Complications in patients undergoing continuous ambulatory peritoneal dialysis (personal experience and literature review)

Ahmed Mitwalli, George Wu, Holger Schilling, Dimitrios a. Oreopoulos

We reviewed the complications we encountered among 126 CAPD patients whom we treated between January I , 1983 and June 30, 1984. Fifty-five were new patients while the remaining 71 were already on CAPD. Among catheter related complications, exit site infection was the most frequent and developed in nine patients; it led to peritonitis with the same organism in four patients. The incidence of peritonitis was one episode every 13.1 patient months among non-diabetics and one episode every 12.3 patient months in diabetics. Eight catheters were removed because of recurrent or persistent peritonitis. Cardiovascular and gastrointestinal complications were the most frequent medical complications. Six patients had operationsfor hernia repair. Of these 126 patients, 25 received a transplant, 19 died, 15 had their CAPD interrupted and 67 are still on CAPD. The most fre.quent causes of CAPD interruption were inability to cope (4) and loss of ultrafiltration (4). Cardiovascular problems were the most frequent causes of death. Only one patient died as a result of sepsis secondary to peritonitis . In conclusion, whereas peritonitis still remains the most frequent complication ofCAPD, it ceased to be the most frequent cause ofCAPD failure.

The complications seen in patients on continuous ambulatory peritoneal dialysis (CAPD) have been explored in two extensive reviews (1,2) and in several articles (3,4). However as more patients stay on CAPD for longer periods and our experience improves, we thought it worthwhile to review the complications seen in our patients on CAPD (new and old) during the period January I, 1983 to June 30, 1984. This paper describes the results of this review.

Patients and Methods

Of the 126 patients in this review, most were dialysed with the standard CAPD technique using the spike insertion (5). Eighty-two patients used two-liter exchanges four times/day -the most frequent schedule, eight were dialysed with 3-liter exchanges, three times/day (6), 16 were dialysed with 2-liter exchanges three times/day, 14 were dialysed with 1.5 liter exchanges four times/ day, two with 1.5 liter exchanges five times/day and four patients were dialysed using 2-liter exchanges five times/day.

At the beginning of this period 71 of the patients had been on CAPD and 55 were new to CAPD. There were 99 non-diabetics (54 men, 45 women, with an average age 53.4 14 years), and 27 diabetics (21 men, six women with an average age 55 16 years). The average duration on CAPD during the study was 10.3 6.4 months for the non-diabetics and 11.4 6 months for the diabetics (Table I). However the average total duration of CAPD was 25 months for the non-diabetic and 24 months for the diabetics.


Complications

The complications will be described under three headings: those related to (A) the catheter, (B) peritonitis, and (C) other than peritonitis (Table II) . Also presented are the various reasons for which patients underwent operation, the causes of failure among those patients in whom CAPD had to be interrupted, and the causes of death.

COMPLICA TIONS RELA TED TO THE CATHETER These include exit site infection (n = 9), leak (n = 1), drainage problems (n = 1) and catheter replacement (Table III). During this study exit site infection was responsible for four episodes of peritonitis in non-diabetics. In this group eight catheters were removed because of recurrent or persistent peritonitis and/or exit site infection; the catheter was replaced twice in two diabetics for the same reasons. One non-diabetic had a continuous leak of dialysis solution around the exit site, while one diabetic had an outflow obstruction that probably was due to extensive intra-abdominal adhesions.

PERITONITIS

This infection is still the most frequent complication (7) in both groups. In the non-diabetic group 42 patients had 78 episodes of peritonitis -an incidence of one episode every 13.1 patient-months. Four of these 78 episodes were caused by exit-site infection (purulent discharge with same organism in culture).

In the diabetic group, 10 of 27 patients had 25 episodes of peritonitis -an incidence of one episode every 12.3 patient months. None of these episodes was related to exit-site infection (Table IV).


COMPLICATIONS OTHER THAN PERITONITIS

Medical complications of CAPD: It is difficult to determine whether these are the result of CAPD alone or related to the underlying disease and/or old age. In some patients a combination of these three factors may be responsible for the development of these complications.

Cardiovascular complications are listed in Table V. The important among them were: Coronary artery disease: Seven patients in the non-diabetic group had angina and one had an acute myocardial infarction. During the same period, only two of the 27 diabetic patients had angina and one had an acute myocardial infarction.

Fluid overload, heart failure and pulmonary edema: This combination is fairly common during peritoneal dialysis (8-11). Seven non-diabatic patients and one diabetic had 13 episodes of pulmonary edema or CHF requiring admission and removal of fluid by extra dialysis -i.e. increase in frequency of exchanges or an IPD session for 24-48 hours.


Arrhythmias: Tachyarrhythmias are frequent during dialysis, especially in patients with underlying heart disease or those receiving digitalis (8,12,13). Since digitalis is poorly dialyzed (14), the correction of electrolytic abnormalities during dialysis may precipitate digitalis intoxication. Two of our non-diabetic patients had arrhythmias and one required a pacemaker insertion. Only one diabetic had arrhythmia as a complication.

Two non-diabetic patients had pericarditis -with or without effusion, this was treated with extra dialysis, pericardiocentesis and indocid.

One diabetic was admitted to the hospital twice because of hypotension; in one episode this was due to hypovolemia combined with antihypertensive medications; in the second, the cause was unknown.


Gastrointestinal Complications (Table VI): Five non-diabetic patients (3% ) and three diabetics complained of nausea and vomiting (7.5%). Two non-diabetics and one diabetic had esophagitis, gastritis and/or duodenitis. Four non-diabetics had diarrhea. One patient of each group had pancreatitis.

Respiratory Complications: Upper respiratory tract infections (URTI), bronchitis, and pneumonia were infrequent during this study (Table VII). One non-diabetic was admitted twice for investigation of a lung lesion which eventually was shown to be metastatic carcinomatosis.

Neurological Complications (Table VIII): It is difficult to assess such complications during dialysis because they are similar to the uremic syndrome (15-17). One non-diabetic showed evidence of progressive neuropathy, and two diabetics had progressive peripheral neuropathy which could have been due to diabetes or ESRD. Two nondiabetic patients had seizures. One non-diabetic had respiratory and cardiac arrest, which produced anoxic brain damage and severe and persisting myoclonus.

Genitourinary Complications (Table IX): These complications are infrequent. An unexpected and surprising complication in these patients is formation of kidney stones because they pass only small amounts of urine which contain extremely low amounts of calcium (18). One diabetic had two episodes of renal colic and on both occasions passed a stone made of matrix (protein) material. One non-diabetic had an episode of scrotal swelling, which was part of generalized edema; it disappeared with fluid removal.


Miscellaneous Complications: One non-diabetic had an infected toe associated with peripheral vascular disease, while two diabetics had four episodes of infected feet or toe(s) but none led to osteomyelitis. One non-diabetic had three episodes of deep-vein thrombosis, before he was discovered to have pancreatic carcinoma.

Two non-diabetics had severe depression requiring hospital admission.

REASONS FOR OPERATION

Abdominal herniation, a complication of long-term CAPD, probably is due to the continuous increase in intra-abdominal pressure in patients with weak abdominal walls. Five of our non-diabetics had hernias -three incisional and three inguinal (one patient had two different hernias). One diabetic had two admissions for hernia repair.

Two of the non-diabetics and one diabetic had below-knee amputation secondary to poor peripheral circulation (Table X).

OUTCOME

Table XI shows the outcome of these 126 CAPD patients: 25 had a kidney transplant, 19 died, 15 had their CAPD interrupted, and 67 remain on CAPD.


Causes of Failure (Table XII): CAPD had to be interrupted in 15 patients. Of these, six, four men and two women, one diabetic and five non-diabetics were transferred to intermittent peritoneal dialysis (IPD); two because they could not cope, one because of ultrafiltration failure and two because of recurrent fungal peritonitis; one elderly patient developed hemianopia and could not see well enough to do her own dialysis.

Nine patients (six men, three women, one diabetic and 8 non-diabetics) were converted to hemodialysis (HD). Three because of ultrafiltration failure, two because they could not cope, one because of persistent nausea and vomiting, one because of rapidly progressive peripheral neuropathy, another because of extensive bowel adhesions, which interfered with catheter function and the last because of a colostomy -this man developed fecal peritonitis secondary to diverticulitis.

Causes of Death (Table XIII and XIV): Nineteen patients died during the study period -14 males, five females, six were diabetics and 13 were non-diabetics. Three patients died suddenly, two at home, the third in hospital. Two died with a massive myocardial infarction, one died with refractory CHF and very poor left-ventricular function. Three died with sepsis secondary to peritonitis in one patient who did not come to hospital, due to advanced Hodgkin's disease in the second and the cause was unknown in the third. Two patients died from cancer -diffuse carcinomatosis and an adenocarcinoma of the lung. One patient had a massive intracerebral hemorrhage. One patient died of perforated peptic ulcer and shock, and another of "total body failure." Three patients asked to have dialysis discontinued and died shortly afterwards; two patients died from undetermined causes.


Discussion

Patients with end-stage renal disease face not only the complications related to dialysis but also those related to the underlying disease and its side effects, the most common of which is atherosclerosis. Most of the complications related to the peritoneal dialysis are preventable.

In this review of our experience with 126 CAPD patients over an 18-month period (January 1, 1983 to June 30, 1984), peritonitis was the major complication in both diabetics and non-diabetics. There are four principal routes of peritoneal invasion by bacteria, namely intraluminal, periluminal, transmural and hematogenous (27). The most common route seems to be the intralumial i.e. through the connection, therefore the closed system of dialysis is said to reduce the frequency of peritonitis (22,23). In our group only four non-diabetics developed peritonitis as a result of a documented exit-site infection; although this was infrequent, usually it required catheter removal to eliminate the infection and prevent further peritonitis (20 ,22 ,23).

Of the catheter-related complications, outflow obstruction has decreased significantly with the use of the Toronto Western Hospital catheter, and dialysate leakage has become less common with paramedian implantation. To date, skin-exit-site infection remains the main catheter-related complication. Since the latter often may lead to peritonitis, research into its prevention is urgently required.

As noted earlier the medical complications of the CAPD patient could be a result of the dialysis itself, of underlying disease or of old age. The high incidence of cardiovascular death probably is the result of accelerated atherosclerosis which, in turn, may be worsened by the hypertriglyceridemia that develops during CAPD (28) .Research into this relationship and prevention ofhypertriglyceridemia may lower the incidence of this complication. The gastrointestinal complications -in this series, anorexia, nausea and vomiting, which were noted in eight patients were not severe enough to force a discontinuation of dialysis except in one. Hiatus hernia and drug-induced vomiting especially that due to digoxin and phosphate binders is the most frequent underlying cause. Gastroparesis is a frequent cause of vomiting in diabetics, and fungal esophagitis, which can cause vomiting, should be considered, if the diabetics receive antibiotics for long periods.

Pulmonary complications -acute purulent bronchitis, pneumonia and pleural effusions may be a direct consequence of peritoneal dialysis (24,25), especially in severely uremic patients, in whom the level of consciousness may fluctuate. The morbidity and mortality associated with these pulmonary complications can be reduced significantly if the attending staff is alert to these problems.

In 15 of our patients CAPD was interrupted and they were transferred to IPD (six) or HD (nine). The most frequent causes of failure were decreased ultrafiltration (four patients) and inability to cope (four patients). Peritonitis caused interruption in three patients -a change from our previous experience (3). Although most patients with ultrafiltration failure required hemodialysis, one was able to continue on intermittent peritoneal dialysis. Even though this abnormality was less frequent than in other series (26), it remains one of the most serious complications of long-term CAPD and further research is needed to clarify its pathogenesis, and to guide its prevention.

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Discussion
Q: How many episodes of peritonitis leads you to take a patient off from CAPD and place them on another form of therapy?

Oreopoulos: There are two types of peritonitis and I would separate them as severe and recurrent peritonitis. In our population almost half of the patients stop because of severe peritonitis, such as due to diverticulitis, staphylococcus aureus, and pseudomonas. Other half of the patients have recurrent peritonitis. I have a patient who for the last 3 years had 10 episodes of peritonitis and still continues to have good ultrafiltration. So, we do not have any fixed number above which we'll stop the CAPD. If we don't jeopardize the patient's life and the patient can continue satisfactorily on CAPD, we'll let him continue.

Q: Please comment why you found a much higher death rate than other people's experience.

Oreopoulos: Twenty-five per cent of the deaths on CAPD were due to peritonitis. The fatality of the peritonitis is 2-3%. That is out of lOO episodes of peritonitis 2 or 3 will die. This is the same as what others are experiencing.

From the Division of Nephrology and the Department of Medicine, Toronto Western Hospital and the University of Toronto.

Dr. A. Mitwalli was working under a scholarship from the government of Saudi Arabia and Dr. H. Schilling under a scholarship from the Deutsche Forschungs gemeinschaft.