What are the possible causes and recommended evaluation and management for chills occurring during or shortly after a dialysis session?

Chills During Dialysis: Evaluation and Management

Chills occurring during or shortly after dialysis should be immediately evaluated for infection, particularly bloodstream infection (BSI), as approximately 60% of hemodialysis patients presenting with chills have an infection and 33.5% have bacteremia. 1

Immediate Assessment

When a dialysis patient develops chills, perform the following evaluation:

Critical Risk Stratification

High-risk features requiring immediate blood cultures and empirical antibiotics:

• Presence of fever (increases bacteremia risk by 1.6-fold) 1
• Central venous catheter as dialysis access (increases bacteremia risk by 6.2-fold) 1
• Leukocytosis or abnormal white blood cell count 1
• Hypoalbuminemia 1
• Hypotension developing during or after dialysis 2

Lower-risk profile (6% bacteremia rate):

• AV fistula or graft as access
• No fever
• Normal white blood cell count
• Normal albumin
• No obvious infection source 1

Vascular Access Examination

For catheter patients:

• Examine exit site for infection signs (erythema, purulence, tenderness) 3
• Recognize that high pulsatile blood flow through catheters can dislodge colonizing organisms, precipitating sepsis even without visible exit site infection 2
• Common organisms: Staphylococcus aureus (most common), Enterococcus faecalis, Enterobacter cloacae, Pseudomonas species 4, 2

For AV fistula/graft patients:

• Inspect for signs of access site infection
• Lower infection risk overall but still requires evaluation 1

Differential Diagnosis Beyond Infection

Pyrogenic Reactions

• Contaminated dialysate or reused dialyzer exposure to bacterial endotoxins 2
• Presents with fever, chills, hypotension during or shortly after dialysis 2
• Water quality issues: bacterial levels >200 CFU/mL or endotoxin >2 EU/mL indicate contamination 3

Dialyzer/Material Hypersensitivity

• Allergic reactions to dialyzer membrane or other circuit components 5, 6
• Can range from mild (managed with antihistamines, corticosteroids) to severe (requiring immediate treatment cessation) 5

Acute Phase Reactions

• Rare reactions to medications (e.g., gadolinium-based contrast agents in some preparations) 7
• Presents with fever, chills, nausea within hours of exposure 7

Hemodynamic Instability

• Excessive ultrafiltration causing symptomatic hypotension 8
• While typically presents with cramping and "feeling sick," can include chills as part of systemic response 8

Management Algorithm

For High-Risk Patients (catheter, fever, leukocytosis, or hypoalbuminemia):

1. Obtain blood cultures immediately (before antibiotics if possible) 1
2. Initiate empirical broad-spectrum antibiotics covering gram-positive organisms (including MRSA given 50-60% nasal carriage in dialysis patients) and gram-negatives 4, 1
3. Consider infective endocarditis in patients with:
   • Cardiac history (prior valve disease, prosthetic valves, stents)
   • Persistent bacteremia despite appropriate antibiotics
   • Obtain transesophageal echocardiography if suspicion exists 9
4. If blood cultures remain negative, consider metagenomic next-generation sequencing for fastidious organisms (Cutibacterium acnes, Corynebacterium species) 9

For Lower-Risk Patients (fistula/graft, afebrile, normal labs, no obvious source):

1. Obtain blood cultures 1
2. Observe closely without immediate antibiotics 1
3. Investigate dialysate quality: Check water treatment system for bacterial/endotoxin contamination 3
4. Review dialysis prescription for excessive ultrafiltration or rapid fluid removal 8
5. Initiate antibiotics if cultures positive or clinical deterioration occurs 1

Infection Prevention Measures

Catheter care protocol (reduces BSI risk) 3:

• Hand hygiene before all catheter manipulation
• Exit site disinfection with alcohol-based chlorhexidine >0.5% for ≥60 seconds
• Hub scrubbing with chlorhexidine or 70% alcohol for ≥15 seconds before connection/disconnection
• Staff and patient wear masks during catheter access

AV access care 3:

• Wash access site with soap and water
• Disinfect with alcohol-based chlorhexidine, 10% povidone-iodine, or 70% alcohol before cannulation

Critical Pitfalls

• Do not assume chills are benign: 60% have infection, 33.5% have bacteremia 1
• Do not rely on exit site appearance alone: Catheter-related bacteremia can occur without visible exit site infection 2
• Do not delay antibiotics in high-risk patients: Catheter patients with fever require immediate empirical coverage 1
• Do not overlook endocarditis: Consider in patients with cardiac history and persistent or recurrent bacteremia 9
• Do not ignore water quality: Monthly bacterial and endotoxin testing of dialysate is mandatory 3