[Para] Prelims to Finals Quick Reviewer (Mar Mariano) PDF

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Summary

MEDICAL PARASITOLOGYo Parasites are organisms that depend on another living creature, referred to as the host, for survival o 2 types of host: 1. Intermediate host: harbors the ASEXUAL cycle (larval stage) of development 2. Definitive / Final host: harbors the SEXUAL stage (mature stage) of the para...

Description

FEU – DR. NICANOR REYES MEDICAL FOUNDATION SCHOOL OF MEDICINE

MEDICAL PARASITOLOGY PRELIMS o o

o

Parasites are organisms that depend on another living creature, referred to as the host, for survival 2 types of host: 1. Intermediate host: harbors the ASEXUAL cycle (larval stage) of development 2. Definitive / Final host: harbors the SEXUAL stage (mature stage) of the parasite Parasites can be divided into: o Protozoa (single-cell organisms) o Metazoa (multi-cellular organisms)

PROTOZOA CYST

TROPHOZOITE

Non-motile Non-feeding (due to tough cyst wall) Chromatoidal bodies (stored food) Infective stage Found in formed stool and water fecal specimen Resistant (due to tough cyst wall) Preservative: 5-10% Formalin

Motile (w/ locomotive organs) Feeding (absorb nutrients via plasma membrane)

Organs of locomotion: PCF

Pathogenic stage Found in soft/watery stool Easily destroyed (must be examined within 30mins) Preservative: Polyvinyl Alcohol Pseudopodia (finger-like)

Parasitic Amoeba:  Entamoeba histolytica  Entamoeba coli  Endolimax nana  Iodamoeba buetschlii  Entamoeba gingivalis (Trophozoite form ONLY)  Entamoeba hartmanni  Entamoeba disparr (same as E. histolytica)

RECALL  Infective stage: CYST  Pathogenic stage: TROPHOZOITE  Where does EXCYSTATION take place? SMALL INTESTINES  Where does ENCYSTATION take place? LARGE INTESTINES  Trophozoites will only be found in the LARGE INTESTINES  Intestinal Amoebiasis (E. histolytica) o Primary lesion: small and produces no signs and symptoms o At the muscularis mucosa: Flask-shape lesion of amoebiasis (small opening and a long neck); “Pepsi cola” lesion o Tumor-like lesion: Amoebic granuloma or Amoeboma  Extraintestinal Amoebiasis (E. histolytica) o Liver  Single lesion  Amoebic Liver Abscess  Anchovy sauce-like material  Hepatomegaly  RIGHT lobe of liver  Common among males  4th and 5th decade of life o Lungs  Hematogenous route: BOTH LUNGS  Extension of amoebic liver abscess: RIGHT LUNG  DOC for E. histolytica: METRONIDAZOLE

Cilia (thread-like) Flagella (hair-like)

E. histolytica is both pathogenic AND invasive.

PROTOZOA I. o o o

RHIZOPODEA (commonly amoeba) w/ pseudopodia Found in the lumen of the large intestine: CECUM (EXCEPT E. gingivalis – Buccal cavity) All are NON-PATHOGENIC except E. histolytica

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Entamoeba histolytica:

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Cyst: o Dx feature: Cigar-shaped/rounded or spherical/rod-shaped chromatoidal bodies o 1-4 nuclei Trophozoite: o Characteristic motility: Active, progressive, directional o Dx feature: ingested RBCs, Bull’s eye karyosome o ONE nucleus Most common habitat: Cecum 2nd most common habitat: Rectosigmoid 2.

Entamoeba coli

Cyst: o Dx feature: PROMINENT multinucleated cyst o 1-8 nuclei o Whisk-broom appearance of chromatoidal bodies Trophozoite: o Characteristic motility: Sluggish, non-progressive, non-directional o ONE, large nucleus o Eccentric karyosome

FREE-LIVING PATHOGENIC (OPPORTUNISTIC) Naegleria fowlerii Acanthamoeba cumbertsoni Acanthamoeba polyphaga Acanthamoeba castellani Acanthamoeba astronyxis

NAGLERIA FOWLERI Primary Amoebic Meningoencephalitis (PAM) Trophozoite and Cyst forms Trophozoite: Amoeboid or flagellate Highly motile Aquatic (found in water)

Occurs in healthy individuals 3.

Endolimax nana

Cyst: o Dx feature: Ground-glass appearance cytoplasm o Cross-eyed appearance of karyosome: “punched-out” nucleus o 1-4 nuclei Trophozoite: o Characteristic motility: Sluggish o ONE nucleus 4.

Iodamoeba buetschlii

Cyst: o Dx feature: Large glycogen vacuole (2/3 of organism) o Glycogen vacuole: Iodine cyst of Wenyoun o 1-2 nuclei, usually 1 Trophozoite: o Dx feature: Large glycogen vacuole (1/3 of organism) o ONE nucleus 5. Entamoeba gingivalis Trophozoite form only o ONE nucleus o Central karyosome o Habitat: Buccal cavity o Disease: Pyuria alveolaris o Associated w/ Trichomonas tenax

ACANTHAMOEBA Granulomatous Amoebic Encephalitis (GAE) Trophozoite and Cyst forms Acquires organisms through the eyes, breaks in skin, respiratory tract, genitourinary tract Eyes: “Black eye” Preceded by trauma Among those using soft lenses (contact lenses) Also known as Amoebic Keratitis Occurs in chronically ill, debilitated or immunocompromised individuals CHRONIC infection, with granuloma formation, similar to brain tumors

ACUTE infection, similar to Fulminating Bacterial Meningitis Signs and sx of meningitis: 1. Severe headache Encephalitis 2. Projectile vomiting 3. Nuchal rigidity / Stiff neck DOC: Amphotericin B DOC: Sulfadiazine Signs and Sx of encephalitis: 1. Headache 2. Seizures Tool for Diagnosis: Cerebrospinal Fluid (CSF) II.       

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CILIATEA Balantidium coli ONLY Organ of locomotion: Cilia (arising from the basal granules) LARGEST intestinal protozoa to infect man o Habitat: LARGE INTESTINE Cyst and trophozoite forms 2 nuclei (Macro- and micronucleus) Type of encystment: PROTECTIVE Lesion: o “Coca-cola”: big opening and large rounded end o Big lesions DOC: Metronidazole

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ZOOMASTIGOPHOREA Commonly called flagellates Organ of locomotion: Flagella (arising from the kinetoplast, consisting of parabasal bodies and blepharoplast)

B. Blood & Tissue Flagellates

A. Atrial Flagellates (longitudinal binary fission) Inhabit luminal organs or structures of the body  Chilomastix mesnili 

Giardia lamblia (Alma Moreno – “carpeting”)

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Trichomonas tenax (assc. w/ E. gingivalis) Trichomonas hominis

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Trichomonas vaginalis (“Ping-pong” infection)

Dientamoeba fragilis

(Lorna Tolentino) Inhabit the blood and/or internal organs and are vectortransmitted

Leishmania & Trypanosoma

L

tropica brasiliensis donovanii

LEISHMANIA: Pathogenic: Amastigote Infective: Promastigote

T

gambiense rhodisiense

cruzi T. gambiense & rhodisiense: AFRICAN sleeping sickness Trypomastigote: BOTH pathogenic and infective stage T. cruzi: South American Chaga's dse. Pathogenic: Amastigote Infective: Trypomastigote

DOC: o o o

L. donovani: Pentavalent antimony sodium gluconate, amphotericin B, pentamidine isethionate T. gambiense & T. rhodisiense: Pentamidine isethionate, Suramin sodium, Melarsoprol, Tryparsamide T. cruzi: Primaquine, Benznidazole

1. Chilomastix mesnili Cyst: o Dx feature: Lemon/nipple-shape protuberance o Hour-glass cytostome o ONE nucleus Trophozoite: o Characteristic motility: Corkscrew/Boring motion o Pear-shaped due to spiral groove o Hour-glass cytostome Non-pathogenic Habitat: Cecum Lab dx: DFS

2. Giardia lamblia Cyst: o Dx feature: Retracted cytoplasm, a pair of axoneme o 4 nuclei Trophozoite: o Characteristic motility: Falling leaf-like, gliding kite o Tumbling motility o 4 pairs of flagella o o o o o o o o o o

Pathogenic Non-invasive MOT: ingestion of cysts Pathogenesis: Carpeting/Coating intestinal mucosa (Alma Moreno) Habitat: Small intestine (Duodenal crypts) Malabsorption Traveller’s diarrhea/Lenningrad’s curse Steatorrheic/gruelly stool Lab dx: DFS, Entero test (String test) DOC: Metronidazole

3. o o o o o

Dientamoeba fragilis Trophozoite only Dx feature: Tetracoccic kayosome (4 karyosomes) 1-4 nuclei, usually 2 MOT: ingestion of trophozoite with the eggs of E. vermicularis Pathogenic Non-invasive

4. -

Trichomonas spp. Trophozoite only

Trichomonas tenax Jerking motility

Trichomonas hominis Tumbling motility

Inconspicuous cytostome Buccal cavity: Along the tartar of teeth, gums and tonsil)

Post-trailing end of axostyle Conspicuous cytostome

ONE nucleus at anterior part

ONE nucleus with central karyosome

Pyuria alveolaris (assc. with E. gingivalis) Non-pathogenic

Non-pathogenic

Rigid axostyle

Large intestine (Cecum)

Trichomonas vaginalis Moving Dx feature: Siderophil granules present along the axostyle Inconspicuous cytostome Vagina Prostate gland Urethra Ping-pong infx Creamy, frothy vaginal discharge DOC: Metronidazole Pathogenic

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FEU – DR. NICANOR REYES MEDICAL FOUNDATION SCHOOL OF MEDICINE RECALL  Pathogenic Amoeba: o E. histolytica o B. coli o G. lamblia o T. vaginalis o T. homins o T. tenax o D. fragilis  Organisms where the infective stage is TROPHOZOITE (no cyst forms): o E. gingivalis o T. vaginalis o T. hominis o T. tenax o D. fragilis  BOTH pathogenic and invasive o E. histolytica o B. coli  Organisms with cytostome o B. coli (in trophozoite form only) o C. mesnili (trophozoite and cyst) – “hour-glass” appearance cystostome o T. hominis (“conspicuous” cytostome)  Trophozoites w/ 2 nuclei: o B. coli o G. lamblia o D. fragilis

MIDTERMS IV. o

SPOROZOA No specific organ of locomotion because they are intracellular parasites producing SPORES

CLASS # of hosts Vector Genera

COCCIDIA

HEMOSPORINA

1 None Isospora Cryptosporidium Toxoplasma Sarcocystis

2 Insect vectors Plasmodia

Opportunistic coccidia:  Toxoplasma gondii – in any tissue  Cryptosporidium parvum - in the brush borders of the stomach and intestine  Pneumocystis jirovecii – in lungs Coccidia:  Isospora belli  Sarcocystis hominis  Sarcocystis lindemanii  Eimeria (spurious parasite: pass through the body without any changes or maturation) Isospora Eimeria Cryptosporidium Sarcocystis Toxoplasma

Asexual and sexual stages occurring in ONE host Needs 2 hosts for life cycle

Hemosporina:  Plasmodium falciparum (#1 in Phils)  Plasmodium vivax  Plasmodium malariae (often in Phils)  Plasmodium ovale (#1 in Africa) MALARIA Definitive host: o Insect vector (Anopheles Mosquito) o Sexual stage o Infective stage to DH: Gametocytes o Life cycle: Sporogony o Will produce: Sporozoites Intermediate host: o Man o Asexual stage o Infective stage to IH: Sporozoite o Life cycle: Schizogeny o Will produce: Merozoites Stipplings: o Francis Magalona -> P. falciparum – Maurer’s dots o Vilma Santos -> P. vivax – Schuffner’s dots o Manila Zoo -> P. malariae – Ziemann’s dots

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Plasmodium vivax

Plasmodium malariae

Plasmodium falciparum

Disease

Benign tertian

Benign Quartan

Malignant tertian Subtertian Aestivo-Autumnal

Found in

Predominant in the world

In temperate and subtropical regions Occasionally in Philippines

Common in Philippines

YT

Reddish/pinkish chromatin dot w/ ring of bluish cytoplasm Ring form: signet ring appearance

Single dot with bluish ring of cytoplasm Signet ring

Polymorphic/pleomorphic Multiple infections May have double chromatin dots

GT

Enlarged RBC Amoeboid cytoplasm

MT

Amoeboid cytoplasm

Increase in bluish cytoplasm (compact) About 5% of GT is in band form Compact cytoplasm

YS

2 chromatin dots

2 chromatin dots

GS

3-11 chromatin dots

MS

Haphazard arrangement of chromatin dots 48 hrs

3-5 chromatin dots Daisy/rosette/ margarette arrangement of chromatin dots 72 hrs

12-24

6-12

18-24-32

Microgametocyte: scattered chromatin dot Macrogametocyte: enlarged chromatin dot at periphery

Microgametocyte: chromatin dot scattered at the center Macrogametocyte: enlarged chromatin dot at periphery

Microgametocyte: Banana-shaped, scattered chromatin dot Macrogametocyte: crescent-shaped, compact chromatin dot

Stipplings / Malarial pigments (Hematin)

Schuffner’s dots

Ziemann’s dots

Maurer’s dots

Affinity to

Young RBC

Mature, senescent, old RBC

Young and mature, senescent, old RBC

ES cycle # of merozoites

Gametocytes

Only YT and gametocytes are seen in PBS. Intermediate stages are seen in the capillaries and internal organs. If YT is present in PBS, there is overwhelming infx  warning sign of perinicious anemia 3-7 chromatin dots

RECALL 

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Plasmodium ovale: o Oval shape RBC o NOT present in the Philippines o Present in Africa, S. America, Myanmar, Thailand Most severe to less severe: o P. falciparum o P. vivax o P. ovale o P. malariae Malaria endemic regions in the Philippines: o Bicol o Palawan o Mindoro (Oriental and Occidental) o Sulu Province (Sulu, Basilan, Tawi Tawi) o Quezon City (Novaliches) o Rizal province (Montalban, Antipolo) Malarial pigment o Also known as Hematin pigment o Hemoglobin  Heme (contains iron) + Globin (protein component) o Plasmodium consumes the globin part and heme becomes a waste product o Heme becomes the malarial pigment seen in the cytoplasm of the plasmodium 2 types of Relapse (reappearance of Malaria): o Recurrence: P. vivax and P. ovale  Plasmodium w/ HYPNOZOITE stage  May undergo Secondary Exo-erythrocytic cycle o Recrudescence: P. falciparum and P. malariae  No hypnozoite stage Only MEROZOITES can infect RED BLOOD CELLS Only SPOROZOITES can infect LIVER CELLS Febrile paroxysm: 1. Cold stage: Chills 2. Hot stage: Fever 3. West stage: Profuse sweating Best time to collect blood sample: BEFORE the height of the fever (Schizonts will be observed) Thin blood smear: Specific diagnosis Thick blood smear (dehemoglobinated blood): Rapid diagnosis Primaquine: greatest ability to kill plasmodium in the INTRA-HEPATIC stage

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FEU – DR. NICANOR REYES MEDICAL FOUNDATION SCHOOL OF MEDICINE METAZOA o o

Helminthes (worms) 2 phyla: Nematodes and Platyhelminthes

I. o o o o o

NEMATODES Round worms Cylindrical, elongated and unsegmented bodies Development: egg  larva  adult Sex is separated Complete digestive system: o Mouth o Buccal / Oral / Pharyngeal Cavity o Gut o Females: Anus o Males: Cloaca – common opening for digestive and reproductive systems o Phasmids – caudal chemoreceptors NO Circulatory and Respiratory system

o A.

B.

C.

Adenophorea (Aphasmidea) o Trichuris trichiura o Capillaria philippinensis o Trichinella spiralis Secernentea (Phasmidea) o Ascaris lumbricoides (ascaris of humans) o Toxocara canis (ascaris of dogs) o Toxocara cati (ascaris of cats) o Anisakis (ascaris of sea animals) o Human Hookworms: Necator americanus and Ancylostoma duodenale o Animal hookworms: Ancylostoma braziliense and Ancylostoma caninum o Strongyloides stercoralis o Gnathostoma spinigerum o Enterobius vermicularis o Angiostrongylus cantonensis Filarial worms (Infective stage: L3 Filiform Larva) o Wuchereria bancrofti o Brugia malayi o Loa loa o Onchocerca volvulus o Mansonella ozzardi o Mansonella perstans

RECALL 

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Blood-lung phase: SANA o Strongyloides stercoralis o Ascaris lumbricoides o Necator americanus o Ancylostoma duodenale Auto-infection: CHEST o Capillaria philippinensis o Hymenolepis nana o Enterobius vermicularis o Strongyloides stercoralis o Taenia solium Anemia: o Hypochromic – T. trichiura o IDA – Hookworm o Perinicious – P. falciparum Diarrhea: o P. falciparum o T. trichiura o C. philippinensis o S. stercoralis (on and off) Charcot-Leyden crystals: o T. trichiura (in colon exudates) o A. lumbricoides (in sputum) Larviparous: o C. philippinensis o T. spiralis o Microfilariae o A. lumbricoides ** Loeffler’s syndrome: o A. lumbricoides o S. stercoralis Unsegmented eggs (laid unembryonated) o G. spinigerum o A. cantonensis Segmented egg (laid embryonated): o E. vermicularis VLM Triad (T. cati, T. canis, Strongyloides, Hookworm, Gnathostoma, Spirometra): o Eosinophilia o Hepatomegaly o Hyperglobulinemia Cephalic Alae: T. cati & T. canis Cephalic & Caudal Alae: E. vermicularis Greater blood loss: Ancylostoma (0.15mL/worm/day) > Necator (0.03mL/wormday) Uncinariasis: Necator americanus | Oxyuriasis: Enterobius vermicularis

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Parasite Common name IH DH Infective stage to DH MOT Habitat Male Worm

Female Worm

Egg/Larva Morphology

Manifestation s

Lab dx

DOC

ADENOPHOREA

SECERNENTEA

T. trichiura

T. spiralis

C. philippinensis

A. lumbricoides

S. stercoralis

Whipworm

Trichina worm

Pudok worm

Giant intestinal roundworm

Threadworm

None (Direct infection) Man

Man Rats & Pigs

Fishes Man

None (Direct infection) Man

Embryonated egg

Encysted Larva

L3 Filariform larva

Ingestion Cecum, appendix, colon, lower ileum Tail-end coiled 360deg Lancet-shaped spicule Sacculate testes Straight tail end Sacculate ovaries (+) Stichocytes Oviparous

Football/barrel shaped Bipolar mucus plugs

o Mild to moderate infx: asymptomatic o Heavy/massive infx: chronic diarrhea, diffuse colitis, dysentery, abdominal cramps o Hypochromic anemia o Rectal prolapse

DFS

Ingestion of improperly cooked pork Duodenum, jejunum Conspicuous conical papillae Single testes Stichosomes in uterus Single ovary Oviparous

Calcified in glycogen-poor tissues

Stages: o Invasion: abdominal pain o Larval Migration: fever, myalgia, edema o Encystation: Muscle pain, fever o Tissue repair & recovery

Biopsy Xenodiagnosis

None Man

E. vermicularis Society/Seat/Communit y/Pin worm None Man

Accidental host: Man

Embryonated egg

L3 Filariform larva

Embryonated egg

L3 Filariform larva

Ingestion

Ingestion

Skin penetration

Ingestion

Ingestion

Jejunum

Ileum

Small intestine

Cecum

Tissues/Organs

Tail-end tortuously coiled

Bifid/notched tail w/o sheath

Bulbous esophagous (Diagnostic) Cephalic alae

4 pairs perianal nipple-shaped papilla

Long, chitinous, copulatory spicule Overhanging sheath

G. spinigerum

DH: Dog & Cat

Oviparous & larviparous Vulva: pouting

Oviparous

Bihorned uterus Short vulva

Bulbous esophagous (Diagnostic) Cephalic alae

Long vagina, directed anteriorly

Flattened, bipolar mucus plugs Pitted shell

o 3 layers: o Albuminous: bile-stained (absent in decorticated egg) o Glycerol layer o Vitelline: protect the larva (absent in unfertilized egg)

Rhabditiform larva: o Feeding o Open-mouth Filariform larva: o Non-feeding o Closed-mouth

Plano-convex Inverted “D” shape<...