Infections in an Immunocompromised Host

Question 1

opportunistic pathogen

Answer 1

organism capable of causing disease only when the host’s resistance is lowered by other diseases or drugs.

OR

Causes atypical or more severe infectious clinical syndrome in a compromised host.

If a patient presents with an unusual pathogen causing infection or a severe infection, consier screening for immunodeficiency

Question 2

what bacteria could this be?

Answer 2

gram negative bacilli

• pseudomonas, stenotrophomonas, enterobacterieae (ecoli, klebsiella, enterobacter, yersinia, salmonella, shigella)
• bacterides fragilis

this ended up being pseudomonas aeruginosa

Question 3

outline the enterobacteriae

Answer 3

Question 4

treatment for pseudomonas (name 6)

Answer 4

pseudomonas is a gram negative bacteriae.

• aztreonams
• gentamycin and tobramycin (aminoglycosides)
• colistin
• carbapenems/piptaz

FQ/cirpofloxacin

• Ceftazidime (3rd generation cephalosporin)

Question 5

What part of the immune system is defective?

Answer 5

suspecting AID/HIV because of the recurrent infection. This would mean her CD4+ helper T cells would be affected. She is susceptible to intracellular pathogens, viruses, fungi and parasites.

She has a fungal and viral infections– indicates a T cell deficiency (or PMN)

Question 6

clinical manifestations of PJP on an exam and on x ray findgins?

Answer 6

• progressive dyspnea, cyanosis
• tachycardia, tachypnea
• fever
• non-produtive cought
• chest pain
• pneumothorax

Chest X ray findings: bilateral diffuse infiltrates extending from hilum typically. but it can still bey unilateral, nodules etc.

• lymphadenopathy

Question 7

You suspect PJP in immunocompromised patient. What do you order and how do you treat?

Answer 7

bronchoscopy fluid sample or lung tissue (histological staining or PCR)

• high dose of TMP-SMX (sulfamethoxazole)– covers gram positive and gram negative, or predinosone

Question 8

when should you give PJP prophylaxis

Answer 8

in HIV+ and immunocompromised individuals.

• CD4<200 for primary prophylaxis. You should stop it once immune reconstitution occurs.

Question 9

what do you give for PJP prophylaxis

Answer 9

low dose septra for PJP, until stabilized with HIV treatment. Also give nystatin and fungin for thrush

Question 10

risk factors for candida esophagitis

Answer 10

high grade colonization due to HIV, diabetes, hematologic malignancies, chemotherapy, broad spectrum antibiotic use, impaired esophageal motility etc.

Question 11

common yeast seen in subsaharan africa that really affects people with HIV

Answer 11

cryptococcus neoformans.

Question 12

a person from subsaharan africa who is HIV positive is suspected to have cryptococcus neoformans because of indolent meningitis, fever, mental status changes, and suspected pneomonia. What do you do to diagnose and treat it?

Answer 12

diagnosis:

-lumbar puncture– then a fungal stain and CRAG antigen test

treatment:

amphoterocin PLUS FLUCYTOSINE (induction)– 2 weeks or until CSF is sterilized.

• THEN you give high dose fluconazole (ergosterol synthesis inhibitor)

Question 13

although neoformans affects immunocomrpomised hosts, which cryptococcus seen in pacific rim affects healthy hosts, causing meningitis and pneumonia?

Answer 13

cryptococcus gattii– it is difficult to treat and there’s poor outcomes.

Question 14

someone presents with fever, malaise, splenomegaly, cerival lymphadenopathy, sore throat, rash, and atypical lymphocytosis (indicating acute infection). Additionally, they own a cat and don’t practice good hand hygiene. what is a suspected toxin?

Answer 14

toxoplasma gondii.

Question 15

diagnosing toxoplasma gondii

Answer 15

1. serology:

igM within one week, IgG appears within 1-2 weeks and persists for life.

2. Histology: significant for isolation of parasite in CSF and retina.
3. CT

Question 16

treatment for an immunocompromised case of toxoplasmosis

Answer 16

pyrimethamine, sulfadizaine, folinic acid

OR
TMP-SMX, clindamycin

Question 17

what part of the immune system is defective?

Answer 17

he has physical barrier dysruption because of IVs, AND he also has severe prolonged marrow suppressionbecause he’s not taking to the graft. therefore, T cell, B cell, blood borune and physical barrier immunity is being affected.

Question 18

diagnosing aspergillus infection on radiography– what is a characteristic feature?

Answer 18

Question 19

diagnosing and treatment for aspergillus

Answer 19

1. bronchoscopt or tissue biopsy with fungal stains and culture.

treatment

1. voriconzaole
2. amphotericin

Prophylaxis: AML, MDS, allo-stem cell transplant and posaconazole.

Question 20

daignosing CMV

Answer 20

1. serology via IgM and igG
2. PCR using blood and tissue/body fluids
3. histopatholoogy: tissue sample.

Question 21

sympyoms of a CMV primary infection? wb a systemic/reactivation of the diesase?

Answer 21

reactivation includes fever, fatigue, cytopenias and elevated liver enzymes.

Question 22

reasons why someone might have reactivation of CMV

Answer 22

• stress
• focal organ disease like colitis, hepatitis, myocarditis, encphalitis.

Question 23

treatment of CMV

Answer 23

gangcyclovir (IV) or valgancyclovir (po)

prophylaxis:

• daily prophylaxi during high risk periods post-transplant
• weekly CMV viral load monitoring with early preemptive treatment if viral load becomes detectable.

Question 24

what part of the immune system is defective?

Answer 24

Question 25

3 most common pathogens that affects someone with hyposplenism

Answer 25

streptococcus pneumo

kaemophilus influenzae

neisseria meningtidits

(people with sickle cell anemia at high risk)

Question 26

how to prevent infection in hyposplenic/asplenic patients?

Answer 26