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