Severe Hypocalcemia in a Patient with Recurrent Chondrosarcoma

Hypocalcemia is relatively uncommon paraneoplastic syndrome. Only one case of hypocalcemia has been reported in a patient with chondrosarcoma. We herein report a case of a 32-year-old woman with metastatic chondrosarcoma with tetany. Her imaging findings revealed multiple calcific metastatic lesions in the lungs, pancreas, left atrium, and pulmonary vein. A laboratory examination showed hypocalcemia with no evidence of any other disease that could induce hypocalcemia. On the basis of the laboratory and clinical findings, we concluded the etiology of her severe hypocalcemia to be excessive calcium consumption by the tumor itself.

Impaired growth and intracranial calcifications in autosomal dominant hypocalcemia caused by a GNA11 mutation

OBJECTIVE

Autosomal dominant hypocalcemia (ADH) is characterized by hypocalcemia and inappropriately low PTH concentrations. ADH type 1 is caused by activating mutations in the calcium-sensing receptor (CASR), a G-protein-coupled receptor signaling through α11 (Gα11) and αq (Gαq) subunits. Heterozygous activating mutations in GNA11, the gene encoding Gα11, underlie ADH type 2. This study describes disease characteristics in a family with ADH caused by a gain-of-function mutation in GNA11.

DESIGN

A three-generation family with seven members (3 adults, 4 children) presenting with ADH.

METHODS

Biochemical parameters of calcium metabolism, clinical, genetic and brain imaging findings were analyzed.

RESULTS

Sanger sequencing revealed a heterozygous GNA11 missense mutation (c.1018G>A, p.V340M) in all seven hypocalcemic subjects, but not in the healthy family members (n=4). The adult patients showed clinical symptoms of hypocalcemia, while the children were asymptomatic. Plasma ionized calcium ranged from 0.95 to 1.14mmol/L, yet plasma PTH was inappropriately low for the degree of hypocalcemia. Serum 25OHD was normal. Despite hypocalcemia 1,25(OH)2D and urinary calcium excretion were inappropriately in the reference range. None of the patients had nephrocalcinosis. Two adults and one child (of the two MRI scanned children) had distinct intracranial calcifications. All affected subjects had short stature (height s.d. scores ranging from -3.4 to -2.3 vs -0.5 in the unaffected children).

CONCLUSIONS

The identified GNA11 mutation results in biochemical abnormalities typical for ADH. Additional features, including short stature and early intracranial calcifications, cosegregated with the mutation. These findings may indicate a wider role for Gα11 signaling besides calcium regulation.

Bone density assessment in a cohort of pediatric patients affected by 22q11DS

OBJECTIVE

Hypoparathyroidism and hypocalcemia are two of the most frequent clinical characteristics of 22q11-deletion syndrome (22q11DS). The aim of this study was to evaluate bone metabolism and density in a cohort of patients affected by 22q11DS.

METHODS

In 8 pediatric patients (mean age 11.5 years; range 7-16.4) affected by 22q11DS, creatinine, albumin, total and ionized calcium, phosphate, 25(OH) vitamin D, parathyroid hormone, osteocalcin, C-terminal telopeptide and interleukin 6 were assessed. Furthermore, bone mineral density (BMD) was determined by dual-energy X-ray absorptiometry procedure. 14 healthy children were considered as controls.

RESULTS

Most of the studied subjects were overweight and lacked quality physical activity. 40 % of the subjects had reduced calcium levels in the absence of related clinical symptoms and all patients also had inadequate levels of Vitamin D. The values of L1-L4 BMD were within the reference range in all patients (z score <2). However, after comparing the age-matched indexes of bone mineralization of patients with those of controls, the former had lower bone mineralization indexes than the latter.

CONCLUSIONS

In pediatric patients with 22q11DS, an initial and slight bone loss is evident. The incidence of hypocalcemia is underestimated because hypocalcemia is asymptomatic. Several factors contribute to bone impairment in children who still have to achieve bone mass peak. Therefore, we suggest strict monitoring of bone metabolism as well as BMD measurement in patients affected by 22q11DS.

Symptomatic intracranial hypertension and prolonged hypocalcemia following treatment of Paget's disease of the skull with zoledronic acid

Skull involvement in Paget's disease of bone can lead to neurological symptoms, prompting treatment. Intravenous zoledronic acid (ZA) has emerged as an effective and safe treatment option for patients with Paget's, leading to sustained remission and improved quality of life. A previously untreated 61-year-old female presented with 2-year history of facial asymmetry with progressive hearing impairment. Serum calcium levels were normal with upper normal levels of PTH and low 25OHD levels. Serum alkaline phosphatase was markedly increased and bone scan showed extensive pagetic involvement of the skull. Head CT and MRI revealed hydrocephalus with cerebellar tonsillar herniation, platybasia and basilar invagination. In the absence of clinical signs or symptoms of intracranial hypertension, she was treated with intravenous ZA after 15-day supplementation with calcium and vitamin D. Twelve hours after the infusion, the patient became confused, agitated and disoriented and developed urinary incontinence; cortical sulci became effaced on CT indicating increased intracranial pressure. Over the following days, she developed frank hypocalcemia requiring intravenous calcium infusion and calcitriol. Neurological status returned to normal within 24 h of onset, except for urinary incontinence. Nine months later she remained incontinent and still required calcitriol to maintain normocalcemia. Zoledronic acid is a first-line option for the treatment of Paget's disease, yet there can be complications in particular clinical scenarios such as pagetic hydrocephalus, as seen in this case. Plentiful supplementation of calcium and vitamin D before bisphosphonate therapy is paramount in order to minimize the risk of prolonged post-treatment hypocalcemia.

Hypocalcemia with bony metastases in prostate cancer

A 65 year old man presented with a two-month history of low back pain and fatigue and urinary symptoms over the preceding month. He was found to have had a hepatomegaly & a large nodular prostate on rectal examination. Investigations revealed a normal full blood count and renal profile, raised alkaline phosphatase and Prostate Specific Antigen (PSA), and low serum Calcium. A bone scan was performed which revealed widespread bony metastases in the axial and appendicular skeleton resulting in a 'superscan', consistent with prostatic metastases. We recommend that calcium levels be checked in all patients with prostate cancer and metastatic bone disease as this may have a bearing on their symptoms and the use of bisphosphonate therapy.

[Post-operative complications and predictive factors in a series of 117 total thyroidectomies for substernal goiter]

OBJECTIVE

The recurrential nerve palsy (RNP), the hypocalcemy and bleeding are traditional complications of the thyroid surgery. The objective is to bring back the postoperative rates of complications and to compare them with the patient's history and the goiter features (CT-scan extensions and weight) in order to identify predictive factors of these complications.

PATIENTS AND METHOD

One hundred and seventeen patients with a goiter below the subclavicular vessels on the cervicothoracic CT-scan and with a benign extemporane histopathology were operated between february 1997 and January 2004 and included in this retrospective study. The initial clinical assessment reports the respiratory and digestive functional signs, researches a palpable mass and studies the mobility of the vocal folds. The post-operative complications rates (RNP hypocalcemy and bleeding) are analyzed according to the patient's history and the goiter extensions in order to correlate these factors with the complications occurence.

RESULTS

Five unilateral RNP occurred and two of them remained permanent, particularly for patients with thyroid surgery history (NS). The right/left or anterior/posterior extensions did not seem determining factors. Nevertheless the volume of the goiter suspected by the tracheal latero-deviation seems to play a role but without statistical confirmation. Among the thirty-four hypocalcemies, six were defined like permanent, without correlations with the surgical history nor the systematic identification of parathyroid glands. The volume and the younger age of the patient tend nevertheless to support the hypocalcemy. Three post-operative bleeding cases were reported, which one needed a reoperation, with a correlation with thyroid surgical history. None the factors among volume, extension or the age of the patient seem to play a role.

CONCLUSION

The cervico-thoracic CT-scan is essential since echography does not manage to identify the lower pole of the gland. It helps to define the goiter and to analyze its extensions, very usefull to predict surgical difficulties in the preoperative information of the patient. Complications occurrence seems related on the volume and the thyroid surgical history.

Malignant infantile osteopetrosis: a rare cause of neonatal hypocalcemia

Malignant infantile osteopetrosis is a rare autosomal recessive disorder characterized by presentation in the first few months of life with manifestations relating to an underlying defect in osteoclastic bone resorption. This report describes a 10 day-old boy in whom neonatal hypocalcemia was present and whose brother had died with the diagnosis of osteopetrosis.

Parathyroid scintigraphy during hypocalcaemia in primary hyperparathyroidism

BACKGROUND

Minimally invasive parathyroid surgery in patients with primary hyperparathyroidism (PHPT) demands high imaging accuracy. By increasing blood flow to the parathyroid adenoma before injection of a perfusion marker, we intended to improve the parathyroid scintigraphy. We have named the technique stimulated parathyroid scintigraphy (SPS).

METHODS

Twenty minutes after injection of 100 MBq (99m)Tc-pertechnetate a thyroid scintigram was performed in 25 patients with PHPT. During the thyroid scintigraphy sodium citrate was infused which lowered plasma calcium by a mean of 14 +/- 1.3%. Then 700 MBq (99m)Tc-sestamibi was injected and another scintigram of the neck was obtained. Perchlorate was given at the end of the sestamibi scintigram to increase the wash-out of (99m)Tc-pertechnetate from the thyroid gland, and after 2 h a delayed scintigram was obtained. A subtraction of the thyroid scintigram from the initial sestamibi scintigram was performed. The results of SPS and a conventional (99m)Tc-sestamibi dual-phase parathyroid scintigraphy were compared with the operative findings. In nine patients the parathyroid adenoma was also localized with ultrasound and the flow pattern before and after citrate infusion was visualized with Doppler technique.

RESULTS

Eighty-eight per cent of the adenomas were localized correctly with the SPS technique compared with 62% at the conventional parathyroid scintigraphy. Tissue perfusion of the nine adenomas increased after citrate infusion.

CONCLUSIONS

SPS has a high accuracy and it is easy to perform. If only subtraction SPS is performed the whole examination can be completed within an hour, which is acceptable for same day surgery.

Hypocalcemia and myocardial function in uremia

To investigate whether hypocalcemia affects cardiac performance in uremic patients, we studied the hemodynamic changes with short- and long-term correction of hypocalcemia in 4 uremic patients on dialysis using continuous wave Doppler study. At rest, 1 h of intravenous calcium infusion increased calcium level from 1.74 +/- 0.17 to 1.92 +/- 0.16 mmol/l (p less than 0.05). Cardiac output represented by minute distance increased from 10.5 +/- 2.0 to 12.1 +/- 2.5 m (p less than 0.05), but heart rate and blood pressure were unchanged. The peak velocity and acceleration of ascending aortic blood flow increased during calcium infusion. With long-term replacement, calcium level increased from 1.74 +/- 0.17 to 1.94 +/- 0.15 mmol/l (p less than 0.05), but resting hemodynamics were unchanged. On exercise testing, exercise duration increased from 10.6 +/- 1.6 min to 12.9 +/- 1.5 min (p less than 0.01), but hemodynamic parameters at peak exercise were similar. We conclude that acute calcium replacement enhanced cardiac contractility in uremic patients, but cardiac performance at rest and peak exercise was not improved with long-term therapy. This reflects different cardiac responses to acute versus chronic calcium replacement.

Muscle function as a determinant of mandibular growth in normal and hypocalcaemic rat

The aim of the present investigation was to study the influence of low muscle function on the form, growth and structure of the mandible in rats with a metabolic bone disturbance due to hypocalcaemia. Growing rats were randomly divided into four groups where two factors were combined: hard or soft diet consistency to normal or calcium deficient diet. The experimental period was 30 days. At day 0 and day 15 the animals were injected with oxytetracycline. At the end of the experiment X-rays were taken from the mandibles for cephalometric analysis and the bone remodelling pattern was studied under a fluorescence microscope and with help of microradiograms. The cephalometric analysis showed that calcium deficiency was an unfavourable factor for the growth of the mandible as a whole, while muscle function was a significant factor affecting the angular and the condylar processes. General decreased bone apposition and increased endosteal resorption were found in the two calcium deficient diet groups. The cortical bone in these groups was thinner and the trabecular system sparser than in the two normal diet groups. The hard diet groups had higher bone apposition rate and better organized trabecular system than the respective soft diet groups. It was concluded that changes in the mechanical strain environment of the mandible, caused by reducing the vigorous mastication, is a powerful determinant of remodelling behaviour at certain sites, even in situations when a metabolic bone disturbance exists.