HEMATOLOGYHot Topics and Morphology

BCSLS Telehealth BroadcastJune 16, 2005

Kin Chenghigbc@yahoo.ca

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

Questions??

• higbc@yahoo.ca

• kin.cheng@fraserhealth.ca