Hypercalcaemia as a prodromal feature of indolent Pneumocystis jivorecii after renal transplantation

Rare Causes of Hypercalcemia: 2021 Update

CONTEXT

Primary hyperparathyroidism and malignancy are the etiologies in 90% of cases of hypercalcemia. When these entities are not the etiology of hypercalcemia, uncommon conditions need to be considered. In 2005, Jacobs and Bilezikian published a clinical review of rare causes of hypercalcemia, focusing on mechanisms and pathophysiology. This review is an updated synopsis of rare causes of hypercalcemia, extending the observations of the original article.

EVIDENCE ACQUISITION

Articles reporting rare associations between hypercalcemia and unusual conditions were identified through a comprehensive extensive PubMed-based search using the search terms "hypercalcemia" and "etiology," as well as examining the references in the identified case reports. We categorized the reports by adults vs pediatric and further categorized the adult reports based on etiology. Some included reports lacked definitive assessment of etiology and are reported as unknown mechanism with discussion of likely etiology.

EVIDENCE SYNTHESIS

There is a growing understanding of the breadth of unusual causes of hypercalcemia. When the cause of hypercalcemia is elusive, a focus on mechanism and review of prior reported cases is key to successful determination of the etiology.

CONCLUSIONS

The ever-expanding reports of patients with rare and even unknown mechanisms of hypercalcemia illustrate the need for continued investigation into the complexities of human calcium metabolism.

Pneumocystis jirovecii pneumonitis: cause of acute hypercalcaemia in chronic haemodialysis patient

A 76-year-old renal transplant patient due to autosomal dominant polycystic kidney disease who resumed chronic haemodialysis was admitted to our hospital for confusion and lassitude. He was afebrile and physical examination revealed diffuse bilateral rales with decreased respiratory sounds in lower right lung. Laboratory data showed hypercalcaemia (total calcium 3.92 mmol/L (normal range 2.2-2.6 mmol/L), ionised calcium 1.87 mmol/L (1.15-1.35 mmol/L)), low intact parathyroid hormone (iPTH) 15 ng/L, (15-65 ng/L) and high 1,25(OH)2D3 128.9 pg/mL, (15.2-90.1 pg/mL). Chest CT-scan revealed bilateral apical lung lesions after 15 days of antibiotics. Bronchoalveolar sample was PCR positive for Pneumocystis jirovecii He was treated with an extra session of haemodialysis with 1.25 mmol/L dialysate calcium concentration, oral trimethoprim-sulfamethoxazole was started and oral corticosteroid dose increased to 1 mg/kg for 1 week. Hypercalcaemia decreased progressively after initiation of these treatments. We concluded a case of hypercalcaemia secondary to P. jirovecii infection.

Hypercalcemia Heralding Pneumocystis jirovecii Pneumonia in an HIV-Seronegative Patient with Diffuse Cutaneous Systemic Sclerosis

Pneumocystis pneumonia (PCP) is a life-threatening fungal infection occurring in immunocompromised patients such as HIV-positive patients with low CD4 cell count or patients under heavy immunosuppressive therapy. We report the case of a 59-year-old male with severe diffuse cutaneous systemic sclerosis presenting with asthenia, dry cough and worsening shortness of breath for the last 15 days. Biological studies were remarkable for PTH-independent severe hypercalcemia with low 25-hydroxyvitamin D and a paradoxically elevated 1,25-dihydroxyvitamin D. Early bronchoalveolar lavage allowed for PCP diagnosis and targeted treatment. We discuss the underlying physiopathology and difficulties regarding prophylaxis and treatment.

Hypercalcemia associated with Pneumocystis jirovecii pneumonia in renal transplant recipients: case report and literature review

Background: Pneumocystis jirovecii associated pneumonia is a potentially life-threatening opportunistic infection, occurring most frequently in the first year after renal transplantation, and may be associated with hypercalcemia. Clinical presentation:We report the case of a renal transplant recipient presenting with Pneumocystis jirovecii associated pneumonia and hypercalcemia due to ectopic production of 1,25-dihydroxyvitamin D, 6 years after renal transplantation. Calcemia and 1-25 hydroxyvitamin D levels normalized after our patient was treated by trimethoprim-sulfamethoxazole. Discussion: We review similar cases to delineate the clinical and biological profile of patients with Pneumocystis jirovecii pneumonia associated hypercalcemia. Conclusion:Physicians should evoke this diagnosis in renal transplant recipients presenting with pulmonary infection associated with hypercalcemia.

Hypercalcemia is common during Pneumocystis pneumonia in kidney transplant recipients

A few cases of hypercalcemia related to Pneumocystis jirovecii pneumonia (PJP) have previously been described, supposedly associated with an 1α-hydroxylase enzyme-dependent mechanism. The prevalence and significance of hypercalcemia in PJP remain unclear, especially in kidney transplant recipients (KTR) who frequently display hypercalcemia via persisting hyperparathyroidism. We here retrospectively identified all microbiologically-proven PJP in adult KTR from 2005 to 2017 in the Lille University Hospital, and studied the mineral and bone metabolism parameters during the peri-infectious period. Clinical features of PJP-patients were analyzed according to their serum calcium level. Hypercalcemia (12.6 ± 1.6 mg/dl) was observed in 37% (18/49) of PJP-patients and regressed concomitantly to specific anti-infectious treatment in all cases. No other cause of hypercalcemia was identified. In hypercalcemic patients, serum levels of 1,25-dihydroxyvitamin D were high at the time of PJP-diagnosis and decreased after anti-infectious treatment (124 ± 62 versus 28 ± 23 pg/mL, p = 0.006) while PTH serum levels followed an inverse curve (35 ± 34 versus 137 ± 99 pg/mL, p = 0.009), suggesting together a granuloma-mediated mechanism. Febrile dyspnea was less frequent in hypercalcemic PJP-patients compared to non-hypercalcemic (29 versus 67%). In summary, hypercalcemia seems common during PJP in KTR. Unexplained hypercalcemia could thus lead to specific investigations in this particular population, even in the absence of infectious or respiratory symptoms.

Severe hypercalcemia preceding a diagnosis of Pneumocystis jirovecii pneumonia in a liver transplant recipient

Background

Incidence of the opportunistic infection Pneumocystis jirovecii pneumonia (PJP) in solid organ transplant patients ranges from 5 to 15% with a mortality of up to 38%.

Case presentation

We present a liver transplant recipient who developed hypoxemic respiratory failure related to PJP soon after treatment for allograft rejection. His presentation was preceded by severe hypercalcemia of 14.6 mg/dL and an ionized calcium of 1.7 mmol/L which remained elevated despite usual medical management and eventually required renal replacement therapy. As approximately 5% of PJP cases have granulomas, here we review the role of pulmonary macrophages and inflammatory cytokines in the pathophysiology of granuloma-mediated hypercalcemia. We also discuss the interpretation of our patient’s laboratory studies, response to medical therapy, and clinical risk factors which predisposed him to PJP.

Conclusions

It is important for clinicians to consider PJP as an etiology of granulomatous pneumonia and non-parathyroid hormone mediated hypercalcemia in chronically immunosuppressed organ transplant recipients for timely diagnosis and management.

A case of Pneumocystis pneumonia, with a granulomatous response and vitamin D-mediated hypercalcemia, presenting 13 years after renal transplantation

Vitamin D-mediated hypercalcemia is an uncommon complication of Pneumocystis infection. A granulomatous response resulting from Pneumocystis infection is also atypical. In this report, we describe an exceptional case of granulomatous Pneumocystis pneumonia associated with vitamin D-mediated hypercalcemia, in a patient who presented unusually late after renal transplantation. The patient's hypercalcemia resolved with treatment of the infection.

Hypercalcemia: a consultant's approach

Due to their daily involvement in mineral metabolism, nephrologists are often asked to consult on children with hypercalcemia. This might become even more pertinent when the hypercalcemia is associated with acute kidney injury and/or hypercalciuria and renal calcifications. The best way to assess the severity of hypercalcemia is by measurement of plasma ionized calcium, and if not available by adjusting serum total calcium to albumin concentration. The differential diagnosis of the possible etiologies of the disturbance in the mineral homeostasis starts with the assessment of serum parathyroid hormone concentration, followed by that of vitamin D metabolites in search of both genetic and acquired etiologies. Several tools are available to acutely treat hypercalcemia with the current main components being fluids, loop diuretics, and antiresorptive agents. This review will address the pathophysiologic mechanisms, clinical manifestations, and treatment modalities involved in hypercalcemia.

Acute Kidney Injury Secondary to Hypercalcemia in a Kidney Transplant Patient With Pneumocystis jirovecii Pneumonia: A Case Report

BACKGROUND

Persistent hyperparathyroidism is one of the main causes of hypercalcemia following kidney transplantation; differential diagnosis is required.

CASE PRESENTATION

We report the case of a 61-year-old kidney transplant recipient who underwent transplant in September 2016. She was admitted in March 2017 presenting with a 3-week history of asthenia, hypotension, and cough. Laboratory analysis showed acute kidney injury with hypercalcemia and elevation of inflammatory markers. She was initially treated with hydration therapy. A few days after admission she developed respiratory failure: chest computed tomography showed a ground-glass pattern. A diagnosis of Pneumocystis jirovecii was made on bronchoalveolar lavage. A subsequent graft biopsy was performed that revealed intratubular calcium deposition without signs of rejection. The patient was given trimethoprim/sulfamethoxazole, with improvement in pulmonary and renal function as well as improvement in hypercalcemia.

CONCLUSIONS

P jirovecii infection can trigger activation of intra-alveolar macrophages that leads to extrarenal vitamin D production with subsequent hypercalcemia. This rare event should be considered in renal transplant patients with pulmonary infection accompanied by hypercalcemia. In our case, hypercalcemia also provoked acute kidney injury.

Prophylaxis and treatment of Pneumocystis Jirovecii pneumonia after solid organ transplantation

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic infection diagnosed in immunocompromized patients. After solid organ transplantation, early infection has decreased as a result of effective prophylaxis, but late infections and even outbreaks caused by interpatient transmission of pneumocystis by air are present in the SOT community. Different risk factors for PJP have been described and several indications for PJP prophylaxis have to be considered by clinicians in patients even years after transplantation. Diagnosis of PJP is confirmed by microscopy and immunofluorescence staining of bronchial fluid but PCR as well as serum ß-D-Glucan analysis have become increasingly valuable diagnostic tools. Treatment of choice is Trimethoprim/sulfamethoxazole and early treatment improves prognosis. However, mortality of PJP in solid organ transplant patients is still high and many aspects including the optimal management of immunosuppression during PJP treatment require further investigations.

Hypercalcaemia preceding diagnosis of Pneumocystis jirovecii pneumonia in renal transplant recipients

BACKGROUND

The overall incidence of Pneumocystis jirovecii pneumonia (PJP) in solid organ transplant recipients is 5-15%. A timely diagnosis of PJP is difficult and relies on imaging and detection of the organism.

METHODS

We present a case series of four patients displaying hypercalcaemia with an eventual diagnosis of PJP and document the management of the outbreak with a multidisciplinary team approach. We discuss the underlying pathophysiology and previous reports of hypercalcaemia preceding a diagnosis of PJP. We also reviewed the evidence concerning PJP diagnosis and treatment.

RESULTS

Within our renal transplant cohort, four patients presented within 7 months with hypercalcaemia followed by an eventual diagnosis of PJP. We measured their corrected calcium, parathyroid hormone (PTH), 1,25-dihydroxycholecalciferol [1,25-(OH)2D3] and 25-hydroxycholecalciferol [25(OH)D] levels at admission and following treatment of PJP. All four patients diagnosed with PJP were 4-20 years post-transplantation. Three of the four patients demonstrated PTH-independent hypercalcaemia (corrected calcium >3.0 mmol/L). The presence of high 1,25(OH)2D3 and low 25(OH)D levels suggest negation of the negative feedback mechanism possibly due to an extrarenal source; in this case, the alveolar macrophages. All four patients had resolution of their hypercalcaemia after treatment of PJP.

CONCLUSIONS

Given the outbreak of PJP in our renal transplant cohort, and based on previous experience from other units nationally, we implemented cohort-wide prophylaxis with trimethoprim-sulphamethoxazole for 12 months in consultation with our local infectious diseases unit. Within this period there have been no further local cases of PJP.

Life-Threatening Hypercalcemia During Prodrome of Pneumocystis jiroveci Pneumonia in an Immunocompetent Infant

Severe hypercalcemia in infants is usually attributed to genetic etiologies and less commonly to acquired ones. An 8-week-old girl presented with failure to thrive, mild respiratory distress, and life-threatening hypercalcemia (23.5 mg/dL). Serum 1,25(OH)₂-vitamin D (1,25(OH)₂-D) level was elevated and parathyroid hormone undetectable. Evaluation for genetic mutations and malignant etiologies of hypercalcemia was negative. Treatment with intravenous hydration, loop diuretic, and calcitonin failed to correct the hypercalcemia, which was subsequently controlled with bisphosphonate therapy. Due to progressive respiratory deterioration, a bronchopulmonary lavage was done on day 17 of her hospitalization disclosing Pneumocystis jiroveci infection. The subsequent immunological investigation showed no abnormalities. She was treated with trimethoprim/sulfamethoxazole resulting in gradual clearing of her lungs and normalization of serum 1,25(OH)₂-D level. A year later, she remains healthy with normal biochemical parameters of mineral metabolism. We conclude that in a child with hypercalcemia with suppressed parathyroid hormone and elevated 1,25(OH)₂-D, once the genetic etiology for elevated 1,25(OH)₂-D and malignancy are ruled out, one should investigate closely for a chronic granulomatous disease. Among the latter Pneumocystis jiroveci pneumonia infection should be considered even in an immunocompetent child.

Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

Hypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)₂D], and impaired degradation of 1,25(OH)₂D. The ingestion of excessive amounts of vitamin D₃ (or vitamin D₂) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)₂D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)₂D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)₂D is impaired as a result of mutations of the 1,25(OH)₂D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)₂D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)₂D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)₂D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.

Mineral and bone disorder after kidney transplantation

After successful kidney transplantation, accumulated waste products and electrolytes are excreted and regulatory hormones return to normal levels. Despite the improvement in mineral metabolites and mineral regulating hormones after kidney transplantation, abnormal bone and mineral metabolism continues to present in most patients. During the first 3 mo, fibroblast growth factor-23 (FGF-23) and parathyroid hormone levels decrease rapidly in association with an increase in 1,25-dihydroxyvitamin D production. Renal phosphate excretion resumes and serum calcium, if elevated before, returns toward normal levels. FGF-23 excess during the first 3-12 mo results in exaggerated renal phosphate loss and hypophosphatemia occurs in some patients. After 1 year, FGF-23 and serum phosphate return to normal levels but persistent hyperparathyroidism remains in some patients. The progression of vascular calcification also attenuates. High dose corticosteroid and persistent hyperparathyroidism are the most important factors influencing abnormal bone and mineral metabolism in long-term kidney transplant (KT) recipients. Bone loss occurs at a highest rate during the first 6-12 mo after transplantation. Measurement of bone mineral density is recommended in patients with estimated glomerular filtration rate > 30 mL/min. The use of active vitamin D with or without bisphosphonate is effective in preventing early post-transplant bone loss. Steroid withdrawal regimen is also beneficial in preservation of bone mass in long-term. Calcimimetic is an alternative therapy to parathyroidectomy in KT recipients with persistent hyperparathyroidism. If parathyroidectomy is required, subtotal to near total parathyroidectomy is recommended. Performing parathyroidectomy during the waiting period prior to transplantation is also preferred in patients with severe hyperparathyroidism associated with hypercalcemia.

Pneumocystis jirovecii pneumonia with an atypical granulomatous response after kidney transplantation

Pneumocystis jirovecii pneumonia (PCP) continues to be a leading cause of morbidity and mortality in kidney transplant recipients. Granulomatous PCP is an unusual histological presentation that has been described in a variety of immunosuppressive conditions. Previous studies have demonstrated an association between granulomatous disorders and hypercalcemia, the purported mechanism of which is extrarenal production of 1,25-dihydroxyvitamin D by activated macrophages. Here, we report a case of granulomatous formation in a kidney transplant recipient with PCP who presented with hypercalcemia and suppressed parathyroid hormone, both of which resolved after successful treatment of the pneumonia. In immunocompromised patients, pulmonary infection associated with hypercalcemia should raise the suspicion of PCP and other granulomatous disorders.