Common Clinical Presentations of Parasitic Infections

Transcription

1 Common Clinical Presentations of Parasitic Infections Hepatosplenomegaly Enlarged lymph nodes Anaemia Dysentery Parasites causing this clinical presentation How did the parasite produce this presentation (Pathogenesis) Mode of infection

2 A child presenting with hepatosplenomegaly Helminths causing hepatosplenomegaly: Schistosoma Skin penetration by Furcocercous cercaria HOW? Schistosoma eggs that pass in the circulation as emboli to the liver cause hepatosplenomegaly

3 A child presenting with hepatosplenomegaly Protozoa causing hepatosplenomegaly: Leishmania infantum, Leishmania donovani, Leishmania chagasi Visceral leishmaniasis Trypanosoma b.gambiense, Trypanosoma b.rhodesiense Sleeping sickness Trypanosoma cruzi Chagas disease Promastigote Stumpy metacyclic trypanosomes

4 Taken by How can Leishmania cause hepatosplenomegaly? Via blood stream to Reticulo-endothelial cells present in human viscera Amastigotes multiply in skin macrophage Promastigotes Amastigotes Through the bite of female Phlebotomus injecting Promastigote stage with saliva When amastigotes enter reticulo-endothelial cells present in liver & spleen Hepatosplenomegaly occurs

5 How can African Trypanosomes cause Hepatosplenomegaly? How can American Trypanosomes cause Hepatosplenomegaly? Short stumpy metacyclic trypanosomes enter the site of bite with saliva of Glossina Polymorphic trypanosomes To blood stream To liver & spleen Hepatosplenomegaly occurs Short stumpy metacyclic trypanosomes contaminate skin abrasion by winged bug faeces C-shaped Trypanosoma cruzi amastigote

6 Parasites causing Enlarged lymph nodes Helminths affecting lymph nodes: W.bancrofti Usually affects lymph nodes draining genitalia & lower limbs Brugia malayi Usually affects lymph nodes draining legs below knees & arms below elbows O.volvulus Hanging groin containing enlarged lymph nodes

7 Enlarged lymph nodes Protozoa affecting lymph nodes: Leishmania infantum, Leishmania donovani, Leishmania chagasi Visceral leishmaniasis Trypanosoma b.gambiense, Trypanosoma b.rhodesiense Sleeping sickness Trypanosoma cruzi Chagas disease Winterbottom sign Toxoplasma gondii Toxoplasmosis

8 Anaemia Decrease in number of RBCs below 4 millions / ml Helminthic infections causing anaemia: a- Schistosomiasis b- Trichuriasis c- Ancylostomiasis Iron deficiency: Due to blood loss d- Diphyllobothriasis Megaloblastic: Due vit B12 deficiency Schistosomiasis Due to hypersplenism Trichuriasis Due to toxic products of the worm Blood in urine Blood in stool

9 Protozoal infections associated with anaemia Malaria: haemolytic anaemia due to rupture of infected red cells. Babesiosis: haemolytic anaemia due to rupture of infected red cells. merozoites Sleeping sickness: Polymorphic trypanosomes hypoplastic anaemia due to bone marrow affection. Leishmania amastigotes Visceral leishmaniasis:

10 Mode of Infection with Schistosoma Skin penetration by furcocercous cercaria from contaminated canal water. Aided by: - Surface tension of drying droplets of water. - Proteolytic enzymes secreted by penetration glands. Proteolytic enzymes - Strong lashing movement of the tail pressing the body of the cercaria into the skin.

11 Mode of infection with T.trichiura D.latum A.duodenale Ingestion of embryonated eggs in contaminated raw vegetables and contaminated water. ingestion of plerocercoid larva in improperly cooked infected salmon, Perch or Trout fish Skin penetration by filariform larvae Negative geotropism Positive hygrotropism Thermotropism

12 Mode of infection with Malaria Babesiosis Through the bite of female Anopheles injecting sporozoite stage with saliva Through the bite of Hard Tick injecting sporozoite stage with saliva

13 Mode of infection with Visceral leishmaniasis Sleeping sickness Through the bite of female Phlebotomus injecting Promastigote stage with saliva Through the bite of Glossina injecting short stumpy metacyclic trypanosomes

14 A patient presenting with Dysentery Painful frequent evacuation of small quantities of stool containing mucus tinged with blood. This indicates that the large intestine is affected Parasites causing dysentery: 1- Schistosoma mansoni. 2-Trichuris trichiura. 3- Strongyloides stercoralis (heavy infection). 4- Entamoeba histolytica. 5- Balantidium coli. 6- Leishmania (visceral) 7- P.falciparum

15 How can helminths cause Dysentery 1- Schistosoma mansoni 2- Trichuris trichiura 3- heavy infection with Strongyloides stercoralis Egg pass in stool with mucus and blood Anterior part of worms embedded in intestinal mucosa cause oedematous, hyperaemic, fragile mucosa. stool with mucus & blood Number of worms increase and fill the small and large intestine stool with mucus & blood

16 How Entamoeba and Balantidium cause Dysentery Balantidium trophozoite Entamoeba trophozoite Boring action of cilia Histolytic enzyme Flask-shaped ulcer Flask-shaped ulcer

17 How can Leishmania cause Dysentery? Via blood stream to Amastigotes multiply in skin macrophage Taken by Reticulo-endothelial cells present in human viscera Promastigotes Amastigotes When amastigotes enter payer s patches of Intestinal mucosa: Diarrhoea & dysentery occur

18 How can P.falciparum cause Dysentery? Knobs develop on surface of infected RBCs Knobs are parasite antigens expressed on the surface of infected red cells containing trophozoites and schizont stages. Infected RBCs adhere to receptors found on endothelium of blood capillaries of intestine Normal RBC Diminished blood supply to intestine necrosis of intestinal wall cause dysentery. Infected RBC

19 Mode of infection with Trichuris trichiura Strongyloides stercoralis Ingestion of embryonated eggs in contaminated raw vegetables and contaminated water. Skin penetration by filariform larvae Negative geotropism Positive hygrotropism Thermotropism

20 Mode of infection with Entamoeba histolytica Balantidium coli Ingestion of quadrinucleate cyst Ingestion of cyst - In contaminated raw green vegetables and contaminated water. - Through flies and food handlers. - By faeco-oral route (hand to mouth). This is called autoinfection.

21 Mode of infection of Visceral Leishmania Falciparum malaria Through the bite of female Phlebotomus injecting Promastigote stage with saliva Through the bite of female Anopheles gambia injecting sporozoite stage with saliva

22 Case A female patient went to dermatology clinic suffering from skin lesion. On examination, the doctor noticed a skin ulcer with sharp edge and indurated margin The patient gave a history of an arthropod bite. a- What is your provisional diagnosis? A case of Cutaneous leishmaniasis b- How can you confirm your diagnosis? Amastigotes at edge of ulcer microscopy culture, c- How can you manage such condition? skin test serological tests Pentostam I.M., Physical, chemical methods, ID injection of interferon gamma of ulcer

23 Case A young Egyptian arriving from Jordan where he was working as a laborer and living in campus. He has a chronic ulcer on his arm with sharp-cut edge that resist treatment by known antibiotics. a- What is your provisional diagnosis? Cutaneous leishmaniasis. b- How can you confirm your diagnosis? By microscopy, culture, skin test or serological tests. c- How can you manage such case? Pentostam I.M. and surgical or chemical treatment for ulcer. d- How can you control such infection? Treat patients, protect the healthy, control of sandfly.

24 Case A newly born baby was born with Hydrocephalus, convulsions and fever. His mother gave a history of having a cat at home a- What is your provisional diagnosis? Congenital toxoplasmosis. b- How was the baby infected? Tachyzoites from infected mother crossed the placenta and infected the foetus. c- How can you confirm your diagnosis? By serology: Detection of anti toxoplasma IgM antibodies in baby s blood.

25 Case A pregnant female attending an outpatient clinic for pregnancy follow up حمل) (لمتابعة was asked to do some investigations. Among these was testing for IgG anti- Toxoplasma antibodies that proved to be positive. a- How would the doctor proceed? The doctor should repeat the test after 2 weeks. b- How would the doctor interpret the results if: i- The titer remains the same ii- There is rising titer Treatment is not indicated Treatment is indicated c- Mention other immunoglobulin classes that are of value to the diagnosis. Detection of IgM anti-toxoplasma antibodies d- If treatment is indicated, what drug would you prescribe? Spiramycin is the indicated drug