Case Presentation: A 54-year-old male was diagnosed with left renal pelvic, caliceal and ureteral transitional cell carcinoma(CA) 3 years before presentation. Patient had a history of transitional cell CA of the bladder that had extended to both kidneys despite local intervention. Patient underwent left sided nephroureterectomy 2 years later because of massive disease burden. Renal function was preserved with one functional kidney, however the disease burden in the remaining kidney also became non-amenable to local therapy and patient underwent a right sided nephroureterectomy.  He was started on hemodialysis(HD) but developed new-onset resistant hypertension(HTN) despite achieving dry weight goals.  Patient had multiple ED visits in the two months prior to presentation for severe headaches related to severe HTN.

Patient presented to us in the ED with altered mental status. At presentation his blood pressure (BP) was elevated (189/123). A CT head was done and was unremarkable. His workup did not reveal any metabolic cause of his encephalopathy. Patient was admitted to the ICU and management of hypertensive emergency was initiated with resumption of patient’s home regimen that included amlodipine, carvedilol, clonidine, hydralazine, metoprolol and valsartan. An EEG was done which showed marked slowing consistent with diffuse encephalopathy. MRI of the brain was done which showed bilateral fronto-parietal and occipital areas of non-enhancing edema, suggestive of posterior reversible encephalopathy syndrome (PRES). HD was resumed the next day. Patient’s mental state gradually improved with aggressive BP control but he had some residual memory deficits. He was discharged to a long term acute care facility for management of BP and HD.

Discussion: Renin-angiotensin-aldosterone axis based in the kidneys is one of the major regulators of BP. Loss of this axis leads to reduction in mean arterial pressure and total peripheral resistance as demonstrated by the widespread use of antihypertensives that target this axis. Various studies and reviews of literature have shown bilateral nephrectomy to be curative for HTN in patients with end-stage renal disease who received bilateral nephrectomy for reasons other than HTN. It is very rare for a normotensive patient to develop treatment resistant HTN after bilateral nephrectomy. Our patient developed PRES, a potentially fatal neurological syndrome associated with failure of cerebral autoregulation and resultant vasogenic edema.

Conclusions: The development of this phenomenon in an adequately dialyzed anephric patient indicates the possible presence of a renal derived vasodepressor substance whose loss led to treatment resistant HTN in our patient. Further research is warranted to identify this substance for development of a newer class of antihypertensive agents.