Pit Viper, Tropidolaemus subannulatus �in Sinsin, Cebu City: �A Case Report

Decs Arpaphil A. Kuizon, MD

2^nd year Resident

Co-authors:

Beethoven N. Bongon, MD, FPCP

Joseph Ian Reyes, MD, DFM

OBJECTIVES

OBJECTIVES

SPECIFIC OBJECTIVES

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• To present the history, physical examination and work up of the patient presenting with signs of envenomation

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• To outline the course in the ER with regards to medical management

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• To emphasize the need for an interprofessional approach to the management of venomous snake

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INTRODUCTION

• Snake related injury (SRI) is a potentially fatal illness produced either by mechanical injury or envenomation from a snake.

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• The South-East Asia Region is one of the world’s most affected regions, due to its high population density, widespread agriculture activities, presence of numerous venomous snakes and lack of necessary community awareness to address the problem.

The major venomous snakes of the world can be divided into three groups:�

1. Viperidae (vipers and pit vipers)

2. Elapidae (includes Cobras, kraits, or sea snakes)

3. Colubrid snakes (former family Colubridae)

CASE PRESENTATION

Name: R.L.

Age/Sex: 17 years old/Male

Status: Single

Religion: Roman Catholic

Nationality: Filipino

Birthday: June 25, 2006

Address: Lantawan, Sinsin, Cebu City

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Chief complaint: Snake bite

NOI: Animal Bite (Snake)

POI: Lantawan, Sinsin, Cebu City

DOI:  11/10/2023

TOI: 03:00 PM

SOI: Lateral aspect of the right forearm

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History of Present Illness

• 4 hours prior to consult, patient went to the forest in Sinsin with his father looking for a firewood when a snake fell from the tree and bit his right forearm sustaining a punctured wound which leads to spontaneous minimal bleeding, patient’s S.O. tried to induce more bleeding at wound area. No intervention was done. Thus, sought consult in VSMMC for further management.

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Past Medical History 

(-) DM

(-) HPN

(-) Asthma

(-) previous hospitalization

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Immunization History:

Complete childhood immunization

(+) COVID19 vaccine 2 primary doses: Pfizer

(-) Tetanus vaccine

Family History: 

Maternal and Paternal: HPN

Personal and Social history

Physical Examination:

General survey: Awake, alert, ambulatory, and not in respiratory distress with the following vital signs:

Temp: 36.8°C

HR: 88 bpm

RR: 23 cpm

BP: 110/80 mmHg

02 sat: 98% at room air

Wt: 46 kg

Ht: 160 cm

BMI: 18.0 kg/m2

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SKIN: (-) jaundice, warm to touch, good turgor, (+) punctured wound at the lateral aspect of the right forearm, (+) erythema and swelling, no cyanosis

HEENT: anicteric sclerae, pink palpebral conjunctiva, (-) ptosis

C/L: ECE, CBS, no tachypnea, no dyspnea

CVS: Distinct heart sounds, no murmur

ABDOMEN: Nondistended, NABS, soft, nontender

EXTREMITIES: strong peripheral pulses, CRT <2 seconds, no edema

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ASSESSMENT:�

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Punctured wound, lateral aspect of the right forearm, secondary to animal bite (snake) with local signs of envenomation

INTERVENTION

• Tetanus Toxoid 0.5 cc/vial, Inject deep IM right deltoid
• Tetanus Immunoglobulin 250 IU/mL, deep IM left deltoid
• Whole Blood Clotting Test (-)
• Referred to VSMMC Emed Toxicologist (Dr Bongon)
• Snake identified as, Tropidolaemus subannulatus
• Advised for admission, patient opted HAMA
• THM: Doxycycline 100mg/tab 2tabs now then 1 tab BID for the next 6 days
• Instructed to follow up at the OPD Pedia department on weekdays
• Advised to watch out for any signs of envenomation and may come back at the ER anytime.

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Follow ups:

Follow ups:

CASE DISCUSSION

Tropidolaemus subannulatus

Bornean keeled green pit viper or

North Philippine temple pit viper 

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Common names:

E: North Philippine temple pit viper�G: Philippinische Tempelviper 

Epidemiology

According to WHO,

• 4.5–5.4 million individuals are bitten by snakes annually
• 1.8–2.7 million experiencing significant clinical effects
• 81,000–138,000 deaths as a result of complications

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Distribution:

• Brunei
• Malaysia (Sabah and Sarawak on Borneo)
• Indonesia (Belitung, Borneo: Kalimantan, Buton, Kalimantan, Sangihe Archipelago, and Sulawesi)
• Philippines (Balabac, Basilan, Bohol, Dinagat, Jolo, Leyte, Luzon, Mindanao, Negros, Palawan, Panay, Samar, Sibutu, and Tumindao, Cebu, Romblon)��

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T. subannulatus is recorded in three major islands:

1. Luzon: Cagayan, Isabela, Bulacan, Cavite, Quezon, Camarines Norte, and Albay.
2. Visayas: Samar, Leyte, Bohol, Negros Occidental, and Negros Oriental.
3. Mindanao: Agusan del Norte, Agusan del Sur, Lanao del Norte, Lanao del Sur, Basilan, Dinagat, and Jolo

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Barangay Cansuje in Argao, Cebu was the locality where the T. subannulatus was first documented on Apr 2018. The habitat was comprised of an extensive forest cover, the largest among the areas comprising the Cebu

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VIPERIDAE

• have relatively long fangs (solenoglyph) which are normally folded flat against the upper jaw but, when the snake strikes, are erected

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• SUBFAMILIES:

A: pit-vipers (Crotalinae)

B. typical vipers (Viperinae)

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CROTALINAE

• Are called pit vipers because of the bilateral depressions or pits located midway between and below the level of eye and nostril

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• possess a special infra-red heat-sensing organ, the loreal pit organ, to detect their warm-blooded prey.

MORPHOLOGICAL DIFFERENCES BETWEEN MALE AND FEMALE Tropidolaemussnakes

PATHOPHYSIOLOGY

CLINICAL FEATURES

CLINICAL FEATURES

Early symptoms and signs:

Nausea and vomiting

Weakness

Oral numbness

Tingling of the tongue and mouth

Dizziness

Muscle fasciculation

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Systemic effects:

• Tachypnea
• Tachycardia
• Hypotension
• Altered level of consciousness

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• local swelling at the bite site becomes apparent within 15 to 30 minutes, but in some cases, swelling may not start for several hours.
• In severe cases, edema can involve an entire limb within an hour.
• In less severe cases, edema may progress over 1 to 2 days.

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DIAGNOSIS

• Fang marks and a history consistent with exposure to a snake

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• Snake envenomation involves the presence of a snakebite plus evidence of tissue injury.

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Clinically�

TREATMENT (FIRST AID)

TREATMENT

EMERGENCY ROOM MANAGEMENT

EMERGENCY ROOM MANAGEMENT

EMERGENCY ROOM MANAGEMENT

EMERGENCY ROOM MANAGEMENT

DISPOSITION AND FOLLOW UP

FOR DISCHARGE:

Preventions (WHO, 2016)

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In the farm yard, compound, or garden:

• Try not to provide hiding places for snakes.
• Clear away termite mounds, heaps of rubbish, building materials etc. from near the house.
• Do not have tree branches touching the house.
• Keep grass short or clear the ground around your house and clear underneath low bushes

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In the countryside:

• Firewood collection at night is a high risk activity
• Watch where you walk
• Use of protective clothing (boots and gloves) should be promoted as the most obvious means of reducing occupational risk of snakebite
• Step on to rocks or logs rather than straight over them – snakes may be sunning themselves on the sides.

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On the road:

• never intentionally run over snakes on the road
• The snake may also be injured and trapped under the vehicle, from where it will crawl out once the vehicle has stopped or has been parked in the house compound or garage.

In rivers and sea:

Fishermen should avoid touching sea snakes caught in nets.

Sea snakes are air- breathing and are therefore drowned if caught in drift or trawl nets, but, unlike fish, may survive if laid on the beach

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Journal Article: Frequency, clinical characteristics and outcomes of Tropidolaemus species bite envenomations in Malaysia, 2023

• This is a retrospective cohort study of bites from Tropidolaemus species in Malaysia referred to RECS from 2015 to 2021
• All pit vipers are venomous
• T. wagleri and T. subannulatus are generally not considered to be aggressive and the envenomation is atypical among many pit vipers
• T. subannulatus venom does not affect clotting

RESULTS:

• Majority were male and between 18 to 59 years old
• Happened during the daytime and outdoors
• Local pain, puncture wounds, localised swelling, bleeding, and erythema were the most common effects of Tropidolaemus spp. bite. Vasoactive substances and enzymatic toxins interact to cause localised swelling and erythema.
• Tropidolaemus spp. envenomation has not been shown to induce shock and coagulopathy.
• Majority of bites only result in mild-to-moderate local envenomation presenting with pain and swelling.
• No patients developed tissue necrosis, cardiovascular instability or coagulopathy.

WHO, 2016

• Adults inject 45% of the venom glands' content in the first bite
• Mechanical inefficiency or the snake’s control of venom discharge
• Snakes do not exhaust their store of venom, even after several strikes, and they are no less venomous after eating their prey
• About 50% of bites by Malayan pit vipers and Russell’s vipers, 30% of bites by cobras and 5-10% of bites by saw-scaled vipers do not result in any symptoms or signs of envenoming.

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ELAPID SNAKE

have relatively short fixed front (proteroglyph) fangs�

This family includes cobras, king cobra, kraits, coral snakes, Australasian snakes and sea snakes.

Elapidae are relatively long, thin, uniformly-coloured snakes with large smooth symmetrical scales (plates) on the top (dorsum) of the head

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COLUBRID SNAKE

3. COLUBRID SNAKES

• largest snake family and includes about two-thirds of all living snake species.
• Most species are aglyphous and nonvenomous, while others are opisthoglyphous and can be venomous to varying extents.
• In some species, such as rat snakes, the venom system appears to have regressed

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“Raising community awareness about prevention of snakebites is the most effective strategy for reducing snakebite morbidity and mortality.”

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References:

• Emergency Medicine, Tintinalli’s, Ninth Edition
• Guidelines for the Management of Snake bites 2nd edition WHO regional office for Southeast Asia, 2016
• Frequency, clinical characteristics and outcomes of Tropidolaemus species bite envenomations in Malaysia , 2023