Hypercalcemia: mechanisms, differential diagnosis, and remedies

Calcium Alkali Syndrome Treated With Hemodialysis

Malignancy, primary hyperparathyroidism, and vitamin D intoxication are the most common causes of hypercalcemia. Symptoms of hypercalcemia are nonspecific and require a plasma calcium level to diagnose. Undiagnosed hypercalcemia can cause renal failure long-term. Here, we describe a unique case of hypercalcemia resulting in acute kidney injury (AKI) secondary to overconsumption of calcium carbonate (Tums).

Phosphorus and calcium: a review for the adult nutrition support clinician

Phosphorus (P) and calcium (Ca) serve vital roles in the human body and are essential components of nutrition support therapy. Regulation of P and regulation of Ca in the body are closely interrelated, and P and Ca homeostasis can be affected by several factors, including disease states, clinical condition, severity of illness, and medications. Nutrition support clinicians must understand these factors to prevent and treat P and Ca disorders in patients receiving nutrition support therapy. This review provides an overview of P and Ca for the adult nutrition support clinician, with some emphasis on the hospitalized inpatient.

Treatment of electrolyte disorders in adult patients in the intensive care unit

PURPOSE

The treatment of electrolyte disorders in adult patients in the intensive care unit (ICU), including guidelines for correcting specific electrolyte disorders, is reviewed.

SUMMARY

Electrolytes are involved in many metabolic and homeostatic functions. Electrolyte disorders are common in adult patients in the ICU and have been associated with increased morbidity and mortality, as has the improper treatment of electrolyte disorders. A limited number of prospective, randomized, controlled studies have been conducted evaluating the optimal treatment of electrolyte disorders. Recommendations for treatment of electrolyte disorders in adult patients in the ICU are provided based on these studies, as well as case reports, expert opinion, and clinical experience. The etiologies of and treatments for hyponatremia hypotonic and hypernatremia (hypovolemic, isovolemic, and hypervolemic), hypokalemia and hyperkalemia, hypophosphatemia and hyperphosphatemia, hypocalcemia and hypercalcemia, and hypomagnesemia and hypermagnesemia are discussed, and equations for determining the proper dosages for adult patients in the ICU are provided. Treatment is often empirical, based on published literature, expert recommendations, and the patient's response to the initial treatment. Actual electrolyte correction requires individual adjustment based on the patient's clinical condition and response to therapy. Clinicians should be knowledgeable about electrolyte homeostasis and the underlying pathophysiology of electrolyte disorders in order to provide the optimal therapy to patients.

CONCLUSION

Treatment of electrolyte disorders is often empirical, based on published literature, expert opinion and recommendations, and patient's response to the initial treatment. Clinicians should be knowledgeable about electrolyte homeostasis and the underlying pathophysiology of electrolyte disorders to provide optimal therapy for patients.

Hypercalcemia in malignant and inflammatory diseases

Hypercalcemia is one of the most common metabolic abnormalities in human disease. Although there are many causes, most cases are due to neoplasia. Understanding the pathophysiology can lead to correct diagnosis and effective therapy for most patients.

Calcium metabolism in sarcoidosis and its clinical implications

OBJECTIVE

: To examine the clinical implications of disturbed calcium metabolism in sarcoidosis and how the pathophysiology affects management strategies.

METHODS

: The literature concerning calcium metabolism in sarcoidosis was reviewed.

RESULTS

: Dysregulated calcium metabolism is a well-recognized complication of sarcoidosis, resulting in hypercalcaemia (prevalence 5-10%), hypercalcuria (40-62%) and reduced bone density (40-55%). Extrarenal synthesis of calcitriol [1,25(OH)(2)D(3)] is central to the pathogenesis of abnormal calcium homeostasis, but alterations in parathyroid hormone (PTH) activity and the expression of PTH-related peptide have also been demonstrated. The immunosuppressive properties of calcitriol suggest that the raised levels seen in sarcoidosis could represent an adaptive response to the undefined antigen that causes sarcoidosis.

CONCLUSIONS

: The mechanisms of abnormal calcium metabolism in sarcoidosis need to be understood when treating hypercalcaemia, hypercalcuria and corticosteroid-induced osteoporosis. Studies are required to determine if the currently available therapies for osteoporosis are safe and effective in sarcoidosis.

Hypercalcemia complicating leukemic transformation of agnogenic myeloid metaplasia-myelofibrosis

Hypercalcemia is a common and potentially life-threatening metabolic derangement associated with many malignancies, especially solid tumors and multiple myeloma. Hypercalcemia has been reported only rarely with acute myelogenous leukemia. We describe a patient who developed hypercalcemia in association with transformation of agnogenic myeloid metaplasia into M7 acute myelogenous leukemia. Laboratory investigation revealed low levels of serum parathyroid hormone, undetectable levels of parathyroid hormone-related peptide, and normal levels of 25-hydroxyvitamin D. These observations suggest that another mediator was responsible for hypercalcemia in this patient. Awareness of this rare complication of acute myelogenous leukemia is essential for prompt diagnosis and management.

Abordagem clínico-laboratorial no diagnóstico diferencial de hipercalcemia

A hipercalcemia é anormalidade metabólica comum, porém pouco diagnosticada por ser freqüentemente assintomática. Aproximadamente 90% dos casos são decorrentes de hiperparatireoidismo primário (HPT) ou doença maligna complicada por hipercalcemia, estando prevalentes em pacientes ambulatoriais e hospitalizados, respectivamente. Laboratorialmente, o HPT e hipercalcemia humoral maligna apresentam algumas semelhanças, tais como: aumento do AMPc nefrogênico, hipofosfatemia e hipercalciúria. Porém, o quadro clínico da hipercalcemia associada à malignidade é mais severo e, geralmente, o paciente apresenta-se clinicamente debilitado pela doença, com múltiplas metástases. A dosagem sérica de PTH intacto (PTHi) é fundamental para o diagnóstico definitivo, estando o PTHi elevado ou normal no HPT primário, e suprimido na malignidade. Os mecanismos de hipercalcemia da doença maligna são: secreção de fatores humorais que alteram a homeostase do cálcio e fatores locais produzidos pelos tumores metastáticos ou hematológicos no osso, causando aumento da reabsorção osteoclástica. A proteína relacionada ao hormônio da paratireóide (PTHrP) tem sido implicada na maioria dos casos de hipercalcemia devido a tumores sólidos. Outros fatores como interleucina-6, fator de crescimento tumoral, fator de necrose tumoral e interleucina-1 podem modular os efeitos do PTHrP nos órgãos-alvo, e em alguns tumores, ativam diretamente o osteoctastos como por exemplo no mieloma múltiplo. A hipercalcemia pode estar menos freqüentemente associada a algumas doenças endócrinas como tireotoxicose, feocromocitoma, doença de Addison e neoplasia endócrino múltipla tipos I e IIA. Algumas drogas podem causar esse distúrbio metabólica, merecendo destaque a vitamina D, os diuréticos tiazídicos e o lítio. A sarcoidose é exemplo de doença granulomatosa que pode associar-se à hipercalcemia em 10% dos casos e hipercalciúria em 50%. O diagnóstico diferencial das hipercalcemias é essencial para que haja uma abordagem terapêutica eficaz dessa anormalidade metabólica.

Hypercalcemia

OBJECTIVES

To provide a review of hypercalcemia of malignancy, including the incidence, pathophysiology, signs and symptoms, treatment, and nursing interventions.

DATA SOURCES

Research studies, review articles, proceedings from nursing conferences, and book chapters.

CONCLUSIONS

Hypercalcemia of malignancy is difficult to diagnose because the signs and symptoms are similar to those experienced by patients with end-stage cancers. Knowing the cancers and histologic cell types that are at high risk for hypercalcemia assists in early diagnosis and treatment. Treatment decisions must consider potential benefits and their risks and affect on quality of life.

IMPLICATIONS FOR NURSING PRACTICE

Hypercalcemia of malignancy as a metabolic oncologic emergency requires accurate assessment and rapid intervention. Early recognition by the patient, family, and health care professionals can result in improved quality of life.

Current drug therapy for multiple myeloma

Recent years have witnessed tremendous advances in the molecular pathogenesis and management of multiple myeloma. Standard chemotherapy (melphalan and prednisone; MP) has been the mainstay of treatment of multiple myeloma for about 3 decades. However, it is no longer considered the 'gold standard', particularly for those patients who will subsequently undergo intensive chemotherapy with autologous or allogeneic peripheral blood stem cell (PBSC) or bone marrow transplantation (BMT), or for patients with refractory myeloma. A variety of induction combination chemotherapy regimens have been developed, some of which have demonstrated an improved response rate and duration and a superior 5-year survival rate when compared with standard chemotherapy. The early use of high dose chemotherapy with autologous PBSC support or BMT has significantly increased the complete remission rate, and has prolonged event-free sur vival and overall survival. Allogeneic bone marrow or PBSC transplantation may be a good option for selected patients with poor prognostic features. The role of interferon-alpha in multiple myeloma is still inconclusive despite many years of clinical evaluation. The clinical application of chemosensitising agents that can inhibit P-glycoprotein (P-gp) expression and function, and particularly the development of more potent P-gp modulators such as valspodar (PSC 833) and elacridar (GF120918) has made it possible to reverse multidrug resistance in some refractory patients and to enhance the efficacy of chemotherapeutic agents. Immunotherapeutic approaches to purging of autologous bone marrow or PBSC, or as adjuvant therapy for minimal residual disease, show great promise. Finally, a number of new therapies specifically designed to treat many of the complications of multiple myeloma are improving clinical outcomes and quality of life for these patients.