Medical management of common poisoning (for undergraduate teaching)

1. Medical management of
common poisoning
Dr. Sandeep Lahiry
IPGME&R, Kolkata
*for undergraduate training
sndplry@gmail.com

2. Overview
• Organophosphorus poisoning (OP)
• Corrosives ingestion
• Snake Envenomation
• Sedatives Overdose
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3. OP : Background
Organophosphorus: Insecticides > Pesticides
5 lac deaths yearly worldwide; Self-harm (60%)
Highly toxic: Tetraethyl pyrophosphate & Parathione
Intermediate toxicity: Coumaphos, Chlorpyrifos & Trichlorfon
Low toxicity: Malathione, Diazinon & Dichlorovos
MOA: Inhibits Esterase (BChE > AChE)
AChE: Synapse, red cell membranes – concern*
BChE: Plasma (pseudoChE)
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4. OP: Symptomatology
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+ M (PNS) + N (SNS) + M/N(CNS) + N (NMJ)
Bronchospasm
Bradycardia
Miosis
S alivation
L acrimation
U rination
D efecation
G ut cramps
E mesis
Tachycardia
Mydriasis
Hypertension
Sweating
Confusion
Agitation
Respiratory failure
Coma
Muscle weakness
Paralysis
Fasciculation
M: Muscarinic Receptors; N: Nicotinic Receptors; PNS: Parasympathetic Nervous System;
SNS: Sympathetic Nervous System; CNS: Central Nervous System; NMJ: Neuromuscular Junction

5. OP: Management
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1. Remove contaminated clothing
2. ABC + O2 + Position (Left lateral decubitus + Lower head- aspiration?)
3. Check Vitals every 5mins + Chest Auscultation (spasms?)
4. 2 i.v channels: C1 & C2
• C1 : Atropine (1-3mg) bolus + NS (0.9%) INF
• C2: 2-PAM (2g) over 20-30min » 0.5-1g/hr INF
5. Agitated? Sedate to prevent hyperthermia (?)
6. Assess response (every 5min) [HR >80 bpm; SBP > 80mmHg; Clear chest]
7. Stable? Continue 2-PAM until atropine free for 12-24hrs
8. Unstable? Intubate (dyspnea) ± Vasopressors (hypotension)
9. Monitor for Cholinergic crisis

6. Corrosives
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• Acids
1. HCl (>50%)
2. NaClO4
3. CH3COOH
4. Rare: H2SO4 (battery); H2O2
(cosmetics); 5% NaHCL2
(Bleach)
MOA: Coagulation Necrosis
Sanitary cleaners
• Alkalis
1. NaOH
2. KOH
More dangerous
MOA: Liquefaction Necrosis
Complication: 1. Strictures or Perforations
2. Metabolic Acidosis

7. Corrosive Poisoning
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Symptoms : Dysphagia, Retrosternal chest pain, Stomach Pain, Dysphonia
Signs (oral) : Hypersalivation, Ulcerations, Edema, Whitish plaques, Contact Bleed
Pathophysiology
1. Hours : Small blood vessel thrombosis/injury
2. Days : Inflammation, Bacterial invasion, Granulation tissue
3. Weeks : Collagen deposition (healing), Tissue fibrosis (strictures)
Severity
1º : Mucosal edema, erythema
2º : Deep ulcers, strictures
3º : Perforations

8. Corrosive Poisoning
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Approach: To avoid perforation or stenosis
• 12 - 24 hrs : Esophago-gastro-dudenoscopy
Controversy: ASAP ? 48hrs ?
Avoid in asymptomatic (2%) ?
Avoid >48hrs? Iatrogenic perforation
• Acute phase (4th – 14th Day): CxR & Straight X-Ray Abdomen
Avoid:
1. GI Lavage / Induced Vomiting / Charcoal : Risk of perforation
2. Milk + Cold water: Controversial
3. Sucralfate: may help

9. Corrosive Poisoning
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• Perforation? Immediate Surgery
• Neutralization? Not recommended
• Antibiotics? Controversial
• Strictures? Stents / NG Tube / Intra-lumen dialation (>6 weeks)
• Steroids? Controversial
• *Nutrition:
< IIA : TPN < 48hrs; Liquid diet: 48hrs – 10th day; Soft diet: > 11th day
> IIB : “Esophageal rest” for 10 days /NPO + Feeding jejunostomy
*Based on Kendall’s endoscopic classification of post-corrosive injuries
IA: Erythema, Edema; IIA: Sup. Erosions; IIB: Circumferential ulcers; III: Deep grey/black ulcers; IV: Perforation

10. Sedative Overdose
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Most Common : BZD (suicidal > 60%)
Symptoms : Obtunded, Nystagmus, Slurred speech, Hallucinatins, Hypotonia
Signs : Low BP, Respiratory depression
Investigations : CBC + U/E + RFT. Rule out hypoglycemia
Management:
• Mainly supportive, symptoms + history is diagnostic (>90%)
• Decontamination: < 1-2 hrs may have a role
• Flumazenil: Competitive BZD receptor antagonist
Indication: Iatrogenic BZD overdose (BZD naïve patients only)
Naloxone (0.4mg): reverses respiratory depression in associated opiod overdose

11. Scenario
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India: >200 species, 52 poisonous
Classification of poisonous snakes:
1. Vasculotoxic (Vipers)
2. Neurotoxic (Elapids: Cobras, Kraits)
3. Musculotoxic (sea-snakes)
Dry bites:
20% pit vipers, 75% sea-snakes
>50% envenomination

12. 9/26/2018

13. Signs & Symptoms
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14. Presumptive Diagnosis
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VIPERS : Local Envenomination (LE) + Bleeding/Clotting disturbance
COBRAS : LE + Neurotoxicity (Paralysis)
KRAITS : Minimum LE + Neurotoxicity (Paralysis); Bitten on land
Sea-snakes : Minimum LE + Neuro/Muscle toxicity (Paralysis);
Bitten at or near sea/freshwater
AKI, Shock, Rhabdomylosis (dark brown urine), chemosis can occur in either
Treatment: Pre-hospital Care & Hospital Care

15. Pre-hospital care
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1. Immediately rush to hospital or /AE
2. Do not catch snakes, take pictures instead !
3. Bite area: NO INCISON or SUCTION or TOURNIQUETS or ICE
4. Elapid Venoms have minimum LE: Pressure immobilization
Crepe bandage wrapping
40-70 mmHg : Upper Limbs
55-70 mm Hg: Lower Limbs
NO Walking ?

16. Hospital care
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1. Remove all ligatures, assure the patient
2. Quick History, Assess Vitals + LE severity
3. Assess of neurotoxicity: Ptosis, upward gaze inability, dyspnea, paralysis?
4. Care of wound
• Simple soap-water cleaning » sterile dressing » padding/splinting
• Wound debridement (if needed)
• Keep extremity elevated: risk of edema or compartmental syndrome
3. Blood tests: ABO typing + cross matching + CBC + U/E + RFT + Coag. Profile
4. Suspected Rhabdomylosis? Creatine kinase, Urine: RBCs/Myoglobin
5. Check CBC, Coag. Profile every 6hrs until normalizes.
6. Quick coagulopathy assessment: Test-tube Clot test (2ml, 20 min)
7. 2 i.v channel: C1 + C2
8. C1: 20-40mL/kg ± 5% Albumin (10-20mL/kg); Vasopressors if unresponsive

17. Hospital care
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1. C2: INF reconstituted AVS in 250mL NS (0.9%) over 1hr
• Dose? LE severity- Mild: None; Moderate: 4-6vials, Severe: 6vials
• Upto 10-20 vials may be needed, depending upon envenomination
• No pretesting required
• ATR: Stop AVS » Adrenalin (0.01mg/kg) + Steroid (prednisone 1-2 mg/kg or
hydrocortisone 100mg) + Antihistaminic (diphenhydramine 1mg/kg)
• Restart AVS when ATR subsides
2. Tetanus immunization
3. Blood/blood products transfusion s.o.s
4. Prophylactic antibiotics: unless incision/suction given at bite site
5. NSAIDS for pain relief
6. Observation: 8hrs for dry bites; 24hrs for LE
7. AKI or Rhabdomylosis: Nephrology opinion and Hemodialysis

18. Hospital care
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Elapid Bites
1. Pretreatment with Atropine 0.6mg i.v (child: 0.02 mg/kg)
2. i.v Edrophonium 10mg (child: 0.25mg/kg) or i.m Neostigmine 1.5-2mg (child:
0.025-0.08 mg/kg)
3. Improvement ?
• Atropine INF 0.6mg over 8hrs
• Neostigmine 0.5mg i.v/s.c every 30 min as needed (child: 0.01 mg/kg)
4. Persistent dyspnea or no improvement ?
• Intubate » Ventilation support
• Trial of AChE

19. Suggested reading
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1. Guidelines for management of snake bites in SE Asia: WHO
https://goo.gl/9IvD8T
2. Eddleston M, Buckley NA, Eyer P, Dawson AH. Management of acute
organophosphorus pesticide poisoning. Lancet. 2008;371(9612):597-607.
doi:10.1016/S0140-6736(07)61202-1.
3. Benzodiazepine Toxicity Treatment & Management https://goo.gl/hpoLfl
4. Chibishev A, Pereska Z, Chibisheva V, Simonovska N. Corrosive Poisonings in
Adults. Materia Socio-Medica. 2012;24(2):125-130. doi:10.5455/msm.2012.24.125-
130.