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