Hypercalcemia, arrhythmia, and mood stabilizers

Mortality associated with lithium and valproate treatment of US Veterans Health Administration patients with mental disorders

BackgroundThe mood stabilisers lithium and valproate might plausibly have differing associations with mortality because of differing effects on mental health and various physiological indicators.AimsTo assess associations between lithium, valproate and non-suicide mortality.MethodIntention-to-treat, propensity score-matched cohort study.ResultsLithium was associated with significantly reduced non-suicide mortality in the intent-to-treat cohort over 0-90 days (hazard ratio (HR) = 0.67, 95% CI 0.51-0.87) but not longer. In secondary analyses, a sizeable reduction in mortality was observed during active treatment with lithium across all time periods studied (for example 365-day HR = 0.62, 95% CI 0.45-0.84), but significantly increased risks were observed among patients discontinuing lithium by 180 days (HR = 1.54, 95% CI 1.01-2.37).ConclusionsPatients initiating lithium had lower non-suicide mortality over 0-90 days than patients initiating valproate and consistently lower non-suicide mortality among patients maintaining treatment, but elevated risk among patients discontinuing treatment by 180 days. Although residual confounding or selection effects cannot be excluded, this study suggests potential benefits to enhancing lithium treatment persistence and the monitoring of patients discontinuing lithium. There is a need for further research.

Atrioventricular nodal dysfunction secondary to hyperparathyroidism

The relationship of hyperparathyroid-associated hypercalcemia with clinical significant bradyarrythmias still remains controversial. We present a 66-year-old patient with dizziness, headache and paroxysmal 2:1 atrioventricular block. A 24-hour Holter report revealed symptomatic intermittent 2(nd) degree (2:1) atrioventricular block with a mean heart rate of 46 bpm. A 2D echocardiogramm showed normal ejection fraction and there was no valve dysfunction or calcification. The biochemistry results showed elevated serum calcium level, low phosphate level, elevated serum parathyroid hormone level and normal serum levels of potassium, magnesium and sodium. The urine calcium excretion was 390 mg/24 h. A coronary angiography was performed and revealed no critical lesions. The patient continued to have symptoms despite of the treatment of hypercalcemia and a DDDR pacemaker was implanted. He had a Sestamibi-scan of the neck, that was suggestive of parathyroid adenoma, and parathyroidectomy was performed. The presuming mechanism is the degeneration of AV node due to calcium deposit.

Lithium-induced sinus node dysfunction at therapeutic levels

Lithium is used as an antimanic and mood-stabilising drug. It can cause various adverse effects such as nausea, vomiting, polyuria, fine tremors, myocarditis and arrhythmias. We are describing a case of lithium induced sinus-node dysfunction in a patient with serum lithium levels in therapeutic range.

Mechanisms and treatment of hypercalcemia of malignancy

PURPOSE OF REVIEW

Hypercalcemia of malignancy is a common paraneoplastic syndrome and a frequent complication of advanced breast and lung cancer, and multiple myeloma. The development of this malignancy complication often purports a poor prognosis. Thorough evaluation to establish the cause of hypercalcemia is essential because some patients may actually have undiagnosed primary hyperparathyroidism.

RECENT FINDINGS

Production of humoral factors by the primary tumor, collectively known as humoral hypercalcemia of malignancy (HHM), is the mechanism responsible for 80% of cases. The vast majority of HHM is caused by tumor-produced parathyroid hormone-related protein followed by infrequent tumor production of 1,25-dihydroxyvitamin D and parathyroid hormone. The remaining 20% of cases are caused by bone metastasis with consequent bone osteolysis and release of skeletal calcium. Key therapies are saline hydration to promote calciuresis and bisphosphonates to reduce pathologic osteoclastic bone resorption. Calcitonin and glucocorticoids, especially in 1,25-dihydroxyvitamin D-mediated HHM, also have calcium-lowering effects.

SUMMARY

Recent discoveries on mechanisms of malignancy-associated hypercalcemia highlight the critical role of the osteoclast. Bisphosphonates and other novel therapies being evaluated in clinical trial target this bone-resorbing cell type and provide effective and durable serum calcium reduction.

Lithium-induced sinus node disease at therapeutic concentrations: linking lithium-induced blockade of sodium channels to impaired pacemaker activity

The present report describes a case of sinus node arrest in a manic-depressive patient being treated with lithium carbonate with a therapeutic serum level of lithium. A permanent rate-modulated ventricular pacemaker was inserted and lithium therapy was continued. A review of literature revealed several other similar case reports in which both therapeutic and toxic levels of serum lithium levels were associated with sinus node dysfunction and bradyarrhythmias. Because lithium is a potent blocker of cardiac sodium channels, and given the critical importance of sodium channels in pacemaker activity, lithium-induced sodium channel blockade is likely an important mechanism in sinus node dysfunction.

Normalization of lithium-induced hypercalcemia and hyperparathyroidism with cinacalcet hydrochloride

An underrecognized side effect of long-term lithium carbonate therapy is hyperparathyroidism with associated hypercalcemia and hypocalciuria. Because cessation of lithium carbonate therapy usually does not correct the hyperparathyroidism and associated hypercalcemia, parathyroidectomy frequently is necessary. This is the initial report of 2 patients with lithium carbonate-induced hyperparathyroidism treated with cinacalcet hydrochloride (HCl), which normalized serum calcium levels and reduced intact parathyroid hormone (iPTH) secretion. The patients, both with bipolar disease and a 15- to 30-year history of lithium carbonate therapy, were evaluated for stage 3 chronic kidney disease, persistent hypercalcemia, and hyperparathyroidism. A 67-year-old woman was administered cinacalcet HCl, 30 mg/d, for 11 months. Mean serum calcium level decreased from 10.8 +/- 0.4 mg/dL (2.69 +/- 0.10 mmol/L) to 9.9 +/- 0.4 mg/dL (2.47 +/- 0.10 mmol/L; P < 0.001), and iPTH level decreased from 139 +/- 31 pg/mL (139 +/- 31 ng/L) to 114 +/- 39 pg/mL (114 +/- 39 ng/L; P = not significant). A 63-year-old man was administered 30 mg/d of cinacalcet HCl for 8 months, then 60 mg/d for another 2 months. Mean serum calcium and iPTH levels decreased from 11.0 +/- 0.5 mg/dL (2.74 +/- 0.12 mmol/L) to 10.3 +/- 0.4 mg/dL (2.57 +/- 0.10 mmol/L; P < 0.001) and 138 +/- 10 pg/mL (138 +/- 10 ng/L) to 73 +/- 7 pg/mL (73 +/- 7 ng/L; P = 0.03), respectively. Urinary fractional excretion of calcium was low for both patients before (<0.026 and <0.015) and after (0.026 and 0.008) treatment with cinacalcet HCl. These findings suggest that cinacalcet HCl can provide an alternative nonsurgical means to control this disorder in patients with hypercalcemia of variable severity for whom surgical treatment is not a consideration because of perceived mildness of disease or unsuitability of the patient for surgical intervention.

Metabolism, lifestyle and bipolar affective disorder

Lifestyle, illness and treatment factors in people with bipolar disorder (BD) may confer additional risk of morbidity and mortality to the increasing rates of obesity, metabolic syndrome, diabetes mellitus and cardiovascular mortality in the general population.The aim of this review is to examine whether the risk of obesity and related morbidity and mortality are raised in BD, and possible contributory effects of lifestyle, illness and treatment factors to this risk.Systematic search of Medline and Cochrane Collaboration for relevant studies followed by a critical review of literature was carried out.Mortality from cardiovascular causes and pulmonary embolism (standardized mortality ratio approximately 2.0), and morbidity from obesity and type 2 diabetes mellitus may be increased in BD compared to the general population. Reduced exercise and poor diet, frequent depressive episodes, comorbidity with substance misuse and poor quality general medical care contribute to the additional risk of these medical problems in people with BD. There is no evidence that patients with BD are more sensitive than other patients to weight gain and medical problems associated with long-term use of psychotropic medication; in fact long-term treatment with lithium, antipsychotics and tricyclic antidepressants may reduce overall mortality. Psychiatrists, general practitioners and other health professionals should work together to systematically assess and manage weight gain and related medical problems to reduce the morbidity and mortality associated with obesity in BD. There is insufficient evidence to associate any of these factors with specific drug treatments. More research is required to understand how BD changes the risk for physical health comorbidity.