Septicaemia and pulmonary embolism complicating use of arteriovenous fistula in maintenance haemodialysis

Thrombosis in end-stage renal disease

Although renal failure has classically been associated with a bleeding tendency, thrombotic events are common among patients with end-stage renal disease (ESRD). A variety of thrombosis-favoring hematologic alterations have been demonstrated in these patients. In addition, "nontraditional" risk factors for thrombosis, such as hyperhomocysteinemia, endothelial dysfunction, inflammation, and malnutrition, are present in a significant proportion of chronic dialysis patients. Hemodialysis (HD) vascular access thrombosis, ischemic heart disease, and renal allograft thrombosis are well-recognized complications in these patients. Deep venous thrombosis and pulmonary embolism are viewed as rare in chronic dialysis patients, but recent studies suggest that this perception should be reconsidered. Several ESRD treatment factors such as recombinant erythropoietin (EPO) administration, dialyzer bioincompatibility, and calcineurin inhibitor administration may have prothrombotic effects. In this article we review the pathogenesis and clinical manifestations of thrombosis in ESRD and evaluate the evidence that chronic renal failure or its management predisposes to thrombotic events.

Detection of microemboli in the subclavian vein of patients undergoing haemodialysis and haemodiafiltration using pulsed Doppler ultrasound

BACKGROUND

The pathophysiology leading to pulmonary side effects during haemodialysis and haemodiafiltration is not yet fully understood. Chronic microembolization, which can be demonstrated by pulsed Doppler ultrasound, may be one cause.

METHODS

The study cohort consisted of 24 long-term dialysis patients undergoing haemodialysis (n=21) and online-haemodiafiltration (n=3), respectively. The subclavian vein downstream to the venous access was investigated during different phases of the procedure using a 2-MHz pulsed ultrasound device.

RESULTS

In all periods investigated (connection, dialysis, disconnection), numerous microembolic signals (MES) were found in the subclavian vein. The numbers of MES detected during haemodiafiltration (314-709 MES per 10 min) were higher than during haemodialysis (0-81 MES per 10 min).

CONCLUSIONS

The composition (gaseous or solid) and origin (pump, tubing system or shunt) of the microemboli detected remains unclear. Chronic microembolization may be one cause of pulmonary complications of haemodialysis and haemodiafiltration. The detection method described in this article will help us to better understand this process and to determine what role microemboli might play in pulmonary and central nervous system disorders. It may also help to optimize the devices and techniques used.

Inverse paradoxical embolism in a patient on chronic hemodialysis with aortic bacterial endocarditis

We present a 45-year-old patient on chronic hemodialysis who suffered aortic endocarditis by Staphylococcus haemolyticus after bacteremia associated with a venous catheter, which was used temporarily during the maturing phase of a Cimino-Brescia arteriovenous fistula in the left forearm. Three weeks after starting antibiotic therapy, the patient suffered a septic pulmonary embolism. The catheter had been removed 4 weeks before the embolism. Thrombophlebitis of lower limbs, infection or thrombosis of the vascular access, and the involvement of right-sided cardiac structures were all discarded. We assumed that the pulmonary episode was probably a consequence of the paradoxical passage of embolic material, detached from the aortic valve, from arterial to venous circulation through the arteriovenous fistula.

Clinical considerations in hemodialysis access infection

Hemoaccess infections remain a substantial cause of morbidity in patients on hemodialysis, especially with the increasing reliance on prosthetic devices as the average age of the hemodialysis population increases. Access manipulation, either through needle puncture or secondary surgical procedures, is the primary etiology of infection. Other conditions such as access location, patient hygiene, and intravenous drug use can cause contamination. Local evidence of inflammation or infection, especially pain and purulence, are the most reliable signs of infection; however, the access can be infected and there may be minimal systemic symptoms. Medical therapy must be directed primarily against Staphylococcus aureus, with vancomycin being used most frequently. There are distinct conditions in which infection with gram-negative bacilli is also common. A coordinated effort between medical management and surgical intervention is essential to optimize therapy. Several situations, such as loss of vascular integrity or infection at anastomosis sites, mandate full excision of the graft. However, the access or at least the access site, can be preserved through creative surgical intervention along with aggressive medical treatment. Approaches to the diagnosis and treatment of infection in autologous arteriovenous fistulae, polytetrafluoroethylene arteriovenous conduits, and cuffed dual-lumen venous hemodialysis catheters are discussed.

Fate of infected and eroded hemodialysis grafts and autogenous fistulas

Between 1970 and 1991, we placed 1,090 grafts (bovine and polytetrafluoroethylene) in 1,041 patients and created 1,034 autogenous fistulas in 856 patients for hemodialysis. Subsequent revisions for complications resulted in a total of 3,944 operations performed in patients with grafts and 1,633 operations in patients with autogenous fistulas. A total of 255 infections developed in 158 of the patients with grafts, whereas 8 infections developed in 7 patients with autogenous fistulas. The puncture infection rate was 5%/yr (12%/yr for a second puncture infection). The clean wound infection rate was 3% for grafts and 0.4% for autogenous fistulas. We made an attempt to salvage the graft, usually with a segmental bypass, in 75% of patients with a graft infection. Grafts were salvaged in 80% of patients in whom salvage was attempted (60% of all patients with an infection). The results in the few patients with infected autogenous fistulas were relatively poor.

Pulmonary embolism in end stage renal disease

Clinically significant pulmonary embolism is considered to be rare in patients with end stage renal disease. Two cases with long standing renal disease on dialysis, are reported where pulmonary embolism contributed significantly to morbidity and mortality. One patient had hypotension during dialysis. The differential diagnosis of sustained hypotension during dialysis or in the ICU should include pulmonary embolism. Establishing the diagnosis may require pulmonary angiography.

Emergencies in continuous dialysis patients: diagnosis and management

The number of patients undergoing long-term hemodialysis and peritoneal dialysis is growing in the United States. To provide adequate emergent care to these patients emergency physicians must understand the alterations in normal physiologies present in these patients and how this may affect care. Cardiovascular disease and infection (especially Staphylococcus aureus sepsis) are the leading causes of death among dialysis patients. These patients are also subject to a significantly higher incidence of life-threatening electrolyte disturbances, particularly hyperkalemia and hypercalcemia, than the general population. Suicide, cardiac tamponade, intracranial hemorrhage, bleeding disorders, and bowel infarction are also much more frequent. The inability of dialysis patients to excrete drugs, metabolites, toxins, and fluids significantly alters their responses to common emergencies and should directly influence their care. Failure to recognize these differences in physiology may result in the use of standard forms of emergency therapy that may compound, rather than treat, the underlying disorder. Although most dialysis patients who come into an emergency department have conditions that can, and should, be managed by their nephrologist, the presence of a life threatening emergency requires prompt, appropriate therapy by the emergency physician.

The patient with chronic renal failure who is undergoing dialysis or renal transplantation: another consideration for antimicrobial prophylaxis

A patient with chronic renal failure who is undergoing dialysis or renal transplantation is susceptible to a number of infections. Transient, usually asymptomatic bacteremias occur in a wide variety of dental manipulations, particularly those involving the mucous membranes. Certain bacteremias may cause serious complications in these already compromised patients. Therefore, antimicrobial prophylaxis is essential when these patients undergo bacteremia-causing dental procedures.

Staphylococcal septicaemia, endocarditis, and osteomyelitis in dialysis and renal transplant patients

Septicaemia is a common and potentially lethal hazard of haemodialysis and renal transplantation; it is usually caused by Staphylococcus pyogenes. In 6 patients with S. pyogenes septicaemia, fatal endocarditis and spinal osteomyelitis have each occurred once, and 3 patients have had recurrent episodes of septicaemia. The management of septicaemia in these patients must include a search for metastatic infection, and prolonged therapy with 2 antistaphylococcal agents is necessary to ensure eradication of infection. Access site infection in dialysis patients must be treated vigorously, and recognized as potentially hazardous by patients. The risk of sepsis in dialysis and transplant patients cannot be excluded, but devastating consequences may be avoided by simple measures.

Spinal epidural abscess in patients on maintenance haemodialysis (a presentation of two cases)

Two cases of spinal epidural abscess in patients on maintenance haemodialysis, one of them secondary to infection in an arteriovenous fistula, are described. Both cases presented the typical symptoms known from the literature, but were diagnosed too late to prevent neurological sequelae. The condition is rare, but dialysis patients are to be considered a risk group because of their reduced immunocapacity and increased hazard of infection, especially fistula and shunt infections. Awareness of this, and knowledge of its early symptoms are required for timely neurosurgical intervention and thus prevention of irreversible spinal cord damage.

The flora of renal haemodialysis shunt sites

During investigations of the microbial flora of the skin over haemodialysis shunt sites it has not proved possible to predict clinical infection by a preceding colonization of the shunt site with a pathogenic organism. The normal non-pathogenic flora of the sites is not specifically related to the flora of other sites on the body though Staphylococcus aureus on a shunt site appeared to be acquired principally from the nose when the shunt was in the arm or from the perineum when the shunt was in the leg. Cimino shunt sites had a greater density of organisms than did Scribner shunt sites; this may be related to the disinfection procedures.

A studyof the pharmacokinetics of clidamycin in normal subjects and patients with chronic renal failure

A single dose of 150 mg clindamycin was given to nine patients with terminal renal failure being treated by maintenance haemodialysis and the blood levels were measured. Four of these patients were studied during haemodialysis and five between haemodialyses. Clindamycin (150 mg) was also given orally to four normal subjects.

The mean serum half-life in the normal subjects was 2·15 hr. For the dialysis patients the mean serum half-life off dialysis was 1·58 hr while that on dialysis was 1·85 hr.

There is evidence that clindamycin is excreted normally in chronic renal failure and that blood levels are not affected by haemodialysis. Normal adult doses, 150-300 mg four times a day, can be given safely in patients with chronic renal failure.