protozoan disease
TRANSCRIPT
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PROTOZOAN DISEASES
AMEBIASIS:
Etiology: 2 morphologically identical but genetically distinct sp:
1. E. dispar = more prevalent sp.2. E. histolytica = pathogenic sp.
= symptomatic disease
Can be killed by heating to 550C
Resistant to low temperature and chlorine
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Epidemiology:
Prevalence of 5 – 81%
Humans – major reservoir
Means of infection: food and drink contaminated with E. cyst in direct fecal – oral route
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Pathogenesis:
Trophozoites Galactose – specific lectin
receptor Colonic mucosa
Cysteine – rich proteinase Tissue destruction
(flask-shaped ulcers)
Commonly invade:-cecum -transverse colon -sigmoid colon
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Clinical Manifestations:
Intestinal Amebiasis:
incubation period = 2 weeks gradual onset, colicky abdominal pain, frequent bowel movementassociation with tenesmus stools blood stained, fair amount of mucus, few
leukocytes 1/3 of pts with fever amebic colitis = affects all age group
= increased incidence 1-5 y.o.
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Hepatic Amebiasis:
< 1% infected fever is hallmark assoc. with abdominal pain, distention, enlargement and tenderness of liverlab findings: sl. Leukocytosis
moderate anemia inc. ESR inc. Alkaline phosphate >50% (-) stool exam
computed tomography and MRI – localize and delineate size of abscess cavity
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Diagnosis:Stool exam – 3X (90% sensitivity) Sigmoidoscopy Tissue biopsy Aspirate of liver abscess Antigen detection tests – differentiate E. dispar from E. histolytica
Treatment: Luminal Amebicides 1. Iodoquinol 2. Paromomycin 3. Diloxonide furoate
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Extraluminal Amebicides: 1. Metronidazole
2. Nitroimidazole
3. Chloroquine
4. Dehydroemetine
All individuals with E. histolytica trophozoites or cysts in their stools, whether symptomatic or not, should be treated
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Iodoquinol - asymptomatic carriers - 30-40 mg/k/24 hours in 3 divided doses orally X 20 days
Paromomycin - non-absorbable aminoglycoside - 25-35 mg/k/24 hours in 3 divided doses orally X 7 days
Metronidazole- tissue amebicidal drug - 30-50 mg/k/24 hours in 3 divided doses
(max. 500-750 mg/dose) orally X 10 days - A. R. nausea, abdominal discomfort, metallic taste
Dehydroemetine – Metronidazole – resistant to E. histolytica
- 1 mg/k/24 hours (IM, SQ) Chloroquine - for amebic hepatic abscess
Stool exam should be repeated every 2 weeks until (-)
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Prognosis: = death occurs in 5% having extraintestinal
infection
Prevention: 1. proper sanitary measures 2. avoiding fecal – oral contact 3. regular exam. of food handlers
No prophylactic drug or vaccine available
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GARDIASIS:
Giardia lamblia = flagellated protozoan infecting duodenum and S. I.
= clinical manifestation from asymptomatic to acute or chronic diarrhea and
malabsorption
= significant pathogen with malnutrition,
immunodeficiency and cystic fibrosis
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Life Cycle: Composed of 2 stages:
1. trophozoites 2. cysts
Ingested cyst (10-100 cysts)
2 trophozoite in S. I
Excystation
Lumen of duodenum and proximal jejunum
stools (2 mos.)
viability not affected by usual chlorine conc.
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Epidemiology:
inc. in childhood and decreased in adolescents
water contaminated with G. cyst – major reservoir
foodborne transmission is documented
resistant to UV light irradiation
boiling effective for inactivating cysts
person-person spread in low hygiene, lack of toilet training child care centers
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Clinical Manifestation:
inc. period = 1-2 but may be longer asymptomatic, excretion, acute infectious diarrhea, chronic diarrhea no extraintestinal spread but may migrate to bile and pancreatic ducts signs and symptoms: with or without fever, nausea, anorexia, diarrhea and abdominal distention and cramps stools profuse and watery and later greasy and foul smelling, no mucus, blood or fecal leukocytes
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Diagnosis:
Definitive: cysts or trophozoites in stools or duodenal fluid by DFS (within 1 hour) Cyst – infectious form Others: Aspiration or Biopsy of duodenum or upper jejunum
Enterotest Polymerase Chain Reaction (PCR) for environment
monitoring Gene probe-based detection system
DFS – 70% diagnosis single exam 85% 2nd stool exam >90% 3rd stool exam
Medications can interfere presence of parasite in stool Radiographic: irregular thickening of mucosal folds NO blood count: NO eosinophilia
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Treatment: Metronidazole – drug of choice Paromomycin Furazolidone – 92% cure rate
Prevention: 1. .Strict hand washing after contact with feces 2. .Adequate purification of water supply 3. .Travelers advice to avoid uncooked foods
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BALANTIDIASIS:
Balantidium coli - ciliated protozoan - largest protozoan - close assoc. with pigs
(host of org.) - infects L. I.
Symptoms similar with Amebiasis
No extraintestinal spread
Diagnosis: Direct Saline Smear – trophozoites and cysts
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Treatment:
1. Metronidazole (35-50mg/k/24hrs) divided by doses
(max. dose 750mg/day) orally X 5 days
2. Tetracycline (40mg/k/24hrs) divided by 4 doses (max. dose 500mg/dose) orally X 10 days in > 8 years
3. Iodoquinol (40mg/k/24hrs) divided by 3 doses (max. dose 650mg/dose) orally by 20 days
Prevention: Prevent contamination of the environment by pig
feces
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SPORE – FORMING INTESTINAL PROTOZOA
1. Cryptosporidium
2. Isospora digestive tract
3. Cyclospora
4. Microsporidia – many organ systems - broad spectrum of disease
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I. CRYPTOSPORIDIUM:Leading cause of diarrhea in children worldwide Common cause of outbreaks in child care centers
Etiology:Cryptosporidium parvum Infection due to infectious oocyst 2 stages:
a)Asexual – autoinfection at luminal surface of epithelium
b) Sexual – production of oocysts Cysts immediately infectious
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Epidemiology:
In developing countries and <2 years of age
Etiologic agent of persistent diarrhea
Transmission: - contact with infected animals
- person to person
- contaminated water - zoonotic (cows)
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Clinical Manifestation:
Incubation period – 2-14 days Profuse, watery, non-bloody diarrhea, diffuse crampy abdominal pain, nausea, vomiting and anorexia Non-specific symptoms: myalgia, headache, weakness
fever – 30-50% cases malabsorption, lactose intoerancedehydration, weight loss, malnutrition–
in severe cases In immunocompromised hosts:
= assoc. with biliary tract disease = fever ® upper quadrant pain, nausea, vomiting and diarrhea = detected in pancreatic duct of child with AIDS
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Diagnosis:
Self-limited
Supportive care
Immunocompromised: Paromomycin (25-35mg/k/24hrs)
4 doses orally Paromomycin (1g/day) and Azithromycin (600mg daily) followed by
Paromomycin monotherapy X 8 weeks in adult patients with AIDS
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II. ISOSPORA:
Isospora belli Diarrhea in intestinal outbreaks, travelers, contaminated water and food More common in tropical and subtropical climates Not assoc. with animal contact May infect 15% of AIDS patients Life cycle same with Cryptosporidium except oocysts are not immediately infectious and must undergo maturation below 37OCClinical manifestation: indistinguishable from
Cryptosporidiosis but fever is more common Eosinophilia may be present
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Diagnosis: AFS of stool Fecal leukocytes not detected
Treatment:
1. Trimethoprim – Sulfamethoxazole (TMP – SMZ) (5mg TMP, 25mg SMZ/k/dose) max.
160mg TMP, 800mg SMZ/dose orally 4 X/day X 10 days then 2 X a
day X 3 weeks
2. Pyrimethamine alone or Folinic acid – in patients intolerant of Sulfonamide drugs
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III. CYCLOSPORA:
Cyclospora cayetanensis–AKA cyanobacterium– like bodyCommon in <18 months of age Pathogenesis and path. findings similar to isosporiasis Patients almost always have diarrhea Linked to contaminated food and water Clinical manif. similar to Crypto and Isosporiasis Moderate illness: Median of 6 stools/day with median duration of 10 day (range 3 – 35 days)
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Assoc. symptoms: fatigue, abdominal bloating or gas, abdominal cramps, nausea, muscle joints and pains, fever, chill and weight loss
Oocysts remain infectious for days to weeks
Diagnosis: Ident. of oocysts in stool - modified AFS
- phenosafranin stain - autofluorescence
Fecal leukocytes not present
Treatment: TMP – SMZ (5mg TMP, 25mg/k/dose SMZ)
2X/day; max. 160mg TMP, 800mg SMZ/dose orally X 7 days
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IV. MICROSPORIDIA:
Infect most animal groups including humans Assoc. with GI disease:
a) Enterocytozoon beineusi b) Septata intestinalis
Spores inject contents to host cells to cause infection Spores detected in urine and resp. epithelium Spores remain infectious up to 4 monthsAlmost exclusively reported in patients with AIDS Diarrhea is intermittent, copious, watery and non-bloody Biliary disease can occur
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Diagnosis: Hematoxylin – Eosin Periodic acid – Schiff (PAS) Giemsa and Gram stain AFS Electron Microscopy
Treatment: No proven therapy Albendazole (adult dose: 400mg 2X/day X 4 weeks) Atovaquone – dec. symptoms, no clinical trials
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TRICHOMONIASIS
Trichomonas vaginalis Sexually transmitted >60% - female partners of infected men 30 – 80% male sexual partners of infected women rare in menarche: if (+) in younger child – a possibility of sexual abusecan be transmitted to neonates thru infected birth canal
pathogenesis:Vaginal secretions – 101 – 105 or more
protozoa/ml pear-shaped
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clinical manifestations:-incubation period – 5 – 28 days -10% - 50% asymptomatic female -copious, malodorous yellow vaginal discharge -vulvovaginal irritation -dysuria, dyspareunia -P.E: frothy discharge with vaginal erythema and
cervical hemorrhages (“strawberry cervix)
Most males are asymptomatic
5 – 15% of men with non-gonococcal urethritis
Symptomatic males: Dysuria Scant urethral discharge – 36% resolve
spontaneously
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Diagnosis: Demonstration of protozoan in genital secretions Wet mount technique = 60-70% infected females
= 50-90% infected men
A (-) wet mount method does not rule out diagnosis of trichomoniasis
Culture of the organism = most sensitive
= >95% sensitive = not routinely available
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Treatment:1. Nitroimidazole 2. Metronidazole 3. Tinidazole 4. Ornidazole
Metronidazole = 2g orally single dose in adoles females
250mg 3X/day or 375mg 2X/day orally X
7days in infected children – 15mg/k/24hrs / 3 doses orally X 7 days
All sexual partners should be treated
It is now recommended to treat trichomoniasis during pregnancy – safe in last 2 trimesters
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TOXOPLASMOSIS:
Toxoplasma gondiiAcquired perorally, transplacentally, rarely parenterally, transfusion, transplacented organ Organism persist for lifetime Organism remain in tissues especially CNS, skeletal and heart muscles oocysts excreted by infected cats Cat excreted 105 – 107 oocysts/day Acquired by oral route via uncooked or raw meat
containing cysts or by ingestion of oocysts
= pork – 5.35%= lamb – 60% = beef – 0-9%
Freezing meat – 200C or heating 600C – uninfectious
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Pathogenesis:
Ingestion of Oocysts
bradyzoites released from cyst
sporozoites from oocysts
GIT lymphatics
disseminate throughout body
- pneumonitis- myocarditis- necrotizing encephalitis
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Congenital Toxoplasmosis:
Mother acquires infection during gestation
Disseminate hemaatogenously to placenta (transplacentally) or during
vaginal delivery
1st trimester – 17% infected
3rd trimester – 65% infected
almost all infected fetuses manifest chorioretinitis by adolescence
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Clinical Manifestation:
Acquired Toxoplasmosis:fever, stiff neck, arthralgia, maculopapular rash sparing palms and soles, localized or gen. lymphadenopathy, hepatomegaly, hepatitis, meningitis, brain abscess, pneumonia, pericardial effusion, myocarditis
Ocular Toxoplasmosis:blurred vision, photophobia, loss of central vision strabismus, microophthalmia, microcornea, cataract, nystagmus
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Congenital Toxoplasmosis:
SKIN: rashes, petechiae, ecchymoses, large hemorrhages 20
thrombocytopeniaJaundice due to hepatic involvement
Systemic signs: Endocrine: hypothalamic or pituitary involvement
myxedema, persistent hypernatremia, D.I. without polyuria –
polydispsia, sexual precosity
CNS: hydrocephalus, seizures EYES: chorioretinal lesions – 50% severe visual
impairment EARS: Sensorineural hearing loss
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Diagnosis: 1. Culture – isolation from blood or body fluids
- demo. of tachyzoites in tissues and body tissues - cysts in placenta or tissues of fetus
2. Serologic testing:a) Sabin-Feldman dye test – sensitive & specific - measures IgG antibodies b) IgG – indirect fluorescent – antibody (IgG – IFA)
- does not correlate severity of illness c) Agglutination test – detect IgM antibodies d) IgM – IFA – dx of acute infection in older children e) Double Sandwich ELISA – more sensitive and
specific than IgM-IFA test f) Immunosorbent agglutination assay (ISAGA) g) Indirect hemaglutination (IHA) measures diff. T.
gondii antibodies
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Treatment: 1. Pyrimethamine + Sulfadiazine or Trisulfapyrimidines
= act synergistically = treat many forms of toxoplasmosis
2. Spiramycin – prevent transmission of infection to fetus
Acquired Toxoplasmosis: Pyrimethamine – 2mg/k/24hrs (max.
50mg) 1st 2 days 1mg/k/24hrs (max. 25mg/24hrs)
Folinic Acid – 5-20mg 3X/week orally Sulfadiazine – in >1year of age
- 75mg/k/24hrs LD then 50mg/k/24hrs
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Ocular Toxoplasmosis:Pyrimethamine Sulfadiazine 1 week Leukovorin
Congenital Toxoplasmosis: should be treated for 1 year
Oral Pyrimethamine – 1-2mg/k/24hrs X 2days then,
1mg/k/24hrs X 2 or 6months then, 1mg/k/24hrs M – W – F
Sulfadiazine – 100mg/k/24hrs LD100mg/k/24hrs / 2 doses
Calcium leukovorin – 5 –10mg/k/24hrs M-W-F
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Pregnant Women with Toxoplasmosis:Spiramycin and Pyrimethamine + Sulfadiazine
= reduces infection in placenta and severity of disease
Spiramycin – 1g every 8hrs. without food
Prognosis: Early treatment for congenital infection cures manifestations Guarded – infected babies
Prevention:1. Counseling women about methods of
preventing transmission of T. gondii during pregnancy
2. Eat well cooked meat 3. Avoid contact with oocysts excreted by cats
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PNEUMOCYSTIS CARINII
Pneumocystis carinii pneumonia (interstitial plasma cell pneumonitis)
Extracellular parasite of the lungs
Epidemiology: Mostly affected - <4years of age Immunocompromised patient - 40%
= infants and children 70% = adults with AIDS 12% = leukemia 10% = organ transplant
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Pathogenesis: 2 types of histopathologic features of P. carinii pneumonia:
a) infantile interstitial plasma cell pneumonitis = 3-6mos. of age
b) diffuse desquamative alveolar dis. = immunocompromised children and
adult
Clinical Manifestation:Tachypnea without fever intercostal, suprasternal and infrasternal retractions nasal flaring cyanosis rales not detected chest radiograph: bilateral diffuse alveolar disease with granular pattern
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Diagnosis:
demonstration of P. carinii in the lung
1) bronchoalveolar lavage
2) tracheal aspirate
3) transbronchial lung biopsy
4) bronchial brushings
5) percutaneous transthoracic needle aspiration
6) open lung biopsy – most reliable
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Treatment:TMP – SMZ – (15-20mg TMP, 75-100mg SMZ/k/24hrs) 4 doses
IV or orally = 3 weeks with AIDS 2 weeks in other patients
Pentamidine isethionate (4mg/k/24hrs) SD IV – resistant to TMP –
SMZ
Prednisone = inc. survival rate in mod. – severe infections
= >13 years old–80mg/24hrs/ 2 doses 1–5 days
40mg/24hrs 6 – 10th days
20mg/24hrs 11 – 21st days
= children – 2mg/kg/24hrs 1st 7 – 10 days
taper next 10-14 days
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Prognosis:
without treatment – fatal
10 – 30% mortality rate
chemoprophylaxis - TMP – SMZ Dapsone Aerosolized pentamidine
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MALARIA (PLASMODIUM)
acute and chronic protozoan illness charac. by paroxysms of fever, chills, sweats, fatigue, anemia and splenomegaly
Etiology: Plasmodium protozoa Transmitted to humans by female Anopheles mosquito 4 species:
1. P. falciparum 2. P. malariae 3. P. ovale 4. P. vivax
Life Cycle:a) Asexual phase – in human host b) Sexual phase – mosquito
Exoerythrocytic phase = cells in the liver Erythrocytic phase = in rbc’s
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Exoerythrocytic phase:
Inoc. of sporozoites to blood stream by Female Anopheles mosquito
Hepatocytes (multiply asexually)
Schizont (1-2 weeks)
Rupture of hepatocytes
Release of merozoites to circulation
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Erythrocytic phase:
Merozoites from liver center erythrocytes
Ring formation _____trophozoite
Multiply to form erythrocytic merozoite
bloodstream
rbc membrane rupture (fever)
ingested by mosquito
male and female gametocyte fuse to form
zygote
sporozoites enter the salivary glands of mosquito
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Epidemiology:Transmitted through blood transfusion, use of contaminated needles, pregnant woman to her fetus
Pathogenesis:
4 important pathologic process:a) fever = when the rbc ruptures and merozoites
are released b) anemia = hemolysis, sequestration of rbc’s in the
spleen and other organs, suppression of the rbc prod. in BM c) immunopathologic events = formation of immune
complexes, immuno-suppresion, release of cytokines
(TNF) d) tissue anoxia = resulting from cytoadherence of
infected erythrocytes
= occur in P. falciparum malaria
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• Clinical Manifestations:Incubation period:1. P. falciparum = 9-14 days2. P. vivax = 12-17 days or as long as 6-12
months3. P. ovale = 16-18 days4. P. malariae = 18-40 days
Prodromal symptoms = 2-3 days= headache, fatigue, anorexia, myalgia, slight fever, pain in chest,
abdominal and joint pains
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• P. falciparum = most severe form
= infects both immature and mature erythrocytes
P. ovale & vivax = infects immature rbc’s
P. malariae = infects mature erythrocytes
= mildest & most chronic
P. ovale = least common type
= in conjunction with P. falciparum
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• Diagnosis of P. falciparum malaria constitute a medical emergency
• Diagnosis:
Giemsa-stained peripheral smear
thick smear = scan large no. of rbc’s quickly
thin smear = identification of malaria species & determine % of infected erythrocytes
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• A single negative blood smear does not rule out malaria
• Other tests:
Monoclonal Antibody test = as sensitive as thick smear
PCR
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• Treatment:
1. Therapeutic
- Chloroquine phosphate = oral DOC
- Quinidine gluconate = IV DOC
2. Supportive
1. blood transfusion to maintain hematocrit
of >20%
2. exchange transfusion in P. falciparum malaria with parasitemia of 15%
3. careful IV rehydration
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4. supplemental oxygen + ventilatory support for pulmonary edema or cerebral malaria
5. IV glucose for hypoglycemia6. anticonvulsants7. dialysis for renal failure
Complications:1. cerebral malaria = 20-40% fatality rate2. renal failure3. “Blackwater fever” = clinical syndrome that
consist of sevre hemolysis, hemoglobinuria and renal failure
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• Prevention:
1. reducing exposure to infected mosquitoes
2. travelers to endemic areas should remain in well screened areas
3. using of mosquito repellants
4. use of chemoprophylaxis
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SCHISTOSOMIASIS
Etiology:
Schistosoma sp:
1.S. haematobium
2.S. mansoni
3.S. japonicum
4.S. intercalatum
5.S. menkongi
Flukes or trematodes that parasitize bloodstream
Cercariae – infective stage
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Anatomic sites migrated by schistosoma S. haematobium – perivesical and periureteral venous plexus S. mansoni – inferior mesenteric veins S. japonicum – superior mesenteric veins S. intercalatum and mekongi – mesenteric vessels
Charac. egg morphologic features: S. mansoni – lateral spine S. haematobium – terminal spine S. japonicum – smaller size and short curved spine
Humans – only definitive host
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Clinical Manifestations:Papular pruritic rash (schistosomal dermatitis or
swimmer’s itch)Katayama fever = serum sickness – like syndrome
- acute onset of fever, chills, sweating, lymphadenopathy,
hepatosplenomegaly, eosinophilia S. japonicum – may migrate to brain vasculature
Diagnosis: Kato’s thick smear
Treatment: Praziquantel
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TRICHINOSIS
Etiology: Trichinella spiralis
Transmitted by ingestion of pork or other meat carrying
parasite
Larva penetrate gut wall, striated muscle, CNS, heart
Clinical manif: 1st week = gastroenteritis
muscle = periorbital, facial edema, myalgia
= common in masseters, diaphragm, intercostals
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Diagnosis: - periorbital edema - myalgia fever - eosinophilia
- muscle biopsy - bentonite flocculation test- inc. creative kinase + lactose
dehydrogenase = 50%
Treatment:Mebendazole – eliminate adult worm from gut
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TRICHURIASIS
Etiology: Trichuris trichiura or whipworm Final habitats: cecum and ascending colon Clinical manif: abdominal pain, colic, distention Adult worm suck 0.005ml of blood/worm/day
Anemia, blood diarrhea, rectal prolapse – massive infantile trichuriasis
Associated with Shigellosis and protozoan infections of GIT Treatment: Mebendazole – 70 – 90% cure rate
- 90 – 99% reduce egg output
- 100mg bid X 3 days or 500mg once a day
Albendazole – alternative - 400mg X 3 days
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STRONGYLOIDIASIS
Etiology: Strongyloides stercoralis Filariform larva Capable of infecting same individual (autoinfection) Pathogenesis: Dermatitis – repeated skin penetration
- larva currens Loffler’s Syndrome
Clinical manif: Pruritus and popular erythematous rash Abdominal pain, vomiting, diarrhea Diagnosis: feces or duodenal fluid for larva Treatment: Ivermectin – 200mg/k/24 hrs X 1-2 days Thiabendazole – 50mg/k/24 hrs divided by
2 doses X 2 days
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LYMPHATIC FILARIASIS
Etiology: 1. Brugia malayi (Malayan filariasis) 2. Wuchereria bancrofti (Bancroftian filariasis)
Characterized by: - lymphadenitis - lymphangitis - lymphatic obstruction and
hydrocoele - elephantiasis
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Clinical manifestation: -Fever -Lymphangitis of extremity -Lyphadenitis -Headaches, myalgias
Diagnosis: Blood – microfilariae
Treatment: 1. Diethylcarbamazine – modifies course of acute
lymphangitis 2. Ivermectine
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HELMINTHIC DISEASES
Ascariasis: Ascaris lumbricoides Common in pre-school and early school age
Etiology:Mature larva containing egg – infective stage Female – life span 1-2 years
200,000 eggs/24 hours
Epidemiology:MOT– hand–mouth, fingers contaminated by soil contactFoods - raw
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Pathogenesis:
Ingested eggs
larva
intestinal wall pulmonary tissues
alveolar spaces
bronchial tree and
trachea
re-swallowed
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Clinical Manifestation: Pulmonary ascariasis: Cough blood-stained sputum +
Eosinophilia = Loeffler’s – like
Syndrome GI : Abdominal pain and distention
Intestinal obstruction – 1-6 year old ,sudden, severe, colicky
abdominal pain and vomiting (bile –
stained)
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Diagnosis: DFS Kato’s thick smear method Pulmonary ascariasis or GI is based on clinical symptoms and high index of suspension
Treatment:1. Albendazole – 400mg PO SD 2. Mebendazole – 100mg BID X 3 days 500mg once 3. Pyrantel pamoate – 11mg/k once (max.1g) PO
4. Piperazine – 50-75mg/k X 2 days PO- neuromuscular paralysis and expulsion of parasite
Prevention: 1. Deworming every 3-6 months 2. Improve sanitary practices
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HOOKWORMS
Ancylostoma Necator americanus
Etiology: 1. Ancylostoma:
a) A. duodenale – classical hookworm infection b) A. ceylanicum c) A. caninum – eosinophilic enteritis syndrome d) A. braziliense – cutaneous larva migrans
2. Necator americanus – anthropophilic hookworm = infect humans thru skin penetration
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Pathogenesis:
• adhere to mucosa & submucosa of S.I. (cutting plates) = causes intestinal blood loss
•In moderate to severe infections: Anemia + IDA
Clinical Manifestations:
• “ground itch” = skin penetration
• Cough = Laryngotracheobronchitis; pharyngitis
• Chronic: Chlorosis – yellow green pallor
• Malnutrition
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Diagnosis :
• DFS
• Colonoscopy
Treatment:
• !. Nutritional support
• 2. Albendazole
• 3. Mebendazole
• 4. Pyrantel pamoate
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Prevention:
• 1. Sanitation
• 2. Health education
• 3. Avoidance of human feces as fertilizers
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ENTEROBIASIS (Pinworm Infection)
• Enterobius vermicularis
• Embryonated egg in fingernails, clothing, beddings or house dust
• Gravid female migrate by night to perianal region
• Humans = only natural host
• High in 5-14 years of age
Clinical Manifestations:
• nocturnal anal pruritus
• sleeplessness
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Diagnosis:
• parasite eggs or worms in stools
• pressing adhesive cellophane tape technique
Treatment:
• 1. Albendazole
• 2. Mebendazole
• 3. Pyrantel pamoate
•Repeat treatment after 2 weeks
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TOXOCARIASIS:
• Visceral larva migrans
= < 10 yrs of age
= fever, hepatomegaly, pulmonary disease & eosinophilia
= Toxocara cati – feline ascarid
= Toxocara canis – canine ascarid
Clinical manifestations:
• fever = 80%
• cough with wheezing = 60-80%
• seizures = 20-30%
• Hepatomegaly = 65-87%
• rales or rhonchi = 40-50%
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• urticarial rash = 20%
• lymphadenopathy = 8%
• decreased visual acuity = 75% (ocular larva migrans)
Diagnosis: ELISA
Treatment:
• In pulmonary disease: Prednisone
• Ocular Larva Migrans : Diethylcarbamazine
Albendazole
Mebendazole
Prevention:
• Wash hands after playing with pets
• Periodic deworming of dogs & cats
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TAPEWORM INFECTIONS
TAENIASIS:
1. Taenia saginata = beef tapeworm
2. Taenia solium = pork tapeworm
Difference:
T. saginata = 4 anterior suckers
= > 20 uterine branches
T. solium = scolex with double row of hooks
= < 10 uterine branches
Treatment: Preaziquantel
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DIPHYLLOBOTHRIASIS:
• Diphyllobothrium latum = fish tapeworm
= longest human tapeworm
• Uses Vitamin B12 for production of segments
• Inhibits Vitamin B12 uptake by inactivating Vit. B12 intrinsic factor
• Megaloblastic anemia
• Treatment: Praziquantel = 5-10 mg/k P.O. single dose
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HYMENOLEPIASIS:
• Hymenolepis nana = dwarf tapeworm
= in rodents, ticks, fleas
= poor hygienic conditions
Treatment:
•Praziquantel
•Niclosamide
DIPYLIDIASIS:
• Dipylidium caninum = tapeworm of domestic dogs & cats
Treatment: Praziquantel
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CYSTICERCOSIS:
•Infection due to T. solium
•Common parasitic cause of CNS disease (Neurocysticercosis)
•Invade primarily the brain and muscle tissues
Clinical manifestations:
• seizures – primary finding
- 70% of cases
- 80% generalized
- initially simple or complex partial
•4th ventricle = most common site of obstruction
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Diagnosis:
• CT scan
•EITB (Enzyme Linked Immunotransfer Blot)
Treatment:
•Albendazole
•Corticosteroids
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ECHINOCOCCOSIS:
•Hydatid disease of Hydatidosis
•Most serious human cestode infection
•Echinococcus species:
1. E. granulosus = unilocular or cystic hydatid disease
2. E. multiformis = alveolar hydatid disease
•Lungs = commonly affected
•Right lobe of the liver = 70% affected in adults
Treatment:
•Surgery = in alveolar hydatidosis
•Prophylactic Albendazole
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MYCOTIC INFECTIONS
Neonatal Infections:
•Candida species = common cause
•Oral thrush & diaper dermatitis
•Isolated from GIT & vaginal flora
•10% term infants – GIT & respiratory tract
- 1st 5 days of life
•30% in <1,500 grams neonate
•Systemic infections in VLBW infants
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Risk factors:
•Abdominal surgery
•Prolonged ventilatory support
•Prolonged IV catheterization
•Use of IV alimentation
•Administration of broad spectrum antibiotics
Clinical manifestations:
•Asymptomatic
•Associated with sepsis or shock in severe cases
•Disseminated candidiasis = mimics bacterial sepsis with respiratory distress, apnea, bradycardia, temperature instability, glucose intolerance, abdominal signs and symptoms
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•Cutaneous: diffuse erythroderma or vesiculopustules
>50% renal involvement
•CNS – 1/3 of cases
- meninges, ventricles, cerebral cortex with abscess formation
•Endolphthalmitis = 20-50% of cases
•Candidal endocarditis = central venous catheters extending to atrium
•Pneumonia = 70% of cases
Diagnosis:
•Culture = body fluids
•Buffy coat smears = show yeast
= preliminary diagnosis
•Skin scrapings
•Ultrasonography = CV, renal, CNS
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Treatment:
1. Amphotericin B = Drug of choice
= 0.5-0.1 mg/k/24 hrs IV
= active against yeast & mycelial forms
= duration of therapy depends on the extent of infection, clinical response, drug toxicity
= adverse reaction: Nephrotoxicity
2. Liposomal Amphotericin B = 5 mg/k/24 hr
= less renal toxicity
= in neonates with renal compromise
3, Flucytosine = 100-150 mg/k/24 hrs every 6 hrs P.O.
= CNS and parenchymal kidney infections
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ORAL CANDIDIASIS:
•Oral thrush or oral pseumembranous candidiasis
•2-5% in newborns
•7-10 days of age
•Recurrent or persistent thrush = use of antibiotics during 1st year of life
•Removal of plaques causes bleeding = confirms the diagnosis
•Asymptomatic or with pain, causes decreased feeding
•No history of antibiotic intake = diabetes mellitus, HIV infection
Treatment:
•Mild = no therapy
•Severe = nystatin, Miconazole gel, Amphotericin B suspension, Gentian violet
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DIAPER DERMATITIS:
•Complicates oral antibiotic treatment of otitis media
•Treatment: Nystatin cream, powder or ointment
1% Clotrimazole cream
2% Miconazole ointment
1% hydrocortisone = inflammation
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VULVOVAGINITIS:
•Common in pubertal & post pubertal women
•Predisposing factors: pregnancy
oral contraceptive use
poor hygiene
use of oral antibiotics
Clinical manifestations:
•Pain or itching
•Dysuria
•Vulvar or vaginal erythema
•Cheesy exudate
•Thrush like mucosal palques
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Treatment:
•Nystatin cream
•Clotrimazole
•Miconazole
•Fluconazole
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CRYPTOCOCCOSIS:
•Cryptococcus neoformans =
•Soil contaminated with avian droppings, fruits & vegetables carried by cockroaches
•60% in adults
•5-10% in HIV infected adults
•Acquired by inhalation of fungal spores
•Disseminate into the brain, meninges, skin, eyes, skeletal; system
•Pulmonary cryptococcosis = granuloma
= subpleural location
= contain yeast forms
•CNS = cystic cryptococcomas
= 20% non-HIV infected patients
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Clinical Manifestations:
•Pneumonia = most common form
= fever, cough, pleuritic chest pain
= x-ray: poorly localized bronchopneumonia
•Disseminated infection = follows primary pulmonary disease
= in immunocompromised individuals
•Meningitis = sub acute or chronic
= headache as initial symptom – good outcome
= cryptococcal antigen titer < 1:32
= 15-30% mortality
= >50% relapse in HIV infection
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•Skeletal infection = 5% of cases
= soft tissue swelling and tenderness
= arthritis ( effusion, erythema, pain on motion)
= vertebrae – common site
•Ocular infection = acute loss of visual acuity, eye pain, visual floaters, photophobia
= >20% mortality rate
= 15% recover full vision
Diagnosis:
•Cuture
•Histology
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Treatment:
•In immunocompromised host with asymptomatic or mild disease = oral fluconazole (200-400 mg/24 hrs) for 3-6 months
•Immunocompetent with progressive pulmonary disease or non-HIV infected = Amphotericin B (15mg/k/24 max. 1.5 g total dose)
•CNS and disseminated infections = combination of Amphotericin B and Flucytosine
•Cutaneous infections = surgical biopsy for diagnosis and apply appropriate topical antifungals
•Skeletal = surgical debridement & systemic antifungal
•Chorioretinitis = amphotericin B + Flucytosine of Fluconazole
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HISTOPLASMOSIS:
• Histoplasma capsulatum = contaminated bird droppings or decayed wood
• Often carried by wings of birds
• Resembles Ghon complex of TB
• 3 forms:
1. Acute pulmonary infection
2. Chronic pulmonary histoplasmosis
3. Progressive disseminated histoplasmosis
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Acute Pulmonary Histoplasmosis:
•Follows initial or recurrent respiratory exposure to microconidia
•Flu-like symptoms: headache, fever, chest pain, cough
•Hepatosplenomegaly in children and infants
•In severe cases: respiratory distress, hypoxia – may require intubation, ventilation, steroid therapy
Chronic Pulmonary Histoplasmosis:
•Opportunistic infection in adults with centrilobular emphysema
•Rare in children
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Progressive Disseminated Histoplasmosis:
•Affects infants & immunosuppressed individuals•Infants <1 year & follows primary pulmonary histoplasmosis•Fever = most common
= last for weeks to months•Hepatosplenomegaly, anemia, thrombocytopenia
Diagnosis:•Culture of bronchoalveolar lavage fluid•Culture of blood = >90% patients with progressive disseminated histoplasmosis
Treatment:•Amphotericin B = DOC•Ketoconazole•Itraconazole
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MUCORMYCOSIS:
•Characterized by vascular invasion, thrombosis and necrosis
•Rhinocerebral and pulmonary infections – inhaled spores
•Occur in patients with leukemia, DM, Fanconi’s anemia
•Headache, retro orbital pain, fever, nasal discharge
•Nasal discharge = dark & bloody
•Nasal mucosa = black with necrotic areas
•Brain abscess may occur
•Pulmonary mucormycosis: fever, tachypnea, productive cough, pleuritic chest pain, hemoptysis
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Diagnosis:
•Culture
•Histology
Treatment:
•Amphotericin B (1-1.5mg/k/24 hrs to a total dose of 70 mg/kg)
•Extensive surgical debridement