Sarkoidose: Renale Manifestationen

Renal sarcoidosis

Renal sarcoidosis (RS) is a rare form of sarcoidosis that results in granulomatous inflammation of renal parenchyma. We describe the epidemiology, pathogenesis, clinical features, diagnostic approach, treatment strategies and outcomes of this condition. RS occurs most commonly at the time of initial presentation of sarcoidosis but can at any time along the course of the disease. The most common presenting clinical manifestations of RS are renal insufficiency or signs of general systemic inflammation. End-stage renal disease requiring dialysis is a rare initial presentation of RS. The diagnosis of RS should be considered in patients who present with renal failure and have either a known diagnosis of sarcoidosis or have extra-renal features consistent with sarcoidosis. A renal biopsy helps to establish the diagnosis of RS, with interstitial non-caseating granulomas confined primarily to the renal cortex being the hallmark pathological finding. However, these histologic findings are not specific for sarcoidosis, and alternative causes for granulomatous inflammation of the renal parenchyma should be excluded. Corticosteroids are the drug of choice for RS. Although RS usually responds well to corticosteroids, the disease may have a chronic course and require long-term immunosuppressive therapy. The risk of progression to ESRD is rare.

Sarcoidosis and autoimmune diseases: differences, similarities and overlaps

PURPOSE OF REVIEW

Sarcoidosis is a rare, multisystem granulomatous disease of incompletely understood pathogenesis. Clinically, it shares common features with several systemic and organ-specific autoimmune diseases, although known autoantibodies or useful serologic markers for diagnosis and monitoring of disease activity are lacking. Sarcoidosis can both coexist with or mimic connective tissue diseases or vasculitis. Here, we review possible common etiologic factors between sarcoidosis and autoimmune disease, comparing clinical, laboratory and imaging features.

RECENT FINDINGS

Autoimmune diseases may precede or follow the diagnosis of sarcoidosis. Overall, the prevalence of both co-existing is unknown because of limited evidence. The presence of autoantibodies in sarcoidosis should raise suspicion of an underlying autoimmune disease that mimics or co-occurs with sarcoidosis. Silica dust exposure has been associated with an increased prevalence of both sarcoidosis and rheumatoid arthritis. In another study, autoimmune thyroid disease, Sjogren's syndrome and ankylosing spondylitis have been reported to be more frequent in sarcoidosis compared with healthy controls.

SUMMARY

A systematic diagnostic work-up is necessary to detect overlapping disease features in patients with sarcoidosis. Immune-modulating therapies need to be taken into account as these can induce paradoxical reactions.

The importance of histopathology in the diagnosis of isolated renal sarcoidosis: a case report

Introduction:

Sarcoidosis is a systemic inflammatory disease of unknown etiology, characterized by the presence of non-caseating granulomas in several organs; renal impairment alone is a rare condition. When it affects the kidneys, the most prevalent manifestations are hypercalcemia and hypercalciuria. This paper aims to address the topic of renal sarcoidosis, by means of a case report, and reinstate the importance of histopathology in its diagnosis.

Methods:

The data came from an observational clinical study with a qualitative approach, through an interview with the renal sarcoidosis patient and data from her medical records.

Case report:

Patient D.M.S., 50 years old, Caucasian, presented with reddish eyes and body pains lasting for fifteen days as first manifestations of the disease. Upon kidney ultrasound scan, we found renal parenchymal nephropathy. Serial renal function and metabolic tests reported anemia and progressive urea and creatinine changes, as well as hypercalcemia and hypercalciuria, confirming acute kidney failure (AKF). A histopathological examination suggested the diagnosis, which was confirmed by clinical, laboratory and histopathological data. There was therapeutic resolution after steroid therapy.

Discussion:

The symptomatology of sarcoidosis is diverse and often non-specific. Renal manifestation, which usually occurs after organ involvement, is present in less than 5% of patients, and about 1% to 2% of these patients may develop AKF.

Conclusions:

The use of histopathology together with clinical and laboratory data to diagnose isolated renal sarcoidosis, rule out other etiologies and introduce early treatment is of paramount importance.