HaematologyTier 2Disease (DEADMAN)

Complications of therapeutic interventions, such as catheter-related infections and thromboses, and anticoagulant-related skin necrosis

Description

Therapeutic interventions in haematology (central venous catheters, anticoagulation, chemotherapy) carry recognised, specific complications - catheter-related infection and thrombosis, and anticoagulant-related skin necrosis - each requiring prompt recognition given their potential severity

Central venous catheters (for chemotherapy administration, stem cell transplant, or long-term treatment access) are near-ubiquitous in haematology practice, and catheter-related complications are correspondingly common

Catheter-related bloodstream infection arises from biofilm formation on the catheter surface, seeding organisms directly into the bloodstream; catheter-related thrombosis reflects a combination of endothelial injury from catheter placement, local blood flow disruption, and the prothrombotic state often present in cancer patients
Anticoagulant-related skin necrosis (classically with warfarin) results from a transient procoagulant state in the first days of warfarin initiation - warfarin inhibits protein C (a vitamin K-dependent natural anticoagulant) faster than it inhibits the procoagulant factors (II, IX, X), creating a brief window of relative hypercoagulability, particularly dangerous in patients with an underlying protein C or S deficiency

Catheter-related infection: fever/rigors temporally associated with catheter use, blood cultures drawn from both the catheter and a peripheral site (differential time to positivity supports a catheter source)
Catheter-related thrombosis: swelling/pain in the catheter-bearing limb, confirmed by Doppler ultrasound or venography
Warfarin-induced skin necrosis: characteristic painful, well-demarcated purpuric/necrotic skin lesions appearing within the first few days of starting warfarin, particularly in fatty tissue areas (breast, thigh, buttock)

Catheter infection: antibiotics +/- catheter removal depending on organism and severity; catheter thrombosis: anticoagulation, with catheter removal considered depending on ongoing need and resolution
Warfarin-induced skin necrosis prevention: always overlap warfarin initiation with a fast-acting parenteral anticoagulant (heparin/LMWH) until the INR is therapeutic for at least 2 consecutive days, specifically to cover the early protein C-depletion window - this is standard practice precisely to prevent this complication
If skin necrosis occurs, stop warfarin immediately, reverse with vitamin K, and continue anticoagulation with an alternative agent

Central venous catheter placement, cancer-associated thrombosis, protein C/S deficiency (increased warfarin necrosis risk), heparin-warfarin bridging

Warfarin-induced skin necrosis is a specifically preventable complication - the standard practice of bridging with heparin/LMWH during warfarin initiation exists precisely to cover the early protein C-depletion window, and omitting this bridge (or stopping the parenteral agent too early, before 2 consecutive therapeutic INR days) is the recognised avoidable cause

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