Amoebiasis

a good presentation

1. AMOEBIASIS Jagadish Prasad Mishra 6 th semester

2. Learning Objectives Definition Epidemiology Epidemiological determinants Clinical presentation Diagnosis and further investigation Prevention and treatment

3. Amoebiasis Amoebiasis is an infection with the intestinal protozoa Entamoeba histolytica . About 90% of infections are asymptomatic Remaining 10% produce a spectrum of clinical syndromes

4. Amoebiasis

5. Epidemiology World Worldwide in distribution 3 rd most common parasitic death India, China, Mexico, Africa, South America 2-60% prevalence(based on ELISA and PCR studies from stool samples) 100,000 deaths/yr 500 million infections 50 million cases/yr Data-2007

6. Epidemiology India 15% prevalence (3.6-47.4%) Variation according to sanitation level and clinical diagnostic criteria

7. Epidemiological determinants Agent Virulence factor Host factor Environmental factor Mode of transmission Incubation period

8. Agents Entamoeba histolytica Trophozoites 18-40 μ m in D Cytoplasm – # outer clear ectoplasm # inner granular endoplasm # food vacuoles with RBCs, leukocytes & tissue debris Motile by pseudopodia extensions Nucleus with central karyosome , surrounded by delicate membrane lined with chromatin granules Non infectious

9. Agents Entamoeba histolytica Precyst Intermediate form Oval with blunt pseudopodia No food vacuoles Cysts Spherical, 10 - 15 μ m in D Uninucleate , later bi- or quadri - nucleate Thick chitinous wall Glycogen mass – not in quadrinucleate Chromidial or Chromatoid bars Infectious

10. Invasive x Noninvasive strains A zymodem comprises those Entamoeba strains that share the same electrophoretic pattern and mobility for certain enzymes like – malic enzyme, phosphoglucomutase , hexokinase , glucose phosphate isomerase , aldolase etc 24 different zymodems – 21 of human strains 7 pathogenic zymodems The invasive and non invasive strains may appear identical may represent two distinct species Invasive strain – E.histolytica (give rise to fecal cysts) Non invasive strains reclassified as E.dispar .

11. Agent factor Source of infection is a case or carrier -1∙5 X 10 7 cysts per day Reservoir is only human – several years Resistant to chlorine in normal conc. Readily killed by freezing or heating(55°C) Period of communicability- very long

12. Host factor People in developing countries that have poor sanitary conditions Immigrants from developing countries Travellers to developing countries People who live in institutions that have poor sanitary conditions HIV-positive patients Men who have sex with men All age groups affected No gender or racial differences Severe if children, old, pregnant, PEM Develops antiamoebic antibodies in tissue invasion

13. Host factor Liver abscesses due to amoebiasis are 10 times more frequent in adults than in children Amoebic liver abscess 7 times more in men than women Predominance among men aged 18-50 years Increased among postmenopausal women Hormonal effect and alcohol can be risk factors

14. Environment factor Low socio-economic status Poor sanitation, sewage contamination Night soil for agriculture Seasonal variation(more in rainy season)

15. Faeco - oral route Contaminated water and food D irect hand to mouth(cysts under finger nails) Vegetables irrigated with sewage polluted water Agency of flies, cockroaches, rats, etc. Sexual contact via oral-rectal route Modes of transmission

16. Incubation period 2- 4 weeks

17. Life cycle of E. histolytica Source:- medical-dictionary.com

18. Life Cycle of E. histolytica

19. Clinical presentation Most common type of amoebic infection is asymptomatic cyst passage Intestinal amoebiasis – abdominal cramps with mild diarrhea to colitis and dysentery Extra-intestinal amoebiasis – Amoebic liver abscess, rarely lungs, skin, genitalia and CNS are affected Amoeboma – inflammatory and edematous reaction around trophozoites

20. Clinical presentation Asymptomatic carriers 90% without symptoms does not damage lumen

21. How the Amoebiasis Manifests Most cases of amoebiasis have very mild symptoms or none. Wide spectrum, from asymptomatic infection to luminal amoebiasis and amoebic colitis Clinical symptoms are usually vague More severe infection may cause fever, profuse diarrhoea, vomiting, abdominal pain, jaundice, anorexia, and weight loss. Invasive intestinal amoebiasis (dysentery, colitis, appendicitis, toxic mega colon, amoebomas )

22. Clinical presentation Amoebic colitis- Abdominal cramp to severe pain Fever, vomiting, anorexia Mucus in stool, dysentery Flask shaped ulcer in intestine

23. <0.5% S everely ill with high fever Intestinal bleeding , perforation P aralytic illus CFR-40% Uncommonly, a chronic form of amoebic colitis can be confused with inflammatory bowel disease Clinical presentation Fulminant colitis-

24. Amoeboma Pseudotumoral lesion Necrosis, edema and inflammatory thickening of mucosa and submucosa of intestinal wall 1% of cases Palpable mass with trophozoites Always coexists with ulceration Single, rarely multiple in different parts of colon, on skin at site of amoebic liver aspiration

25. Difference between amoebic and bacillary dysentery Character Amoebic dysentery Bacillary dysentery Number 6-8 motions per day > 10 motions per day Amount Copious Small Odour Offensive Odourless Colour Dark red Bright red Reaction Acidic Alkaline Consistency Non-adherent Adherent Macroscopy

26. Difference between amoebic and bacillary dysentery Character Amoebic dysentry Bacillary dysentry RBCs In clumps Discrete or in Rouleaux Pus cells Few Numerous Macrophages Few Numerous, many have RBCs and may mimic EH Eosinophils Present Scarce Charcot-Leyden crystals Present Absent Pyknotic bodies Present Absent Ghost cells Absent Present Parasites Trophozoites of EH Absent Bacteria Many motile bacteria Few or Absent Microscopy

27. Metastatic lesions in liver Amoebic liver abscess- Most common extra-intestinal presentation The parasite reaches liver via portal system Occurs within 5 months of dysentery in 95% of cases But concomitant active diarrhea is seen in less than a third of cases Pain and point tenderness over right hypochondrium and fever Jaundice rare, pleural effusion is common

28. Amoebic liver abscess

29. Older pt. from endemic areas usually have chronic disease Right lobe is commonly affected, abscess of left lobe is more dangerous due to its proximity to heart –> rupture –> pericardial effusion Necrotic cavitary lesion filled with cellular debris and parasite trophozoites – Anchovy sauce pus Metastatic lesions in liver

30. Complications of ALA Rupture is the most dreaded complication It may spread to pleura, lungs, peritoneum, pericardium or open outside through the anterior abdominal wall

31. Pulmonary amoebiasis - Rupture from ALA into pleural space Hepato -bronchial fistula with necrotic material in sputum may mimic blood – trophozoites can be present Serous pleural effusion or contiguous spread from ALA Metastatic lesions in other organs

32. Metastatic lesions in other organs

33. Cerebral amoebiasis - Rare, complication of hepatic/ pulmonary abscess Single small lesion in cerebral hemisphere Cutaneous amoebiasis - In areas of drainage of liver abscess/colostomy wound Granulomatous ulcerations Metastatic lesions in other organs

34. Splenic amoebiasis - Amoebiasis of penis- Amoebic pericarditis - Rupture of liver left lobe abscess High fever, epigastric pain dyspnoea , pericardial rub Metastat ic lesions in other organs

35. Samples : Stool ( 3 consecutive samples) Biopsy material from the ulcers (colonoscopy or sigmoidoscopy ) Aspirate from liver abscess Serum Pleural fluid Pericardial fluid Sputum Laboratory diagnosis

36. Microscopy - Both saline and iodine wet mounts are prepared Any motile trophozoite is better seen in saline mount Iodine mount stains the internal structures and is used to identify cysts Charcot- leyden crystals can be seen Permanent stains can also be used to stain smears Laboratory diagnosis

37. Laboratory diagnosis For amoebic liver abscess and other metastatic lesions- Radiological examination Radio isotope tracing of liver Ultrasonogrphy of upper abdomen CT and MRI abdomen

38. Serology- Antibody detection ELISA IHA IFA Copro -antigen detection by ELISA is another recent and very useful method Antigen detection Coagglutination ELISA Laboratory diagnosis

39. Symptomatic case :- (amoebic colitis and amoebic liver abscess) Treatment

40. Luminal infections and -(with above) Treatment

41. Treatment Percutaneous radiography guided aspiration of abscess:- large left lobe liver abscess, bacterial superinfection , pyogenic abscess, pleuropulmonary amoebiasis , empyema , amebic pericrditis Simple aspiration of amoebic liver abscess

42. Asymptomatic cases and cyst passers- Treatment

43. Prevention 1.Primary prevention- a. Sanitation-safe disposal of human excreta, good sanitary practice like washing hands after defecation and before eating b. Water supply-water filtration(sand filters), boiling c. Food hygiene- prevent fecal contamination of food and drink, vegetables washed with aqueous acetic acid(5-10%) d. Health education- food handlers and public 2.Secondary prevention

44. Prevention 2. Secondary prevention- a. Early diagnosis b. Treatment

45. Contd … E. dispar is morphologically indistinguishable from E. histolytica and so is E. moshkovskii Most asymptomatic cases of amoebic infestation are believed to be one of these two species The other species are also non-pathogenic but can be microscopically differentiated

46. Summary Amoebiasis is an infection with the intestinal protozoa Entamoeba histolytica . About 90% of infections are asymptomatic Worldwide in distribution Infectious- cyst form Poor sanitation, sewage contamination Wide spectrum, from asymptomatic infection to luminal amoebiasis and amoebic colitis Invasive intestinal amoebiasis (dysentery, colitis, appendicitis, toxic mega colon, amoebomas ) Amoebic liver abscess- Most common extra-intestinal presentation Diagnosis by stool microscopy and other investigations Treatment tinidazole is prefered Prevention is good sanitary practice

47. Reference PARK’S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE PARASITOLOGY, K. D. Chatterjee HARRISON’S PRINCIPLE OF INTERNAL MEDICINE Medscape Wikipedia

48. Thank You