Treatment of renal sarcoidosis: is there a guideline? Overview of the different treatment options.

Sarcoidosis is a multisystem granulomatous disease of unknown aetiology characterized by the presence of noncaseating granulomas. It may affect any organ including the kidney. A disordered calcium metabolism is most often responsible for the development of renal failure. Granulomatous interstitial nephritis is the most typical histological finding, but it rarely leads to renal insufficiency. Since development of renal insufficiency in sarcoidosis is uncommon, we lack large (randomized) trials concerning the treatment of this disorder. We gather most information from case reports and small series. Our knowledge of pulmonary sarcoidosis is more comprehensive. It is, however, impossible to treat renal manifestations identically because some of the drugs used in pulmonary sarcoidosis are nephrotoxic. Moreover, renal sarcoidosis is a specific entity with its own characteristics and response to therapy. A guideline for treatment is currently missing. Based on a review of the literature, we present an overview of the different treatment options to promote a more uniform and scrutinized approach of this disease. Hypercalcaemia and hypercalciuria can be treated with corticosteroids, (hydroxy)chloroquine or ketoconazole. Preventive measures play a supportive role. In granulomatous interstitial nephritis, glucocorticoids are the standard of care. In patients with failure of or a contraindication to corticosteroids or in those patients who need a high maintenance dose of corticosteroids, azathioprine or mycophenolate mofetil can be used. TNF-alpha inhibitors are useful in case of steroid-resistant sarcoidosis or in patients who develop severe steroid toxicity. With increasing insight in the pathogenesis of sarcoidosis, other immunosuppressive drugs have been proposed, but more research is necessary before their routine use can be advocated.

Diagnosis of pheochromocytoma in a hemodialysis patient through measurement of plasma catecholamines.

We report the case of a patient on chronic hemodialysis treatment with paroxysms of severe arterial hypertension accompanied by tachycardia, pallor, sweating and tremor. Measurement of plasma catecholamines revealed norepinephrine level of 4625 pg/mL (reference range 191-225 pg/mL), epinephrine level of 1035 pg/mL (58-76 pg/mL) and dopamine level of 148 pg/mL (50-100 pg/mL). MRI showed a left adrenal mass of 2 cm. After the patient was started on an alpha-1 adrenergic receptor blocker, she underwent a left adrenalectomy. Anatomopathological examination confirmed the diagnosis of pheochromocytoma. Although urinary testing is not possible in anuric hemodialysis patients, diagnosis of pheochromocytoma can be made through measurement of plasma free metanephrines and/or plasma catecholamines.

The value of tuberculin skin testing in haemodialysis patients.

BACKGROUND: Chronic haemodialysis patients are at increased risk for developing tuberculosis (TB). Appropriate screening methods to detect latent Mycobacterium tuberculosis infection are required. The aim of this prospective multi-centre study was to evaluate the tuberculin skin test (TST) as a screening method for detection of M.tuberculosis infection in haemodialysis patients. METHODS: A total of 224 patients in two haemodialysis centres were prospectively tested, using 2 units of tuberculin PPD RT23. Up to three booster injections were given with a 7 day interval to patients not responding to the previous test. The results were compared with clinical and radiological data. RESULTS: The cumulative prevalence of a positive TST was 14.7% for the first test, 27.8% for the second test and 32.6% for the fourth test. There was no influence of age, gender, haemodialysis centre, dialysis efficiency, nutritional state, levels of zinc, vitamin D therapy, primary renal disease, (previous or active) immunosuppressive therapy or response to hepatitis B vaccination. There was a significant, but weak, correlation between TST positivity and a history of positive TST or TB. Chest radiography and positive TST were not correlated, yet a positive chest X-ray increased the detection of patients with latent M.tuberculosis infection up to 47.8%. CONCLUSIONS: In haemodialysis patients, a positive response of >30% to repeated TST was obtained. Two consecutive TSTs were sufficient to recruit most of the booster reactions. Since only a weak correlation was found with anamnestic data, regular TST evaluation in combination with a chest X-ray, is a useful tool to detect infection with M.tuberculosis in haemodialysis patients.