Infection overview Flashcards
What elements must you consider when a patient presents with an infection?
- Host
- Environment
- Pathogen
always consider pathogen last
According to Dr. Ahmadi, what about the HOST is most important to consider?
Immune competent or immune compromised
According to Dr. Ahmadi, what about the ENVIRONMENT is most important to consider?
Port of entry, community or hospital acquired
According to Dr. Ahmadi, what about the PATHOGEN is most important to consider?
MOA, pathogenicity, virulence
Patient with liver disease presents for routine exam. According to Dr. A, what should you consider and why?
Possibility of occult infection. Research shows 2/3 of those w/chronic liver disease have an occult infection.
3 types of immune compromised states
- Primary immune deficiency
- Secondary or acquired immune deficiency
- Autoimmune disease
Examples of primary immune deficiency
Neonate, elderly
Examples of secondary immune deficience
AIDS, chemotherapy, relative immune deficiency (DM, cancer, poor nutrition state)
Autoimmune disease Dr. A mentions in relation to immune deficiency
SLE
What is surprising about SLE in relation to immune deficiency?
Although they have hyperactive immune systems, they’re not good at offering protection
Image: what does the pathogen want to in the body?
Attach → proliferate → avoid phagocytes → damage host via either toxins or invasion
Image: what do abs do to attempt to stop the pathogen at the attachment level?
Attachment: abs attach to fimbriae, lipoteichoic acids, and some capsules
Image: what do abs do to attempt to stop the pathogen at proliferation level?
Proliferation: a) Abs trigger complement-mediated damage to gram neg outer lipid bilayers, b) Abs block transport mechanisms & receptors (e.g., iron chelating compounds)
Image: what do abs do to attempt to stop the pathogen at the phagocyte avoidance level?
Avoidance of phagocytes: a) Abs to M proteins and capsules give opsonization via Fc and C3 receptors, b) Abs neutralize immunorepellents
Image: what do abs do to attempt to stop the pathogen at the host damage level?
Toxins: Abs neutralize toxins
Invasion: Abs neutralize spreading factors, enzymes (e.g., hyaluronidase
What type of organisms are those with B Cell deficiencies at risk for?
Encapsulated organisms, e.g., Streptococcus pneumoniae, Hemophilus influenzae
What organism is the most common cause of community acquired pneumonia?
Streptococcus pneumoniae
What types of infections are people with B cell deficiencies prone to?
Pneumonia, Sepsis, Infections of Sinuses, Ears and GI tracts
What types of infections are people with T cell deficiencies prone to?
Fungal, viral, and intracellular bacterial infections – e.g., chronic mucocutaneous candidiasis alerts you to T cell deficiency
Classic intracellular organism frequently seen, even in immune competent
Mycoplasma – chain coughing w/no other presenting symptoms
Syndrome that commonly causes T Cell deficiency
DiGeorge Syndrome: partial or complete absence of T cell immunity; lack of thymus; region of the developing embryo that is affected controls the development of the face, parts of the brain, the thymus, the parathyroid glands, the heart and the aorta.
Syndrome that leads to combined T and B deficiency
- Wiskott-Aldrich syndrome
- Normal IgA and IgG but very low IgM (so ACUTE phase is most problemetic)
What type of infections are those with Wiskott-Aldrich syndrome prone to?
Prone to infections with Encapsulated Bacteria
- Pseudomonas, Strep, H. Influ,
Conditions that leads to combined T and B cell deficiency
- RAG-1 or RAG-2 deficiency
- Bare lymphocyte deficiency
- MHC class I and II deficiency
- Wiskott-Aldrich syndrome
- Ataxia-telangiectasia (AT)
RAG-1 or RAG-2 deficiency: what does RAG stand for?
Recombinant activating gene
RAG-1 or RAG-2 deficiency: signs and symptoms
- No symptoms are detected during pregnancy, birth and within the first few weeks of life.
- The clinical signs are characterized by chronic respiratory disease, recurrent acute pneumonia, therapy-resistant mucocutaneous candidiasis, eczematous dermatitis and systemic bacterial infections.
Effect of recurrent infections and chronic enteritis of RAG-1 and RAG-2 deficiencies
- a therapy-resistant growth failure. Intracellular parasites (Listeria, Legionella), viruses (EBV) and cytomegaloviruses (CMV) cause lethal complications.
- All SCID children die within few months if they are not provided with haematopoietic stem cells.
What is Chédiak-Higashi syndrome?
- Defect in Cytoplasmic Granules (microtubule polymerization)
- Associated With Oculocutaneous albinism
