Humoral hypercalcemic crisis in a pregnant woman with uterine leiomyoma

Hypercalcemia Resulting from Necrotizing Leiomyoma in a Pregnant Female

Patient: Female, 38-year-old

Final Diagnosis: Hypercalcemia resulting from necrotizing leiomyoma in pregnancy

Symptoms: Pain

Medication: —

Clinical Procedure: Cesarean section

Specialty: General and Internal Medicine • Obstetrics and Gynecology

Cystic pelvi-abdominal mass in pregnancy: An uncommon presentation of a subserosal leiomyoma

Uterine leiomyomas are common benign neoplasms. While generally easily diagnosed, variations in size and type of degeneration can drastically alter the imaging findings and result in diagnostic uncertainty. We present the case of a 34-year-old female with a large, cystic, pelvi-abdominal mass that was discovered in advanced pregnancy and misdiagnosed as an ovarian tumour. Intra-uterine demise of a viable foetus during an induction of labour and clinical deterioration necessitated further imaging and emergent surgical intervention. Further imaging, intra-operative findings and histopathological correlation revealed a pedunculated uterine leiomyoma with hyaline degeneration and areas of necrosis, complicated by left ovarian vein thrombosis. In addition to the intra-uterine demise, the unfortunate outcome included a total abdominal hysterectomy and unilateral salpingo-oophorectomy in a young patient. Typical leiomyomas are easily detected with imaging, however the varied clinical presentation and imaging findings in degenerating leiomyomas can prove a diagnostic challenge. This case describes a rare manifestation of a common condition and its subsequent diagnostic dilemma resulting in dire foeto-maternal outcomes.

Keywords

Leiomyoma; Hypercalcaemia; Ovarian Vein Thrombosis; Pregnancy; Intra-Uterine Foetal Demise.

Suspected Hypercalcemia of Benignancy Associated with Canine Vaginal Leiomyoma

Hypercalcemia was identified in a canine patient with a benign vaginal leiomyoma. Subsequent diagnostic workup did not reveal hypercalcemia of malignancy. Surgical resection of the leiomyoma resulted in a conversion to normocalcemic status. Although rare, hypercalcemia of benignancy should be considered in a patient in which hypercalcemia is identified via clinical pathology.

Humoral hypercalcemia of pregnancy treated with bisphosphonates

Hypercalcemia can be hazardous during pregnancy, most cases being due to primary hyperparathyroidism. We report a case of hypercalcemia with suppressed PTH levels necessitating treatment with bisphosphonates during pregnancy. A 38-year-old woman at the 26th week gestation was admitted because of symptomatic hypercalcemia. She did not take any medication that could influence her calcium levels. Physical examination was unremarkable. Laboratory tests on admission were: calcium 12.7 mg/dL (8.5-10.5 mg/dL), phosphorus 1.8 mg/dL (2.5-4.5 mg/dL) and PTH on 3 consecutive tests 1.2, 1.3 and 1.2 pg/mL (15-65 pg/mL). Her 24h urine calcium was 900 mg, 25-OH-D 40 ng/mL (30-58 ng/mL) and 1,25-OH-D 99 pg/mL (80-146 for women in the third trimester). Abdominal ultrasound revealed multiple hypervascular liver lesions consistent with hemangiomas by MRI. Breast and neck ultrasound were normal, and chest CT revealed few non-significant 0.3-0.7 cm pulmonary nodules with no change after an interval of 3 months. She was treated with isotonic saline, loop diuretics and calcitonin. Despite this treatment, calcium levels remained high (14.1 mg/dL), and pamidronate was initiated. On 35th week gestation, she underwent a cesarean section complicated by hypocalcemia of the newborn. Eight weeks after delivery, her calcium levels are 9.4 mg/dL and PTH 18 mg/dL. According to the extensive workup and the post-partum normalization of PTH and calcium levels, we conclude that excessive secretion of placental PTHrP was the cause of hypercalcemia in this patient. No significant adverse effect of bisphosphonate on the mother or baby were seen at the short term follow up.

Selective Calcium-Dependent Inhibition of ATP-Gated P2X3 Receptors by Bisphosphonate-Induced Endogenous ATP Analog ApppI

Pain is the most unbearable symptom accompanying primary bone cancers and bone metastases. Bone resorptive disorders are often associated with hypercalcemia, contributing to the pathologic process. Nitrogen-containing bisphosphonates (NBPs) are efficiently used to treat bone cancers and metastases. Apart from their toxic effect on cancer cells, NBPs also provide analgesia via poorly understood mechanisms. We previously showed that NBPs, by inhibiting the mevalonate pathway, induced formation of novel ATP analogs such as ApppI [1-adenosin-5'-yl ester 3-(3-methylbut-3-enyl) triphosphoric acid diester], which can potentially be involved in NBP analgesia. In this study, we used the patch-clamp technique to explore the action of ApppI on native ATP-gated P2X receptors in rat sensory neurons and rat and human P2X3, P2X2, and P2X7 receptors expressed in human embryonic kidney cells. We found that although ApppI has weak agonist activity, it is a potent inhibitor of P2X3 receptors operating in the nanomolar range. The inhibitory action of ApppI was completely blocked in hypercalcemia-like conditions and was stronger in human than in rat P2X3 receptors. In contrast, P2X2 and P2X7 receptors were insensitive to ApppI, suggesting a high selectivity of ApppI for the P2X3 receptor subtype. NBP, metabolite isopentenyl pyrophosphate, and endogenous AMP did not exert any inhibitory action, indicating that only intact ApppI has inhibitory activity. Ca²⁺-dependent inhibition was stronger in trigeminal neurons preferentially expressing desensitizing P2X3 subunits than in nodose ganglia neurons, which also express nondesensitizing P2X2 subunits. Altogether, we characterized previously unknown purinergic mechanisms of NBP-induced metabolites and suggest ApppI as the endogenous pain inhibitor contributing to cancer treatment with NBPs.

Hypercalcemia in pregnancy - a multifaceted challenge: case reports and literature review

Hypercalcemia in pregnancy is an uncommon event that can cause major maternal morbidity and/or fetal or neonatal morbidity and mortality. Management is a challenge for the clinicians, especially as regards to investigations in pregnancy, surgery, and the use of cinacalcet and bisphosphonates. We present three case reports and discuss management.

Desensitization properties of P2X3 receptors shaping pain signaling

ATP-gated P2X3 receptors are mostly expressed by nociceptive sensory neurons and participate in transduction of pain signals. P2X3 receptors show a combination of fast desensitization onset and slow recovery. Moreover, even low nanomolar agonist concentrations unable to evoke a response, can induce desensitization via a phenomenon called “high affinity desensitization.” We have also observed that recovery from desensitization is agonist-specific and can range from seconds to minutes. The recovery process displays unusually high temperature dependence. Likewise, recycling of P2X3 receptors in peri-membrane regions shows unexpectedly large temperature sensitivity. By applying kinetic modeling, we have previously shown that desensitization characteristics of P2X3 receptor are best explained with a cyclic model of receptor operation involving three agonist molecules binding a single receptor and that desensitization is primarily developing from the open receptor state. Mutagenesis experiments suggested that desensitization depends on a certain conformation of the ATP binding pocket and on the structure of the transmembrane domains forming the ion pore. Further molecular determinants of desensitization have been identified by mutating the intracellular N- and C-termini of P2X3 receptor. Unlike other P2X receptors, the P2X3 subtype is facilitated by extracellular calcium that acts via specific sites in the ectodomain neighboring the ATP binding pocket. Thus, substitution of serine275 in this region (called “left flipper”) converts the natural facilitation induced by extracellular calcium to receptor inhibition. Given their strategic location in nociceptive neurons and unique desensitization properties, P2X3 receptors represent an attractive target for development of new analgesic drugs via promotion of desensitization aimed at suppressing chronic pain.