Infections of the Immunocompromised Host

Question 1

How can humoral (B cells - neutralisation, C activation, opsonisation) be affected?

Answer 1

• Bruton agammaglobulinaemia (failure of production of B cells)
• Reduced antibody production in lymphoproliferative disorders (CLL, multiple mueloma)
• Intensive radiotherapy and chemotherapy

Question 2

How can cellular immunity (T-cells - help macrophages, help B cells, kills infected cells) be affected?

Answer 2

• DiGeorge syndrome (failure of production of T cells)
• Malignant lymphoma
• Cytotoxic chemotherapy
• Immunosuppressive drugs
• SCTs
• Infections (i.e. HIV)

Question 3

What are the causes of febrile neutropenia?

Answer 3

• Non-infective causes include malignancy, chemotherapy, transfusion, antibiotics, colony stimulating factors and allergies

Question 4

What are the SIRS criteria?

Answer 4

• ≥ 2 of below
• Temprature >38°C or < 36°C
• HR >90
• RR >20
• WBC > 12,000/mm³, < 4,000/mm³, or > 10% bands

Question 5

What are the Sepsis criteria?

Answer 5

• SIRS
• Source of infection
• Organ dysfunction (hypotension, confusion, tachypnoea)

Question 6

What are the criteria for Septic Shock?

Answer 6

• Sepsis induced hypotension requiring inotropic support or hypotension that is unresponsive (within 1 hour) to adequate fluid resuscitation (i.e. systolic BP <90mmHg or a reduction of >40mmHg from baseline)

Question 7

How is neutropenic sepsis managed?

Answer 7

• Assess within 15 minutes of presentation
• Assess sepsis severity using NEWS
• Institute SEPSIS 6 within 1 hour (O₂FLUID)
• If NEWS ≤5, and no penicillin allergy give Tazocin, if allergy give Vancomycin and Ciprofloxacin
• If NEWS ≥5, and no penicillin allergy give Tazocin and Gentamicin, if allergy give Vancomycin and Ciprofloxacin
• If suspect SSTI add vancomycin
• If suspect atypical pneumonia add clarithromycin
• Previous/known ESBL infection/carrier use meropenem

Question 8

What are the criteria for Q-SOFA?

Answer 8

• Diagnosis of infection + SOFA score of ≥2 from the following:
• RR ≥22/min
• Systolic BP ≤100 mmHg
• Altered mental status

Question 9

What is included in the Sepsis 6? (O2FLUID)

Answer 9

• O2 (High flow oxygen)
• Fluid (IV fluids)
• Lactate (Measure lactate and Hb)
• Urine (Monitor urinary output)
• Immunology (Blood cultures)
• Drugs (IV antibiotics)