Lecture 50 - 3rd Asessment - Protozoan

Learning Objectives Important Protozoan Infections  Must Know: 

Importance to Kuwait



Diagnostic & Infectious stages

Mode of Transmission  Pathology & Clinical Presentation 





Laboratory Diagnosis



Prevention

Should Know: 

Principles of Management/ Prophylaxis

IQBAL @HSC.EDU.KW

PROTOZOA  Unicellular, occur singly/ colony Encyst to survive outside body infective stage

mode of transmission

 Reproduce actively fission]

 Transmission:

[binary

Important Protozoan Infections  G I Infection Amoebiasis Giardiasis

[Entamoeba histolytica] [Giardia lamblia]

 Sexually Transmitted Infection Trichomoniasis [Trichomonas vaginalis]

 Opportunistic Infection Cryptospridiasis

[Cryptosporidium

Important Protozoan Infections  G I Infection Amoebiasis [Entamoeba histolytica] Giardiasis [Giardia lamblia] Sexually Transmitted Infection Trichomoniasis [Trichomonas vaginalis]  Opportunistic Infection Cryptospridiasis [Cryptosporidium sp.]

Important Protozoal Infections  Vector Borne Infections Malaria [Plasmodium sp.] Leishmaniasis [Leishmania sp.] Zoonotic Infections Toxoplasmosis [Toxoplasma gondii]

Clinical Case# 1 • A 12-year old Indian boy presented at outpatient with fever, acute abdominal pain & diarrhea for 6 days • He was passing loose stools 4 - 5 times/day • There was mucus and sometimes blood in the •Hestool visited India a month ago with his family

His elder brother who works in a cafeteria shop also esented with the same symptoms for 2-3 days but e symptoms were mild

Clinical Queries • • • •

What is your provisional diagnosis? What’s the etiological agent of this infection? How did he get the infection? What’s the significance of travel to India? • How would you diagnose this infection? • How would you manage this patient? Why his brother presented with mild symptoms?  Should his brother resume his work at the restaurant?  Can this patient or his brother transmit infection to others?

Amoebic Infection   Strains: 





Entamoeba histolytica Entamoeba coli

Pathogenic Nonpathogenic

Dientamoeba fragilis

Pathogenic (mild)

“ Nonpathogenic strains are known as E. dispar ” All except E. gingivalis live in the large intestine 

Free living Amoebae:   Acanthamoeba sp.

Naegleria fowleri

Entamoeba histolytica Infection:



 

700 ­ 850 million  

Symptoms: 75 ­ 100  million  (colitis/ liver abscess) Deaths: 50­110,000 Invasive Strains: India, Indonesia, Mexico,  S. Africa

High Risk Groups:   

Institutionized individuals (20 ­ 70%) Immigrants Immunocompromized

Entamoeba histolytica   

Prevalence very high in Tropics Mode of transmission: Feco-oral; Contaminated food/ water Infective Stage:Cyst ….. Excystation in Duodenum Diagnostic Stage: Cyst and Trophozoite

Trophozoite 

Cyst, E. histo

Cyst, E. coli

Microscopy of Stool Smear Habitat: Wall & lumen of Large intestine

E. histolytica      Trophozoite

Microscopy of Stool Smear:  Cysts                Iodine Trichrome staining

       E. histolytica

     E. coli        

Amoebiasis Pathogenesis Approx. 10 cysts can produce infection 

Factors:  Intestinal flora  Diet: Carbohydrate diet facilitates invasion  Host immunity  Strain virulence

Amoebiasis Pathogenesis 

Mechanism:  Role of galactose-specific lectin receptors

Role of pore-forming proteins  Proteolytic enzymes  Activation of alternate complement pathway

Amoebiasis Pathology 

Enteritis



Ulcers



Peritonitis



Amoeboma



Hepatic abscess

Flask shaped

Amoebiasis Pathology



Peritonitis



Amoeboma



Hepatic abscess

Clinical Case 2 • A 39-Year old Kuwaiti presented at outpatient with fever & pain in the Right hypochondrium 2 weeks. • He has no diarrhea • His general condition is fine but has lost some weight 2 Months ago: • He visited Mexico 6 months ago • He had diarrhea with mucus & blood • There was no nausea or vomiting

Amoebic Abscess

Investigation

Ultrasound: A cystic lesion in the Right lobe of liver. Differential Diagnosis: Hydatid cyst Amebic abscess Pyogenic abscess Secondaries

Amoebic Abscess Investigation

Amoebic Abscess Investigation    Aspirate:  viscid chocolate, reddish colored              Anchovy sauce    Microscopy:      Fresh specimen                 Degenerated liver cells, RBCs

    No Neutrophils  No pathogen is seen on Gram’s stain

           

Investigation

 

I. Stool Exam    II. Serology         III. Ultrasound

                                   

      I. Stool Exam:

 

Direct Stool Exam:  Loose,  mucus with blood.

             

       Microscopy:     Trophozoites :      Acute cases                         

                  Cysts

         Carriers

Investigation III. Ultrasound:   Necrotic hepatoma           Pyogenic liver abscess           Hydatid cyst  

 

       

•

Additional Tests:    Isoenzyme characterization PCR

Management   Tissue infection:

Adult

Child

Ist Choice: Metronidazole  or  Tinidazole

750 mg

50/mg/kg/d

x 10d

2g/d

60mg/kg/d

x 3d

30mg/kg/d

30mg/kg/d

x 10d

20mg/kg/d 30mg/kg/d

x 10d x 10d

30mg/kg/d

x 10d



2nd choice: Paromomycin

Luminal carriage:

 

Ist choice: Diloxanide furoate 500mg 2nd choice: Paromomycin 30 mg/kg/d or Iodoquinol 650 mg tid

Clinical Queries • • • •

What is your provisional diagnosis? What’s the etiological agent of this infection? How did he get the infection? What’s the significance of travel to India? •How would you diagnose this infection? •How would you manage this patient? Why his brother presented with mild symptoms?  Should his brother resume his work at the restaurant?  Can this patient or his brother transmit infection to others?

Amoebiasis

(E. histolytica)

Prevalence very high in tropics

•Mode of Transmission: –

Feco-oral

- Contaminated food/ water

Cyst is the infective stage •Pathogenesis: –

Proteolytic enzymes/ Toxins

- Lysis of macrophages

•Pathology: –

Flask shaped ulcers in large intestine

–

Amoeboma,

Peritonitis,

Hepatic abscess

•Presentation: - Carriers

- Mild diarrhoea

- Bloody mucoid diarrhoea

- Abscess

•Diagnosis: - Microscopy [Trichrome staining] •Prevention: Improved personal hygiene

- Serology

You must yield the right-of-way to an approaching vehicle when you are: 1 Already in a traffic circle. 2 Already in an intersection. 3 Going straight ahead. 4 Turning left.

Free Living Amoebae Naegleria fowleri Trophozoite: Amaeboid and flagellate; motile; Infective Cysts: Round; single nucleus; thick double wall Association with water: soil; lakes, ponds, coastal water, fresh water, sewage, Pathogenesis: Acute, H/o swim • through olfactory mucosa • submucosal nerve plexus to CNS

Free Living Amoebae Naegleria fowleri Pathogenesis: Primary Amaebic Meningoencephalitis (PAM) Predisposing Factors: Healthy Pts; Contact with water (H/O swim) Portal of Entry: Olfactory neuroepithelium Incubation Period: 1-15 days; Fatal in 98% Pathology: Necrosis of cortex, Olfactory Bulbs & base of brain

Diagnosis: History: CSF: Examine wet mount (motile trophozoite) IFA:

Treatment: Amphotericin B

Free Living Amoebae Acanthamoeba sp. Trophozoite: Amaeboid and flagellate; motile; Infective Cysts: Thick double wall, outer wall wrinkled Association with water: Bottled mineral water, coastal Fresh tap water, Contact lens wash solution Clinical Diseases: I. Granulamatous amebic encephalitis (GAE) (chronic, no H/o swimming, H/o trauma)

II. Keratitis:

Keratitis, uveitis, corneal ulceration

Free Living Amoebae Acanthamoeba sp. Predisposing Factors: Immunodeficient Pts; AIDS, Chronic Diseae Portal of Entry: Lungs, Skin Incubation Period: Weeks to months; Fatal in 100% Pathology: Multiple necrotic foci in brain

Diagnosis: Direct smears, Cultures of corneal scrapings Stain with Giemsa and Gram.

IFA: Treatment: Prevention:

Clotrimazole, Pentamidine are effective. Amphotericin B is ineffective; Use Ketoconazole

Chlorination of water

Clinical Case •A young boy presented with redness, irritation and watering of Right eye for 7 days • His condition deteriorated and his vision became blurred •The culture of Eye-swab was negative for microorganism •He was advised to use antibiotic eye drops •He has been using contact eye lens since 1 year

Clinical Case 6 weeks later: •The condition of his eye deteriorated further and his vision became blurred •Corneal ulcers developed

Amebic keratitis

You come to an intersection which is blocked by other traffic. You should: 1 Go slowly until the traffic ahead moves. 2 Get as close as possible to the other car. 3 Stay out of the intersection until you can pass through 4 Sound your horn to make the cars move up.

Clinical Case A young boy presented with loose fatty stools alternating with constipation for One month  He is not eating well and he has lost 7 Kg  There is no mucus or blood in the stools Important Points: * Young boy, loose fatty stool with constipation

Giardiasis       Giardia lamblia Prevalence very high in Tropics  



Mode of transmission: Feco-oral; Contaminated food/ water Infective Stage: Cyst ….. Excystation in Duodenum Diagnostic Stage: Cyst and Trophozoite

Trophozoite 

Cyst, G. lamblia

Microscopy of Stool Smear         Iodine Trichrome staining

Trophozoite 

Cyst, G. lamblia

Pathogenesis

Uptakes pancreatic bile salts & thus interferes with pancreatic lipase

Giardiasis

Pathology

An Alkaline pH & a rich –CH diet favors multiplication





Mechanical damage of villi 

Malabsorption



Fatty diarrhea

Chemotherapy: Quinacrine HCl

Clinical Case A young female presented with vaginal discharge for >5 days The discharge is foul smelling & whitish Microscopy of the discharge showed motile flagellate organism Important Points: * Foul smelling vaginal discharge * Motile flagellate organism on microscopy

Trichomoniasis

Trichomonas vaginalis

Prevalence high in Young Women  Mode of transmission: Sexual  Infective & Diagnostic Stage: Trophozoite               There is No Cystic Stage

   Both partners must be treated by Metronidazole

Case Presentation •A Renal transplant patient on immunosuppressive therapy presented with acute profuse greenish watery diarrhea of 5 days duration. •There is no nausea or vomiting •He lost Points: 7 Kg of weight in one week Important * Patient on immunosuppressive therapy

Cryptosporidiosis

Cryptosporidium sp.

Causes profuse greenish watery diarrhoea Associated with Immunocompromized patients Mode of transmission: Feco-oral, contaminated water  Infective & Diagnostic Stage: Oocyst [4-5 µ]  Special Staining: Acid fast stain (Safranin-Methylene Blue)

 Management: Improve hygiene Rehydration Nitazoxanide/ Paromomycin              

Cryptosporidium sp.

Cryptosporidium sp.

Pathogenesis

Cryptosporidiosis Pathology 

Cellular infiltration of lamina propria



Mechanical damage of villi



Watery diarrhea

Cyclosporiasis

Cyclospora sp.

Causes profuse watery diarrhoea Associated with Immunocompromized patients   

Mode of transmission: Feco-oral, contaminated water Infective & Diagnostic Stage: Oocyst [8-10 µ] Special Staining: Acid fast stain (SMB) Oocysts don’t stain uniformly

 Management: Improve hygiene Rehydration Trimethoprim-sulfamethoxazole [Septrin 2 BDx7d]             

Cryptosporidium sp. and Cyclospora sp.

Cryptosporidium sp.

Cyclospora sp.

Children under age ___ must be secured in an approved child safety seat. Six Three Five Four

Waterborne Protozoan Pathogens

• Naegleria fowleri • Acanthamoeba spp. • Giardia lamblia • Entamoeba histolytica • Cryptosporidium parvum • Cyclospora sp.

Protozoan Infections Causing Diarrhea

• Entamoeba histolytica

Blood/mucus

• Dientameba fragilis

Mild

• Giardia lamblia

Fatty, No blood

• Balantidium coli

Blood/mucus

• Cryptosporidium parvum Greenish watery • Cyclospora sp. Watery

Amoebiasis

(E. histolytica)

Prevalence very high in tropics

•Mode of Transmission: –

Feco-oral

- Contaminated food/ water

Cyst is the infective stage •Pathogenesis: –

Proteolytic enzymes/ Toxins

- Lysis of macrophages

•Pathology: –

Flask shaped ulcers in large intestine

–

Amoeboma,

Peritonitis,

Hepatic abscess

•Presentation: - Carriers

- Mild diarrhoea

- Bloody mucoid diarrhoea

- Abscess

•Diagnosis: - Microscopy [Trichrome staining] •Prevention: Improved personal hygiene

- Serology

Giardiasis

G. lamblia

Prevalence very high in tropics

Mode of transmission – Feco-oral route – Infective stage:

Pathogenesis:

- Contaminated food/ water Cyst

secreting proteolytic enzymes/ toxins ?

mechanical damage of villi

Pathology: Presentation: Diagnosis: Prevention:

Microvilli damage, Carriers, Microscopy

Malabsorption

Fatty diarrhoea [Trichrome staining]

Improved personal hygiene

Trichomoniasis

T. vaginalis

Prevalence high in young women Mode of transmission: sexual intercourse NO cyst stage is present

Pathogenesis: Pathology: Presentation:

Proteolytic enzymes/ toxins ? Multiple small ulcers on vagina/urethra Frothy foul smelling vaginal discharge Itching/ irritation,

Diagnosis: Prevention:

Males are asymptomatic

Microscopy; Motile trophozoites Treat both partners

Cryptosporidiosis

C. parvum

Immunocompromised patients: 

Mode of transmission:



Pathogenesis:

associated with AIDS

Feco-oral, contaminated food/ water

Proteolytic enzymes/ toxins ? Cellular infiltration of lamina propria



Pathology:

Villous atrophy



Presentation:

Majority asymptomatic,

Outbreaks

Profuse greenish watery diarrhoea 

Diagnosis:

Microscopy of stool smear with SMB stain IFA

(Oocysts)



Management:

Rehydration, Paromomycine



Prevention:

Good personal hygiene