingested metyrapone through breast milk is, however, largely unknown. CASE DESCRIPTION: We report the excretion of metyrapone into breast milk and subsequent infant exposure from a lactating woman on 250 mg of metyrapone three times daily. Due to limited supply of breast milk, the infant was fed ∼50% breast milk and 50% formula. At steady state, the average concentrations in the studied breast milk and absolute and relative infant doses were 176 µg/L, 26.45 µg/kg/d, and 0.7%, respectively, for metyrapone, and 310 µg/L, 46.52 µg/kg/d, and 1.21% for its active metabolite metyrapol. The breastfed infant was found to have a plasma metyrapone concentration of 0.05 µg/L, with no evidence of disruption to his adrenocortical axis biochemically. CONCLUSION: These findings indicate that maternal metyrapone use during breastfeeding did not pose a notable risk to this breastfed infant. The infants' exposure to metyrapone was further minimized by avoiding nursing for 2 to 3 hours after each metyrapone dose.

Profound Hypokalaemia Resulting in Maternal Cardiac Arrest: A Catastrophic Complication of Hyperemesis Gravidarum?

We present a case of a 39-year-old G8P6 Pacific Islander woman who at 15+5 weeks' gestation had an out-of-hospital cardiac arrest secondary to profound hypokalaemia which was associated with severe hyperemesis gravidarum (HG). Her clinical course after arrest was complicated by a second 5-minute cardiac arrest in the Intensive Care Unit (ICU) (pre-arrest potassium 1.8), anuric renal failure requiring dialysis, ischaemic hepatitis, and encephalopathy and unfortunately fetal demise and a spontaneous miscarriage on day 2 of admission. Despite these complications, she was discharged home 4 weeks later with a full recovery. Following a plethora of inpatient and outpatient investigations, the cause of her cardiac arrest was determined to be profound hypokalaemia. The hypokalaemia was presumed second to a perfect storm of HG with subsequent nutritional deficiencies causing electrolyte wasting, extracellular fluid (ECF) volume reduction, and activation of the renin-angiotensin-aldosterone axis (RAAS). This combined with the physiological changes that promote potassium wasting in pregnancy including volume expansion, increased renal blood flow, increased glomerular filtration rate, and increase in cortisol contributed to the patient having a profoundly low total body potassium level. This diagnosis is further strengthened by the fact that her pre- and post-pregnancy potassium levels were within normal limits in the absence of supplementary potassium. This case highlights the potentially life-threatening electrolyte imbalances that can occur with HG and the importance of recognising the disease, comprehensive electrolyte monitoring, and aggressive management in pregnancy.