Clinic
Studies
Nigeria
Warrell et al. 1975: 10 B. arietans bites; identification: morphological (8/10) or immunological with ELISA (Greenwood et al. 1974) (2/10).
Classification:
- Local envenoming 10/10
- Extent of the swelling (grade 1–6; scale of Warrell et al. 1974):
Grade 1: 2/10
Grade 2: 1/10
Grade 3: 1/10
Grade 5: 4/10
Grade 6: 2/10 - Intensity of the swelling (according to the method of Reid et al. 1963c): difference in circumference between the bitten extremity and the healthy extremity up to 28%.
- Systemic envenoming 4/10
Criteria: spontaneous bleeding with thrombopaenia, hypotension, bradycardia.
South Africa
Visser and Chapman 1978: 9 B. arietans bites that ended fatally.
Case reports
Visser and Chapman 1978: 2 cases (South Africa).
Pugh and Theakston 1987a: 3 cases (Nigeria; identification: immunological with ELISA).
Phillips et al. 1973
Theakston and Wyatt 1985
Seedat et al. 1974: 2 cases (South Africa).
Signs & symptoms
Autopharmacological effects
Vomiting 2/10 (Warrell et al. 1975).
Arterial hypotension 3/10 (Warrell et al. 1975). Arterial hypotension caused by increased vascular permeability and vasodilatation, among other factors (Osman and Gumaa 1974, Schaeffer et al. 1985).
All 9 fatal cases described by Visser and Chapman (1978) were in a state of hypovolaemic shock.
Local effects
Local pain 10/10 within 10 min after the bite (Warrell et al. 1975).
Local swelling 10/10 within 20 min after the bite, at the latest after 1–2 days, swelling disappeared after 5 days–3 weeks (Warrell et al. 1975).
Local blistering 5/10; necrosis 3/10, 17 h, 48 h and 7 days after the bite, respectively (Warrell et al. 1975).
Ecchymosis (on the bitten extremity) 2/10 (Warrell et al. 1975).
Thrombosis of the popliteal artery 1/10 (Warrell et al. 1975).
Haemostatic effects
Spontaneous systemic bleeding 3/10: gingival bleeding (1/3) 4 h after the bite, epistaxis (2/3) days after the bite (Warrell et al. 1975).
Cardiac effects
Hypotension, bradycardia: among other factors direct myocardial effect of the venom? (Warrell et al. 1975).
Renal effects
Acute kidney failure 1/10: among other factors direct nephrotoxic effect? (Warrell et al. 1975).
Acute kidney failure 2/2 (Seedat et al. 1974).
Morbidity
Extensive tissue defects and chronic ulceration of neglected wounds (necrosis) (Warrell et al. 1975).
Case fatality rate
2/10 (Warrell et al. 1975). Principal causes of death acute and prolonged hypotensive state without significant blood loss, blood loss as well as complications of necroses (Warrell et al. 1975).
All 9 fatal cases described by Visser and Chapman (1978) were in a state of hypovolaemic shock.
Laboratory and physical investigations
1. Haemostasis
Type of haemostatic defect
Haemorrhagic activity (Mebs and Panholzer 1982); platelet-activating effect (→ thrombocytopaenia) (Phillips et al. 1973); coagulation-activating/fibrinolytic effects probably not very marked in humans (Warrell et al. 1975).
Haemostatic parameters
| Overview haemostasis | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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A
+ |
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H | CT | (FSP) | Tc | PT | aPTT | TT | I | FSP | D | II | V | VIII | X | XIII | PC | ATIII | PI | tPA | α2AP | |||||||||||||||||||||||||||||||||||||||||||
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B
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C
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B
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Essential bed-side tests |
Tests for full clinical assessment | Tests for research purposes | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| A |
Haemorrhagic activity: the venom contains a haemorrhagic component that contributes to the risk of bleeding (Warrell et al. 1975, Mebs and Panholzer 1982). |
| B |
CT: normal clotting time 9/9. Investigations in individual patients revealed that clotting factors were not decreased and FSP were not raised (Warrell et al. 1975). |
| C |
Platelets: thrombocytopaenia 3/10: 27,000, 68,000, 100,000/µl 2–4 h after the bite (Warrell et al. 1975). |
2. Leucocytes
Neutrophilic leucocytosis 5/10 (Warrell et al. 1975).
3. Haemoglobin
Anaemia 3/10 (possible causes: microangiopathic haemolysis, epistaxis, blood loss in the bitten extremity) (Warrell et al. 1975).
4. ELISA
(Greenwood et al. 1974)
5. Renal biopsy
Proliferative glomerulonephritis 2/2 (Seedat et al. 1974).
Treatment (symptomatic)
- Acute and prolonged hypotensive state without blood loss: intravenous fluids (Warrell et al. 1975).
- Blood loss affecting the circulation: blood transfusion (Warrell et al. 1975).
- Pain: codeine phosphate (Warrell et al. 1975).
Treatment (specific)
Antivenoms
Behringwerke (Bitis, Echis, Naja);
Fitz-Simons (Bitis, Hemachatus, Naja);
SAIMR (Bitis, Dendroaspis, Hemachatus).
Studies
No controlled studies available.
Indications for administration of venom
Signs of systemic envenoming: spontaneous bleeding, thrombocytopaenia, hypotension, bradycardia (Warrell et al. 1975).
Signs of local envenoming: local swelling extending over more than half of an extremity (Warrell et al. 1975).
Dose
80 ml or more of a specific antivenom (Warrell et al. 1975).
Efficacy
- With regard to the development of necroses: 4 patients with extensive swelling (whole extremity) and blistering, who received antivenom early on, did not develop necroses (Warrell et al. 1975).
- With regard to symptoms of shock: antivenom was effective against hypotension and bradycardia if the intravascular volume was restored at the same time (Warrell et al. 1975).