Lect 2 GH - Microorganisms in PB

What are 4 blood borne org's that may be encountered in PB?
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How many org's are expected per RBC?1, 2 or 4Why is a blood smear review important, even when other causes of anaemia are obvious?Bc it underscores that babesiosis can be a cause of post - HSCT anaemia * Haematopoietic stem cell transplantationCase study: - Underwent HLA-matched unrelated donor HSCT with ABO incompatibility - 14 months post HSCT he presented with fever, headache, malaise, profound anaemia - Lactate dehydrogenase elevated - Bilirubin elevated - Haptoglobin low - Direct antiglobulin test was negative - Non immune haemolytic anarmia - Intraerythrocyte ring forms - Maltese cross formsBabesia microtiWhat 3 antibiotics used for 6 weeks - for B. microti infection?1. Doxycycline 2. Clindamycin 3. AtovaquoneWhat does sleeping sickness refer to?African trypanosomiasisWhich two Trypanosoma organisms are responsible for causing sleeping sickness aka. African trypanosomiasis?1. T.b. gambiense 2. T.b. rhodesiense (?)Which species is responsible for causing >98% of cases of sleeping sickness aka. African trypanosomiasis?T.b. gambienseHow is African trypansomiasis transmitted?Tsetse fly (Glossina spp)Chronic and intermittent fever, headache and lymphadenopathy are the leading signs of the first stage of?African trypanosomiasisWhat happens in the first and second stage of African trypanosomiasis aka. seeping sickness?1st: Trypanosomes multiply in subcutaneous tissues, blood and lymph causing fever, headaches, joint pain, itching 2nd: Parasites cross blood-brain barrier to CNS causing behaviour changes, confusion, sensory disturbances, poor coordinationWhat are the infective and diagnostic stages in African trypanosomiasis?Infective: 1 (Tsetse fly injects metacyclic trypomastigotes) Diagnostic: 4 (Trypmastigotes in blood)Case study: - 49, female - 2 week holiday to Spain, Tanzania - Presented with malaise, fatigue, arthralgia, high fever - Anthropod bite - Thrombocytopenia ( 55 x 10^9/L) - Treated with IV suramineT. rhodesienseWhat causes American trypanosomiasis aka. Chagas' disease?Infection with T. cruziOne way T. cruzi can be transmitted is by the Reduviidae by. What is the subfamily?TriatominaeWhat are 5 other way T. cruzi can be transmitted?1. Food contaminated with triatomine bug faeces 2. Blood infusion from infected donor 3. Infected mother to newborn during childbirth 4. Organ transplant from infected donor 5. Lab accidentsChagas' disease presents in 2 phases, the acute and chronic. What happens in each?Acute: Lasts 2 months post infection, high number of parasites in circulating blood, most patients are symptomatic Chronic: ~30% pt's suffer cardiac disorders, ~10% pt's suffer from digestive, neurological or mixedIn the chronic phase of American trypanosomiasis, ~10% pt's suffer from digestive alterations. How does this present?Enlarged oesophagus or colonWhat are the infective and diagnostic stages in American trypanosomiasis?Infective: 1 (Triatomine bug passes trypmoastigotes in faeces, trypomastigotes enter bite wound or mucosal membranes) Diagnostic: 4 (Intracellular amastigotes transform into trypomastigotes, then burst out of the cell and enter the bloodstream)What organism is easily damaged by the spreading of specimens in thick films?Trypanosoma cruziWhat are the 3 species causing Trypanosomiasis?1. Trypanosoma brucei gambiense 2. Trypanosoma brucei rhodensiense 3. Trypanosoma cruziWhich two Trypanosoma species cannot be distinguished from each other? Describe themT. b. gambiense and T. b. rhodesiense - 13 to 42 uM long with single flagellum - Central nucleus - Small dot like kinetoplastHow does Trypanosoma cruzi differ from T.b.gambiense and T.b.rhodesiense?T. cruzi measures 12-30 uM and has a larger kinetoplast than T.b.gambiense and T.b.rhodesienseA concentration technique for Trypanosomiasis diagnosis is the quantitative Buffy coat method. After centrifugation what happens?The capillary tube is left to stand upright for 5 min before the plasma interface area is examined for motile trypomastigotesWhy should care be taken when handling samples suspected of being infected with trypomastigotes?Because an infection can occur if the organisms penetrate the skinWhat are the following traits characteristic of? 1. More microbiological i.e. characterised by micro methods 2. Can be visualised on blood smear 3. 'Free' or phagocytosed 4. May affect automated analysis of sample (e.g. individual bacteria wrongfully classified as platelets, clumps of fact may be misclassified as leukocytes)BacteraemiaCase study: - 66 yrs, male, diabetic - Presented with breathlessness, vomiting, fever - Initial FBC -> Hb 135g/L, platelets 155 x 10^9, WBC's 18.3 x 10^9L - After 6 hrs -> Hb 44g/L, platelets 39 x 10^9, WBC's 20.4 x 10^9 - D-dimer assay 35,857 ng/mL (<250) - Fibrinogen 0.3 g/L - INR 3.6 - Supports disseminated intravascular coagulopathy - Blood serum turned black secondary to haemolysis - PB showed microspherocytes with erythophagocytosis and Thrombocytopenia - Neutrophils showed left shift, vacuolation and identified with intracytoplasmic bacillus - Blood samples cultured an isolate of what organism?Clostridium perfringens - secretes alpha-toxin that has phospholipase activity and can induce massive haemolysisCase study: - 78 yrs, female, ascites (fluid collects in abdomen) - Presented with weakness, loss of appetite, fever, chills - PB showed neutrophilia with left shift (promyelocytes 0.3 x 10^9L, myelocytes 1.9, metamyelocytes 2.2, band neutrophils 2.2, segmented neutrophils 19.7) - Distorted granulocytes containing toxic vacuoles and intracellular uniform rod-shaped structures suggestive of phagocytised bacilli - What did blood cultures suggest? (2 species of bacillus)Klebsiella pneumonia Psedomonas aeruginosaCase study: - 38 yrs, female, arsenic trioxide consolidation for acute promyelocytic leukemia - Giemsa stained blood review showed small dark purple rods in ~15% of neutrophil granulocytes, extracellular bacteria forming chains - Gram stain confirmed presence of Gram-negative bacteria - Blood confirmed diagnosis of catheter-related bacteraemia due to what?Enterobacter aerogenesApart from undetermined ehrlichiosis/anaplasmosis, what are 3 other bacteria that specifically infect leukocytes? (i.e. that's the distinguishing factor)1. Anaplasma phagocytophilum 2. Ehrlichia chaffeensis 3. Ehrlichia ewingiiWhat organism causes the disease Anaplasmosis aka. Human Granulocytic Ehrlichiosis (HGE)?Anaplasma phagocytophilumHow is Anaplasma phagocytophilum (HGE) transmitted?Tick borne transmission - Amblyomma spp, Ixodes sppThe following changes can be seen PB, what organism is responsible for this? - Lymphopenia - Thrombocytopenia - Inclusions with granulocytes - Morulae (aggregates of organisms) - May be present in small number of cells (~0.1% granulocytes)Anaplasma phagocytophilum - AnaplasmosisWhat does morula (e) refer to?Aggregates of organismsThe following changes were observed in BM. What is responsible for this? - Myeloid hyperplasia - Megakaryocytic hyperplasia - Reactive histiocytosis - Lymphohistocytic aggregates - Granuloma - Haemophagocytic syndrome has been reportedAnaplasma phagocytophilum. As Erhlichia chafeensis shows myeloid, trilineage hypoplasiaWhat is the difference between HME and HGE?HGE - Refers to Anaplasma phagocytophilum HME - Refers to Ehrlichia chaffeensisHow does one distinguish Erhlichia ewingii from Erhlichia chaffeensis?Impossible to distinguish E. eringii from E. chaffeensis infections just based on clinical signs. Molecular - based tests are required.Case study: What organisms is responsible? - 63 yrs, female - Presented with fever, confusion, dysarthria (slurred speech), thrombocytopenia (26 x 10^9/L), mild transaminitis 2 weeks post tick bite - PB smear showed morulae inside neutrophils - Patient responded to IV doxycyclineHGE - Human Granulocytic Erhlichiasis - Anaplasma phagocytophilumCase study: What organism is responsible? - 64 yrs, male - Presented with hypotension, respiratory failure, low grade fever for 3 weeks, cough, fatigue, intermittent sweats, chronic diarrhoea, headache - Recent multiple tick exposure - WBC: 19.27 x 10^9/L, 84% neutrophils and 14% bands - Most of the granulocytes contained intracytoplasmic inclusionAnaplasma phagocytophilum5 spirochaete bacteria:1. Borrelia burgdorferi 2. Borrelia hermsii 3. Borrelia recurrentis 4. B. parkerii 5. B. turicataeWhat is spirochaete bacteria causes Lyme disease?Borrelia burgdorferiWhat is spirochaete bacteria causes relapsing fever?Borrelia hermsiiWhat spirochaete bacteria causes louse-borne relapsing fever?Borrelia recurrentisIf a patient presented with relapsing fever, headaches, myalgia, arthralgia and chronic fatigue. What would you expect to be responsible?Lyme disease - Borrelia burgdorferiWhat would you expect to find in a PB smear for Borrelia burgdorferi, the organism responsible for Lyme disease? Hint: BM shows lymphoid hyperplasia and epithelioid granulomas1. Normocytic anaemia 2. Thrombocytopenia 3. Leukocytosis 4. Spirochaetes (most likely to be present during febrile episodes)What would you expect to see in a BM sample showing Lyme disease (Borrelia burgdorferi)?1. Lymphoid hyperplasia 2. Epithelioid granulomasCase study: What is the organism? - 49 yrs, female, healthy - Presented with headache, fever to 103F (39C), mild myalgia (muscle pain), heart rate 119 bpm, BP 80/40 - WBC: 12.5 x 10^9/L (mild leukocytosis with left shift) - PB smear showed spirochetes - Treated with ciprofloxacin and made full recoveryBorrelia hermsii - confirmed via serological testing positive IgG antibodiesThere is an ongoing debate about the presence of what disease in Australia? What is it caused by?Lyme disease - Borrelia burgdorferiInfants and immunocompromised individuals are at higher risk of systemic disease caused by what kind of infection?Fungal infection - fungaemiaWhat are 3 main species that cause fungaemia?1. Candida sp. 2. Cryptococcus neoformans 3. Histoplasma capsulatumWhat is found in PB - fungaemia?Intracellular organisms (neutrophils, monocytes) and extracellular 'free' organismsWhat causes the following to be found in BM? 1. Granulomas 2. Lymphohistocytic aggregates 3. Diffuse histiocytic infiltrates 4. Haemophagocytic syndrome reportedFungaemiaCase study: What is responsible for this? - 77 yrs, female, IgA multiple myeloma MM, neurological symptoms - Mild anaemia (Hb 105 g/L) - WBC (7.8 x 10^9/L) - Lymphopenia (0.15 x 10^9/L) - Severe thrombocytopenia (41 x 10^9/L) - BM aspirate showed no signs of dysmegakaryopoiesis or plasma cell invasion, several histiocytes with intracellular encapsulated bodiesDisseminated cryptococcosis caused by Cryptococcus neoformansWhat are two methods fungal cells may be confirmed? What sample is used?1. India ink stain 2. Cryptococcal antigenemia test - Cerebrospinal fluid sampleIn cases involving Nematoda, what may be observed in the PB?Larval stages of filaroid nematodes i.e. nematode larvaeWhat are the 6 main species of nematodes?1. Wuchereria bancrofti 2. Brugia malayi 3. Brugia timori 4. Loa loa 5. Mansonella perstans 6. Mansonella azzardiHow are nematodes transmitted?Via infected mosquitoes or infected Chrysops fliesHow are Wuchereia bancrofti, Brugia malayi, Brugia timori nematode species transmitted?Infected mosquitoHow are Loa loa nematodes transmitted?Infected Chrysops flyWhat comment can be made for Mansonella Perstans?Extends to tip of blunt tailWhat comment can be made for Mansonella ozzardi?Doesn't extendWhat does nocturnal periodicity refer to?- Microfilariae of Wuchereria and Brugia exhibit nocturnal periodicity - Samples collected at night are more accurate (10pm to 2am)How are nematode infections diagnosed?Detected using immunoassay for circulating filarial antigens. Blood samples collected at any time of the day.How is lymphatic filariasis diagnosed?Identification of microfilariae in thick and thin blood smears that have been Giemsa stainedWhy is an immunoassay for circulating filarial antigens instead of microfilariae more preferred method of Nematoda detection?Sensitivity for detection of microfilariae can be low and variable and filarial antigens can be detected in blood samples at any time during the day unlike microfilariae with nocturnal periodicityWhat are 4 methods of microfilariae detection?1. Capillary tube detection 2. Quantitative Buffy coat and microhaemtocrit methods 3. Microscopy 4. MorphologyIn Nematoda microscopy, where are the organisms usually found in smears? *They're large organisms so can be visualised at low magnification x 10)Towards the leading edge of THIN blood filmWhat is the size difference in Wuchereria bancrofti and Brugia spp?Wucherer bancrofti: 250 uM Brugia spp: 200 uMWhat are some morphology features used to identify microfilariae? (3 points)1. Sheath 2. Cephalic space 3. Arrangement of nuclei in tail i.e. column of caudal nucleiCase study: What was he diagnosed with? What organism was identified? - 25 yrs, male, Indian (Mumbai), 5 months post arrival in Singapore - Presented with fever, myalgia for 5 days - WBC: 5.21 x 10^9/L (3.4 - 9.6 x 10^9/L) - Hb: 139 g/L - Platelets: 24 x 10^9/L - Parasitic load: P.vivax trophozoites - Treated with 1 dose of ivermectin (12 mg) and docycline (100 mg) twice a day for 6 weeksDiagnosed with microfilaremia - Wuchereria bancrofti