Incidence of serum sickness following Indian polyvalent antivenom therapy in a cohort of snake-envenomed patients in rural Sri Lanka

Figures & data

Table 1. Summary of demographic and clinical effects of envenoming in patients recruited to this study.

	Antivenom received (n = 98)	Antivenom not received (n = 423)
Gender: Males (%)	70 (71)	243 (57)
Age: median (interquartile range) in years	43 (31–54)	44 (32–55)
Offending snake species (%)
Daboia russelii	83 (85)	13 (3)
Bungarus caeruleus	7 (7)	3 (1)
Naja polyocellata	3 (3)	4 (1)
Hypnale hypnale	0	194 (46)
Non-venomous snakes	0	53 (13)
Unauthenticated snakes	5 (5)	156 (37)
Local envenoming (%)
Pain	88 (90)	304 (72)
Swelling	86 (88)	269 (64)
Necrosis	7 (7)	45 (11)
Systemic envenoming (%)
Venom-induced consumption coagulopathy	67 (68)	5 (1)
Neurotoxicity	59 (60)	0 (0)
Non-specific features of envenoming	62 (63)	5 (1)
Renal replacement therapy	1 (1)	3 (1)
Microangiopathic haemolytic anaemia	3 (3)	5 (1)

Table 2. Antivenom, premedications, and acute adverse reactions of the 98 patients who received antivenom.

Antivenom dose (in vials)
median (interquartile range)	20 (20–30)
Antivenom brand
Serum Institute of India (Bharat)	47 (48%)
VINS Bioproducts	41 (42%)
No information	10 (10%)
Acute adverse reactions for antivenom therapy (Brown grading)
No acute adverse reactions	31 (32%)
Grade I	33 (34%)
Grade II	15 (15%)
Grade III (severe anaphylaxis)	19 (19%)
Premedications for antivenom therapy
No premedication	6 (9%)
Epinephrine alone or epinephrine with other medications	86 (88%)
Hydrocortisone alone or hydrocortisone with other medications	32 (33%)
Other combinations	2 (2%)

Table 3. Features of serum sickness among patients recruited to this study.

	Antivenom received (%) (n = 98)	Antivenom not received (%) (n = 423)
Fever	10 (10)	2 (0.5)
Rash	5 (5)	0 (0)
Arthralgia/myalgia	4 (4)	0 (0)
Malaise	16 (16)	10 (0)
Headache	12 (12)	0 (0)
Abdominal pain	1 (1)	0 (0)
Nausea/vomiting	1 (1)	0 (0)

Table 4. Details of the four patients who met the criteria for serum sickness.

	Patient 1	Patient 2	Patient 3	Patient 4
Age (years)	28	58	40	46
Gender	Male	Male	Female	Female
Snake	Daboia russelii	Daboia russelii	Daboia russelii	Daboia russelii
Clinical effects	Local effects, non-specific features of systemic envenoming, VICC, neurotoxicity	Local effects, VICC, neurotoxicity	Local effects, non-specific features of systemic envenoming, VICC, neurotoxicity	Local effects, non-specific features of systemic envenoming, VICC, neurotoxicity
Antivenom therapy-dose (brand, batch number)	20 vials (VINS 01AS21072)	30 vials (VINS 01AS21079)	20 vials (VINS 01AS21079)	20 vials (VINS 01AS21079)
Premedication for antivenom	Epinephrine (SC)	Epinephrine (SC) Hydrocortisone (IV) Chlorphenamine maleate (IV)	Epinephrine (SC) Hydrocortisone (IV)	Epinephrine (SC)
Adverse drug reactions to antivenom (Brown grading)	Grade II	No reaction	Grade III	Grade III
Treatment for acute adverse reaction	Metoclopramide (IV)	–	Epinephrine (IM) Salbutamol (nebulisation)	Epinephrine (IM) Hydrocortisone (IV) Chlorphenamine maleate (oral)
Tetanus toxoid	Not given	Given	Not given	Not given
Antibiotics given	Flucloxacillin	Flucloxacillin Clindamycin	Flucloxacillin	Flucloxacillin
Duration of hospital stay	2 days	3 days	3 days	3 days
Regular corticosteroid therapy	No	No	No	No
Previous antivenom therapy	No	No	No	No
Features of serum sickness	Fever, urticarial rash, arthralgia, myalgia, headache, generalized lymphadenopathy	Fever, urticarial rash, arthralgia, malaise, excessive sweating	Fever, arthralgia, myalgia, malaise, headache, abdominal pain, nausea, vomiting	Fever, erythematous rash, arthralgia, myalgia, malaise
Onset of serum sickness	5 days post-antivenom	8 days post-antivenom	10 days post-antivenom	6 days post-antivenom
Treatment received for features of serum sickness	Readmitted to the study hospital and treated with corticosteroids for suspected serum sickness after excluding an infection	Readmitted to a hospital and treated for cellulitis.	Treated as a viral fever in a hospital as an outpatient.	Treated as a viral fever by a general practitioner

IM: intramuscular; IV: intravenous; SC: subcutaneous; VICC: venom-induced consumption coagulopathy