Ventricular fibrillation due to hypocalcemia after parathyroidectomy with autotransplantation of parathyroid tissue in a dialysis patient

Is severe hypocalcemia immediately life-threatening?

Objective

Severe hypocalcemia (Ca <1.9 mmol/L) is often considered an emergency because of a potential risk of cardiac arrest or seizures. However, there is little evidence to support this. The aim of our study was to assess whether severe hypocalcemia was associated with immediately life-threatening cardiac arrhythmias or neurological complications.

Methods

A retrospective observational study was carried out over a 2 years period in the Adult Emergency Department (ED) of Nantes University Hospital. All patients who had a protein-corrected calcium concentration measure were eligible for inclusion. Patients with multiple myeloma were excluded. The primary outcome was the number of life-threatening cardiac arrhythmias and/or neurological complications during the stay in the ED.

Results

A total of 41,823 patients had protein-corrected calcium (pcCa) concentrations measured, 155 had severe hypocalcaemia, 22 were excluded because of myeloma leaving 133 for analysis. Median pcCa concentration was 1.73 mmol/L [1.57-1.84]. Seventeen (12.8%) patients presented a life threatening condition, 14 (10.5%) neurological and 3 (2.2%) cardiac during ED stay. However these complications could be explained by the presence of underlying co-morbidities and or electrolyte disturbances other than hypocalcaemia. Overall 24 (18%) patients died in hospital. Vitamin D deficiency, chronic kidney disease and hypoparathyroidism were the most frequently found causes of hypocalcemia.

Conclusion

13% of patients with severe hypocalcaemia presented a life-threatening cardiac or neurological complication on the ED. However a perfectly valid alternative cause could account for these complications. Further research is warranted to define the precise role of hypocalcaemia.

Micronutrients and their supplementation in chronic cardiac failure. An update beyond theoretical perspectives

Physicians' use of micronutrients to improve symptoms or outcomes in chronic illness has until recently been guided by limited data on the actions of individual agents in vitro or in animal studies. However several recently published clinical trials have provided information about which groups of patients are likely to benefit from which combination of micronutrients. Patients with chronic cardiac failure (CCF), particularly elderly individuals, have several reasons to be deficient in micronutrients including reduced intake, impaired gastrointestinal absorption and increased losses on the background of increased utilisation due for example to increased oxidative stress. Studies of nutritional supplementation in CCF patients have usually concentrated on specific agents. However given that many micronutrients have synergistic influences upon metabolic processes this strategy might merely lead to a shifting of a limiting step. Rather, a strategy of increasing the availability of multiple agents at once might be more logical. The aim of this article is to briefly review the experimental rationale for each of the micronutrients of potential benefit in chronic heart failure and examine the current clinical trial evidence supporting their use.

Chronic heart failure and micronutrients

Heart failure (HF) is associated with weight loss, and cachexia is a well-recognized complication. Patients have an increased risk of osteoporosis and lose muscle bulk early in the course of the disease. Basal metabolic rate is increased in HF, but general malnutrition may play a part in the development of cachexia, particularly in an elderly population. There is evidence for a possible role for micronutrient deficiency in HF. Selective deficiency of selenium, calcium and thiamine can directly lead to the HF syndrome. Other nutrients, particularly vitamins C and E and beta-carotene, are antioxidants and may have a protective effect on the vasculature. Vitamins B6, B12 and folate all tend to reduce levels of homocysteine, which is associated with increased oxidative stress. Carnitine, co-enzyme Q10 and creatine supplementation have resulted in improved exercise capacity in patients with HF in some studies. In this article, we review the relation between micronutrients and HF. Chronic HF is characterized by high mortality and morbidity, and research effort has centered on pharmacological management, with the successful introduction of angiotensin-converting enzyme inhibitors and beta-adrenergic antagonists into routine practice. There is sufficient evidence to support a large-scale trial of dietary micronutrient supplementation in HF.

Clinical course after total parathyroidectomy without autotransplantation in patients with end-stage renal failure

In patients with chronic renal failure, hyperparathyroidism is a common problem and surgical parathyroidectomy (PTX) is frequently required. The three different surgical approaches are subtotal PTX, total PTX with autotransplantation, and total PTX without autotransplantation. Recurrence of hyperparathyroidism varies from 5% to 80% in different studies for the first two surgical approaches. To minimize the risk for recurrence, and because we fear severe relapses with calciphylaxia, we perform total PTX without autotransplantation. From October 1993 to October 1997, 20 patients (9 men and 11 women) underwent total PTX without autotransplantation (median age, 52 years; range, 23 to 74 years; median dialysis time before PTX, 6.5 years; range, 1 to 22 years). All patients were supplemented with vitamin D analogues postoperatively. Patients were followed up for 1 to 48 months (median, 20 months). Bone pain, when present, disappeared within the first week after total PTX. Postoperatively, most patients had temporary hypocalcemia. In the long term, five patients had asymptomatic hypocalcemia. One patient, however, repeatedly had hypocalcemic seizures. Five patients developed asymptomatic hypercalcemia when supplemented with calcitriol. At the end of the individual's observation time, parathyroid hormone (PTH) levels were less than normal in six patients, normal in seven patients, and increased in seven patients despite total PTX. We conclude that total PTX should be reconsidered an option for the treatment of hyperparathyroidism secondary to renal failure. There was no evidence of clinical bone disease after total PTX. Apparently, remaining ectopic parathyroid tissue accounts for PTH levels after total PTX.