Infection Flashcards
What type of infections do neutrophils play a role in?
- Bacterial
- Fungal
What type of infections do monocytes play a role in?
Fungal
What type of infections do eosinophils play a role in?
Parasitic
What type of infections do T lymphocytes play a role in?
- Fugal
- Viral
- PJP
What type of infections do B lymphocytes play a role in?
Bacterial
What supportive factors are aimed at reducing sepsis in haematological malignancy?
- Prophylaxis
- Growth factors e.g. G-CSF
- Stem cell rescue/transplant
- Protective environment e.g. laminar flow rooms
- Intravenous immunoglobulin replacement
- Vaccination
What prophylaxis can help reduce sepsis in haematological malignancy?
- Antibiotics (ciprofloxacin)
- Anti-fungal (fluconazole or itraconazole)
- Anti-viral (aciclovir)
- PJP (co-trimoxazole)
What is the cause of neutropenia?
Marrow failure proves a higher risk than immune destruction
How is the degree of neutropenic risk classified?
Neutrophils
- <0.5x10^9 = significant risk
- <0.2x10^9= high risk
What duration of neutropenia carries a high risk?
- Neutropenic >7 days
- In AML therapy and stem cell transplantation there is profound neutropenia ~14-21 days
What are additional risk factors for infection?
- Disrupted skin / mucosal surfaces
- Hickman line, venflons
- Altered flora/ antibiotic resistance
- Prophylactic antibiotics
- Lymphopenia
- Disease process e.g. Lymphoma
- Treatment eg Fludarabine, ATG
- Stem cell transplantation, GVHD
- Monocytopenia
- Hairy cell leukaemia
- Chemotherapy
What is the pattern of bacterial causes of febrile neutropenia?
- Gram-positive bacteria (60-70%)
- Gram-negative bacilli (30-40%)
- These patterns may now relate to antibiotic prophylaxis, emerging infections, use of lines etc
What gram positive bacteria are implicated in febrile neutropenia?
- Staphylococci: MSSA, MRSA, coagulase negative
- Streptococci: viridans
- Enterococcus faecalis/faecium
What gram negative bacteria are implicated in febrile neutropenia?
- Escherichia coli
- Klebsiella spp: ESBL
- Pseudomonas aeruginosa
- Enterobacter spp
What are possible sites of infection in haematological patients?
- Respiratory tract
- Gastrointestinal (Typhlitis)
- Dental sepsis
- Mouth ulcers
- Skin sores
- Exit site of central venous catheters
- Perianal (avoid PRs!)
What type of infection are immunocompromised patients particularly at risk of?
Fungal
Give examples of fungal infections.
- Candida
- Aspergillus
What can fungal infections in immunocompromised patients lead to?
Life threatening deep seated infection
What contributes to the risk of fungal infection?
Monocytopenia and monocyte dysfunction
Where are fungal infections likely to affect?
- Lung
- Liver
- Sinuses
- Brain
How does neutropenic sepsis present?
- Fever with no localised signs ( single reading of 38.5 or 2 readings of 38, 1 hour apart)
- Rigors
- Chest infection/ pneumonia
- Skin sepsis - cellulitis
- Urinary tract infection
- Septic shock
What is the timeline of sepsis?
- Signs of systemic inflammation (SIRS)
- Presumed infection and organ dysfunction
- Severe sepsis/ septic shock
What action should be taken for sepsis?
Sepsis 6
What are the sepsis 6?
- Administer high flow oxygen
- Take blood cultures, other cultures, consider source control
- Give appropriate IV antibiotics within ONE hour
- Measure serum lactate concentration
- Start IV fluid resuscitation
- Assess/measure urine output
What does delay in sepsis treatment lead to?
Every hour’s delay in administering antibiotics increases chance of mortality by 8%
How is neutropenic fever investigated?
- History and examination Blood culture: Hickman line & peripheral
- CXR
- Throat swab & other clinical sites of infection
- Sputum if productive
- FBC, renal and liver function, coagulation screen
How should neutropenic sepsis be managed?
- ABC resuscitation
- Broad spectrum IV antibiotics (tazocin, 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
When may patients 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
What infections are severly lymphopenic patients at particular risk of?
- Atypical pneumonia
- Pneumocystis Jirovecii (PJP)
- CMV
- RSV
- Viral
- Shingles (Varicella Zoster)
- Mouth ulcers (Herpes simplex)
- Adenovirus
- EBV (PTLD)
- Fungal
- Candida, aspergillus, mucormycosis
- Atypical mycobacteria
- Skin lesions, pulmonary and hepatic involvement