182. Immunocompromised Pt Flashcards by Tegan Turner

Innatve vs acquired immunity basic differences?

innate - occur regardless o fhow often infection and get activated immediately

acquired - take some time after repeat exposure and 3-5d to mount

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Nonmicrobe sp immunity: Physical barrier examples

skin
mucosa
cilia
biofilm
gastric acid
antimicrobial peptides
pro on skin and mm

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Nonmicrobe sp immunity: Physical barrier what impairs these?

smoking
pulmonary disease
mechanical ventilation
tracheostomy
abnormal peristalsis

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Initial inflammatory response and innate immunity: goal of this and microbes to do it?

promote phagocytosis and microbial killing while activating the immune system

inflammatory response to release CK - cause migration and adhesion of PMN and monocyte to bacterial invasion

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Nonmicrobe sp immunity: Reticuloendothelial system

composed of tissue macrophages and blood borne counterparts, monocytes - removes particulate matter from lmph and blood

particlarly LN, spleen, liver, marrow, lung

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Nonmicrobe sp immunity: Reticuloendothelial system - particular good for which bacteria?

encapsulated
pneumococci, meningococci, H influ

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Adaptive/Microbe specific Immunity: Humoral: Antibody - which cells are these and what can they do?

B cell, also help to present to T cell

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: which is first to appear in system in response to new Ag?

IgM

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgM vs IgG

IgM: first, less affinity but provides some recognition to b cell prolif prior to making IgG

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgA - where do you typically find this one?

GI
nasal and oral secretions
tears
other mucous fluids

bacterial, viral and protozoan

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgE.- where is this?

mast cell surface, basophils
hypersen responses

particular helminth

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgG - how much accounts for total Ig mass?

75%

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgG - can it cross the placenta?

yes

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgG - how long does fetus have mums IgG?

first 6mo

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Adaptive/Microbe specific Immunity: Humoral: immunoglobulins: IgG - G2 subtype has sp affinity for polysacc of bacterial cell capsules of which 2 bacteria in paritcular?

strep pneumoni
H influ

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Adaptive/Microbe specific Immunity: Humoral: Complement: what is this?

cascade of interaction of 30 PRO to produce inflamm, leukoctyosis, recruite leukocytes to sites of infection
neutralize viruses
enhances binding of opsonin
lyses bacteria cell walls and membranes

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Adaptive/Microbe specific Immunity: Humoral: Complement: which Ig activate this? (2)

IgM
IgG

classical pathway

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Adaptive/Microbe specific Immunity: Humoral: Complement: what activates the alternative pathway?

repeating chemical structure molecules like bact cell wall and capsulse

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Adaptive/Microbe specific Immunity: Humoral: Complement: what is the merging point of classic and alt paths?

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Adaptive/Microbe specific Immunity: Humoral: Complement: terminal leg of this includes C5-c9 forming the membrane attack complex - what does this do?

cell wall and membranes insertion, leads to death

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In pt with mild complement deficiencies, is risk of disease with Niesseria meningitidis and gonorrhea worse or better?

milder

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Adaptive/Microbe specific Immunity: In cell mediated immunity - what cells does this include?

T ymphocytes
NK
mononuclear phagocytes

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Adaptive/Microbe specific Immunity: cell mediated immunity - where are most T cells?

marrow, thymus, spleen, LN

spleen and LN are where see antigens

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CD4 vs CD8 roll of T cells?

cd4 help other cells including enh b cell antibody production, production of CK

cd8 kill virally infected target cells themselves

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Defects in cell mediated immunity (T cells) are at risk for which disseminated infections by bacteria?

TB Listeria Salmonella

Defects in cell mediated immunity (T cells) are at risk for which disseminated infections by viruses?

cmv herpses varicella

Defects in cell mediated immunity (T cells) are at risk for which disseminated infections by fungi?

candida cypto aspergillus pneumocystis

Defects in cell mediated immunity (T cells) are at risk for which disseminated infections by protozoa?

toxoplasma

2 major granulocytic phagocytes?

neutrophils macrophages

Eosinophils are particular helpful for which bugs?

helminths

Half of neutrophils in BM circulate where? and other half ?

plasma lungs, liver, spleen, endothelium

What bugs are particularly well opsonized by neutrophils?

s pneumo gas h influ staph aureus

Which bacteria does crp opsonize?

one of initial inflamm response PRO opsonizes s pneumo

Splenectomy or functional asplenia concerning bacrteria

s pneumonia h influ n meningitid canpcytophaga canimorsus bordetella

Key antibiotics for immunocompromised pt

aminoglycosides ext sepctrum pen - piptazo cephalo: cefepime carbapenem: imi, mero other: vanco amphotericin B acyclovir

Acyclovir dose for a mucocutaneous herpes zoster in an immunocomp pt:

5mg/kg IV q8h or 400mg PO daily

Acyclovir dose for a mild vs seve herpes zoster in an immunocomp pt:

mild: 800mg PO five times daily or 10mg/kg IV q8h

Acyclovir dose for a primary varicella in an immunocomp pt:

10mg/kg IV q8h

What are unique considerations for febrile neutropenia evaluation and management in children?

-IV cath common site - swab all sources -peripheral culture if possible -urine culture and urinalysis given ++ common -cxr only if sx -initiate monotherapy as soon as culture done - piptazo, penem -transfer of ped ca pt to hospital with experienced management when available

Solid organ ca pt - often febrile neutropenia?

If suspected listeria, how to tx?

ampicillin

If worried about salmonella, tx with which abx?

third gen cephalosporin or FQ

Pt with solid tumors, lymphoma and leukemia are at risk of pneumonia from what sp? tx with?

legionella resp FQ or azithromycin

Nocardiosis - what is this?

severe bact infection with weakly acid fast gram +, filamentous rod, branching

MC manifestation nocardiosis?

nodular infiltrates pneumonia no fever

Tx nocardia?

sulonamides with other agents

What immunocomp pt are at risk for cryptococcus infection?

lymphomas CLL and CML HIV solid organ transplant db renal insuff cirrhosis

MC manifestation of cryptococcus?

meningitis

Meningitis secondary to cryptococcus dx?

crypto angtigen in serum and csf, fungal culture, tissue biopsy often high opening pressure and can cause obstr hydrocephalus

Which pt are at risk from pneumocystis jirovecii pneumonia?

AIDS leukemia lymphoma solid tumors taking high dose CS

What abx is prophylactic for PJP?

septra

What parasitic infection is the only helminthis organism producing severe infection in pt with deficient cell mediated immunity?

strongyloides

strongyloides - sx

cns, skin can have wheeze cough dyspnea, hemoptysis, hemorrhagic rash

top 3 viruses causing serious infecton in cancer pt?

varicella zoster herepes simplex cmv

What tx can pt with decreasedm cellulular mediated immunity get for influenza?

oseltamivir

Hypogammaglobulinemia is common in which 2 ca?

CLL MM

What opportunistic infections can mimic cancer spread?

nocardia, toxo in brain Budd chiari mimic: asperigllus, mucor, rhizopus --> causing thrombus Renal vein thrombosis: gram neg bacilli candida - ureter like post obstr uropathy Pulmonary nodules - histo pneumocystitis, legionella, aspergilus, nocardia

What are diabetes pt incr risk of infection?

defect in imm function, excess substrate for bacteria and fungal growth, vascular insuff - microangiopathy and AS, sensory neuropathy to wound neglect neutrophils and monocyte impaired cellular immunity has decr prolif response

Why does etoh use/cirrhosis incr risk of infection?

suppression immune system altered blood flow depression mental status delay in seeking medical care malnutrition cig smike chronic lung disease complement deficiency secondary to loss of C3 (made by liver) IgM bactericidal decrease granulocytopenia and dminished leukocyte mobilization

Spont bacteremia and sepsis infections in pt with cirrhosis: caused by which bugs?

ecoli K pneumoniae salmonella streptococci vibrio vulnifivus aeromonas

SBP infections in pt with cirrhosis: caused by which bugs?

ecoli k pneumoniae s pneumo enterococci

etoh pt: PMN count 250 cells/mm3 - tx with?

ceftriaxone or cipro until cultures return

Additionally, patients receiving treatment for SBP have been shown to have increased survival and decreased inci- dence of hepatorenal syndrome when administered albumin 1.5 g/kg at ?d and 1 g/kg on day ? of treatment.

on presentation d3

Why do pt with renal failure get more infections?

often concomittent diabetes sites of infection at breaks in skin from vascular access, peritoneal dialysis uremic pruritis reduced renal clearance CKD - general immune hyporesponsiveness: neutrophils slow, CMI imapired, leukopenia common. Humoral imm: lower IgG response, inadequate response to vaccines

Renal failure pt - often assume ? + and tx as such

MRSA

What bugs predominate in perionteal dialysis pt perionitis?

s aures, s epidermidis strep gram - bacilli candida

What bug specifically does asplenia put you at risk for?

s pneumo

Bugs from asplenia (list 6)

s pneumo H influ n meningitidis gram - bacilli: ecoli, pseudomonas babesia ehrlichiosis - tick borne bordetella

Diseases causing functional hyposplenism

sickle cell ulcerative colitis celiac sarcoidosis amyloidosis RA SLE

What finding on blood smear indicates hyposplenism?

howell jolly bodies

For pt with asplenia, may not find a source. What abx should you give?

ceftriaxone at meningitic dosing vanco if R prevalent to penicillin

What immunizations does an asplenia person need?

pneumococcus h influ type B N meningitidis influenza

Asplenia: rule for children receiving prophylaxis with oral ? or ? up to age of _ and for at least ?-? years after splenectomy

pen or amox age 5 1-2y

How to steroids effect the immune system?

alter distribution and function of neutrophils, monocytes, lymphocytes difficulty to mobilize them and neutrophil adherence inhibit phagocytosis and IC killing (CMI impaired) complement cannot activate hyperglycemia also contributes

MC sources of infection when on high dose steroids?

s aureus streptococci gram neg bacilli

At what dose of predn does adrenal suppression increase?

>7.5mg/day

Use of CS increases risk of complications from what abdominal disease?

diverticular

List 5 immunosuppressive drugs other CS?

cyclosporine tacrolimus mycophenolate azathioprine methotrexate cyclophosphamide

tumor necrossi factor inhibitors are at incr susecptibility of what kind of infections?

disseminated - tb, non tb mycoplasma, histo, coccidiodomyocisis

What is mucositis?

Mucositis is a frequent prelude to viridans streptococcal bacte- remia, which can produce sudden onset of acute respiratory distress syndrome, a toxic shock–like syndrome, rash, and pneumonia. Impor- tantly, mucositis predisposes the patient to gram-positive infections, and vancomycin is appropriate in addition to a broad-spectrum gram- negative agent.