Infection in immunocompromised patients Flashcards
(19 cards)
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)
-
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?
-
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
If you don’t know the specific bacterium or fungus causing the infection what should you treat the patient with?
Echinocandins eg Caspofungin, Anidulafungin
How should you treat mould fungal infection?
Liposomal amphotericin
Which patients can be severely lymphopenic?
- Stem cell transplant recipients, especially allogeneic
- Recipients of Total Body Irradiation (TBI)
- Graft vs Host Disease
- Nucleoside analogues (fludarabine) or ATG
- Lymphoid malignancy e.g Lymphoma, CLL, ALL
Give examples of pneumonitis, viral, fungal and atypical mycobacterial infections that can infect severely lymphopenic patients and the drugs that treat each (don’t need to know inside out)
- Pneumonitis
- Pneumocystis Jirovecii (PJP) - co-trimoxazole
- Cytomegalovirus (CMV) - ganciclovir
- Respiratory syncytial virus (RSV) - ribavirin
- Viral
- Shingles (Varicella Zoster)
- Mouth ulcers (Herpes simplex)
- Adenovirus - cidofovir
- EBV (PTLD)
- SARS-CoV2
- Fungal
- Candida
- Aspergillus
- Atypical mycobacteria
- Skin lesions
- Pulmonary and hepatic involvement
