Terminology for Blood with Pus Discharge from Pigtail Catheter
The term for blood with pus discharge from a pigtail (percutaneous drainage) catheter is "purulent drainage" or "exit site infection" when associated with signs of infection. 1
Clinical Definitions and Classification
When evaluating drainage from a percutaneous catheter such as a pigtail, the following definitions apply:
Exit site infection: Characterized by erythema, induration, and/or tenderness within 2 cm of the catheter exit site, often associated with pus emerging from the exit site, with or without concomitant bloodstream infection 1
Clinical manifestations of catheter-related infections include:
Microbiological definition: Exudate at catheter exit site yields a microorganism with or without concomitant bloodstream infection 1
Diagnostic Approach
When blood with pus is observed from a pigtail catheter, the following diagnostic steps should be taken:
Collect cultures of the drainage material to identify causative organisms 1
Gram stain of the drainage may be helpful for rapid diagnosis of local infections, though it is less sensitive than quantitative methods 1
Blood cultures should be drawn both from a peripheral vein and through the catheter (if applicable) to assess for catheter-related bloodstream infection 2
Differential time to positivity (DTP) between catheter-drawn and peripheral blood cultures can help determine if the catheter is the source of infection 1
Clinical Significance
The presence of purulent drainage with blood from a pigtail catheter has important clinical implications:
It strongly suggests infection at the catheter site and possibly catheter-related bloodstream infection 1
This finding has greater specificity but poor sensitivity for diagnosing intravascular device-related infection 1
Purulent drainage may indicate biofilm formation within the catheter lumen, which is difficult to eradicate with antibiotics alone 3
Common Pitfalls and Caveats
Do not rely solely on clinical findings for establishing a diagnosis of catheter-related infection, as they have poor specificity and sensitivity 1
Avoid confusing colonization with infection: Catheter colonization is defined as significant growth of a microorganism in culture without clinical signs of infection 1
Consider alternative diagnoses: In cases of pigtail catheters used for drainage of collections (like empyema or liver abscess), the drainage may represent the contents of the collection being drained rather than a catheter-related infection 4, 5
Do not delay appropriate intervention: Purulent drainage may indicate the need for catheter removal or exchange, especially if associated with systemic signs of infection 6
Remember that prompt identification and appropriate management of catheter-related infections are essential to reduce morbidity and mortality associated with these complications 1.