Infection in immunocompromised patients Flashcards
What supportive measures are in place to reduce the risk of sepsis in haematological malignancy? (6)
- Prophylaxis
- Antibiotics (ciprofloxacin) against gram negative infection
- Anti-fungal (fluconazole or itraconazole)
- Anti-viral (aciclovir) esp shingles
- PJP (co-trimoxazole)
- Growth factors e.g. G-CSF - speeds up neutrophil recovery and reduces duration of neutropenia
- Stem cell rescue/transplant - give stem cells to speed up recovery after high dose of chemo
- Protective environment i.e laminar flow rooms with +ve pressure
- IV immunoglobulin replacement
- Vaccination i.e annual flu vaccine
How do we identify patients at highest risk of neutropenia? (3)
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What is the cause of their neutropenia?
- Marrow failure higher risk than immune destruction
-
Degree of neutropenia?
- < 0.5 x 109/l - significant risk
- < 0.2 x 109/l - high risk
-
Duration of neutropenia (for example AML and stem cell transplantation produces profound neutropenia for 14-21 days)
- >7 days - high risk of getting infection
- <7 days - less chance of getting infection
Disrupted skin / mucosal surfaces are a significant risk of infection to immunocompromised patients. Give some examples of situations where this might arise (4)
- Hickman line - central venous catheter most often used for the administration of chemo
- Cannulas
- Mucositis affecting the GI tract
- Graft versus host disease (GVHD) – happens after an allogeneic stem cell transplant where an immune attack of the donor cells predisposes you to infection by disrupting these barriers
Lymphopenia (low WCC) is a risk factor for infection in immunocompromised patients - how does this come about?
- Disease process e.g Lymphoma
- Treatment e.g Fludrabine (chemo), ATG (to reduce transplant rejection)
- Stem cell transplantation
- Graft versus host disease - post transplant
Prophylactic antibiotics can cause infection due to…
Which group of bacteria more commonly causes febrile neutropenia?
- Gram-positive bacteria (60-70%) - more commonly they get in through lines. If you get staph A infection then this is more serious
- Gram-negative bacilli (30-40%) - often resistant to the antibiotic the patient is on.
Which gram positive bacteria most commonly cause infection in immunocompromised patients?
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Staphylococci:
- MSSA
- MRSA
- Coagulase negative
- Streptococci: viridans
- Enterococcus
- Bacillus
Which gram negative bacteria most commonly cause infection in immunocompromised patients?
- E-coli
- Klebsiella: ESBL
- Pseudomonas aeruginosa
- Enterobacter species
Possible sites of infection in immunocompromised patients
- Respiratory tract – v common
- Gastrointestinal (Typhlitis)
- Dental sepsis – patients with poor teeth
- Mouth ulcers
- Skin sores
- Exit site of central venous catheters
- Perianal (avoid PRs!)
How does neutropenic sepsis present?
Fever with no localising signs - single reading of >38.50C or 38.0C on two readings 1 hour apart
- Rigors
- Chest infection / pneumonia
- Skin sepsis - cellulitis
- UTI
- Septic shock
Look
If you have signs of systemic inflammation (SIRS) with presumed infection and organ dysfunction then you can diagnose severe sepsis or septic shock => high risk of poor outcomes and needs urgent management
In relation to the management of sepsis, what is the sepsis 6?
- Give high flow O2
- Take blood cultures, other cultures, consider source control
- Give appropriate IV antibiotics within 1 hour - every hour’s delay increases chance of mortality by 8%
- Measure serum lactate concentration
- Start IV fluid resuscitation
- Assess/measure urine output
Which investigations should be done on a neutropenic patient who has developed a fever?
- History and examination
- Blood cultures - hickman line and peripheral
- CXR
- Throat swab and other clinical sites of infection
- Sputum if productive
- FBC, renal and liver function, coagulation screen
How do you manage/treat neutropenic sepsis?
- Resuscitation – ABC
- Broad spectrum I.V. antibiotics such as Tazocin and Gentamicin
- If a gram positive organism is identified add vancomycin or teicoplanin
- If no response at 72 hours add I.V. antifungal treatment e.g. Caspofungin - empiric therapy
- CT chest/abdo/pelvis to look for source
- Modify treatment based on culture results
Fungal infection in immunocompromised patients:
- Common infective organisms?
- Drugs to treat them?
- Candida species i.e aspergillus = life threatening deep seated infection in the lung, liver, sinuses and brain
- Treat with Voriconazole or Isavuconazole
