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Snake envenomation in a dog
Elizabeth G. Welles* Merrilee Holland**
Auburn University, *Department of Pathobiology, **Department of Clinical Sciences
Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Signalment and history
• 7 yr old, F/S, mixed breed dog, 39 kg
• Bitten by a venomous snake evening of 5-29-07
• Owner, a veterinarian, administered cephalexin, sucralfate, and dexamethasone
• Next morning – hematuria
• Admitted to AUSAC on 5-30-07
Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Southeastern venomous snakes
copperhead, rattlesnakes, cotton mouth, coral snake
Crotalid venom• Enzymatic and non-enzymatic proteins
– Hyaluronidases, collagenases – facilitate venom entry into blood and tissues
– Phospholipases – injure endothelium inflammation, pain, vasculitis loss of fluid hemoconcentration, hypovolemia
– Fbrinolytics, anticoagulants, procoagulants defibrination prolonged APTT, PT, TT, impaired platelet function, increased FDPs
Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Parameter (ref interval) 5-30-07
Hct (%) (37-55) 42.1
WBC(/ul) (6,000-17,000) 19,200
Neutrophils (3,000-11,400) 17,490
Lymphocytes (1,000-4,000) 769
Platelets(/ul) (164,000-510,000) 378,000
Total protein (g/dl) (5.1-7.3) 7.9
ALP (U/L) (4-95) 251
ALT (U/L) (26-200) 215
AST (U/L) (15-50) 596
CK (U/L) (2-357) 5,272
Urine specific gravity 1.007
Urine protein (mg/dl) (<15) 633
Urine blood +3, sed rbc TNTC
Prothrombin time (sec) (6.1-10.1) 17.5
APTT (sec) (8.1-14.4) 21.4
Thrombin time (sec) (7.6-22) >60
Fibrinogen (mg/dl) (100-300) <15
D-Dimer (ng/ml) (1-250) >2,000
Plasma FDP (ug/dl) (0-5) >20
Patient was treated with antivenom, fresh frozen plasma, IV fluids, antibiotics, hydromorphonePresented at SEVPAC 2008 –
Permission granted for use on SEVPAC website only
Parameter (ref interval) 5-30-07 6-5-07
Hct (%) (37-55) 42.1 28.8
WBC(/ul) (6,000-17,000) 19,200 14,450
Neutrophils (3,000-11,400) 17,490 11,705
Lymphocytes (1,000-4,000) 769 1,879
Platelets(/ul) (164,000-510,000) 378,000 376,000
Total protein (g/dl) (5.1-7.3) 7.9 6.1
ALP (U/L) (4-95) 251 147
ALT (U/L) (26-200) 215 38
AST (U/L) (15-50) 596 29
CK (U/L) (2-357) 5,272 116
Urine specific gravity 1.007
Urine protein (mg/dl) (<15) 633
Urine blood +3, sed rbc TNTC
Prothrombin time (sec) (6.1-10.1) 17.5
APTT (sec) (8.1-14.4) 21.4
Thrombin time (sec) (7.6-22) >60
Fibrinogen (mg/dl) (100-300) <15
D-Dimer (ng/ml) (1-250) >2,000
Plasma FDP (ug/dl) (0-5) >20Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Blood smear 6-5-07 Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
• Severity of envenomation estimated from fresh blood smears• Echinocytes echinospherocytes spherocytes• Echinocyte formation (I, II, III) self-limiting (48 hours)• Lecithin lysolecithin (via phospholipase A2) – outer membrane leaflet• Progression to echinospherocyte stage or beyond is irreversible• Cells sphere and lyse or removed by macrophages
Vet Path 1987;24:471-476Vet Path1997;34:442-449
Outer leafletInner leaflet
normal discocytes echinocytes
echinospherocytes spherocytes
Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Vet Path1997;34:442-449
Discocyte (normal biconcave)
Echinospherocytes
Echinocytes
Spherocytes
1
3
2
4
Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only
Blood smear 6-5-07 Presented at SEVPAC 2008 – Permission granted for use on
SEVPAC website only