Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease that commonly affects individuals older than 50 years old. It is characterised by pain and morning stiffness in the shoulder and pelvic girdle. This disease can occur as an isolated phenomenon or in association with giant cell arteritis.1 As regards its aetiopathogenesis, although unknown, several genetic and environmental factors have been identified that might be involved.1,2
Here we describe a case of nephrotic syndrome in a patient with PMR with no evidence of malignant disease.
Case report
An 84-year-old male with a history of allergy to procain and streptomycin, a prosthetic left hip, and a bilateral inguinal hernia was diagnosed with PMR in August 2010 and prescribed treatment with prednisone at 30mg/day. The patient remained independent for performing activities of daily living and suffered no cognitive deterioration.
Upon seeking treatment in the nephrology department (8 months after being diagnosed with PMR), the patient was on treatment with prednisone at 5mg, omeprazole at 20mg/day, enalapril at 5mg/12 hours, levothyroxine at 25mg/day, and chlorthalidone at 12.5mg/day.
The patient was admitted to the nephrology department due to increased volume in the legs and abdominal/scrotal area with 4 days evolution. The patient reported only a slight decrease in the rhythm of diuresis and one occasion of nicturia.
A physical exploration revealed a blood pressure of 150/80mm Hg, heart rate at 80bpm, a globular stomach with dullness in the midgut, and pitting oedema in the legs, with no other relevant results.
A blood work analysis revealed: creatinine: 0.8mg/dl; cholesterol: 354mg/dl; triglycerides: 104mg/dl; albumin: 2.2g/dl; and total protein: 5mg/dl. Haemogram and clotting tests results were normal. Viral serology for hepatitis B and C and human immunodeficiency virus was negative. In the immunological study, antinuclear antibodies and anti-neutrophil cytoplasmic antibodies were negative, with normal complement. IgG was at 450mg/dl (normal range: 751-1560mg/dl), and IgM and IgA were normal. An electrophoresis analysis using a blood sample revealed a decrease in albumin with no signs of monoclonal peaks.
Tumour markers (carcinoembryonic antigen [CEA], Ca19-9, alpha-fetoprotein, and prostate specific antigen [PSA]) were all within normal values. Ca125 was at 136IU/ml (normal range: 0-35IU/ml).
A 24-hour urine protein analysis revealed 9.51g/24h. Creatinine clearance was at 77ml/min. Urine electrophoresis also ruled out the presence of monoclonal peaks, with a negative Bence-Jones proteinuria test.
A chest x-ray revealed right pleural effusion.
A renal ultrasound showed that the kidneys were 11cm in size with no lithiasis or dilation.
We performed an abdominal axial computerised tomography, which revealed thickening of the gastric folds. A gastroscopy was requested, which confirmed the existence of thickened pyloric folds, but with no evidence of malignancy in the histopathological analysis.
Given the patient’s state of nephrotic syndrome, we performed a percutaneous kidney biopsy under ultrasound control with the following findings: 5 glomeruli per cross-section, all of which had normal histological characteristics. Immunofluorescence was negative for studied pathological markers (IgG, IgA, IgM, and C3). Vascular tissue, interstitial spaces and tubules were without lesions. The final diagnosis was of minimal change nephropathy (MCN).
The results of the biopsy led to an increase in the prednisone dose to 1mg/kg/day. One month later, an external consultation revealed clinical and biochemical remission of the nephrotic syndrome, facilitating progressive decreases in the dose of prednisone.
Seven months later, when the patient was on maintenance therapy with prednisone at 5mg/day, the nephrotic syndrome relapsed, requiring an increase in prednisone to 50mg/day. After the nephrotic syndrome disappeared again, the dose of prednisone was progressively decreased to 2.5mg/day.
After one month of treatment with prednisone at 2.5mg/dl, the patient attended consultation with his GP due to oedema. A laboratory analysis revealed proteinuria at 1.66g/day, for which the dose of prednisone was increased to 10mg/day, which resolved the issue. In the last nephrological follow-up, the patient continued on treatment with prednisone at 10mg/day, with no symptoms or proteinuria.
Discussion
Renal involvement in PMR is uncommon.3 The majority of cases involving renal damage are due to amyloid deposits (secondary [AA] amyloidosis).4,5
Both PMR and MCN can occur as paraneoplastic manifestations of cancer. Sidhom et al. described the case of a patient with PMR that was unresponsive to treatment with prednisone; they found renal cancer during the patient’s evolution, and symptoms were controlled following a nephrectomy.6 Alvarez et al. described a patient with MCN as a paraneoplastic manifestation of colon cancer.7 Another case involved a patient in which these two entities were found as the clinical expression of pancreatic cancer.8 However, we have not found any case described in the medical literature to date involving the simultaneous occurrence of both entities in the absence of cancer, as occurred in our patient. In our case, given the initial suspicion that the patient had some type of tumour, and as such, that the PMR and nephrotic syndrome were the result of paraneoplastic processes, we performed a biopsy that did not indicate the presence of a tumour.
As regards treatment, glucocorticoids are the treatment of choice for both PMR (generally at low doses of 10-15mg/day) and MCN (maximum of 80mg/day).9,10 In our case, the increase in the dose of prednisone from 5mg/day to 60mg/day facilitated the remission of the nephrotic syndrome, but a relapse occurred when the dose of prednisone was decreased below the recommended threshold of 10mg/day for the treatment of PMR.
In conclusion, we have described two different diseases in the same patient, with no evidence of association with cancer, and whose aetiopathogenesis may possibly be related given the clinical behaviour of both entities.
Conflicts of interest
The authors have no conflicts of interest to declare.
