A RARE BUT WORRYING SIDE EFFECT OF MINERALOCORTICOIDS

Abstract

TOPIC: Education, Research, and Quality Improvement TYPE: Medical Student/Resident Case Reports INTRODUCTION: Corticosteroids are anti-inflammatory drugs that are known to have multiple side effects. Fludrocortisone, a synthetic mineralocorticoid that lacks glucocorticoid effect, is used in the treatment of hypoaldosteronism but like other corticosteroids is not known to have significant catabolic activity. CASE PRESENTATION: A 58 year old male with hypertension, chronic kidney disease (stage 4) and seizure disorder was admitted for management of persistent hyperkalemia. Initially, serum potassium was 6.2 with BUN of 58 and creatinine of 4.3. Physical exam was negative for orthostatic hypotension. Transtubular potassium gradient (TTKG) during hyperkalemia was calculated to be 3 which pointed to the diagnosis of hypoaldosteronism. Fludrocortisone (FD) was initiated, and potassium level was noted to be trending down and renal function improved to baseline. In the following days, serum chemistry revealed a normal potassium level but a significant rise in BUN, reported to be as high as 102mg/dl. During this period estimated glomerular filtration rate (eGFR) continued to be at baseline, between 20 and 22. Other factors that can cause uremia were ruled out and it was decided to discontinue FD. A significant drop in BUN level was observed, reaching as low as 60. After FD was stopped, a subsequent rise in potassium level was seen which resolved with dietary modifications. DISCUSSION: Fludrocortisone (FD) is a potent mineralocorticoid but has a weak glucocorticoid activity, hence is not known to cause uremia. It is known for treating chronic hyperkalemia in patients with hypoaldosteronism and interdialytic hyperkalemia in ESRD patients. According to a study by Norcliffe-Kaufmann et al., it was reported that patients with FD were found to have higher BUN levels compared to control subjects. For our patient`s persistent hyperkalemia due to hypoaldosteronism, FD was started but subsequently a significant rise in BUN, without changes in renal function, was observed. Uremia can cause debilitating symptoms like extreme fatigue, loss of appetite, headache, nausea and vomiting. In our case, after FD was discontinued a marked drop in BUN and a concomitant increase in potassium were seen. Patient was counseled for strict adherence to low potassium diet which resolved his problem. CONCLUSIONS: In conclusion, since FD has concerning side effects, it should be prescribed with caution in patients with CKD and serial serum chemistry should be followed for abnormalities. Patients, who are taking FD, presenting with uremia and stable renal function should have FD use investigated as one of the underlying cause. For persistent hyperkalemia, other interventions like dietary modification and/or potassium binder can be considered since FD can cause other abnormalities. REFERENCE #1: Dobbin, S., Petrie, J. R., Lean, M., & McKay, G. A. (2017). Fludrocortisone therapy for persistent hyperkalaemia. Diabetic medicine : a journal of the British Diabetic Association, 34(7), 1005–1008. https://doi.org/10.1111/dme.13359 REFERENCE #2: Disorders of Potassium Metabolism. (2011, January 1). ScienceDirect. https://linkinghub.elsevier.com/retrieve/pii/B9781416066408000075 REFERENCE #3: Norcliffe-Kaufmann, L., Axelrod, F. & Kaufmann, H. Developmental abnormalities, blood pressure variability and renal disease in Riley Day syndrome. J Hum Hypertens 27, 51–55 (2013). https://doi.org/10.1038/jhh.2011.107 DISCLOSURES: no disclosure on file for Kisra Anis; no disclosure on file for Zinobia Khan; No relevant relationships by Dileep Kumar, source=Web Response No relevant relationships by Shahzad Shallwani, source=Web Response