parasitic diseases and sepsis ID

leading cause of global febrile illness, primarily affecting kids in subsaharan africa but also has recent cases in tx, florida and maryland and his a big threat for travelers, immigrants military ppl

malaria

which kind of malaria can be fatal most often by causing cerebral malaria (also most common in US cases)

P. falciparum

how is malaria transmitted

female anopheles mosquito (dusk to dawn activity)

caused by plasmodium species (protozoa)

NO person-person (except rare blood or congenital cases)

what 5 species of malaria can infect ppl

P. falciparum, P. vivax, P. ovale, P. malariae, P. knowlesi

most common malaria globally

P. falciparum, P. vivax

why is P. falciparum malaria extra bad

invades RBCs of all ages (not just reticulocytes like other types) → can spread to way more blood cells → more severe disease

which forms of malaria can form liver hypnozoites, therefore making relapse possible

P. vivax, P. ovale

classic paroxysm for malaria

cold stage, hot stage, sweating stage

hallmark malaria sx

fever, initially dialy then tertian or quartan

nonspecific malaria sx

headache, cough, myalgia, vomiting, diarrhea

P. falciparum specific sx

rapid onset, high parasitic load, cerebral malaria risk (big chunks of RBCs make clogs), less fever cycle

P. malariae specific sx

low level chronic parasitemia, can persist for years

P. knowlesi specific sx

rapid 24hr cycle, can resemble falciparum

how do you know if you actually have dengue and not malaria

retro-orbital pain, leukopenia, rash, in lotssss of pain

gold standard malaria dx

thick and thin blood smears

thick smears detect parasites

thin smears help identify specific species

repeat every 12-24hrs throughout the fever cycle (3d) bc itll look different in different stages

malaria labs

rapid diagnostic tests detect parasite antigens

PCR offers high sensitivity for species ID and mixed infxns

CBC sees anemia, thrombocytopenia, maybe high LDH

mildly elevated liver enzymes, bilirubin might be high

first line tx for uncomplicated P. falciparum

artemether-lumefantrine

second line tx for uncomplicated P. falciparum

atovaquone-proguanil

what med do we add to tx P. vivax or P. ovale infections

primaquine (to eradicate liver hypnozoites)

what do we HAVE to check before starting primaquine

confirm G6PD status first

severe malaria tx

IV artesunate

sx of cerebral malaria (seen esp in kids under 5)

AMS, coma, seizures

malaria complications

severe anemia and hemolysis from high parasitemia, cerebral malaria, acute respitory distress syndrome, pulmonary edema, hypoglycemia, lactic acidosis, acute renal failure hemoglobinuria (black water fever aka dark urine from intravascular hemolysis→ leads to kidney damage). shock, multi-organ dysfunction, death

malaria prevention

prevent mosquito bites w nets, DEET, and permethrin treated clothes

chemoprophylaxis varies by destination, can use malarone, doxycycline (daily), or mefloquine/chloroquin (once a week but gives nightmares), start before travel and continue after returning

pt education for travelers, military, immigrants

a common parasite with high global prevalence that is mostly asx but can reactivate and has major risk for congenital infxn w lifelong effects. also the leading cause of posterior uveitis in immunocompetent pts

toxoplasmosis

toxoplasmosis risk factors

CATS!!!🐱specifically their LITTER, not from scratches

less likely to spread to fetus if early in preg but if you do its worse outcome, more likely to spread to fetus later in preg but if you do its not as bad

immunocomp has high risk for reactivation, ocular involvement common in reactivated cases

toxoplasmosis transmission

caused by intracellular protozoan, definitive host is the cat (oocysts shed in feces), transmitted to ppl via ingestion of oocysts or tissue cysts. vertical transmission possible during preg

toxoplasmosis sx in immunocompetent pts

asx or have mild lymphadenopathy

congenital toxoplasmosis sx

chorioretinitis, seizures, hydrocephalus, intracranial calcifications, depends on when its caught

may appear normal at birth but develop sx later

immunocomp toxoplasmosis sx (esp AIDS)

encephalitis, seizures, motor deficits

myocarditis is rare but seen in transplant recipients

ocular toxoplasmosis sx

necrotizing retinitis, vision loss, photophobia

pulmonary toxoplasmosis sx

interstitial infiltrates, fever cough

systemic illness may mimic mono

toxoplasmosis tx in healthy pts

dont treat unless sx are severe or prolonged

toxoplasmosis tx in immunocomp pts

pyrimethamine, sulfadiazine, leucovorin (clindamycin or atovaquone if sulfa allergy

ocular toxoplasmosis tx

pyrimethamine, sulfadiazine, leucovorin + steroids

toxoplasmosis tx for preg pts

spiramycin if under 18weeks preg, switch to pyrimethamine, sulfadiazine, leucovorin

toxoplasmosis tx for neonates

12mo tx w pyrimethamine, sulfadiazine, leucovorin, even if asx

toxoplasmosis prevention

avoid contact w cat litter during preg, serologic screening recommended during preg adn prophylaxis in HIV pts w CD4 under 100 and IgG pos

the most common helminthic infection globally, mostly affecting kids in low resource setting, spread via fecal-oral route and often asx but can cause serious disease, causing malnutrition and impaired development

ascariasis

ascariasis transmission

caused by a large intestinal roundworm (30cm), ingest embryonated eggs from contaminated soil or food→ larvae hatch in intestines → long migratory phase and goes to lungs (causes lung sx) → cough up sputum and swallow it → returns to gut

eggs highly resistant in environment and can survive for years

ascariasis sx

most asx

heavy infxn causes abdominal pain, obstruction, or growth delay

cough, dyspnea, eosinophilia

intestinal obstruction common in young kids w heavy worm burden

worms can migrate to bile duct, pancreas, or appendix→ can cause bilary cholic, cholangitis, or pancreatitis

loffler syndrome =

pulmonary sx of ascariasis during larval migration through the lungs (cough, eosinophilia, dyspnea)

ascariasis dx

made by IDing eggs in stool, adult worms may be seen in stool or vomit

eosinophilia common during pulmonary migration

abdominal xray may show intestinal or worms

ultrasound or CT may detect migrating worms in hepatobiliary system

ascariasis tx first line pharm tx

albendazole (PO, one dose) (mebendazole PO BID for 3d also works)

ascariasis tx in preg

pyrantel pamoate

ascariasis tx in general overall

no need to tx asx ppl in low burden areas

manage complications (like obstruction) w surgery

the second most common tropical parasitic disease (after malaria), transmitted via freshwater exposure, mainly from S. haematobium, S. mansoni, S. japonicum, and associated w chronic organ damage and bladder cancer but not repostable

schistosomiasis

which forms of schistosomiasis have their eggs excreted in the hosts stool

S. mansoni, S. japonicum

which forms of schistosomiasis have their eggs excreted in the hosts urine

S. haematobium

how is schistosomiasis transmitted

no person-person transmission, water exposure required

cause of schistosomiasis

trematodes (flukes) → skin penetration by cercariae → intermediate host is freshwater snail → cercariae released into water and penetrate skin → mature worms migrate to mesenteric or bladder beins → chronic inflammation from trapped eggs causes pathology

schistosomiasis sx

acute swimmers itch = maculopapular rash at penetration site=first stage)

katayama syndrome = fever, eosinophilia, hepatosplenomegaly

chronic intestinal =abdominal pain, diarrhea, blood in stool

hepatic = portal htn, splenomegaly, esophageal varices

urinary = hematuria, dysuria, bladder fibrosis (only S. haematobium)

chronic GU disease linked to bladder cancer (only S. haematobium)

rare CNS disease = seizures, spinal cord dysfxn

severity inc w duration and reinfection

schistosomiasis dx

microscopy of stool or urine for ova and timing is important and concentration techniques improve sensitivity

urine for S. haematobium must be midday

serology useful in travelers w low parasite burden

imaging for chronic complications like fibrosis, varicies etc

eosinophilia common in acute or migratory phase

when should you consider schistosomiasis

in travelers with hematuria, GI bleeding, and/or portal htn

schistosomiasis tx

praziquantel TOC for ALL SPECIES

best given 6-8wks after exposure to target mature worms (not larvae) and repeat tx may be needed in heavy infxns

AVOID steroids unless cns involvement suspected

safe water practices

schistosomiasis prevention

NO vaccine, educate pts, snail control, tx travelers, immigrants and high risk groups proactively

schistosomiasis complications

intestinal = chronic diarrhea, anemia, growth retardation

hepatic = periportal fibrosis

GU = hematuria, bladder wall thickening, hydronephrosis

bladder cancer (squamous cell) from S. haematobium

neurologic = transverse myelitis, spinal cord compression

do we still use SIRS criteria to identify ppl w sepsis

NO bc can still be present in lots of pts that dont have infections and it doesnt work as well as the SOFA score

an exaggerated inflammatory response to an infectious stimulus, often caused by generalized bacterial/fungal infxn and characterized by evidence of infection, fever/hypothermia, hypotension, and end organ damage

sepsis

infection + life threatening organ dysfxn =

sepsis

leading cause of death in noncardicac ICU pts, mostly affecting babies and old ppl, often triggered by pneumonia, UTIs, abdominal infections, or wounds

sepsis

common pathogens that cause sepsis

e. coli, klebsiella, psuedomonas, staph, strep, candida

non infectious causes of sepsis

trauma, burns, surgery, pancreatitis, vasculitis

sepsis etiology

innate immune system activates through toll-like receptors → cytoskine stoem, endothelial damage, microthrombosis → this happens too much and gets dysregulated → organ dysfxn

what is qSOFA

a bedside tool to assess sepsis = RR 22+, systolic BP 100 or less, AMS'

(less involved than full SOFA score)

septic shock =

sepsis + MAP under 65 + lactate over 2 despite fluids

common bodily sources for sepsis

lung, abdomen, urinary tract, skin/soft tissue

signs of organ dysfxn

hypoxemia, oliguria, coagulopathy, encephalopathy, inc lactate

what is the SOFA score (sequential organ failure assessment)

measures dysfxn in 6 organ systems, used to define sepsis, and requires labs (platelets, bilirubin, creatinine, PaO2/FiO2)

qSOFA =

SOFA =

screen outside the ICU

confirm and monitor severity in the ICU/w full labs

how do we define sepsis in relation to the SOFA score

infection + SOFA score 2+

what are the qSOFA criteria

RR 22+

systolic BP 100 or less

AMS (GSC under 15)

a qSOFA score of 2+ =

high risk or mortality or prolonged ICU stay

not diagnostic, triggers further eval for sepsis

labs and imaging for sepsis

CBC, CMP, coags, lactate, PCT, UA, ABG

CXR, CT, U/S, MRI to identify source based on sx

sepsis tx

30mL/kg of crystalloids within 3hrs for hypoprofusion

broad spec abx within 1hr

vasopressors (NOREPINEPHRINE) if mean arterial pressure is under 65 after fluids

watch their LACTATE, mentation, vitals, and urine output

most common helminth infection in the US, mostly seen in school aged kids with fecal-oral transmission (self infection common from butt scratching)

pinworms (enterobius vernicularis)

pinworms (enterobius vernicularis) classic sx

nocturnal perianal itching

pinworms (enterobius vernicularis) dx

tape test early morning (tape on asshole to get eggs)

worms must be moving, not dead

pinworms (enterobius vernicularis) tx

albendazole or mebendazole

all household contacts should be treated also

a sexually transmitted infection caused by trichomonas vaginalis and can be asx (esp in men)

trichomoniasis

trichomoniasis sx in women

frothy yellow-green discharge, itching, strawberry cervix

trichomoniasis dx

NAAT preferred, wet mount may show motile organisms

trichomoniasis tx

oral metronidazole or tinidazole (single dose)

infxn caused by entamoeba histolyica with fecal-oral transmitted via contaminated food or impure water that can cause dysentery, collitis, or liver abscesses and dx w stool microscopy or antigen testing

amebiasis

amebiasis tx

metronidazole followed by intraluminal agent

infxn caused by giardia lamblia (flagellated protozoan) with fecal-oral transmission and commonly seen in daycares, impure water exposure and MSM that must be reported in 1wk and may lead to temp lactose intolerance/malabsorption

giardiasis

giardiasis sx

foul smelling diarrhea (loose, grey/white), farting, bloating, fatigue

giardiasis dx

stool antigen test or PCR (more sensitive than O&P)

giardiasis tx

metronidazole or tinidazole