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HEMATOLOGY Hot Topics and Morphology BCSLS Telehealth Broadcast June 16, 2005 Kin Cheng...
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Transcript of HEMATOLOGY Hot Topics and Morphology BCSLS Telehealth Broadcast June 16, 2005 Kin Cheng...
CASE # 1
–76 year old female
–Previously well
–Acute back pain and vomiting after mowing the lawn
Physical (10:00 PM):
–Afebrile P-108; BP 139/69
–Alert and oriented but “deathly ill looking”
–Soft, non-tender abdomen with bowel sounds
MCHC >365
• Hematocrit: RBC x MCV
• MCH = Hgb / RBC
• MCHC = Hgb / Hct
• 3 x RBC = Hgb
• 3 x Hgb = Hct
MCHC >365 Handling
• Cold agglutinin : Warm sample
• Lipemic, icteric, hemolysed: Saline replacement
• Protein: Warm specimen, rerun
• Spherocytes
SPUN SAMPLE
Spun Hct: 0.11
Pre & Post Saline Replacement
Pre-replace
Post replace
WBC 9.2 R 7.4 R
RBC 2.94 1.01
Hgb 101 31
Platelets 324 100
Pre-saline
Post-saline
Hct 0.223 0.086
MCV 78.1 84.4
MCHC 453 359
Manual Differential
• Neuts: 5.0
• Lymphs: 2.7
• Eos: 0.1
• NRBC: 5 / 100 WBC
Agar Plate
Histogram
• Intubated at 01:30
• Hypotensive post-intubation
• ICU bed found at referral centre (04:00)
• Arrested in transit (04:30)
• Autopsy:
• green discoloration of skin with skin slippage and advanced organ autolysis
• No identifiable source of sepsis
Clostridial Gas Gangrene
• 6/150 species capable of causing gas gangrene
• Toxin and gas producing bacteria
• Lethal
• Necrotize soft tissues
• Clostridial myonecrosis: Common surgical infection if poor surgical technique
Clostridial gas gangrene
• Anerobic, gram pos bacilli (Hematology stain is NOT gram stain)
• Spore forming bacteria
• Found in soil, contaminated raw meat and poultry, normal skin, colon flora
Clostridial infection
• 80% caused by C. perfringens
• 20%:
– C. novyi
– C. septicum
– C. bifermentans
– C. histolyticum
– C. fallax
Clostridium perfringens (welchii)
• Produce 12 types of toxins (lecithinase)
• Extraordinary spectrum of clinical manifestations from transient bacteremia to gas gangrene or sepsis with hemolysis
• Rate of myonecrosis: 2 cm/hr• Fatal within 12 hours.
C. perfringens
• Introduction of bacteria into tissues
• Bacterial proliferation in low (<30%) oxygen environment
• Incubation period: 1 – 12 hrs
• Release exotoxin
C. perfringens
• >17 Exotoxins:
– Lecihinase
– Collagenase
– Hyaluronidase
– Fibrinolysin’hemolysin
C. perfringens
• Alpha toxin: lecithinase– Destroys red cell membranes, muscle cells,
platelets and WBC– Induces platelet aggregation and clot
formatioin
• Kappa toxin: destroys connective tissues
• Theta toxin: Destroys WBC and disarms inflammatory responses.
Clostridium spp
Clinical Illness Organism
Gas gangrene C. perfringens (80%)
Food poisoning C. perfringens
Antibiotic diarrhea C. difficile
Tetanus C. tetani
Botulism C. botulinum
C. perfringens
• Massive intravascular hemolysis
• Hb-emia, Hb-uria, hyperkalemia
• Renal failure, coagulopathy
• Often fully conscious with normal BP
• Shock and death 70-100% mortality
• Survival measured in hours
C. perfringens
• Elderly and immunocompromized• Cancer patients with mucosal disruption
– Chemotherapy & radiotherapy– Tumor infiltration – Malnutrition
• Hepatobilliary disease, liver abscess, colonic perforation, trauma or surgery
• Septic abortion / ruptured ectopic pregnancy
Case # 1
• Despite absence of effective RBC mass patients transiently maintain normal BP and mentation presumably due to free Hb
– Maintenance of intravascular oncotic pressure
– Maintenance of adequate tissue oxygenation