Oppurtunistic infections Flashcards
“Pneumocystis pneumonia
(PCP ping pong)”
Features:
“* Disc shaped yeast or cysts containing dark oval bodies
Previously classified as protozoa
Targetoid/cup-shaped w silver stain”
Location:
Transmission:
“ Inhalation of spores affecting lungs bilatereally
cyst –> trophozoite forms
*OI: HIV w CD4 < 200”
Symptoms:
“Diffuse interstitial pneumonia: intense inflammatory rxn in alveoli of lungs that impairs O2 exchange
*Non-productive cough, accelerated dyspnea (decreased O2 on RA), fever, no consolidations/ lung sounds may be normal (symptoms worsen over weeks)
* Frothy honeycombed/eosinophilic exudate in alveolar spaces
* AIDS-defining illness: Most common OI in AIDS pts”
Diagnosis:
“ Bronchoalveolar lavage (BAL): bronchoscopy w lung samples through fluid rinses
*Methamine silver stain: disc/ovoid shaped, stains for walls of cyst
Giemsa stain: identifies cysts & trophozoites
* CXR: ground glass appearance, diffuse, bilateral reticular or interstitial infilitrate
* LDH Blood Test: NOT specific, usually elevated”
Treatment:
“TMP-SMX (ppx & treatment)
* Atovaquone or Pentamidine (w sulfa allergies)
* Steroids (reduce inflammation if significant)
- HIV PPX: TMP-SMX (CD4 = 50-100)”
CD4 < 200
“Coccidioidomycosis
(presidio san joaquin)”
Features:
“Coccidioidomycosis
(presidio san joaquin)”
Location:
“Southwest US
* San Joaquin Valley, CA
* Dust storms & earthquakes increase spread”
Transmission:
“ Resp transmission (inhale dust with arthrospores)
* NOT contagious person to person
*OI: HIV CD4 < 250”
Symptoms:
“Acute: Mostly asymptomatic
* Vague symptoms: chest pain, fever, cough, fatigue
* Erythema nodosum (painful nodules on legs/shins)
* Self-limited acute pneumonia w fever, cough, arthralgia that lasts a couple weeks
* CXR may show nothing OR cavities & nodules
Chronic:
* Commonly targets skin & lungs
* Necrotizing granuloma formation
*Disseminates to bone & meninges (meningitis)
HIV: focal or diffuse pneumonia, skin lesions, meningitis, liver/LN involvement”
Diagnosis:
“*KOH stain
*Culture (takes VERY long)
Serology (ab titers, IgM indicates recent infection)”
Treatment:
“ Systemic: Amphotericin B
* Local: conazoles
- HIV PPX (TMP-SMX) in those living in endemic areas”
CD4 < 200
“Histoplasma capsulatum
(historian’s cave)”
Features:
“Smaller than RBC
* Dimorphic
* Yeast lives in macrophages”
Location:
“ Midwestern/Central US
* MI & OH Rivers”
Transmission:
“*Airborne/Resp transmission (spores inhaled & ingested by macrophages)
*Bird/bat feces
* Spelunking in caves
* Chicken coops
*OI: HIV CD4 < 150”
Symptoms:
“Acute:
* Vague symptoms: fever, chills, sweats, fatigue
* Erythema nodosum (painful nodules on legs/shins)
Chronic: disseminates to liver, spleen, bone marrow
* Lung granuloma that becomes calcified
*Cavitary lesions in upper lobes, calcified nodules, fibrotic scarring; resembles TB –> SOB, cough
Hepatosplenomegaly w calcifications “
Diagnosis:
“ KOH Stain: Macrophages containing several oval bodies
* Urine rapid antigen test
*Serum rapid antigen test
*Culture of biopsy (takes VERY long)
Serology (ab titers, IgM indicates recent infection)”
Treatment:
“ Systemic: Amphotericin B
* Local: Conazoles
- HIV PPX (TMP-SMX) in those living in endemic areas”
CD4 < 150
Toxoplasmosis (Toxoplasma gondii)
Features:
Location:
Transmission:
“* ingestion of cat oocyst from feces, cysts in meat, crosses placenta (greatest risk during 3rd trimester, but most symptoms if contracted during first semester), blood transfusion/ transplant
* OI: HIV w CD4 < 100”
Symptoms:
“* Immunocompetent: flu like symptoms, self limited
* Immunocompromised: reactivation of infection –> brain abscesses that cause HA, altered mental status, seizures, personality changes, focal neuro deficits
Congenital:
* Chorioretinitis (unlikely w CMV), hydrocephalus (Not seen w CMV, enlarged ventricles), intracranial calcifications (more diffuse than CMV which is along ventricles)
* Petechiae, lymphadenopathy, jaundice, muscular-papular rash, small for gest age, microcephaly”
Diagnosis:
“* Brain biopsy (cysts in tissue)
* CSF (tachyzoite)
*PCR
* Brain CT/MRI: multiple ring-enhancing lesions
*Serology (IgM/IgG)
Congenital:
During pregnancy: US (growth delay, hydrocephalus, calcifications, ascites)
* 18 wk: Fetal blood sample, amniotic fluid sample for PCR
* Newborn: IgM screening”
Treatment:
“Pyrimethamine + Sulfadiazine + Leucovorin (mitigates effects of pyrimethamine)
* Clindamycin (against only tachyzoites, not cysts)
- HIV PPX: TMP-SMX (CD4 = 50-100)
Congenital:
* Spiramycin: reduces transmission by 50%; does NOT tx infected fetus
* Pyrimethamine & Sulfadiazine: 1 yr for infected NB (stops active disease and restores normal functioning)”
CD4 < 100
Cryptosporidium
Features:
“*Low infectious dose
* Long survival in moist environments
Protracted communicability
* Extreme chlorine tolerance”
Location:
Transmission:
“Fecal-oral route: ingestion of oocysts from contaminated drinking water or lakes/water parks, infected animals, raw oysters
OI: HIV w CD4 < 100”
Symptoms:
“ Watery diarrhea within 2 wk of travel that is self-limited
AIDS: prolonged non-bloody diarrhea, abdominal symptoms, poor oral intake, fever, wasting/malabsorption”
Diagnosis:
“Acid fast stain of stool (oocysts)
* Biopsy of sm intestine: cysts on brushborder
ELISA, PCR”
Treatment:
“Supportive
* Nitazoxanide in immunocompetent hosts (inconsistent evidence, but ART should help)
*No PPX for HIV pts”
CD4 < 100
Cystoisoporia (Isospora belli)
Features:
Location:
Transmission:
“*Fecal-oral route: ingestion of oocysts
* Tropical/subtropical areas
* OI: HIV w CD4 < 100”
Symptoms:
AIDS: prolonged non-bloody diarrhea, abdominal symptoms, poor oral intake, fever, wasting/malabsorption
Diagnosis:
“Acid fast stain w stool (oocysts)
ELISA, PCR
* Biopsy of sm intestine”
Treatment:
“ TMP-SMX
*No PPX for HIV pts”
CD4 < 100
Microsporidia
Features:
“* Many species with many presentations
* Smallest one”
Location:
Transmission:
“*Fecal-oral route: ingestion of spores
* OI: HIV w CD4 < 100”
Symptoms:
“Can be systemic or involve eyes, muscles, intestine, biliary tree; chronic diarrhea in immunocompromised (esp AIDS)
AIDS: prolonged non-bloody diarrhea, abdominal symptoms, poor oral intake, fever, wasting/malabsorption”
Diagnosis:
“Modified trichrome stain
*Acid fast stain w stool: oocytes/spores in stool
* ELISA, PCR
* Biopsy of sm intestine”
Treatment:
benzimidazole
*No PPX for HIV pts”
CD4 < 100
“Cryptococcus neoformans
(crypt for cryptococcus)”
Features:
“Urease +
* Capsule w thick proteoglycan capsule (mucicarmine stain)
* Yeast w wide capsular halos on india ink stain
Narrow based, unequal budding”
Location:
Transmission:
“ Inhalation of spores from soil or pigeon droppings
* OI: HIV w CD4 < 100”
Symptoms:
“Early symptoms: cough, chest pain, weight loss, fever, dizziness
* Pneumonia (cough, dyspnea, fever)
*Tropism for CNS: Most common cause of fungal meningoencephalitis (lethal, can cause permanent deficits)
* Skin infections: papule with umbilicated center usually due to disseminated disease (skin biopsy for dx)”
Diagnosis:
“LP: elevated ICP
* CT scan prior (to ruleout any lesions that could precipitate herniation with LP)
*Cryptococcal antigen (specific)
*Low WBC count is a negative prognostic sign
*Elevated protein
*India Ink: visualize capsules as halos
* Culture of CSF
Other tests:
*Latex Agglutination Test: detects repeat polysaccharide capsular antigen & causes agglutination (more sensitive)
* Bronchopulmonary washing
*Tissue sample w mucicarmine (red) or methanamine silver stains
* India Ink Stain: shows yeast with wide capsular halos (less sensitive)
Brain CT: soap bubble lesions in gray matter”
Treatment:
“Induction therapy: Amphotericin + Flucytosine
*Maintenance dose of fluconazole
*Manage high ICP with repeat lumbar punctures to alleviate HA
*No PPX for HIV pts”
CD4 < 100
“CMV
(cyto mega-lo virus)”
Features:
“* dsDNA
* Owl’s eye inclusion bodies
Icosahedral shape”
Location:
Transmission:
“ Binds cellular integrans (heparan sulfate)
*Transmitted via sexual contact, organ transplant, vertically (placenta, TORCHES)
- Primary infection to upper resp & GI tract mucosal surfaces
- Spread during acute phase & in asymptomatic hosts for mo-yrs
* Latent in bone marrow stem cells (B/T lymphocytes & macrophages)
- Blocks MHC-I express –> inhibits CTLs
- Reactivated with immunosuppression
- OI: HIV w CD4 < 50 –> reactivation”
Symptoms:
“Congenital: Greatest risk during 1st trimester - # 1 cause of congenital infection (1-2% infected at birth, 10% infected during birth)*MR DICS - Microcephaly, Retardation, Deaf, Intracranial calcifications, Seizures
*Other symptoms: Jaundice, hepatosplenomegaly, ventriculomegaly (head CT), anemia, pneumonitis - Hydrops fetalis: heart failure –> edema –> spont abortion
- Blueberry muffin rash: thrombocytopenia, petechial rash (similar to rubella)
Immunocompetent hosts: Mononucleosis w sore throat, lymphadenopathy, fatigue (mono spot test = neg, differs from EBV mono)
Immunocompromised hosts: Organ transplant & AIDS pt (CD4 count < 50)
* Interstitial pneumonia: HSCT complication within first 120 days; rapid onset resp symptoms that last < 2 wk, fever, non-productive cough, dyspnea that can progress to hypoxia
*Retinitis: full thickness necrotizing infection that has pizza pie appearance & cotton wool spots on fundoscopy (retinal lesions with intraretinal hemorrhages)
* Esophagitis: Singular/deep linear ulcers (differs from HSV which has multiple shallow ones)
Colitis w ulcerated walls (diarrhea, abdominal pain, fever)
* CNS manifestations: dementia, ventriculoencephalitis, radiculopathy”
Diagnosis:
“Buffy Coat Culture: Tests transplant pts for lg cells w prominent owl’s eye inclusions
*Fundoscopy (retinitis)
* Endoscopy with biopsy: (esophagitis & colitis) large cells w intracellular & intracytoplasmic inclusions
Congenital
* Viral isolation from urine/saliva sample during first 3 wk of life
* PCR on serum, urine or CSF”
Treatment:
“* Ganciclovir (IV): Nucleoside analog that inhibits viral DNA Pol; initial phosphorylation step catalyzed by viral enzyme & final steps by host enzymes; half-life > 24 hr; myelosuppression
*Valganciclovir (PO): Pro-drug of ganciclovir (same MOA & spectrum) but allows for oral dosing; myelosuppression
*Foscarnit in those with resistance to ganciclovir due to mutated UL97 gene (phosphotransferase) & UL54 (viral DNA Pol)
*Prevent interstitial pneumonia in HSCT pts using antivirals 90-120 days post-transplant
*No PPX for HIV pts
Congenital
* Ganciclovir or oral valganciclovir”
CD4 < 50
Mycobacterium avum (MAC, NTB)
Features:
“* Acid fast
*Rod shaped
*Non-motile
catalase +”
Location:
Transmission:
“Inhalation or ingestion
OI: CD4 < 50”
Symptoms:
“ Lung infection similar to TB symptoms
* Insidious onset of fever, weight loss, night sweats, diarrhea (several wks)
Disseminates into bone marrow (anemia, neutropenia, elevated alkaline phosphatase-high turnover of bone marrow) & LNs (lymphadenopathy, hepatosplenomegaly)”
Diagnosis:
“ Blood culture (takes up to 8 wk to grow)
* Biopsy affected organ with culture & pathology”
Treatment:
*2-3 drug combo including at least 1 macrolide (clarithromycin)
CD4 < 50
Mycobacterium tuberculosis
Features:
* Acid fast
Location:
Transmission:
Symptoms:
“Pulmonary TB: cavitary
Miliary TB: hematogenous seeding of lung tissue
- bone marrow/LN: pancytopenia
- brain, bone, peritoneum, pericardium, etc.”
Diagnosis:
Treatment:
Risk with decreased CD4 count
“HSV-1 & HSV-2
(Hermes, the god of herpes)”
Features:
“Herpes Virus Family
* dsDNA, linear
*Enveloped
*Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Location:
Transmission:
Symptoms:
“Above the waist (1) symptoms vs below the waist (2)
Herpetic whitlow: painful hand vesicle/wart; common in dentists
Genital Herpes:
* Most with HIV-2 have not been diagnosed with genital herpes, but shed virus in genital tract
*HSV-1 increasing in first episodes of anogenital herpes (MSM, young women)
Cervicitis: discharge, intermenstrual bleeding
HIV –> Reactivation of HSV: esophagitis, recurrent mucocutaneous & genital ulcers”
Diagnosis:
“Above the waist (1) symptoms vs below the waist (2)
Herpetic whitlow: painful hand vesicle/wart; common in dentists
Genital Herpes:
* Most with HIV-2 have not been diagnosed with genital herpes, but shed virus in genital tract
HSV-1 increasing in first episodes of anogenital herpes (MSM, young women)
Cervicitis: discharge, intermenstrual bleeding
HIV –> Reactivation of HSV: esophagitis, recurrent mucocutaneous & genital ulcers”
Treatment:
“First episode: Acyclovir, Famcyclovir, or Valacyclovir (10 day course, extend if healing incomplete)
*Recurrent: Higher doses of above antivirals for shorter courses
* Suppressive therapy: reduces frequency of recurrence”
Risk with decreased CD4 count
HSV-1
Features:
* dsDNA, linear
Enveloped
Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Location:
Transmission: “ Vertical transmission (TORCHES)
Latent in trigeminal ganglia & reactivated by stress/immunosuppression”
Symptoms:
“First sign is gingivostomatitis (inflammed lips/tongue)
* Rash: dew drops on rose petal appearancen on upper body
Erythema multiform: target-shaped rash w pink-red ring around pale center that appears 1-2 wk post-infection
* Serpiginous/dendritic corneal ulcers seen on slit lamp exam of Keratoconjunctivitis (red eyes)
*Temporal lobe encephalitis (#1 cause of sporadic encephalitis in US) –> hemorrhage/necrosis of tissue –> personality changes, hallucinations
* Esophagitis with volcano-like ulcers (immunocompromised)
* Herpes labialis (cold sores) result from reactivation of virus from stress”
Diagnosis:
“ PCR (gold standard)
* Cell culture has low sensitivity that declines as healing occurs
* Cowdry intranuclear inclusion bodies”
Treatment:
“First episode: Acyclovir, Famcyclovir, or Valacyclovir (10 day course, extend if healing incomplete)
*Recurrent: Higher doses of above antivirals for shorter courses
* Suppressive therapy: reduces frequency of recurrence”
Risk with decreased CD4 count
HSV-2
Features:
* dsDNA, linear
Enveloped
Cowdry bodies: Intranuclear eosinophilic inclusion bodies (also in CMV/VZV)
* Tzank smear w multinucleated giant cells (same as VZV)”
Location:
Transmission: Lies dormant in sacral ganglia
Symptoms:” Aseptic meningitis in adolescents/adults
* Painful inguinal lymphadeopathy
Vesicular genital lesions”
Diagnosis: Tzank smear w multinucleated giant cells (old test, now use PCR)
Treatment:
“* NO cure
* Prevent with acyclovir or valcyclovir”
Risk with decreased CD4 count
“EBV
(ye olde epstein bar)”
Features:
“* dsDNA (linear)
* Enveloped
Atypical CTLs (Downey type II): basophilic, vacuolated cytoplasm & lobulated nucleus
* Reed-Sternberg Cells: Hodgkin’s lymphoma; binucleate w prominent nucleoli (owl eyes)”
Location:
Transmission:
“ Mainly saliva transmission
* Virus envelope gp binds CD21 to infect B cells (CD21 is a receptor & binds gp350) –> spread to lymphoid system
* Latent in B cells (episome)
*Incubation period = 30-50 days
* More common in adults/adolescents in developed countries & in kids in developing countries
Compromised hosts include:
*X-linked lymphoproliferative syndrome: genetic inability to mount normal immune response to EBV
*Infection associated Hemophagocytic Syndrome: CTL/NK cells inability to regulate EBV proliferation; hypercytokinemia
*Post transplant Lymphoproliferative Disorder: risk due to immunosuppression highest in first year after
*HIV infection –> Primary CNS Lymphoma: Lethargy, confusion, seizures, constitutional symptoms (dx: imaging, EBV PCR on CSF if possible)”
Symptoms:
“Heterophile-positive Mononucleosis (agglutinates with non-human RBCs)
* Initial symptoms: 3-5 days of headache, malaise & fatigue; fevers (high as 40’C & last 7-14 days)
* Major symptoms: generalized lymphadeopathy, fever, splenomegaly (T cell proliferation), pharyngitis (sore throat) & tonsilar exudate
*Confused w Strep (which is more common in kids); when given amox/ampicillin for suspected strep –> maculopapular rash
* Periorbital edema
Complications:
* Neuro: meningitis, encephalitis, optic neuritis, cranial nerve palsy, myelitis, psychosis
* Heme: hemolytic anemia, thrombocytopenia, aplastic anemia, leukopenia
Associated Conditions:
* Lymphocytic Interstitial Pneumonitis: pulmonary condition that causes chronic wheezing (very rare)
*Non-Hodgkin’s Lymphoma: VERY common
*Oral Hairy Leukoplakia: seen in HIV pts; non-cancerous lesion usually on lateral tongue similar to candida/oral thrush (But CANNOT be scraped off)
* Leiomyosarcoma: soft tissue tumors that can occur anywhere in body (common in those with AIDS)
*Hodgkin’s Lymphoma: Mediastinal mass/non-tender lymphadenopathy
- Reed-Sternberg cell: binucleate B cells w nucleoli (owl eyes)
- mixed cellularity & lymphocyte depleted subtypes
*Endemic/African Burkitt Lymphoma: large jaw lesion & swelling (non-endemic/sporadic form presents w abd mass)
Nasopharyngeal Carcinoma: Asian ancestry”
Diagnosis:
“ Heterophile Ab: IgM Abs produced by B cells that are reactive against sheep, horse RBCs & do NOT react with specific EBV proteins (non-specific); Monospot test
* EBV Viral Capsid Antigen:
- IgM Ab peaks during 2-6 wks & declines 2-3 mo
- IgG Ab perists for life
* Early Antigens (EA): IgG Ab that appears while symptomatic & indicates ACUTE infection
EBV Nuclear Antigen (EBNA): Abs that indicate LATENT infection (maintains virus in episome)
“
Treatment:
“ Heterophile Ab: IgM Abs produced by B cells that are reactive against sheep, horse RBCs & do NOT react with specific EBV proteins (non-specific); Monospot test
* EBV Viral Capsid Antigen:
- IgM Ab peaks during 2-6 wks & declines 2-3 mo
- IgG Ab perists for life
* Early Antigens (EA): IgG Ab that appears while symptomatic & indicates ACUTE infection
*EBV Nuclear Antigen (EBNA): Abs that indicate LATENT infection (maintains virus in episome)
Risk with decreased CD4 count
Bartonella
Candidiasis
HPV
JC Virus
EBV
Kaposi
What is common between these?
Risk with decreased CD4 count
