Infections in Immunocompromised Hosts

Question 1

Congenital Neutrophil dysfunction or neutropenia

• Disease
• Pathogen
• Treatment

Answer 1

• Disease: Chronic Granulomatous Disease
• Pathogen: Susceptible to Catalase Positive Organisms. Ex. Staph Aureus, Nocardia, Serratia, and Aspergillus.
• Treatment: TMP-SMX, Itraconazole

Question 2

Iatrogenic

Answer 2

• Illness caused by medical examination or treatment

Question 3

Acquired Neutrophil dysfunction or neutropenia

• Disease
• Pathogen
• Treatment

Answer 3

• Usually from Chemotherapy. Risk is related to Degree of neutropenia (how little # of cells?) and Duration of neutropenia
• Disease:
• Pathogen: Gram-POSITIVE = 2/3 of bloodstream infections. ex. Strep, coagulase-negative Staph, and Enterococcus
• Gram negatives would be E.Coli, Klebsiella, and Pseudomonas
• Treatment: Lasts longer than 7 days use antibiotics, and 1/3 of these people will have fungal infections! USually candida or apsergillus

Question 4

Types of pathogens? Primary vs Opportunistic.

Answer 4

• Primary: Often cause infection in normal host. Ex. Staph Aureus and Strep Pneumoniae
• Opportunistic Pathogens: Do not usually cause disaese unless host is compromised. Ex. Pseudomonas, Aspergillus, Pneumocystis jirovecii

Question 5

What the the Humoral Immune System? And what is it for?

Answer 5

• Immune system mediated by Antibodies
• B and CD4 cells!
• It is for Extracellular pathogens, most bacteria, worms, and some viruses!

Question 6

Humoral Immune Dysfunction

• Disease
• Pathogen
• Treatment

Answer 6

• Type of Infections: Response to polysachharide capsule! Affects children after 6 months! Mothers antibodes die off!
• Disease: Malignancy… abnormalities
• Pathogen: Encapsulated Bacteria, Enterovirus

Question 7

Spleen function?

Answer 7

• Removed particles not opsonized
• Humoral immunity.. mainly immunoglobulin response
• Regulates alternative complement pathway

Question 8

Splenic Dysfunction

• Disease
• Pathogen
• Treatment

Answer 8

• Type of Infections: At high risk for encapsulated organisms
• Disease: Meningitis
• Pathogen: Streptococcus Pneumoniae, Haemophilus Influenzae, Neisseria meningitidis

Question 9

Role of helper T cells, cytotoxic T cells, and T Regulatory Cells?

Answer 9

• Helper T cells: Provide B cells with signals necessary for antibody production
• Cytotoxic T cells: destroy cells infected with intracellular pathogens
• T regulatory cells: Suppress auto-reactive T cells

Question 10

Cell Mediated Immune Dysfunction

• Disease
• Pathogen
• Treatment

Answer 10

• Type of Infections: Important for INTRACELLULAR pathogens and timour cells!
• Disease: Pneumocystis! (Means you have T cell deficiency!)
• Primary disease: DiGeorge Syndrime, Wiskott-Aldrich.
• Clinical Manifestations: Fungal infections! Viral infections!
• Pathogen: Normal flora, primary pathogens, opportunistic pathogens!
• Treatment: TMP-SMX

Question 11

What is the timeline for different risks of post organ transplant infections?

Answer 11

• <4 weeks: Nosocomial
• 1-6 months: Period of MOST INTENSIVE IMMUNE SUPPRESSION. HIGH RISK! Thus many opportunistic infections!
• > 6-12 Months: Common to rare disease. Community acquired infections!

Question 12

What is the role of Tumour Necrosis Factor Alpha Inhibitors?

Answer 12

• Soluble messenger that gives a signal to target cell

- Maintains cellular immunity

Question 13

Timor Necrosis Factor-Alpha Inhibitors

• Disease
• Pathogen
• Treatment

Answer 13

• Type of Infections:
• Disease: REACTIVATION OF TB. IF putting in TNFa inhibitors you MUST SCREEN FOR LATENT TB!, Fungi, Bacteria, Parasites, Viruses
• Pathogen: ex. Herpes Zoster Virus

Question 14

Susceptibility to encapsulated bacteria when B cells, and thus Ig’s are low.. HUMORAL DEFICIENCY AND SPLENIC

Answer 14

• SHiNE SKis
• Streptococcus pneumoniae
• Haemophilus Influenzae type B
• Neisseria meningitidis
• Escherichia coli
• Salmonella
• Klebsiella pneumoniae
• Group B strep