Regional Health Forum

Regional Health Forum WHO South-East Asia Region Volume 9 Number 1, 2005

Russell’s Viper Bite: Correlation of Different Clinical Criteria to Peritoneal Dialysis and Clinical Outcome

Russell’s Viper Bite: Correlation of Different Clinical Criteria to Peritoneal Dialysis and Clinical Outcome

Paing Soe*

Introduction

Russell’s viper bite is an important cause of morbidity and mortality in Myanmar and ranks high in the priority health problems identified in successive People’s Health Plans. Acute renal failure is the major cause of death in Russell’s viper bite patients who survive the early effects of envenoming. Acute tubular necrosis was observed in renal biopsy and autopsy specimens of human victims as well as in experimental animals¹.

But the factors associated with requirement of peritoneal dialysis (PD) and with clinical outcome in Russell’s viper bite victims had previously been little known. This study was aimed to correlate different clinical features to the requirement of PD and to the clinical outcome (death or discharge) in viper bite patients. Moreover, survival of patients who required treatment with PD, and those without, were compared and their causes of death were also analysed.

Methodology

Study area and population

A hospital-based prospective study was carried out during the one-year study period (1 September 1993 to 30 August 1994) at the Renal Dialysis Unit, Yangon General Hospital, Myanmar. A total of 107 patients with Russell’s viper bite admitted to the Renal Dialysis Unit directly or referred from other medical units of Yangon General Hospital or other hospitals in Yangon and district hospitals (secondary referral centres) were included in the study. Viper bite was proven by the dead snake brought along on admission, and/or by the features of systemic envenoming (Box 1). Clinical
assessment and history-taking were done on admission. A detailed history regarding first-aid treatment, time of anti-snake venom (ASV) administration, and the nature of health care received was recorded. Clinical features were noted and the progress was recorded daily. The cause of death was verified by the senior medical officer concerned, which was further confirmed by the postmortem examination.

Statistical analysis

Multiple logistic regression analyses were performed with survival status (death or discharge) as the dichotomous outcome (dependent variable) and other variables, such as age; sex; time lapse before ASV; first-aid; mental changes; oedema; haematuria;and subconjunctival haemor-rhage, as independent variables. Addi-tionally, multiple logistic regression analyses were also used to investigate the factors associated with requirement for PD. In these analyses, PD requirement was the dichotomous dependent variable, while others such as age, sex, time lapse before ASV, first aid and other clinical criteria were the independent variables. All statistical analyses were performed using SPSS software. P<0.05 was used as the definition of statistical significance.

Ethical consideration

A written informed consent was obtained from patients after explanation of the nature of the study. This study was approved by the Medical Ethics Committee of the Department of Medical Research, Yangon, Myanmar.

Results

Background characteristics of patients

Among the study population, 91 (85%) were males and 16 (15%) were females. Their mean age was 29.78 years (range: 13 to 68 years). About 80% of them were within the age range of 16 to 45 years with 16-25 years age group (37%) comprising the major victims of viper bite. Of the total incidents 49.5% occurred between 06:00 hrs and 17:30 hrs, and 50.5% between 18:00 hrs and 05:30 hrs. The median time lapse before ASV was three hours (range: 1 to 4 hours). About 56% patients did not receive any form of first-aid therapy. In the remainder, incisions were made at the site of bite (15.2%) or acupuncture performed over the whole limb (21%). A small percentage (1.9%) applied tourniquet proximal to the site of the bite. The clinical manifestations of Russell’s viper bite cases on admission to the dialysis unit are summarized in Table 1.

Correlation of different clinical criteria with the requirement of peritoneal dialysis 

Multivariate logistic regression analysis revealed that the presence of haematuria had a definite relationship with PD requirement. Patients with gross and persistent haematuria within the first week of illness were more likely to require PD during their course of illness. Subconjunctival haemorrhage was also found to have a significant relationship to the requirement of PD (Table 2).

Table 1. Clinical manifestations on admission to dialysis unit

* Orthopnoea, raised jugular venous pressure (JVP), basal crackles, ± triple rhythm ±  generalised oedema

** Systolic blood pressure (SBP) ≤60 mm Hg

Table 2.  Correlates of peritoneal dialysis: results of multiple logistic  regression analysis

^a Other variables which were considered but not statistically significant included age, sex, time lapse before ASV, first aid measure, local reaction, mental changes, chemosis, shock, oliguria and septicaemia.

^b 95% Confidence Interval

Correlation of different clinical criteria to clinical outcome of patients

The results of multivariate logistic regression models that examined the correlates of clinical outcome (death or discharge) are presented in Table 3. Patients who developed mental disturbances either in the form of twitching, fits or coma usually ended in a fatal outcome. When oedema, either in the form of puffy face or generalized oedema was calculated against the clinical outcome, it was found that, those patients with oedema had a more serious prognosis than those who did not develop oedema.

Table 3. Correlates of poor clinical outcome (death): results of multiple logistic regression analysis

^a Other variables which were considered but not statistically significant included age, sex, time lapse before ASV, first aid measure, subconjunctival haemorrhage, chemosis and haematuria

^b 95% Confidence Interval

Other factors that were associated with increased odds of poor clinical outcome (death) were septicaemia, shock and presence of PD indication(s).

PD requirement vs survival

Nearly half of the viper bite victims (49%) were helped to recover and discharged. The rest of them (51%) either succumbed, or signed and left the hospital. Those who left were critically ill and their likely outcome was very poor. Peritoneal dialysis was not required in all patients. Peritoneal dialysis was usually needed and undertaken when biochemical or clinical indications (Box 2) arose in a viper bite patient (44 patients). Very rarely PD was not performed although it was indicated on the basis of biochemical parameters as the patient’s general well-being was good, and the urine output was satisfactory. So the patient was kept under observation with daily monitoring of urea and electrolytes. There was one such case in this study who survived with conservative treatment. The impact of peritoneal dialysis on patient survival is shown in Table 4. It was found that those with PD had less chances of survival.

Table 4. The impact of peritoneal dialysis on patient survival in Russell's viper bite cases

Causes of death in patients with and without PD

The major causes of death in cases that died after peritoneal dialysis were septicaemia, cerebral cause (coma, convulsions, confusion) and disseminated intravascular coagulation. In those patients without peritoneal dialysis, shock was the number one killer, followed by pulmonary oedema, and cardiac arrhythmias (Fig 1).

Patients with shock usually died during the first week of viper bite before the level of blood urea rose enough to require PD.

Discussion

The major victims of viper bites were between the age group of 16 to 35 years of age in this study. Men were more commonly exposed to vipers as evidenced by the predominant sex ratio of 6: 1. It was due to the fact that men were the breadwinners of the family and they went out to work in rural communities, whatever their occupations.

There seemed to be little difference between day and night regarding the time of viper bite (49.5% of the incidents occurred in daytime Vs 50.4% during the night). Farmers were exposed to snakes in the paddy fields during the day, but they were also at risk when they returned home at dusk.

Local reactions did not prove to have any influence in predicting the prognosis of viper bite victims in this study. Although they were found to have influenced the prognosis in 50% of the cases, they were statistically found unrelated to the requirement of PD as well as to the clinical outcome (death or discharge). Contrary to the present finding, some authors reported that the extent of local swelling and the percentage circumference increase of the bitten limb were found to correlate with the length of the snake. There was a strong correlation between the venom yield and the length of the viper. The incidence of systemic envenoming increased with the extent of local swelling and lymphadenopathy.^{2, 3  But} it was stated in another report that, even in fatal patients with systemic envenomation, there were no local reactions at all⁴. Also in Anuradhapura (Sri Lanka), 27% of patients with systemic envenomation had mild or negligible local swelling when admitted to hospital⁵.

In this study, more than half of the cases did not apply any first-aid measures over the site of bite. Multiple puncture (a traditional practice) seemed to be a popular practice (21%) followed by incisions over the site of bite (15.2%). Whatever the nature of first-aid measures may be, it was found that these measures had no influence on PD requirement or clinical outcome of viper bite victims.

According to previous studies, sub-conjunctival haemorrhage and chemoses occurred in patients with severe systemic envenoming and their presence indicated serious prognosis⁶. In the present study, subconjunctival haemorrhage had a significant relationship to the requirement of PD. But they were not proved to be important indicators, which pointed towards a fatal clinical outcome.

Shock can develop at any time during the first week after the bite. Early shock is probably explained by vasodilatation and late shock is precipitated by massive GI haemorrhage or acute pituitary and adrenal insufficiency⁷. Shock (systolic blood pressure ≤ 60 mmHg) was seen in 14.8% of study patients, and it was found to have a significant relationship to poor clinical outcome.

Mg Mg Aye et al. reported that oliguria may develop rapidly within 24 hours after the bite or during the first two to three days. The signs of uraemia may develop within three to seven days of the bite. Another important and reliable sign was gross haematuria⁶. It was in agreement with our finding that if haematuria was persistently found on naked eye examination within the first week of illness, it was likely that the patient would require peritoneal dialysis.

This study might contribute to a better understanding of the importance of clinical criteria in predicting the requirement of PD or clinical outcome in Russell's viper bite patients, and could be helpful in the management of such cases.

Acknowledgement

The author would like to thank the doctors and nursing staff at the Renal Dialysis Unit, and the Laboratory staff at the Yangon General Hospital, for their help and support in conducting this study.

References

1.      Aung Khin. Histological and ultrastructural changes of the kidney in renal failure after viper envenomation. Toxicon, 1978; 16: 71-75.

2.      Tun Pe, Ba Aye, Aye Aye Myint, Tin Nu Swe, Warrel DA. Bites by Russell's viper (Vipera russelli siamensis) in Myanmar: effect of the snake’s length and recent feeding on venom antigenaemia and severity of envenoming. Transactions of the Royal Society of Tropical Medicine & Hygiene, 1991; 85: 804-808.

3.      Myint Lwin, Phillips RE, Tun Pe, Warrel DA., Tin Nu Swe, Mg Mg Lay. Bites by Russell's viper (Vipera russelli siamensis) in Burma: Haemostatic, vascular and renal disturbances and response to treatment. Lancet, 1985; ii: 1259-63.

4.      Maung Maung Aye. Snakes of Burma with venomology and envenomation. M.Sc (Zoology) Thesis 1976, Rangoon Arts and Science University; Pg 52-56.

5.      Phillips RE, Theakston RD, Warrel DA. Paralysis, rabdomyolysis and haemolysis caused by bites of Russel’s viper (Vipera russelli puchella) in Sri Lanka; Failure of Indian (Haffkine) antivenom. Lancet, 1998; ii: 691-716

6.      Maung Maung Aye. Some experience in the management of snake-bite. Burma Medical Journal, 1972; 20: 33-40.

7.      Tun Pe, Phillips RE, Warrel DA, Moore RA, Tin Nu Swe, Myint Lwin. Acute and chronic pituitary failure resembling Sheehan’s syndrome following bites by Russell's viper in Burma. Lancet, 1987; ii: 1259-63.

8.      Warrel DA. WHO/ SEARO guidelines for the clinical management of snakebites in South-East Asia Region. Southeast Asian J Trop Med Pub Health, 1999; 30, supplement 1: 38.

9.      Paing Soe & Saw Naung. A guide to management of Russell's viper bite, 2003. (Unpublished)