Two hours after 10 vials of ASV were given for a Russell's viper bite, a farmer's gums still ooze slightly. The bite was on the left ankle in a sugarcane field 5 hours ago, the first 20WBCT was unclotted and the infusion ended without a reaction. His urine output is 60 ml/hour with no haematuria, and the ward has only a few vials left for the night. He is alert, BP 118/76 mmHg, and there is no other bleeding. The house officer proposes repeating the 20WBCT now and giving 10 more vials if the blood is still unclotted. What is the correct course?

Repeat the 20WBCT at 6 hours before more ASV

Give FFP now in place of more ASV

Repeat the 20WBCT every 30 minutes

Fomepizole is used in methanol poisoning because it

Speeds renal methanol excretion

Inhibits aldehyde dehydrogenase

On the third day after recovering from a cholinergic crisis due to an organophosphate, a man develops weakness of neck flexion, proximal limbs and facial muscles, with falling breathing capacity. He is fully conscious and has no fasciculations. What is the diagnosis?

OP-induced delayed polyneuropathy

Envenomation, heat illness and toxic exposures

45 NEET-PG practice questions on Envenomation, heat illness and toxic exposures, part of General Medicine. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Medium
CT of the brain in a survivor of an illicit-liquor poisoning shows bilateral putaminal necrosis. Which poison is most likely?
1. ALead
2. BMethanol
3. CEthylene glycol
4. DCarbon monoxide
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Answer: B · Methanol
Bilateral putaminal necrosis, sometimes with haemorrhage, is the typical CT or MRI finding after severe methanol poisoning, and survivors may develop parkinsonism. The putamen is vulnerable to formate-induced mitochondrial injury. Carbon monoxide characteristically damages the globus pallidus. Key point: Bilateral putaminal necrosis points to methanol; globus pallidus lesions point to carbon monoxide.
- A: Lead causes encephalopathy with cerebral oedema, not putaminal necrosis.
- C: Ethylene glycol mainly damages the kidneys with oxalate crystals.
- D: Carbon monoxide affects the globus pallidus.
Question 2 · Hard
Two hours after 10 vials of ASV were given for a Russell's viper bite, a farmer's gums still ooze slightly. The bite was on the left ankle in a sugarcane field 5 hours ago, the first 20WBCT was unclotted and the infusion ended without a reaction. His urine output is 60 ml/hour with no haematuria, and the ward has only a few vials left for the night. He is alert, BP 118/76 mmHg, and there is no other bleeding. The house officer proposes repeating the 20WBCT now and giving 10 more vials if the blood is still unclotted. What is the correct course?
1. ARepeat the 20WBCT at 6 hours before more ASV
2. BGive FFP now in place of more ASV
3. CRepeat the 20WBCT every 30 minutes
4. DGive 10 more vials now
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Answer: A · Repeat the 20WBCT at 6 hours before more ASV
After ASV neutralises circulating venom, the liver needs about 6 hours to make enough clotting factors for blood to clot again. The protocol therefore repeats the 20WBCT 6-hourly and gives a further dose only if the blood is still incoagulable at 6 hours. Repeating earlier wastes scarce ASV and raises the risk of reactions. Key point: In haemotoxic bites, recheck the 20WBCT 6 hours after ASV; no extra ASV before then.
- B: FFP is not needed for minor ooze in a stable patient.
- C: Clotting cannot normalise in 30 minutes, so frequent testing misleads.
- D: Extra ASV before 6 hours does not speed recovery of clotting factors.
Question 3 · Easy
Villagers bring a man bitten on the foot by a snake. Which first-aid steps are recommended? 1. Reassure him and immobilise the limb like a fracture 2. Apply a tight arterial tourniquet 3. Cut the bite and suck out the venom 4. Remove rings, anklets and tight clothing and transport quickly
1. A1, 2 and 4 only
2. B1, 2, 3 and 4
3. C1, 3 and 4 only
4. D1 and 4 only
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Answer: D · 1 and 4 only
Recommended first aid ('Do it R.I.G.H.T.') is reassurance, immobilisation of the bitten limb, removing tight items before swelling, and getting to hospital fast. Tight tourniquets cause ischaemia and gangrene and release a bolus of venom when removed. Cutting and sucking add infection and bleeding without removing venom. Key point: Snake-bite first aid: reassure, immobilise, remove tight items and transport; no tourniquet, no cutting.
- A: A tight tourniquet causes ischaemia and is not recommended.
- B: Both the tourniquet and incision are harmful.
- C: Incision and suction are harmful and remove no venom.
Question 4 · Medium
Fomepizole is used in methanol poisoning because it
1. ABinds formic acid
2. BInhibits alcohol dehydrogenase
3. CSpeeds renal methanol excretion
4. DInhibits aldehyde dehydrogenase
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Answer: B · Inhibits alcohol dehydrogenase
Fomepizole is a competitive inhibitor of alcohol dehydrogenase, the first enzyme in methanol metabolism, so methanol is not converted to toxic formic acid and is slowly excreted unchanged or removed by dialysis. Ethanol works the same way by competing for the enzyme, but it causes intoxication and needs level monitoring. Key point: Fomepizole and ethanol block alcohol dehydrogenase, stopping formation of formic acid.
- A: Fomepizole does not bind formate.
- C: It does not increase renal excretion.
- D: Aldehyde dehydrogenase is blocked by disulfiram, not fomepizole.
Question 5 · Medium
On the third day after recovering from a cholinergic crisis due to an organophosphate, a man develops weakness of neck flexion, proximal limbs and facial muscles, with falling breathing capacity. He is fully conscious and has no fasciculations. What is the diagnosis?
1. AAtropine toxicity
2. BGuillain-Barré syndrome
3. COP-induced delayed polyneuropathy
4. DIntermediate syndrome
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Answer: D · Intermediate syndrome
Intermediate syndrome appears 24-96 hours after poisoning, after the cholinergic phase settles, and affects neck flexors, proximal limbs, cranial nerves and respiratory muscles. It is thought to come from prolonged acetylcholinesterase inhibition causing end-plate dysfunction, and patients may need ventilation for days. It does not respond to atropine. Key point: Neck flexor, proximal and respiratory weakness 1-4 days after OP poisoning is intermediate syndrome.
- A: Atropine toxicity causes delirium and dryness, not proximal weakness.
- B: GBS is ascending and has no link to a recent poisoning.
- C: Delayed polyneuropathy appears after 2-3 weeks and is distal.
Question 6 · Hard
Silver nitrate paper held over the gastric aspirate turns black in a man who swallowed tablets kept for storing grain. Two hours later he is in shock (BP 70/40 mmHg) despite 2 litres of saline, with ST changes on the ECG and pH 7.12. Which statement about his management is correct?
1. ASodium thiosulfate is the antidote
2. BPralidoxime reverses the toxicity
3. CGastric lavage with plain water is advised
4. DNo antidote; support with fluids and inotropes
Answer and explanation in LearnFree account
Question 7 · Medium
Within an hour of swallowing a mouthful of 20% paraquat, a farm worker reaches the casualty of a taluk hospital. He is conscious, vomiting and has no mouth ulcers yet. The staff, thinking of pesticides, ask for pralidoxime. What is the most useful first step?
1. AOral Fuller's earth or charcoal
2. BIV pralidoxime infusion
3. CIV atropine bolus
4. DHigh-flow oxygen by mask
Answer and explanation in LearnFree account
Question 8 · Medium
Consider these statements about red scorpion envenomation: 1. Atropine is best avoided 2. Prazosin acts by blocking alpha-1 receptors 3. Myocarditis can lead to pulmonary oedema 4. Propranolol is the first-line drug for the hypertension. Which are correct?
1. A1 and 2 only
2. B1, 2 and 3 only
3. C2, 3 and 4 only
4. D1, 2, 3 and 4
Answer and explanation in LearnFree account
Question 9 · Medium
pH 7.08, HCO3 6 mmol/L, pCO2 20 mmHg, Na 138, Cl 100 mmol/L; measured osmolality 330 mOsm/kg, calculated 290. These belong to a man brought to the district hospital a day after drinking illicit liquor with friends, now complaining that he sees as if through a snowstorm. Two of his friends have also been admitted with vomiting and abdominal pain. He is breathing deeply and rapidly, fundoscopy shows hyperaemic, swollen optic discs and serum lactate is 2.1 mmol/L. Glucose and ketones are normal and urine microscopy shows no crystals. What is the diagnosis?
1. ADiabetic ketoacidosis
2. BMethanol poisoning
3. CIsopropyl alcohol ingestion
4. DSalicylate toxicity
Answer and explanation in LearnFree account
Question 10 · Easy
Which organ injury causes most late deaths after paraquat ingestion?
1. AFulminant hepatic failure
2. BProgressive pulmonary fibrosis
3. CAcute haemorrhagic pancreatitis
4. DCerebral oedema
Answer and explanation in LearnFree account
Question 11 · Medium
An hour after a cobra bite on the hand, a child has bilateral ptosis, diplopia and pooling of saliva. ASV has been started and the airway is being watched. Which adjunct may reverse the weakness?
1. ANeostigmine with atropine
2. BIV dexamethasone
3. CCalcium gluconate infusion
4. DPralidoxime
Answer and explanation in LearnFree account
Question 12 · Easy
Rectal temperature is 41.2 °C in a road worker brought confused from a construction site in Nagpur on a May afternoon; his skin is hot and dry. What is the diagnosis?
1. AHeat stroke
2. BHeat exhaustion
3. CMalignant hyperthermia
4. DHeat syncope
Answer and explanation in LearnFree account
Question 13 · Medium
Urine turns blue-green when sodium dithionite is added in an alkaline medium. The patient is a farmer who drank a weed-killer two hours ago and has painful mouth ulcers. Which poison is confirmed?
1. AGlyphosate
2. BParaquat
3. CAluminium phosphide
4. DChlorpyrifos
Answer and explanation in LearnFree account
Question 14 · Easy
Which sign is the main end-point when titrating atropine in organophosphate poisoning?
1. AA clear chest on auscultation
2. BHeart rate above 140/min
3. CReturn of muscle power
4. DFully dilated pupils
Answer and explanation in LearnFree account
Question 15 · Easy
Which four snakes make up India's 'Big Four', against whose venoms polyvalent anti-snake venom is raised?
1. ACobra, krait, hump-nosed pit viper, saw-scaled viper
2. BCobra, common krait, Russell's viper, saw-scaled viper
3. CKrait, Russell's viper, sea snake, python
4. DCobra, king cobra, krait, bamboo pit viper
Answer and explanation in LearnFree account
Question 16 · Easy
Prazosin is the drug of choice for envenomation by which creature in India?
1. ASpectacled cobra
2. BCommon krait
3. CHoneybee
4. DRed scorpion
Answer and explanation in LearnFree account
Question 17 · Hard
Consider these statements about heat stroke: 1. Patients with exertional heat stroke may still be sweating 2. Dantrolene shortens cooling time and improves survival 3. Rhabdomyolysis, DIC and acute kidney injury are recognised complications 4. Cooling should begin before transfer to hospital. Which are correct?
1. A1, 2 and 3 only
2. B1, 2, 3 and 4
3. C3 and 4 only
4. D1, 3 and 4 only
Answer and explanation in LearnFree account
Question 18 · Easy
Generalised muscle aches, stiffness on moving and dark brown urine began two hours after a fisherman off the Odisha coast was bitten on the foot while sorting his net. CK is 45,000 U/L, there is no bleeding and the 20WBCT is normal. Which snake is most likely?
1. ARussell's viper
2. BSaw-scaled viper
3. CSea snake
4. DCommon krait
Answer and explanation in LearnFree account
Question 19 · Hard
After a hooch tragedy, a man reaches the district hospital with pH 6.98, HCO3 4 mmol/L, a high osmolar gap and loss of vision in both eyes. Fomepizole is not available. Which plan is best?
1. AEthanol alone, then observe
2. BIV thiamine and glucose
3. CEthanol plus urgent haemodialysis
4. DIV bicarbonate alone
Answer and explanation in LearnFree account
Question 20 · Medium
Painful cramps in the calves and abdomen trouble a salt-pan worker in Kutch who drinks only plain water through his hot shift. His temperature is normal and he is alert. What should he be given?
1. AIV calcium gluconate
2. BOral rehydration salts
3. CPlain water in larger amounts
4. DOral diazepam
Answer and explanation in LearnFree account
Question 21 · Hard
Consider these statements about anti-snake venom use in India: 1. A skin test dose should not be done before ASV 2. ASV is given intravenously 3. ASV reliably neutralises hump-nosed pit viper venom 4. ASV is still indicated if signs of envenomation persist a day or more after the bite. Which are correct?
1. A1 and 2 only
2. B1, 2, 3 and 4
3. C2, 3 and 4 only
4. D1, 2 and 4 only
Answer and explanation in LearnFree account
Question 22 · Medium
Bleeding from venepuncture sites, then passage of cola-coloured urine and oliguria, follow a Russell's viper bite in a sugar-cane cutter. After ASV, serum creatinine is 5.2 mg/dL and potassium 6.4 mmol/L (3.5-5.0) with peaked T waves. Besides calcium gluconate, what is the next step?
1. AMore ASV until urine output returns
2. BHaemodialysis
3. CForced alkaline diuresis
4. DIV mannitol
Answer and explanation in LearnFree account
Question 23 · Easy
Which metabolite causes blindness in methanol poisoning?
1. AAcetaldehyde
2. BOxalic acid
3. CFormic acid
4. DFormaldehyde alone
Answer and explanation in LearnFree account
Question 24 · Medium
Paraquat concentrates in the lung even when swallowed, not inhaled. Which mechanism explains this?
1. ADirect inhalation of the fumes
2. BBinding to surfactant protein
3. CExcretion through exhaled air
4. DPolyamine-pump uptake into alveolar cells
Answer and explanation in LearnFree account
Question 25 · Medium
In Thiruvananthapuram, a rubber tapper is bitten by a small brown snake with an upturned snout, identified from a phone photo as a hump-nosed pit viper. His 20WBCT is positive and urine output is falling. What is the best management?
1. ASupportive care: FFP and dialysis as needed
2. BA heparin infusion
3. CPolyvalent ASV until the blood clots
4. DNeostigmine with atropine
Answer and explanation in LearnFree account

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Envenomation, heat illness and toxic exposures

CT of the brain in a survivor of an illicit-liquor poisoning shows bilateral putaminal necrosis. Which poison is most likely?

Villagers bring a man bitten on the foot by a snake. Which first-aid steps are recommended? 1. Reassure him and immobilise the limb like a fracture 2. Apply a tight arterial tourniquet 3. Cut the bite and suck out the venom 4. Remove rings, anklets and tight clothing and transport quickly

Fomepizole is used in methanol poisoning because it

On the third day after recovering from a cholinergic crisis due to an organophosphate, a man develops weakness of neck flexion, proximal limbs and facial muscles, with falling breathing capacity. He is fully conscious and has no fasciculations. What is the diagnosis?

Silver nitrate paper held over the gastric aspirate turns black in a man who swallowed tablets kept for storing grain. Two hours later he is in shock (BP 70/40 mmHg) despite 2 litres of saline, with ST changes on the ECG and pH 7.12. Which statement about his management is correct?

Within an hour of swallowing a mouthful of 20% paraquat, a farm worker reaches the casualty of a taluk hospital. He is conscious, vomiting and has no mouth ulcers yet. The staff, thinking of pesticides, ask for pralidoxime. What is the most useful first step?

Consider these statements about red scorpion envenomation: 1. Atropine is best avoided 2. Prazosin acts by blocking alpha-1 receptors 3. Myocarditis can lead to pulmonary oedema 4. Propranolol is the first-line drug for the hypertension. Which are correct?

Which organ injury causes most late deaths after paraquat ingestion?

An hour after a cobra bite on the hand, a child has bilateral ptosis, diplopia and pooling of saliva. ASV has been started and the airway is being watched. Which adjunct may reverse the weakness?

Rectal temperature is 41.2 °C in a road worker brought confused from a construction site in Nagpur on a May afternoon; his skin is hot and dry. What is the diagnosis?

Urine turns blue-green when sodium dithionite is added in an alkaline medium. The patient is a farmer who drank a weed-killer two hours ago and has painful mouth ulcers. Which poison is confirmed?

Which sign is the main end-point when titrating atropine in organophosphate poisoning?

Which four snakes make up India's 'Big Four', against whose venoms polyvalent anti-snake venom is raised?

Prazosin is the drug of choice for envenomation by which creature in India?

Generalised muscle aches, stiffness on moving and dark brown urine began two hours after a fisherman off the Odisha coast was bitten on the foot while sorting his net. CK is 45,000 U/L, there is no bleeding and the 20WBCT is normal. Which snake is most likely?

After a hooch tragedy, a man reaches the district hospital with pH 6.98, HCO3 4 mmol/L, a high osmolar gap and loss of vision in both eyes. Fomepizole is not available. Which plan is best?

Painful cramps in the calves and abdomen trouble a salt-pan worker in Kutch who drinks only plain water through his hot shift. His temperature is normal and he is alert. What should he be given?

Bleeding from venepuncture sites, then passage of cola-coloured urine and oliguria, follow a Russell's viper bite in a sugar-cane cutter. After ASV, serum creatinine is 5.2 mg/dL and potassium 6.4 mmol/L (3.5-5.0) with peaked T waves. Besides calcium gluconate, what is the next step?

Which metabolite causes blindness in methanol poisoning?

Paraquat concentrates in the lung even when swallowed, not inhaled. Which mechanism explains this?

In Thiruvananthapuram, a rubber tapper is bitten by a small brown snake with an upturned snout, identified from a phone photo as a hump-nosed pit viper. His 20WBCT is positive and urine output is falling. What is the best management?