Parasitic & Fungal Infections Flashcards
Toxoplasmosis
caused by what?
parasite name
Toxoplasma gondii
Toxoplasmosis
transmission
3 modes, host species
- fecal oral
- transplacental transmission
- inoculation via blood transfusion/organ transplantation
cats = hosts
Toxoplasmosis
Signs/sx in typical population
4 sx, 1 sign, 1 statement?
- can be asx
- fever, malaise, headache, sore throat
- cervical lymphadenopathy
Toxoplasmosis
effects of congenital infections
in offspring
CNS abnormalities
retinochoroiditis
hydrocephalus
intracranial calcifications
Toxoplasmosis
infections reactivation can lead to?
4
- reactivation leads to encephalitis, retinochoroiditis, pneumonitis, myocarditis
Toxoplasmosis
Dx
5 different things
- serology (IgG or IgM)
- PCR (amniotic fluid, blood, CSF)
- observation of parasites in stained tissues (meh)
- isolation from blood/other fluids (meh)
- CT or MRI of brain
Toxoplasmosis
what will CT or MRI show?
multiple ring-enhancing lesions
Toxoplasmosis
IgG Serology
IgM Serology
general population vs immunocompromised
- IgG will be positive in all populations
- IgM will only be positive in the non-immunocompromised individuals
Toxoplasmosis- Congenital
when in pregnancy are infections more likely to have serious outcomes?
earlier infection
Toxoplasmosis- Congenital
outcomes from early infection
- spontaneous abortion
- stillbirth
- neurologic problems
Toxoplasmosis
Complications of infections in immunocompromised
AIDS/cancer
- encephalitis with necrotizing brain lesions
- chorioretinitis
- pneumonitis
Toxoplasmosis
how to treat general population vs immunocomp
- self limiting
- Immunodeficient: full therapy for 4-6 wks followed by maintenance therapy with lower dosese
Toxoplasmosis
what to treat in pregnancy
treat primary infection to reduce risk of fetal transmission
Toxoplasmosis
when to treat- retinochoroiditis
treatment ok if decrease in visual acuity, multiple/large lesions, macular lesions, inflammation, >1 mo in duration
Toxoplasmosis
Meds- general population
meds, freq
- pyrimethamine (PO QD)
- sulfadiazine (PO, QID hrs)
- folinic acid/leucovorin QD
Toxoplasmosis
Meds- pregnancy
- spiramycin PO Q8 hrs until delivery
Toxoplasmosis
Prophylaxis dose HIV+ pts
when/what to use
- use in pts with low CD4 counts
- Trimethoprim/sulfamethoxazle
Toxoplasmosis
Prevention
3 categories
- fully cook meat
- cat related care
- hygiene when gardening
Amebiasis
parasites of concern
3: entamoeba……
Entamoeba dispar
Entamoeba moshkovskii
Entamoeba histolytica
Amebiasis
transmission
fecal oral
waterborne
Amebiasis
signs/sx
5- which is most common?
- abd pain
- diarrhea
- severe infections
- extraintestinal disease
- liver abscess (MOST COMMON)
Amebiasis
dx
3 things
- stool test
- serologic testing
- U/S, CT, MRI for liver abscess
Amebiasis
Tx
metronidazole or tinidazole
Malaria
mode of transmission
exposure to female anopheline mosquitoes in a malaria endemic country
Malaria
where is malaria endemic?
5 things
- South America
- Central America
- Africa
- Middle East
- Southeast Asia
Malaria
parasite responsible
plasmodium falciparum
Malaria
Pathophys
- upon bite, mosquitoes inject sporozoites which infect hepatocytes
- Merozoites are released by liver and rapidly infect RBCs
- Mulitple rounds of reproduction = systemic infection (can spread to others if bitten by mosquito)
- infected cells lyse which dumps toxins into bloodstream
- infected RBCs adhere to vein walls
Malaria
“Classical” presentation (not usually how it is)
3 stages
- Cold Stage (chills)
- Hot Stage (fever, HA, v, seizures)
- Sweating Stage (sweats, fatigue)
Malaria
Common Sx
8
- fever/chills/sweats
- headaches
- n/v
- body aches, malaise
Malaria
Clinical Findings
7 things
- severe anemia
- hypotension
- pulmonary edema
- AKI
- hypoglycemia
- acidosis
- hemolysis
Malaria
why does severe anemia occur?
RBCs getting blasted apart by parasites
Malaria
why does hypoglycemia occur?
reduced gluconeogenesis
Malaria
why does acidosis occur?
microcirculatory flow affected, anaerobic glycolysis
Malaria
why does renal impairment occur?
infarcts, capillary leakage
Malaria
why does pulmonary edema occur?
sequestration of parasitized RBCs in lungs and/or cytokine-induced leakage from pulmonary vasculature
Malaria
Dx
- parasite in peripheral blood smears
- urine dipstick for antigen
Malaria
Tx
First Line
Chloroquine- use only when no suspected resistance
Malaria
Tx- chloroquine resistance
Artemisinin
Malaria
Tx- severe malaria
- IV Artemisinin
- Maintenance of fluids/electrolytes
- resp/hemodynamic support
Malaria
prevention
- bed nets/insecticides
- travelers can take prophylactic abx
Malaria
which meds are used prophylactically in travelers?
- chloroquine
- malarone
- mefloquine
- doxycycline
- primaquine
- tafenoquine
what are helminthic infections?
worms :)
Enterobius (Pinworms)
caused by what worm?
Enterobius vernicularis
Enterobius (Pinworms)
who usually gets sick?
chilren under 18 or those in congregate settings
Enterobius (Pinworms)
mode of transmission
oral after scratching
exposure to eggs on contaminated food/fomites
Enterobius (Pinworms)
Pathophys
- eggs hatch in duodenum
- larvae migrate to cecum
- females mature after 1 mo, are viable for another mo after
- migrate through anus nocturnally to deposit eggs on perianal skin
Enterobius (Pinworms)
Key sign to watch for
PPP
perianal pruritus
particularly at night
Enterobius (Pinworms)
Dx
characteristic eggs on perianal skin using clear tape
worms seen in feces
Enterobius (Pinworms)
Tx
- Albendazole or mebendazole (paralyzes parasite)
Enterobius (Pinworms)
when to redose?
2 wks after tx because of frequent reinfection
ancylostoma duodenale and necator americanus (Hookworm)
what have patients usually have done prior to infection?
walked barefoot
ancylostoma duodenale and necator americanus (Hookworm)
Life Cycle
- eggs deposited via feces into warm moist soil
- eggs hatch into larvae that are infective for a week
- larvae contact skin and travel via bloodstream to pulmonary capillaries
- in lungs, larvae penetrate into alveoli and are carried via cillia into upper airway & then swallowed.
- Once in the GI tract, they attach to bowel mucosa & mature into adults where they suck blood
ancylostoma duodenale and necator americanus (Hookworm)
what is blood loss proportionate to?
worm burden
ancylostoma duodenale and necator americanus (Hookworm)
Signs/Sx
7 things
- transient pruritic skin rash (can “see” worm through skin)
- pulmonary sx
- anorexia, diarrhea, abd discomfort
- iron def anemia
- blood/eggs in stool
ancylostoma duodenale and necator americanus (Hookworm)
Dx
- characteristic eggs in stool
ancylostoma duodenale and necator americanus (Hookworm)
Tx
- ivermectin PO
- albendazole PO 3 days
Tapeworms
Taenia saginata
tapeworm from eating raw or undercooked beef
Tapeworms
Taneia solium
tapeworm from eating undercooked pork
Tapeworms
Diphyllobothrium latum
tapeworm from undercooked freshwater fish
Tapeworms
hymenolpeis nana
tapeworm from food contaminated w/ human feces
Tapeworms
signs/sx
3
- GI sx
- anorexia
- wt loss
Tapeworms
Dx
eggs in stool
Tapeworms
tx
praziquantel x1
Ascariasis
what is the most common intestinal worm?
ascaris lumbricoides
Ascariasis
mode of transmission?
ingestion of eggs in contaminated food
Ascariasis
pathophys
- larvae hatch in small intestine
- penetrate the blood-stream
- migrate to lungs
- travel via airway back to GI tract
Ascariasis
Dx
- most are asx
- dx made by ID of eggs in stool/worms
Ascariasis
Tx
- mebendazole
- albendazole
- pyrantel pamoate
Fluke
caused by which 3 things?
- clonorchia sinensis
- opisthorchis viverrine
- fasicola hepatica
Fluke
mode of transmission
- humans get ill by eating undercooked fish, crabs, crayfish, water plants in endemic areas
Fluke
sx
most are asx
mild GI complaints
Fluke
dx
- clinical findings
- eggs in stool
Fluke
tx
Praziquantel
Trichinosis (Roundworm)
causative agent?
trichinella spiralis
Trichinosis (Roundworm)
mode of transmission
ingestion of raw pork
Trichinosis (Roundworm)
sx
7 sx
- primarily asx
- GI sx, fever, myalgias, periorbital edema, HA, cough, rash
Trichinosis (Roundworm)
dx
- elevated muscle enzymes
- serological tests
- muscle biopsy (last resort)
Trichinosis (Roundworm)
tx
mebendazole
albendazole
Filariasis
caused by what?
wuchereria bancrofti
Filariasis
signs & sx
- episodic attacks of lymphangitis
- fever
- chronic progressive swelling of extremities & genitals
Loiasis
transmitted by?
chrysops flies
Loiasis
when adults, migrate to where?
eye
Rocky Mountain Spotted Fever
causative agent
rickettsia rickettsii
Rocky Mountain Spotted Fever
mode of transmission
tick bite
Rocky Mountain Spotted Fever
pathophys
- R. rickettsii damanges vascular endothelial cells
- endothelial cells produce prstaglandings that cause increased vascular permeability
- hyponatremia from release of ADH as a response to hypovolemia/leaky vasculature
Rocky Mountain Spotted Fever
signs & sx
- classic: fever, HA, rash, hx of tick bite
- general: malaise, myalgias, arthralgias
Rocky Mountain Spotted Fever
describe rash
- rash in approx 90% of pts
- rash on palms, soles
Rocky Mountain Spotted Fever
Lab results
initial vs more progressed
- normal WBC, maybe left shift
- thrombocytopenia becomes more severe
Rocky Mountain Spotted Fever
lab testing
- serial serologic examinations by indirect fluorescent antibody can retrospectively confirm diagnosis
Rocky Mountain Spotted Fever
empirical abx therapy
- doxycycline (100mg PO, QID, 5-7 days)
- 10-14 days if case was severe
- Chloramphenicol is second choice
Rocky Mountain Spotted Fever
prevention
- protective clothing
- tick-repellent
- prophylaxis is not recommended
Lyme Disease
caused by?
borrelia burgdorferi
Lyme Disease
location?
seasonality?
- northeastern and north central US
- late spring to summer
Lyme Disease
Stages
- early localized
- early disseminated
- late
Lyme Disease
describe the early localized stage
- erythema migrans
- bulls-eye rash w/ central clearing
- non-specific flu like sx
Lyme Disease
describe the early disseminated stage
- weeks to several months after bite
- acute neurologic sx (palsy, aseptic meningitis)
- cardiac involvement (arrhythmias)
Lyme Disease
describe the late stage
- months to years after infection onset
- arthritis
- encephalopathy or polyneuropathy
Lyme Disease
common sites of tick bites
thigh
groin
axilla
Lyme Disease
Dx
3 criteria & 2 tests
- exposure to tick habitats
- erythema migrans
- 1 late manifestation of disease
- lab confirmation: ab testing, pos western blot test
Lyme Disease
Tx
- Doxycycline (100mg PO, Q12 hrs, 10 days)
Lyme Disease
prophylaxis tx
doxycycline 200mg PO
Histoplasmosis
caused by what?
Histoplasma capsulatum
Histoplasmosis
mode of transmission
exposure to bird and bat droppings (common along Ohio/Mississippi river valleys)
Histoplasmosis
pathophys
- conversion into yeast cells
- engulfed by phagocytes in lungs
- organism proliferates and then lymphohematogenous spread to other organs
Histoplasmosis
sx
- usually asx
- if sx, then respiratory & macular/papular rash
- can be mild to severe
Histoplasmosis
what do severe infections usually have?
atypical pneumonia
Histoplasmosis
Presentation when disseminated in immunocompromised pts
- CNS lesions
- adrenal lesions/insufficiency
- pancytopenia
- pulmonary: cavities, nodules, infiltrates
variable presentation
Histoplasmosis
Dx
5 things
- sputum culture (rarely pos)
- Antigen testing
- CXR
- urine + serum antigen assays
- blood/bone marrow cultures
Histoplasmosis
Tx
immunocompetent pts
- observation if mild sx and immunocompetent
- most cases resolve in 4 wks
- itraconazole (PO, 12 wks)
Histoplasmosis
tx
immunodeficient/severe disease
- hosp: amphotericin B IV (1-2 wks) followed by itraconazole (PO, 12 wks)
Histoplasmosis
who might require lifelong suppressive therapy?
pts with AIDS related infection
Cryptococcosis
mainly caused by
cryptococcus neofromans
Cryptococcosis
risk factors
- chemotherapy for hematologic malignancies
- Hodgkin lymphoma
- corticosteroid therapy
- structural lung disease
- transplant recipients
- TNF-alpha inhibitor therapies
- AIDS
Cryptococcosis
approx 80% of Cryptococcal infections are ?
opportunistic infection in pts with AIDS
Cryptococcosis
most common cause of fungal ____
type of infection
meningitis
Cryptococcosis
mode of transmission
- inhalation
- no P2P transmission
Cryptococcosis
pathophys
- tissue destruction is through increasing fungal burden
Cryptococcosis
outcomes of tissue desctruction
2 things
- pulmonary disease w/ pneumonia
- CNS disease
Cryptococcosis
signs/sx
pulmonary, CNS, integum
- pulmonary: variable (mild/mod cough to ARDS)
- CNS: meningitis, encephalitis, delerium, ataxia, HA, coma, visual disturbance
- pustular skin rash
Cryptococcosis
Dx
3 tests, 2 to do if sx dissemination to specific spots
- lumbar puncture
- antigen detection in blood
- biopsy of lesions
- MRI of brain if mass lesion is suspected
- if pulm sx: sputa
Cryptococcosis
tx in immunocompetent
med, freq, duration asx vs sx
- fluconazole (PO, QD, 6-12 mo)
asx: 6 mo
sx: 12 mo
Cryptococcosis
Tx in severe pulm or CNS disease
Amphotericin B IV QD
Flucytosine PO Q6 hrs
Fluconazole PO QD
Pneumocystosis (PJP)
caused by?
pneumocystis jirovecii pneumonia
Pneumocystosis (PJP)
mode of transmission
airborne transmission of spores
Pneumocystosis (PJP)
who gets infected with this?
- immunodeeficient pts (cancer, transplants, AIDS, corticosteroids)
Pneumocystosis (PJP)
% of AIDS pts that this occurs in? criteria for it occuring?
- 80%
- in AIDS pts who are not receiving prophylaxis
Pneumocystosis (PJP)
signs & sx
7 things
- limited to pulm
- dry cough, SOB
- thick secretions
- spontaneous pneumothorax
- fever, fatigue, wt loss
Pneumocystosis (PJP)
Dx
3 things
- sputum cultures
- pos beta-D-glucan
- CXR and CT scan
Pneumocystosis (PJP)
Tx
start empirically
trimethoprim-sulfamethoxazole (PO)
Coccidioidomycosis (Valley Fever)
caused by?
coccidioides immitis
coccidioides posadasii
Coccidioidomycosis (Valley Fever)
sx & signs of acute infection
7 things, mainly
- ILI ( fever, myalgia, HA, fatigue, cough)
- erythema nodosum
Coccidioidomycosis (Valley Fever)
what can dissemination result in?
3 things
meningitis, bony lesions, skin/soft tissue abscesses
Coccidioidomycosis (Valley Fever)
who has disseminated infections most often?
AIDS patients
Coccidioidomycosis (Valley Fever)
Dx
- chest imagin
- serologic useful
- supportive care/self-limited
Aspergillosis
caused by?
aspergillus fumigatus
Aspergillosis
mode of transmission
- inhalation of spores of fungus
- most common cause of non-candida invasive fungal infection in transplant recipients/pts with hematologic malignances
Aspergillosis
risk factors
5 thigns
- leukemia
- bone marrow
- organ transplant
- corticosteroid use
- advanced AIDS
Aspergillosis
most common disease sites
3
- pulm
- sinus
- CNS
Aspergillosis
Dx
detection of galactomannan in serum
Aspergillosis
Tx
antifungal drugs