Infection in Immunocompromised Host Flashcards
Two categories of immunosuppressed infections?
More readily getting infections with common primary pathogens
Getting infections with opprotunistic pathogens
Spectrum of immune competence?
Healthy>Diabetes>cancer>HIV/transplant
Causes of immunosuppression (4)
Primary immunodeficiencies (eg SCID, B or T cell defects, chronic granulomatous disease)
Secondary immunodeficiencies (eg AIDS, cancer, diabetes, any severe systemic illness)
Stressed physiological states (eg pregnancy, elderly, neonates, nutritional deficiency)
Iatrogenic cause (steroids, chemo, immunosuppressant drugs, radiation, IV lines, surgery)
Example of opportunistic pathogen?
Asperilligus
5 ways to prevent infections in the immunocompromised
Avoid risky activities/places (hospital!!!)
Isolation
Vaccination
Abx prophylaxis
Correct underlying defect
AIDS spectrum of opportunistic pathogens
Specific infection in HIV: Pneumocystis jiroveci (presentation, diagnosis)
Causes lung infection
Non productive cough, SOB, fever
May progress to severe respiratory distress
Diagnosed using silver staining or immunofluorescence or PCR
Tx of pneumocystic pneumonia
High does cotrimoxazole
ICU input
Specific infection in HIV: Cerebral toxplasmosis (presentation, diagnosis)
T. gondii
In healthy hosts is asymptomatic or causes glandular fever like illness
In AIDS, main cause of focal CNS lesions, with ring enhancement on CT
What is HAART?
Highly active antiretroviral therapy, for prophylaxis of opportunistic infections
Boosts CD4 count
What is co-trimoxazole prophylaxis for?
Pneumocystis
What is rifabutin prophylaxis for?
Mycobacterium
What is ganciclovir prophylaxis for?
CMV
What is neutropenia? How is it diagnosed?
Low neutrophils
Lots of causes: chemo, aplastic anaemia, post mone marrow transplant
Difficult to diagnose infection: Absence of pus/localisation, rely on FEVER AS CARDINAL LSIGN
What is the cardinal sign of infection in neutropenic patients?
Fever
Difference in infection susceptability: neutropaenia and AIDS
So in general terms, those who are neutropenic tend to be susceptible to most typical bacteria such
as Pseudomonas and Staphylococcus aureus. Neutropenic patients are also susceptible to most
fungal infections. This contrasts with individuals with cellular immune dysfunction that affects
principally T-cells, who are more susceptible to organisms such as Mycobacteria, Legionella, Listeria
and viruses.
Aspergillus infection in neutropenia
Lung infection which can spread to brain
Difficult to diagnosis due to poor culture
HIGH MORTALITY
Candida albicans in neutropenia
Greater risk due to central lines, parenteral nutrition, broad spectrum abx, perforations
Easier to diagnose, high mortality
Sepsis management in neutropenia
EMPIRICAL THERAPY:
- don’t wait for cultures
- URGENT BROADSPECTRUM ABX (piperacillin and gentamicin)
- Add vancomycin if no improvement
- Add antifungal if no improvement
- Supportive management eg O2 and fluids
What are the two most common organisms to infect burns patietns?
Pseudomonas aeruginosa
Staph aureus
Can spread to bloodstream
Prophylaxis of infection in burns patients
Topical silver suphadiazine
Excision of necrotic areas of burn
Tx of infection in burn patient
Topical and systemic abx
Which bacteria are splenectomy patients susceptible to?
Capsulate bacteria (pneumococcus and also Haemophilus)
Prevention of infection in splenectomy patients
Pneumococcal infection before procedure
Prophylactic abx (penicillin V)
