Parasites Flashcards

1
Q

Protozoa Overview

A

Unicellular Eukaryotes

NEED A LIQUID ENVIRONMENT

Live in VACUOLES –> water balance and food assimilation

Many modes of movement

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2
Q

AMEBIASIS is primarily caused by?

A

ENTAMOEBA HISTOLYTICA

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3
Q

Amebiasis

A

E. Histolytica
Fecal oral transmission, oral/anal sex (MSM)
HALLMARK –> Dense nucleolar ring with central chromatin dye*

Clinical –> More in CHILDREN, PREGGOS, IMMUNOCOMPROMISED

Asymptomatic intraluminal infection –> 80% are asymptomatic E. Histo cyst passengers; 4-10% DEVELOP INVASIVE DISEASE…

Diarrhea with mucous and BLOOD (dysentery)
ABDOMINAL CRAMPING
TOXIC MEGACOLON
AMEBOMA (inflammatory mass in the colon)

AMEBIC LIVER DISEASE –> FEVER, N/V, RUQ pain, Abnormal LFTs, R lobe of liver, Abscess

Thoracic Amebiasis –> 10% of patients with amebic liver disease, spreads transdiaphragmatically

Cerebral Abscess possible!

Treat with METRONIDAZOLE

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4
Q

GIARDIASIS

A

Giardia lamblia
Most commonly identified intestinal parasite in the US

Oral ingestion of cysts (CONTAMINATED WATER); exposure to recreational/fresh WATER (lakes!); Untreated well water; Sexual transmission (MSM); Day Care centers

RISK factors –> common variable immunoglobulin deficiency (IgA); REDUCED ACIDITY (PPI, Gastrectomies)

Clinical –> Asymptomatic cyst passage (1/3), Acute self-limited diarrhea (1/3), Chronic diarrhea with malabsorption (1/3)

Features –> DIARRHEA (FATTY), ABDOMINAL CRAMPS, BLOATING, FLATULENCE, WEIGHT LOSS

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5
Q

CRYPTOSPORIDOSES

A

C. Parvum
Needs an ACID-FAST STAIN for diagnosis!

Contaminated water

Ileocecal region for normal individuals, widespread GI for immunocompromised

RESISTS disinfection, so there can be large water-borne outbreaks –> well water, runoff, urban outbreaks, recreational water, person-person spread

Self-limiting watery diarrhea, abdominal cramps, N/V, fever in normal patients

MUCH bigger problem in immunocompromised –> Childhood diarrhea in developing countries; AIDS –> CD4 < 50 get SEVERE CHRONIC DIARRHEA, WEIGHT LOSS, MALABSORPTION, ELECTROLYTE WASTING

Extra-intestinal disease –> cholangiopathy (biliary obstruction, RUQ pain), pancreatitis, pneumonitis

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6
Q

LEISHMANIA

A

Leishmania donovani

VISCERAL Leishmaniasis –> Kala-Azar –> India, Nepal, Bangladesh, Sudan, Brazil –> SPIKING, PROLONGED FEVERS; Weight loss; HEPATOSPENOMEGALY, PANCYTOPENIA, HYPERGAMMAGLOBULINEMIA

Severe disease in AIDS, transplant patients, malnourished patients

CUTANEOUS Leishmaniasis –> MIDDLE EAST –> > 2000 cases in veterans; NON-HEALING ULCER with ROLLD UP EDGES on an INDURATED BORDER

MUCOSAL Leishmaniasis –> TROPICAL RAINFORESTS of S. America –> Erosive lesions in the mucosal areas around the mouth and ears

TRANSMISSION via the SANDFLY* –> taken up by MACROPHAGES (amastigotes)

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7
Q

TRYPANOSOMIASIS

A

Trypanosome Cruzi (look like C’s on peripheral smear)

Transmitted by BLOOD-SUCKING TRIATOMINE INSECTS

MEXICO and CENTRAL/SOUTH AMERICA

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8
Q

What does Trypanosomiasis cause?

A

CHAGAS DISEASE

Acute –> often bits mucosal areas –> palpebral fissue of the eyes (Periorbital edema with lymphadenopathy = ROMANA’S SIGN); Fever, edema, lymphadenopathy, hepatosplenomegaly; myocarditis; meningioencephalitis

CHRONIC –> CARDIOMYOPATHY -_> one of the more COMMON causes of CHF in South America!!!

Mega-colon, mega-esophagus

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9
Q

AFRICAN TRYPANOSOMIASIS

A

Trypanosomiasis brucei complex

TSETSE FLIES!!!! Only in the RAIN FOREST and SAVANNAHS OF AFRICA –> Exposure to GAME PARKS

Also known as SLEEPING SICKNESS

Bite occurs –> chancre/ulcer/nodule –> disseminates to STAGE ONE –> hemolymphatic stage –> lymphadenopathy, hepatosplenomegaly, fevers

WINTERBOTTOM’S SIGN = POSTERIOR CERVICAL LYMPHADENOPATHY

STAGE TWO –> meningoencephalitic stage –> headache, altered mental status, somnolence, ataxia, coma –> DEATH!

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10
Q

Malaria overview

A

Incredibly important
300,000,000 annually; 900,000 deaths; 80% children in Sub Saharan Africa; HUGE public health problem

Most severe? PLASMODIUM FALCIPARUM!!!!

Transmission through the ANOPHELINE MOSQUITO!!! Spores go to blood –> liver/hepatocytes first

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11
Q

What stage is responsible for RELAPSING malaria?

A

HYPNOZOITE STAGE! Not all of the organisms have this

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12
Q

Clinical Manifestations of Malaria

A

FEVER –> for returning travelers with fever, MALARIA until proven otherwise

Chills/Rigors
Headache
Diarrhea
Jaundice
Tertian (fever every other day) or Quartan (every 3rd day) possible

Hemolytic anemia, thrombocytopenia, abnormal LFTs

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13
Q

P. Falciparum

A

BY FAR DEADLIEST, rapid progression

Invades ALL LEVELS OF RBCs –> alters surface so they become “sticky” and sequester in the vital organs!!!

PERSISTENT FEVERS

LACKS the hypnozoite stage, so NO RELAPSE

Histo –> BANANA GAMETOCYTE on smear, RING FORMS in RBCs

Complications –> Multiple target organs –> CEREBRAL MALARIA = COMA, Lactic Acidosis, Hypoglycemia, ARDS, Acute kidney injury/black water fever

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14
Q

P. Vivax and P. Ovale

A

TERTIAN MALARIA –> Fever every other day

Only TROPICAL Africa

HYPNOZOITE PHASE! Can RELAPSE!

No target organs, so less severe than P. falciparum

All of the cells infected are BIGGER (they infect RETICULOCYTES/immature RBCs which are big)

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15
Q

P. Malariae

A

Relatively benign form

Can be there for many years (20-30)

QUARTAN MALARIA –> every 72 hours/3 days = FEVER

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16
Q

Treatment for Malaria

A

Not sure if we need to know

P. Falciparum is RESISTANT to Chloroquine; so we use QUININE/DOXYCYCLINE

P. Vivax/P. Ovale –> CHLOROQUINE; PRIMAQUINE to prevent relapse!!!!

17
Q

BABESIOSIS

A

B. Microti

Can be acquired in US! NEW ENGLAND (CAPE COD), California, Washington

IXODES SCAPULARIS TICK –> 20% are co-infected with LYME (which is Borellia burgdorferi)

ELDERLY, SPLENECTOMIZED, IMMUNOCOMPROMISED

Fever, Myalgias, Headache, Hemolytic Anemia, Thrombocytopenia, Elevated LFTs –> similar to malaria

CAPE COD*

18
Q

Ascaris Lumbricoides

A

Nearly 1/4 of the WORLD is infected

Transmission via ingestion of parasitic EGGS –> hatched in the small intestine -> larvae penetrate GI –> larvae migrate to lungs, penetrate alveoli –> mature into adults –> worms produce 200.000 eggs/day

WARM, HUMID, TROPICAL CLIMATES –> resource poor countries; children who play on contaminated soil –> Eggs VIABLE FOR SIX YEARS

Large burdens of WORMS in the GI tract/STOOL –> worms can get in the bile and pancreatic ducts and cause OBSTRUCTIVE symptoms –> can migrate through LUNGS and cause PNEUMONIA

19
Q

TRICHURIS TRICHURIA

A

TRICHURIASIS
800 million worldwide

Impoverished children in the urban tropics, subtropics –> adult worms infect the CECUM and ASCENDING colon; DO NOT involve lungs

20
Q

HOOKWORM

A

Infection occurs in TROPICAL and SUBTROPICAL regions

Important cause of IRON DEFICIENCY ANEMIA

Walking BAREFOOT!!!! Exposure to infected soil, resource poor countries

LARVAE penetrate the skin –> pass to lungs and alveoli –> go to trachea/GI –> couched up!!!

GROUND ITCH –> rash at the site of penetration (foot), Eosinophilic pneuomonitis with worm passage; abdominal pain, anorexia, diarrhea, eosinophilia, Fe DEFICIENCY ANEMIA (they literally suck blood from the intestinal walls)

21
Q

STRONGYLOIDAISIS

A

Walking barefoot! Seen in the US – APPALACHIA, SOUTHEAST US

Clinically associated with ESOPINOPHILIC PNEUMONIA

Auto-infection – can live in humans INDEFINITELY; keeps RE-NFECTING the peri-anal skin; can be asymptomatic

ACUTE infection –> Rash at the site, eosinophilic pneumonia, peripheral eosinophilia, abdominal pain/diarrhea, larva currens

HYPERINFECTION –> Associated with STEROIDS, use of TNF-ALPHA inhibitors, heme malignancies, DM, infection with HTLV-1, immunosuppressive therapy

Larvae can penetrate bowel and DISSEMINATE INTO CSF

Associated with POLYMICROBIAL GRAM NEGATIVE SEPSIS –> gram negatives can seed the CNS –> GRAM NEGATIVE MENINGITIS

22
Q

ENTEROBIASIS

A

Enterobus vermicularis –> PINWORMS

Most common among CHILDREN, INSTITUTIONALIZED PATIENTS, HOUSEHOLDS

Adult worms live in the CECUM/APPENDIX –> migrate to PERI-ANAL REGION at night and lay eggs –> can re-infect with ingestion of eggs

PERI-ANAL PRURITIS –> SCOTCH TAPE TEST

23
Q

DIPHYLLOBOTHRIUM LATUM

A

FISH tape worm –> MUST HAVE FISH EXPOSURE*

Ingestion of UNCOOKED FRESH WATER FISH –> Smoked fish, Gefilte Fish, Cerviche/Salmon

Fish contain the LARVAL CYSTS which develop into adult tapeworms in humans

Endemic –> Lake and Delta areas of Siberia, Europe, Scandanavia, Baltics, N. America, Japan, Chile

CLINICAL –> Can grow to 25 METERS in length!!!! Often asymptomatic; B12 DEFICIENCY (tapeworm competes for B12 in the intestine) –> MEGALOBLASTIC ANEMIA, Peripheral neuropathy

24
Q

TAENIA SAGINATA

A

Transmission by eating UNDERCOOKED BEEF that contains larval cysts

Endemic in CATTLE BREEDING AREAS –> Central Asia, Near East, Central and East Africa

OFTEN ASYMPTOMATIC; Occasional abdominal pain

25
Q

TAENIA SOLIUM

A

PORK! PORK! PORK!

Ingestion of raw/undercooked PORK

Ingestion of the EGGS –> egg become larva which goes to the MUSCLE and CNS TISSUE

Mexico, Central America, South America, Africa, Southeast Asia, Phillipines

CYSTICERCOSIS MASSIVE CYSTS in the CNS, SEIZURES, ABNORMAL MRI, IMMIGRANTS***

26
Q

ECHINOCOCCUS

A

Exposure to FOOD PRODUCTS infected with echinococcal eggs

Transmitted by INFECTED DOMESTIC DOGS in LIVESTOCK AREAS

Africa, Middle East, Southern Europe, Latina America, SOUTHWESTERN US

GIGANTIC LIVER CYSTS!!!!!!!!! FEVER, ABDOMINAL PAIN, LARGE CYSTS, EOSINOPHILIA

27
Q

FILARIASIS

A

Vector borne – DENSE EXPOSURE to MOSQUITOES

Endemic in SUB-SAHARAN AFRICA, SE ASIA

Clinical –> RECURRENT FEVERS with INFLAMMATION of the LYMPHATICS

Fever and SWELLING OF THE LEG, ARM, MALE GENITALS

Chronic Lymphedema and DISFIGUREMENT

ELEPHANTIASIS
EOSINOPHILIA
Tropical Pulmonary

28
Q

LOIASIS

A

LOA LOA

EYE WORM –> Worms can migrate through the EYE (may actually report seeing a worm in their eye); Also HAND SWELLING

Recurrent, intermittent swelling of the FACE, EXTREMITIES –> worms migrate through the SKIN

Deer flu, horse fly, mango fly

29
Q

TRICHINELLOSIS

A

Ingestion of UNDERCOOKED MEAT/GAME PRODUCTS

PORK, BOAR, DEER, POLAR BEAR, WALRUS…

Fever, diarrhea, severe myalgias/myositis, facial and peri-orbital edema, peripheral eosinophilia

30
Q

SCHISTOSOMA

A

Exposure to WATER, need a SNAIL INTERMEDIATE (not in the US)

Schistosoma DERMATITIS –> occurs when cercaria PENETRATE THE SKIN; pruritic, maculopapular rash; Swimmer’s itch

ACUTE Schistosoma –> Fevers, Chills, Malaise, Abd pain, diarrhea, lymphadenopathy, hepatosplenomegaly, cough, pulmonary infiltrates, eosinophilia

CHRONIC –> intestinal, portal HTN with splenomegaly, Cystitis with hematuria, NEURO INVOLVEMENT (CNS, Transverse myelitis)

Schistosoma MANSONI = GI symptoms, PORTAL HTN

**Schistosoma HEMATOBIUM –> Can lead to KIDNEY FAILURE due to inflammation induced obstruction –> Can get SCC of the BLADDER!!!!!!

31
Q

PARAGONIMASIS

A

LUNG fluke

ASIA

Caused by consumption of FRESHWATER CRUSTACEANS (crayfish, crabs)

Infection occurs when the TREMATODES are INGESTED and CROSS THROUGH DUODENUM/PERITONEUM –> then migrate across the diaphragm to cause lung disease

Clinical –> VERY SIMILAR TO TB!!! Presents with COUGH with SIGNIFICANT BLOODY SPUTUM (hemoptysis) and CAVITATIONS in the lungs

May have CNS lesions!!!

Eosinophilia