Hyperkalemia in a Dialysis Patient After Colon Diversion
Hyperkalemia in a Dialysis Patient After Colon Diversion
A 56-year-old Caucasian woman with ESRD on regular HD was admitted to the hospital for an elective transplant nephrectomy. She initially developed ESRD at the age of 28 years after having idiopathic membranous nephropathy. In the next 28 years, she underwent two HD periods and two deceased-donor kidney transplantations, until she returned to chronic HD approximately one year before her current admission. As a preparation for a new transplantation, a transplant nephrectomy was planned. Her other relevant medical history included hypertension and coronary three-vessel disease.
The post-operative course after the bilateral transplant nephrectomy was complicated, with an acute coronary syndrome on post-operative day six and an ischemic colitis with hematochezia on day 11. The colonoscopy performed on day 12 showed colitis lesions in the cecum, consistent with ischemic colitis. Over the following two weeks, she experienced repeated hematochezia despite repeated intra-mucosal adrenaline injections and endoclipping of bleeding vessels. Therefore, a resection of the ileocecum with a temporary ileostomy was performed on post-operative day 30. She made a good recovery and her dietary intake slowly improved over the following weeks. However, her routinely measured pre-dialysis serum K three weeks later was 7.2mmol/L. She had no remarkable symptoms or signs of hyperkalemia and the results of an electrocardiogram showed no hyperkalemia-related changes. Her previous pre-dialysis K level ranged between 4.9 and 6.1mmol/L (Figure 1). The results of blood gas analysis showed no evidence of severe metabolic acidosis as a potential cause of hyperkalemia (Table 1). Although her dietary intake of K was restricted, an oral cation exchange resin (sodium polystyrol sulfonate) was administered, and a low potassium dialysate was applied for the dialysis, her pre-dialysis serum K values in the next months remained high (6.1 to 8.3mmol/L).
(Enlarge Image)
Figure 1.
Changes in serum potassium concentration before and after stoma operation. The diamond symbols show the fecal potassium concentration before and after stoma reversal.
Six months later, her bowel continuity was successfully restored. Interestingly, pre-dialysis serum K values returned to their previous level without changes in diet, medication or dialysis regimen. In the following four months until the third deceased donor kidney transplantation, her serum K values remained similar to the previous range before ileostomy. Since we hypothesized that the colon diversion through ileostomy and therefore reduced colonic K secretion contributed to the development of severe hyperkalemia, we measured fecal K concentration before and after the restoration of bowel continuity (Table 2). The fecal K concentration before stoma reversal was 23.4 and 23.1mmol/L on two separate occasions. Under the treatment with an oral cation exchange resin, K concentration was slightly lower (17.0mmol/L). After the stoma reversal, however, fecal K concentration increased markedly to 49.6 and 60mmol/L after one and four weeks, respectively. These findings strongly suggest that the severe hyperkalemia in our patient was caused by the ileostomy and therefore significantly reduced colonic K secretion.
Case Presentation
A 56-year-old Caucasian woman with ESRD on regular HD was admitted to the hospital for an elective transplant nephrectomy. She initially developed ESRD at the age of 28 years after having idiopathic membranous nephropathy. In the next 28 years, she underwent two HD periods and two deceased-donor kidney transplantations, until she returned to chronic HD approximately one year before her current admission. As a preparation for a new transplantation, a transplant nephrectomy was planned. Her other relevant medical history included hypertension and coronary three-vessel disease.
The post-operative course after the bilateral transplant nephrectomy was complicated, with an acute coronary syndrome on post-operative day six and an ischemic colitis with hematochezia on day 11. The colonoscopy performed on day 12 showed colitis lesions in the cecum, consistent with ischemic colitis. Over the following two weeks, she experienced repeated hematochezia despite repeated intra-mucosal adrenaline injections and endoclipping of bleeding vessels. Therefore, a resection of the ileocecum with a temporary ileostomy was performed on post-operative day 30. She made a good recovery and her dietary intake slowly improved over the following weeks. However, her routinely measured pre-dialysis serum K three weeks later was 7.2mmol/L. She had no remarkable symptoms or signs of hyperkalemia and the results of an electrocardiogram showed no hyperkalemia-related changes. Her previous pre-dialysis K level ranged between 4.9 and 6.1mmol/L (Figure 1). The results of blood gas analysis showed no evidence of severe metabolic acidosis as a potential cause of hyperkalemia (Table 1). Although her dietary intake of K was restricted, an oral cation exchange resin (sodium polystyrol sulfonate) was administered, and a low potassium dialysate was applied for the dialysis, her pre-dialysis serum K values in the next months remained high (6.1 to 8.3mmol/L).
(Enlarge Image)
Figure 1.
Changes in serum potassium concentration before and after stoma operation. The diamond symbols show the fecal potassium concentration before and after stoma reversal.
Six months later, her bowel continuity was successfully restored. Interestingly, pre-dialysis serum K values returned to their previous level without changes in diet, medication or dialysis regimen. In the following four months until the third deceased donor kidney transplantation, her serum K values remained similar to the previous range before ileostomy. Since we hypothesized that the colon diversion through ileostomy and therefore reduced colonic K secretion contributed to the development of severe hyperkalemia, we measured fecal K concentration before and after the restoration of bowel continuity (Table 2). The fecal K concentration before stoma reversal was 23.4 and 23.1mmol/L on two separate occasions. Under the treatment with an oral cation exchange resin, K concentration was slightly lower (17.0mmol/L). After the stoma reversal, however, fecal K concentration increased markedly to 49.6 and 60mmol/L after one and four weeks, respectively. These findings strongly suggest that the severe hyperkalemia in our patient was caused by the ileostomy and therefore significantly reduced colonic K secretion.
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