Harpic and corrosive ingestion: why CT replaced endoscopy

A young woman is brought in an hour after swallowing Harpic during an argument. She is talking, her mouth looks almost normal, and she says the pain is settling. The instinct — reassuring mouth, stable patient, book an endoscopy for the morning — is wrong on both counts.

Two things have changed in how corrosive ingestion should be managed, and both cut against what most of us were taught.

First: it is an acid burn, not a detergent

Harpic Power Plus is formulated at approximately 10.5% w/v hydrochloric acid. That is a strong acid ingestion and should be triaged as one. Drain and oven cleaners are usually the opposite — strong alkalis, injuring by liquefactive necrosis — but the emergency pathway is the same for both.

The physical form matters more than people expect. WHO's point, echoed in the surgical literature: solids do maximum damage to the mouth and pharynx, while liquids transit rapidly and burn the oesophagus and stomach. So a liquid like Harpic can leave an unremarkable mouth and a destroyed stomach. The WSES guideline says it plainly:

It is commonly accepted that clinical symptoms do not correlate reliably with the extent of gastrointestinal damage; the absence of pain and of oral lesions does not rule out life-threatening gastrointestinal injuries.

Second: CT, not endoscopy

This is the part that surprises people. The 2019 WSES guideline on oesophageal emergencies states:

Emergency management of caustic ingestion can be performed safely relying on computed tomographic evaluation (Grade 2A).

Contrast-enhanced CT outperformed endoscopy both at detecting transmural injury and at predicting stricture formation, and a CT-based algorithm for selecting patients for emergency surgery significantly improved outcomes compared with endoscopy-based management. Endoscopy's central weakness is that it cannot reliably predict transmural necrosis — which exposes patients either to futile surgery or to inappropriate watch-and-wait.

The protocol: CT of neck, thorax and abdomen 3–6 hours after ingestion, before and after intravenous non-ionic contrast at 2–3 mL/s, 2 mL/kg, with an 18–25 second acquisition and a 90 second scan delay.

The finding that decides surgery: absence of post-contrast wall enhancement. Its presence at any level — oesophagus, stomach, duodenum, bowel, colon — is an indication for emergency surgery.

Endoscopy still has four clear indications: CT unavailable, contrast contraindicated (renal failure, iodine allergy), CT interpretation uncertain, or a paediatric patient — where severe injury is rare and radiation exposure matters. It also remains the main diagnostic and therapeutic tool for strictures later on.

Before either: the airway

Stridor, hoarseness, voice change, drooling or respiratory distress mean the airway is already involved, and oedema progresses. Intubate early and electively rather than late and in extremis. Vapour aspiration — ammonia, formaldehyde — can add airway burns to the ingestion injury.

Five things not to do

Do not neutralise. Acid–base neutralisation is exothermic. Giving an alkali after an acid adds a thermal burn to a chemical one and generates gas in an already-injured stomach.

Do not induce vomiting. The AACT/EAPCCT position paper names corrosives explicitly: ipecac should not be administered after ingestion of a corrosive substance such as an acid or alkali. Vomiting drags the corrosive back across the oesophagus and larynx, burning both a second time.

Do not perform gastric lavage. The position paper's general verdict is that lavage "should not be performed routinely, if at all." Here it is specifically hazardous — passing a tube and instilling fluid into a burned, friable stomach risks perforation.

Do not give activated charcoal. Corrosives are not adsorbed to charcoal, so there is nothing to gain, and it coats the mucosa and obscures the assessment you may need.

Do not pass a nasogastric tube blindly. A freshly burned oesophagus perforates. Nasogastric feeding is appropriate in patients who cannot eat — placed under direct vision, not blind.

The bloods, and why normal ones don't reassure

WSES specifies full blood count; sodium, potassium, chloride, magnesium, calcium; urea and creatinine; bilirubin, ALT and AST; pH and lactate; blood alcohol; and β-hCG in women of childbearing age (Grade 2A).

But: initial normal laboratory values do not rule out transmural necrosis. It is the trend on repeat testing that matters. Predictors of transmural necrosis and poor outcome are severe acidosis with high lactate, deranged liver function, leucocytosis, raised CRP, renal failure and thrombocytopenia.

Specific corrosives also cause systemic effects independent of the burn — hypocalcaemia with phosphoric and hydrofluoric acids, hyponatraemia with strong acids and alkalis, hypokalaemia and acidosis.

What each CT grade means

Mediastinal fat stranding is uniformly present in Grade II. Patients without full-thickness necrosis should have non-operative management (Grade 1C), with close clinical and biological monitoring — and any deterioration should prompt repeat CT and consideration for surgery. Roughly 5% evolve to transmural necrosis.

The months afterwards

Stricture is the commonest and most disabling long-term complication, usually appearing within four months and involving the oesophagus more often than the stomach. Dysphagia or regurgitation should prompt immediate upper GI evaluation.

Endoscopic dilation is first-line and should be attempted 3–6 weeks after ingestion in patients with fewer than three short strictures under 5 cm (Grade 2A), at intervals of 1–3 weeks. Three to five sessions usually suffice. Reconstruction is considered after five to seven failed attempts.

The requirement people skip

Psychiatric evaluation is mandatory in all patients prior to hospital discharge (Grade 2C).

Not a courtesy — a graded recommendation. Most of these ingestions are deliberate, and the guideline notes that long-term control of the psychiatric illness is what prevents recurrence. A patient who is medically fit for discharge is not therefore fit for discharge.

Where the guideline stays silent

WSES makes no recommendation on corticosteroids for caustic injury, does not address prophylactic antibiotics for it, and does not grade early dilution with water or milk. We have not filled those gaps, and neither should a protocol that claims to follow the guideline.

Bottom line

Treat Harpic as an acid burn. Secure the airway before it closes. Do not neutralise, lavage, charcoal, induce vomiting, or pass a blind tube. Get a contrast CT at 3–6 hours rather than booking an endoscopy. Absent wall enhancement means theatre. Normal bloods and a normal-looking mouth mean nothing. And nobody goes home without a psychiatric assessment.

Our corrosive poisoning tool walks through this in six steps, with the CT grade selector giving the disposition directly, and every recommendation labelled with the strength of evidence behind it. It sits alongside our tools for wheat pill and rat poison, copper sulphate and anticoagulant rat poison.

ReviseFCPS1 is built by doctors in Pakistan, for doctors in Pakistan. All our clinical tools are free. If you are preparing for FCPS Part 1, try it free for 7 days — 10,176 doctor-verified MCQs and 8,236 real exam recalls.