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Silent infection in clotted hemodialysis access grafts
1Department of Medicine, Baylor College of Medicine, Houston, Texas, USA.
Insights
Clotted hemodialysis grafts can harbor silent infections, often presenting as fever or sepsis. These grafts should be suspected as an infection source in hemodialysis patients, even without local signs.
Area of Science:
- Nephrology
- Infectious Diseases
- Vascular Surgery
Background:
- Vascular access failure in hemodialysis patients is often due to thrombotic and infectious complications.
- Management guidelines for clotted, nonfunctioning grafts are lacking, particularly concerning silent infections.
Purpose of the Study:
- To investigate the prevalence and clinical significance of silent infections in clotted, nonfunctioning hemodialysis grafts.
- To determine if clotted grafts serve as a hidden source of infection in hemodialysis patients with unexplained fever or sepsis.
Main Methods:
- A study involving 20 hemodialysis patients with unexplained fever/sepsis and 21 asymptomatic controls with clotted grafts.
- Indium scans were performed, followed by surgical removal and bacterial culturing of grafts and blood.
- Comparison of infection rates and pathogens between symptomatic patients and asymptomatic controls.
Main Results:
- All symptomatic patients and 15/21 controls showed positive indium scans, with purulent material found in grafts.
- Bacterial pathogens from blood cultures matched graft cultures in all positive cases, predominantly Staphylococcus aureus and S. epidermidis.
- No graft infection was found in controls with negative indium scans.
Conclusions:
- Clotted, nonfunctioning hemodialysis grafts are frequently associated with underlying infections.
- These grafts should be considered a potential source of infection in hemodialysis patients presenting with fever, even without overt signs of graft infection.
Abstract:
Thrombotic and infectious complications are frequent causes of hemodialysis vascular access failure and contribute considerably to the cost of care for chronic hemodialysis patients. Although there is clear indication for removal of patent grafts in unresolved bacteremia, there are no guidelines for the management of clotted nonfunctioning grafts. To evaluate for the existence and clinical relevance of silent infection in clotted nonfunctioning hemodialysis grafts, a study was conducted with a series of 20 hemodialysis patients who presented with fever (15 patients), or fever and clinical signs of sepsis (five patients), in whom the source of infection was not immediately localized to any organ system. Comparison was made with 21 asymptomatic patients with clotted grafts who served as control subjects. All patients and control subjects came from a pool of 115 chronic hemodialysis patients in an outpatient hemodialysis unit in the Houston metropolitan area, who were on hemodialysis for a period of time ranging from 3 to 15 yr. Indium scans were performed, followed by removal of the clotted grafts in all patients and control subjects. Bacterial cultures of the recovered surgical material and blood were done concomitantly in all study participants. Indium scans showed positive uptake in or around the clotted grafts in all of the patients and in 15 of the control subjects. Purulent material was found in the grafts in all patients and in 13 of 15 indium scan-positive control subjects. When positive, blood culture pathogens were identical to those cultured from the graft material in all instances. The predominant pathogens were Staphylococcus aureus, followed by Staphylococcus epidermidis. There was no evidence of graft infection in the control subjects if indium scan was negative. Chart review dating back to the start of dialysis revealed five past infectious episodes in the patient group, compared with four in the control group. These findings suggest that clotted nonfunctioning grafts are frequent harbingers of infection. They should be suspected as the source of infection in every hemodialysis patient that presents with fever, even in the absence of clinical signs of graft site infection.