Intracellular electrolyte depletion in patients with ileostomies

Sodium depletion and secondary hyperaldosteronism in outpatients with an ileostomy: a cross-sectional study

OBJECTIVE

Patients with an ileostomy may experience postoperative electrolyte derangement and dehydration but are presumed to stabilise thereafter. We aimed to investigate the prevalence of sodium depletion in stable outpatients with an ileostomy and applied established methods to estimate their fluid status.

METHODS

We invited 178 patients with an ileostomy through a region-wide Quality-of-Life-survey to undergo outpatient evaluation of their sodium and fluid status. The patients delivered urine and blood samples, had bioelectrical impedance analysis performed and answered a questionnaire regarding dietary habits.

RESULTS

Out of 178 invitees, 49 patients with an ileostomy were included; 22 patients (45%, 95% CI, 31-59%) had unmeasurably low urinary sodium excretion (<20 mmol/L), indicative of chronic sodium depletion, and 26% (95% CI, 16-41%) had plasma aldosterone levels above the reference value. Patients with unmeasurably low urinary sodium excretion had low estimated glomerular filtration rates (median 76, IQR 63-89, mL/min/1.73m2) and low venous blood plasma CO2 (median 24, IQR 21-26, mmol/L), indicative of chronic renal impairment and metabolic acidosis. Bioelectrical impedance analysis, plasma osmolality, creatinine and sodium values were not informative in determining sodium status in this population.

CONCLUSION

A high proportion of patients with an ileostomy may be chronically sodium depleted, indicated by absent urinary sodium excretion, secondary hyperaldosteronism and chronic renal impairment, despite normal standard biochemical tests. Sodium depletion may adversely affect longstanding renal function. Future studies should investigate methods to estimate and monitor fluid status and aim to develop treatments to improve sodium depletion and dehydration in patients with an ileostomy.IMPACT AND PRACTICE RELEVANCE STATEMENTSodium depletion in otherwise healthy persons with an ileostomy was identified in a few publications from the 1980s. The magnitude of the problem has not been demonstrated before. The present study quantifies the degree of sodium depletion and secondary hyperaldosteronism in this group, and the results may help guide clinicians to optimise treatment. Sodium depletion is easily assessed with a urine sample, and sequelae may possibly be avoided if sodium depletion is detected early and treated. This could ultimately help increase the quality of life in patients with an ileostomy.

A Single Urine Sodium Measurement May Validly Estimate 24-hour Urine Sodium Excretion in Patients With an Ileostomy

BACKGROUND

Sodium deficiency in patients with an ileostomy is associated with chronic dehydration and may be difficult to detect. We aimed to investigate if the sodium concentration in a single spot urine sample may be used as a proxy for 24-hour urine sodium excretion.

METHODS

In a prospective observational study with 8 patients with an ileostomy and 8 volunteers with intact intestines, we investigated the correlations and agreements between spot urine sodium concentrations and 24-hour urine sodium excretions. Spot urine samples were drawn from every micturition during 24 hours, and relevant blood samples were drawn. All participants documented their food and fluid intakes.

RESULTS

There was a high and statistically significant correlation between 24-hour natriuresis and urine sodium concentrations in both morning spot samples (n = 8, Spearman's rho [ρ] = 0.78, P = 0.03) and midday spot samples (n = 8, ρ = 0.82, P = 0.02) in the patients with an ileostomy. The agreement between methods was fair (bias = -1.5, limits of agreement = -32.3 to 29.4). There were no statistically significant associations for evening samples or for samples from volunteers with intact intestines independently of time of day.

CONCLUSION

A single spot urine sodium sample obtained in the morning or midday may estimate 24-hour urine sodium excretion in patients with an ileostomy and thus help to identify sodium depletion.

An iso-osmolar oral supplement increases natriuresis and does not increase stomal output in patients with an ileostomy: A randomised, double-blinded, active comparator, crossover intervention study

BACKGROUND

Patients with an ileostomy often experience fluid and electrolyte depletion because of gastrointestinal loss. This study aimed to compare how an iso-osmolar and a hyperosmolar oral supplement affect ileostomy output, urine production, and natriuresis as proxy measurements of water-electrolyte balance.

METHODS

In a randomised, double-blinded, active comparator, crossover intervention study, we included eight adult ileostomy patients who were independent of parenteral support. We investigated how an iso-osmolar (279 mOsm/kg) and a hyperosmolar (681 mOsm/kg) oral supplement affected ileostomy output mass, urine volume, and natriuresis. In addition to their habitual diet, each participant ingested 800 mL/day of either the iso-osmolar or hyperosmolar supplement in each of two study periods. Each period started with 24-hour baseline measurements, and the supplements were ingested during the following 48 h. All measurements were repeated in the last 24 h.

RESULTS

No statistically significant changes in ileostomy output were detected following the intake of either oral supplement (median (range) 67 (-728 to 290) g/day, p = 0.25) despite increased fluid intake. Compared with the hyperosmolar supplement, the iso-osmolar supplement induced a statistically significant increase in urine volume (470 (0-780) mL/day, p = 0.02) and natriuresis (36 (0-66) mmol/day, p = 0.02).

CONCLUSION

Intake of the two oral supplements did not affect ileostomy output during this short intervention. Natriuresis increased following intake of the iso-osmolar supplement compared to that after ingesting the hyperosmolar supplement, indicating that patients with an ileostomy may benefit from increasing their ingestion of iso-osmolar fluids. ClinicalTrials.gov identifier:NCT03348709.

Pseudo-hypoaldostéronismes

TWO FORMS: Pseudohypoaldosteronisms (PHA) are characterized by end-organ resistance to aldosterone inducing hyperkalemia and hyperaldosteronism. There are two forms of PHA classified according to the level of blood pressure with either hypotension (Type 1 PHA or PHA 1) or hypertension (Type 2 PHA or PHA 2). PHA 1: The association with hypotension and high renin level (PHA 1) is responsible for type 4 tubular acidosis and should suggest congenital or acquired excessive salt loss. Acquired forms are associated with salt wasting of urinary (nephropathy) or digestive (colon resection + ileostomy) origin. Congenital neonatal forms are either sporadic or autosomal dominant or recessive. Sporadic or autosomal dominant forms are caused by mutations in the mineralocorticoid receptor gene and generally remit with age. Autosomal recessive forms are caused by mutations in the gene encoding the amiloride-sensitive sodium channel and are clinically more severe with pulmonary symptoms. PHA 2: The association of hyperkalemia/hyperaldosteronism with high blood pressure should suggest PHA 2 or Gordon's syndrome, still called familial hyperkalemic hypertension. This form of low-renin hypertension is caused by mutations in the WNK genes (WNK 1 for PHA 2C and WNK 4 for PHA 2B), but other genes located on different loci are also involved. These WNK kinases constitute a new signalisation pathway that would regulate blood pressure and homeostasy of Na+, K+, H+ and Cl- ions.

Total exchangeable sodium related to body composition in patients with conventional or reservoir ileostomy

Decreased exchangeable body sodium might be a consequence of proctocolectomy and construction of an ileal reservoir. To investigate this, 35 patients with ulcerative colitis and conventional ileostomy were studied before and after conversion to continent ileostomy and compared with 25 unoperated subjects as reference. The sodium urinary excretion varied between 7 and 229 and 1 and 217 mmol/24 h in patients with conventional and reservoir ileostomy, respectively. The total exchangeable sodium was measured and related to body composition estimated from body weight, total body water, and total body potassium. No effect on exchangeable sodium was observed after conversion: 3100 mmol and 2990 mmol, respectively. Patients with ileostomy, regardless of type, did not differ from reference subjects in their exchangeable sodium when related to total body water. A larger variation of total exchangeable sodium related to total body water suggests unstable sodium homeostasis in patients with ileal reservoir compared with reference subjects.

Altered erythrocyte transmembrane transport of sodium and potassium in patients with conventional or reservoir ileostomy

After proctocolectomy, the loss of the colonic absorptive capacity of sodium is compensated for by increased small intestine sodium absorption and renal conservation of Na by enhanced tubular reabsorption. These processes entail increased cellular sodium transport in the enterocytes and in the renal tubular cells. In order to evaluate if there is a general increase in cellular transport of Na after proctocolectomy for inflammatory bowel diseases erythrocyte Na and K contents and the transmembrane Na fluxes were determined in 35 patients with conventional ileostomy, 23 of which were reinvestigated after conversion to continent reservoir ileostomy. A selected group of another 12 patients having high output from their reservoir ileostomy and low urinary Na were studied concomitantly and 33 healthy subjects served as controls. The intracellular Na content did not differ between the groups while the intracellular K levels were higher in patients with conventional or continent ileostomy compared to controls. In addition, the Na influx and the efflux rate constant of Na were both increased after conversion to reservoir ileostomy. Na influx correlated positively with intake and urinary excretion of Na in conventional ileostomy patients. The results suggest that patients with ileostomy have an increased cellular K uptake and that construction of a reservoir ileostomy further alters cell cation transport by increasing the transmembrane Na turnover.

Sodium and potassium excretion before and after conversion from conventional to reservoir ileostomy

Sodium and potassium in the ileostomy output and urine were determined in 28 patients with ulcerative colitis on a free diet and in eight patients on a defined constant diet, before and after conversion from a conventional ileostomy (CI) to a continent reservoir ileostomy (RI). Feces and urine were collected both in the hospital and at home. Patients with CI on free diet had a median intestinal loss of 62 mmol sodium and those with RI 74 mmol/24 h collected in the hospital (p < 0.05). The figures for at home was 79 and 81 mmol/24 respectively, and were larger than in the hospital (p < 0.01). Sodium loss in the urine (U-Na) and the intake of sodium did not change significantly after conversion. Patients with a low U-Na before conversion also had a low U-Na after, in a few almost nil, implying a need for increased intake of sodium. Patients with a CI and low urinary output of sodium should be carefully studied with respect to their sodium balance before accepting them for conversion to RI. The ileostomy output of potassium increased after conversion (4.3 vs. 6.8 mmol/24 h; p < 0.01) in the hospital (5.3 vs 7.1 mmol/24 h; p < 0.01) at home. Patients on a defined constant diet before and after conversion did not show any significant differences in absorption of sodium, potassium, magnesium or calcium after conversion, but did show a reduced dry weight of the ileostomy output, indicating an increased degradation of intestinal contents in RI patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Prophylaxis of uric acid stone in patients with inflammatory bowel disease following extensive colonic resection

Seven patients (13.0%) among 54 patients with inflammatory bowel disease treated by extensive colonic resection were complicated by renal stone. The mean urinary pH value in cases complicated by renal stones (5.3 +/- 0.4) was significantly lower than among those without stones (6.1 +/- 0.3, P less than 0.01). Sodium bicarbonate (4 gm/day, q.i.d.) was given to 11 patients with renal stones and/or hematuria, whose urinary pH was lower than 5.0 or whose urinary sediments were positive for uric acid crystals since Oct. 1985. Their urinary pH and Na concentration increased significantly and no renal stone complication has been seen in the treated group.

Metabolism of body water and electrolytes after surgery for ulcerative colitis: conventional ileostomy versus J pouch

Some authorities believe that patients with conventional ileostomies are chronically water and salt depleted but there are no data on the metabolism of body water and electrolytes after ileoanal J pouch. To clarify the situation we studied the body composition of 14 patients with well functioning ileostomies and 20 patients with well functioning J pouches. Both groups were compared with two closely matched control groups. Body weight, total body fat, fat-free mass, total body water and extracellular water were measured by neutron activation analysis, tritiated water and bromide dilution respectively; 24-h collections of urine and stool were analysed for volume and electrolyte content. The results show that the body content of water and extracellular fluid in ileostomy patients and J pouch patients is normal. The faecal volume and chemistry is similar in both groups resulting in a similar and significant degree of urinary sodium retention.

Prevention of uric acid stone formation by sodium bicarbonate in an ileostomy patient--a case report

A 38 year old female underwent a proctocolectomy and ileostomy for ulcerative colitis in February, 1974. For 8 year post-operatively, she excreted innumerable renal stones, mainly composed of uric acid. Her urine was highly acidic and hyperuricosuric with a low concentration of sodium. Sodium bicarbonate 4 gm/day, t.i.d., was started in October 1985, after which her renal stone excretion completely ceased (up until March, 1987), except for one incidence of stone excretion when she discontinued therapy for a week. During the sodium bicarbonate therapy, her urinary pH and Na concentration were elevated. Furthermore, sodium bicarbonate significantly elevated the urinary pH and Na concentration of other ileostomy patients. Thus, sodium bicarbonate could be used for the possible prophylaxis of uric acid formation in selected ileostomy patients.

Fasting and postprandial ileal function in adapted ileostomates and normal subjects

The output of 11 established ileostomies was compared with ileal flow measured by intestinal perfusion in five normal volunteers when fasting and during the ileal passage of test meals containing different proportions of medium chain triglyceride and long chain triglyceride. Oroileal transit of the meal was the same in the two groups, but ileostomy output was less than ileal flow of normal persons both fasting (16.3 +/- 10.9 vs 62.4 +/- 24.7 ml/h, p less than 0.001) and after the long chain triglyceride rich meal (35.4 27.0 vs 96.1 +/- 20.2 ml/h, p less than 0.001). After ingestion of the medium chain triglyceride rich meal, ideal flow failed to increase in normal subjects but in ileostomates the changes in flow after medium chain triglyceride and long chain triglyceride rich meals were not significantly different. The fasting ileostomy effluent composition differed from that of normal fasting ileal content in having a higher concentration of potassium (8.0 +/- 2.9 vs 4.7 +/- 0.6 mmol/1, p less than 0.04) and a higher osmolality (353 +/- 63 vs 287 +/- 5 mosm/kg, p less than 0.05). Sodium concentration tended to be lower in ileostomy effluent, but in contrast to previous reports, ileostomy effluent was of consistently alkaline pH (7.2 +/- 0.3). These concentrations were not significantly altered by either type of meal. The long chain triglyceride rich meal increased the ileal flow of bile acids in both normal subjects and ileostomates, whereas the medium chain triglyceride rich meal increased bile acid flow in ileostomates but not in normal subjects, possibly reflecting a different amount of the bile acids in the ileum of the ileostomate. In the adapted ileostomate, the low volume and high potassium concentration of fasting effluent suggest that sodium and water absorption are continuously stimulated by chronic salt depletion.

Body composition in ileostomy patients with and without ileal resection

Body composition was measured in 24 patients who had previously undergone proctocolectomy and ileostomy. One group (control group) had undergone resection of only small amounts of terminal ileum (median 4 cm), the other group of patients (resected group) had undergone resection of greater lengths of small bowel (median 54 cm). These values of body composition were then compared with predicted values in normal subjects. Proctocolectomy and ileostomy without ileal resection did not significantly affect body weight, or the body contents of fat or water, but led to a reduction in total body nitrogen and total body potassium, suggesting a reduction in fat free mass. A modest resection of the terminal ileum undertaken during the course of proctocolectomy decreased body weight largely because of a reduction in body fat. None of the ileostomy patients was found to be dehydrated.

Sodium homeostasis after small-bowel resection

In 16 small-bowel-resected patients, 8 with ileostomy and 8 with at least half of the colon in function, plasma volume, plasma aldosterone concentration, plasma renin activity, and the 4-day excretion of sodium and potassium in urine and stools were determined. Patients with ileostomy had a high faecal loss of sodium: 85-181 (median, 149) mmol/24 h, and were all more or less sodium-depleted with decreased plasma volume of 1.4-2.5 (median, 2.0) l/175 cm (normal range, 2.3-3.8l/175 cm), increased plasma aldosterone of 742-2250 (median, 1131) pg/ml (normal range, 33-220 pg/ml), and extremely low sodium excretion in the urine of 0-3 (median, 1) mmol/24 h. Patients with similar small-bowel resection but with at least half of the colon in function had a much smaller faecal sodium loss of 1-66 (median, 8) mmol/24 h. They showed significantly higher plasma volume, 2.2-3.7 (median, 2.6) l/175 cm; normal plasma aldosterone, 25-232 (median, 124) pg/ml; and normal or almost normal sodium excretion in the urine, 49-168 (median, 118) mmol/24 h. Six jejunostomy patients, who sustained a normal or almost normal sodium balance thanks to parenteral saline, had intravenous infusion over 6 h of 1000 ml isotonic sodium chloride with or without aldosterone added. During aldosterone infusion plasma aldosterone increased to the level in the sodium-depleted ileostomy patients. Urinary sodium excretion decreased significantly. Stomal sodium loss did not change. It is concluded that small-bowel resection in ileostomized patients causes excessive faecal sodium loss and results in chronic sodium depletion with severe secondary hyperaldosteronism.(ABSTRACT TRUNCATED AT 250 WORDS)

Marathon without a colon: salt and water balance in endurance running ileostomates

Five trained ileostomates completed a marathon in a cool environment without ill effect. During the race, the ileostomy losses of sodium (1.0-2.7 mmol.h-1) and of water (9.2-19 ml.h-1) were small, but urinary excretion of sodium was very low (0.2-0.75 mmol.h-1) despite drinking a combination of water and glucose-electrolyte solution. The concentration of potassium in the ileostomy discharge tended to increase, also suggesting a sodium retaining state. Healthy ileostomates after suitable training are successful marathon runners, but the prevalence of mild salt depletion in ileostomates generally suggests that it may be advisable for them to take only glucose-electrolyte solutions when competing at any ambient temperature or when preparing for a marathon which is to take place in a warm environment.

Nutrition after ileostomy

The nutritional consequences of life with an ileostomy have been reviewed. Ileostomists tend to eat earlier in the day and to avoid fruit and vegetables when compared to people without an ileostomy. They are generally well nourished but may be prone to salt and water depletion because of the continual losses in the ileal effluent. The reservoir and absorptive capacities of the intact colon are demonstrated by these studies conducted on people with an ileostomy.

Water and electrolyte balance in subjects with a permanent ileostomy

Water and electrolyte balance has been studied in 39 patients with a permanent ileostomy, who had had a proctocolectomy for ulcerative colitis. The findings have been compared with those in 39 healthy subjects who were matched for age and sex. The ileostomists were found to lose excessive quantities of water and sodium in the ileostomy effluent compared with the corresponding losses in normal faeces. The mean plasma total protein and albumin concentrations were increased in the ileostomists suggesting a state of chronic dehydration. The daily urinary output of sodium was low and the output of potassium was high. The urinary pH was low. The ileostomists had raised mean concentration of aldosterone in the plasma (p less than 0.001) and it is suggested that this is responsible for the body's partial compensation for the depletion of sodium and water, including the so-called ileostomy adaptation.

Diet and health of people with an ileostomy. 2. Ileostomy function and nutritional state

1. Most subjects who have their large intestine removed and an ileostomy formed lead a healthy life after operation, although they are prone to a variety of metabolic problems. In order to determine the factors likely to lead to these metabolic disturbances a detailed assessment of ileostomy output and composition and of dietary intake in relation to nutritional and metabolic status has been made in a group of ileostomy patients living at home.

2. Thirty-six volunteers with established ileostomies (twenty-six ulcerative colitis (UC) patients and ten, Crohn's colitis (CC) patients) made a 24 h collection of urine and ileostomy effluent and kept a 7 d record of dietary intake and the frequency with which they emptied their ileostomy bag. Blood was collected for haematological and biochemical indices of nutritional status and height, weight and skinfold thickness were measured.

3. Effluent output for the whole group was 760±322 g/day (range 273–1612) and was very closely related to effluent sodium output (R 0·98). Stepwise multiple regression analysis of dietary and other variables identified the amount of ileum resected as the main determinant of both effluent output and effluent sodium. The CC group had significantly greater effluent output (1084±340 g/d) compared with the UC patients (635±215g/d) (P< 0·001); and excreted significantly more nitrogen, carbohydrate and sodium than the UC group.

4. The CC patients particularly showed evidence of salt depletion. The mean (±SD) 24 h urine Na loss for CC patients was 31±30 mmol and for UC patients 67±34 mmol (P< 0·01) with five of the ten CC patientsv. four of the twenty-six patients with UC having raised urinary or plasma aldosterone levels.

5. All subjects had normal haematological and biochemical indices of nutritional status in the blood. Height and percentage body fat were also within the normal range when compared with a control population matched for age, sex and occupation, but patients with an ileostomy weighed on average 4·1 kg less than the controls.

6. These studies show that patients with an ileostomy come within the range of the normal population for most nutritional indices although are at increased risk of salt depletion. Effluent volume, which is probably the determining factor in most metabolic complications of ileostomy, is related more to the extent of the small bowel resection than to diet.

Fluid and electrolyte absorption and renin-angiotensin-aldosterone axis in patients with severe short-bowel syndrome

In eight patients who had received long-term parenteral nutrition because of short-bowel syndrome the need for parenteral supply of fluid, sodium, and potassium was estimated by balance studies. Six patients had jejunostomies. In two, most of the colon was preserved. Jejunostomy patients had a huge stool mass (1710--5270 g, median 2530 g/day) with fixed concentrations of sodium (92 +/- 10 mmol/l) and potassium (15 +/- 4 mmol/l). In contrast, two patients with massive small-bowel resection but with more than half of the colon intact showed almost normal sodium absorption and considerably smaller stool mass (170--510 g/day). Despite apparently good health and normal plasma electrolytes, urea, and haematocrit, four of six jejunostomy patients were sodium-depleted with low plasma volume, low sodium excretion in the urine, and increased plasma renin activity and, in the three most severe cases, increased aldosterone. Even in case of sodium depletion the sodium loss from jejunostomy effluents remained high and presumably unaffected by salt-retaining hormones. The study confirms the importance of preservation of part of the colon for maintenance of fluid and electrolyte balance in patients with extensive bowel resection. Jejunostomy patients who are eating normally may need large parenteral saline supply. Assessment of water and electrolyte homeostasis in these patients requires determination of the urinary sodium excretion and is supported by measurements of plasma renin activity and plasma aldosterone concentration.