Type of publication:
Conference abstract

Author(s):
*Zi Hao Reuel Heng, *Rhys Parry, *Omu Davies, *Roger Slater

Citation:
State of the Art 2019, Intensive Care Society Conference, Birmingham, December 9-12.

Abstract:
Background: Severe hypercalcemia is defined as serum calcium > 3.5 mmol/l.
Major causes of hypercalcemia in adults include primary hyperparathyroidism, milk-alkali syndrome and malignant neoplasms. Neoplasms cause hypercalcaemia either by direct invasion (metastasis) or through factors that stimulate osteoclasts (Parathyroid hormone related peptide or PTHrP). Very rarely a benign tumour can be responsible. Clinical features of hypercalcemia correlate with degree and rapidity of rise of serum calcium. Severe hypercalcemia is associated with neurological, renal and gastrointestinal symptoms.
The differential diagnosis of the cause is determined by measuring parathyroid hormone (PTH) levels.
The case: A 33-year-old woman 37/52 pregnant presented with epigastric pain, vomiting, proteinuria and hypertension and a deteriorating GCS (11/15). A CT head was normal. Blood showed hyperuricaemia and acute kidney injury. She was transferred to the operating room for caesarean section with suspected fulminating pre-eclampsia following a fall in GCS to 8. Immediately prior to general anaesthetic induction she had a generalized seizure. She was induced, intubated and commenced on IV magnesium and labetolol. Following successful delivery, a large pedunculated fibroid was noted on the left side of the uterus. She was transferred to intensive care sedated, intubated and ventilated. Routine blood testing demonstrated severe hypercalcaemia, corrected serum calcium of 5.05 mmol/l. PTH was at the lower limit at 1.3 pmol/l (normal range 1.3 – 7.6 pmol/l). Treatment consisted of IV rehydration with 0.9% sodium chloride 4 litres in 24hr, IV Pamidronate (a bisphosphonate) 60mg over 2 hours. Over the next 3 days the serum calcium returned to normal. A literature search uncovered 3 reports of benign uterine leiomyomas having been the source of ectopic PTHrP leading to hypercalcaemia [1,2,3]. In this case, the uterine fibroid was presumed to have been the source of PTHrP. Unfortunately, direct measurement of PTHrP was not possible at the time of presentation. In view of the fact that the calcium had returned to normal with medical treatment and post-delivery, it was decided to defer further surgery. The patient was successfully weaned from ventilatory support after 5 days. She was monitored and calcium remained within normal limits. 3/12 later the fibroid was removed. The histology showed a mitotically active smooth muscle leiomyoma.
Conclusion: Uterine leiomyoma can rarely be a cause of hypercalcaemia in the critically ill obstetric patient. Severe hypercalcaemia can present in a similar manner to pre-eclampsia, and can worsen pre-eclampsia. Intensivists need to be aware of this condition.
Discussion: The clinical picture was strongly suggestive of severe hypercalcaemia associated with a uterine fibroid. The history did not reveal ingestion of excessive calcium-containing antacids sufficient to cause hypercalcaemia. A hypercalcaemic crisis can occur during pregnancy; the immediate postpartum period being the most likely time,. At this time, relative dehydration and an abrupt decrease in placental transport of calcium to the foetus can coexist. Severe hypercalcaemia can rarely produce seizures, the mechanism is thought to be due to cerebro-vasospasm.
References
1.Ravakhah K, Gover A, Mukunda B. Humoral Hypercalcemia Associated with a Uterine Fibroid. Annals of Internal Medicine 1999; 130: 702.
2.Tarnawa E, Sullivan S, Underwood P et al. Severe hypercalcemia Associated with Uterine Leiomyoma in Pregnancy. Obstetrics & Gynecology 2011;117: 473-476
3.Garcha A, Gumaste P, Cherian S et al. Hypercalcemia: An Unusual Manifestation of Uterine Leiomyoma. Case Reports in Medicine 2013; Article ID 815252.

Link to full-text [no password required]