Flashcards in Infections in Compromised Host Deck (16):
What is a primary vs secondary immune defect? Give an example of each?
Primary - a congenital immune defect
i.e. Chronic granulomatous disease
Secondary - Acquired immune defect
i.e. Neoplasia causing obstruction, or neuropenia
Why is a neoplasia causing an obstruction a problem?
I.e. prostate cancer -> prevents draining of urine and gives pathogens a place to live in urethra
What can cause neutropenia and what are the most common pathogens we worry about?
Cause cause shetting of gut lumen / mucosa as well, allowing P. aeruginosa to invade.
We worry about Pseudomonas, aspergillis, and other opportunistic infections
What are the common pathogens at the sites of burn wounds and surgical wounds?
Streptococcus, staphyloccus (normal skin flora)
What is the most common pathogen from IV catheters?
What bacteria cause problems in the setting of biliary tract obstruction, and what is a common complication?
Ascending cholangitis - infection of the bile ducts, often due to malignancies like pancreatic cancer
Bacteria: aerobic gram negative rods, anaerobes, GI enterococci
Why is clinical diagnosis of neutropenic patients often difficult, and why is treatment of crucial?
Impaired immune response -> may not form obvious abscesses or have regular signs of infection (inflammatory signs are muted)
Treatment is crucial because the pathogen will disseminate quickly in the immunocompromised
What is a typical empiric treatment regimen for neutropenic patients?
Must cover P. aeruginosa
Piperacillin/tazobactam or cefepime or imipenem
Aminoglycoside like tobramycin
Why is empiric use of vancomycin for neutropenic patients discouraged?
Pathogens are generally of lower immediate virulence -> can use in catheter-associated infection or proven gram + infection
Do not want to cause more resistance
What is the most common form of antibody deficiency?
CVID - Common Variable Immunodeficiency - Leads to deficiency in Ig antibodies due to lack of T-cell activation of B ells
What is the most important cause of a secondary defective in adaptive immunity?
Malnutrition, especially protein-energy malnutrition, as in kwashiorkor or marasmus
What are four major immune defects associated with susceptibility to encapsulated organisms?
1. Multiple myeloma
2. Chronic lymphatic leukemia
3. Waldenstrom's macroglobulinemia
4. Sickle cell disease
What diseases cause defects in Cell-mediated immunity?
Hodgkin's lymphoma, non-Hodgkin's lymphoma, Chronic Lymphatic Leukemia (same as B cell), hairy cell leukemia.
Why is CMI deficiency bad?
CMI is involved in a much wider array of pathogens than just encapsulated ones, and can lead to chronic opportunistic infections
What are the 3 key pathogens of concern in humoral immune deficiency syndromes?
Encapsulated pyogenic bacteria
1. S. pneumoniae
2. H. influenzae
3. N. meningitidis