A 40-year-old black male patient was referred to the nephrology service to investigate plasma creatinine elevation in the last 6 months. He reported two previous medical evaluations in emergency departments. The first occasion was due to severe abdominal and low back pain with irradiation to hypogastrium, associated with nausea and vomiting. Pancreatic enzymes were elevated and the case was conducted as pancreatitis, but the patient presented no radiological changes. In the second occasion, he had a similar clinical presentation, but with concomitant macroscopic hematuria. Ultrasonography of the urinary tract identified the presence of bilateral nephrolithiasis, microcalculi in the lower third of the right ureter with mild pelvicalyceal dilation and normal-sized kidneys with increased renal parenchymal echogenicity. There was expulsion of the ureteral stone without urological interventions. Because of the persistent elevation of plasma creatinine not justified by nephrolithiasis, the patient was referred for nephrological investigation, but it took some months until the patient got this appointment.
Relevant findings in the physical examination included discolored mucosa +/4, high blood pressure (160/110 mmHg), liver 4 cm from the right costal margin, and palpable spleen and lower limb edema +/4. There were no palpable peripheral lymph nodes. The patient also reported increased urinary volume, sporadic fever and unintentional weight loss around 30 kg over the past 6 months. Past medical history included chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs) and bilateral knee replacement 5 years before presentation, due to a destructive arthropathy of undetermined etiology. He denied previous systemic arterial hypertension, diabetes mellitus, or kidney disease. He was hospitalized for additional investigation.
Admission laboratory tests revealed several laboratory abnormalities: persistent elevation of plasma creatinine, severe hypercalcemia, anemia, thrombocytopenia, and elevation of pancreatic enzymes and alkaline phosphatase, in addition to changes in urinalysis with nonnephrotic proteinuria, hematuria, leukocyturia, and calcium oxalate crystals (Table 1). In the initial days of hospitalization, diuresis ranged from 4 to 6 L/day. Abdominal computed tomography (CT) showed multiple retroperitoneal and iliac lymphadenopathy, enlarged liver with heterogeneous attenuation, and splenomegaly, as well as multiple nonobstructive renal micro calculi and a normal pancreas (Figure 1). In this scenario, the presence of hypercalcemia associated with a consumptive syndrome and lymphadenopathy suggested the initial hypothesis of a neoplastic condition, more likely a lymphoproliferative disease a priori.
The serum parathormone (PTH) level was low, and there was hypercalciuria. Thus, we proceeded the investigation based on differential diagnoses of hypercalcemia with low levels of PTH. There was no history of vitamin D supplementation, and calcidiol level was normal. Unfortunately, we did not have PTH-related peptide (PTHrP) and 1,25(OH)2D analysis. Radiographic study of the long bones, skull, and spine did not identify lytic bone lesions. Serum protein electrophoresis identified polyclonal gamma globulin peak, and the myelogram was unchanged. Diagnostic laparoscopy was indicated for retroperitoneal lymph node biopsy; however, intraoperatively it was decided for the performance of liver biopsy since this organ had multiple white lesions (Figure 2(a)). The histopathological study showed epithelioid granulomas without caseous necrosis, with the presence of asteroid bodies, highly suggestive of sarcoidosis (Figures 2(b)-2(d)). Despite the absence of respiratory symptoms, a chest CT scan showed micronodular infiltrates with perilymphatic distribution and mediastinal and hilar lymphadenopathy (Figure 1), corroborating the hypothesis of sarcoidosis. The angiotensin-converting enzyme (ACE) level test was not available in our service. The purified protein-derived (PPD) test for the tuberculosis bacillus was nonreactive (0 mm), and the culture for acid fast bacilli and fungi from the liver biopsy was negative. Ophthalmologic, cardiac, and neurological assessment was unremarkable.