Caustic Ingestion

Question 1

What is caustic ingestion, and what can it lead to?

Answer 1

Caustic ingestion refers to the ingestion of highly acidic (pH < 2) or alkaline (pH > 11.5) substances, which can cause a range of injuries, from no injury to fatal sequelae. In 20% of cases, ongoing management is needed to prevent stricture formation.

Question 2

What substances commonly cause caustic ingestion in children?

Answer 2

Common substances involved in caustic ingestion include household cleaning products, hair relaxers, and dyes. In children, the ingestion is typically accidental and unwitnessed.

Question 3

What is the clinical challenge with caustic ingestion?

Answer 3

Clinical symptoms and signs related to oesophageal injury are often misleading and may not always correlate with the severity of the injury or the ultimate outcome.

Question 4

What are the major causes of morbidity and mortality in caustic ingestion?

Answer 4

Ingestion of highly acidic or alkaline substances can cause severe aerodigestive and proximal GIT injuries, leading to significant morbidity and mortality.

Question 5

How should children with suspected caustic ingestion be managed?

Answer 5

All children with suspected caustic ingestion require a period of observation and investigation to:
• Confirm or exclude mucosal injury
• Grade the severity of the injury

Children at risk for airway injury or gastro-intestinal perforation require aggressive resuscitation and stabilization as these can lead to life-threatening complications.

Question 6

What is the primary cause of accidental caustic ingestion in children?

Answer 6

Accidental caustic ingestion often occurs when caregivers store household cleaning products and other caustic agents within reach of small children, or when these agents are decanted into unmarked or inappropriate containers like cooldrink bottles.

Question 7

How should all caustic ingestions be initially assumed to affect the child?

Answer 7

All caustic ingestions should be assumed to have caused serious injury until proven otherwise. Most patients ultimately experience mild injuries, but may require several days of intravenous hydration or nasogastric feeds until they can tolerate oral feeds.

Question 8

What types of agents typically cause caustic injuries?

Answer 8

Common agents that cause caustic injuries include:
• Industrial detergents
• Drain cleaners and disinfectants
• Oven cleaners
• Hair relaxers and dyes
• Automatic washing machine and dishwasher detergents
• Industrial peroxide preparations
• Potassium permanganate crystals (‘Condy’s crystals’)
• Lye, Potash, Caustic soda, Lime, Whitewash
• Sodium phosphate
• Ammonium chloride solutions

Question 10

What substances do not typically cause caustic injuries but can still cause harm?

Answer 10

Substances that do not typically cause caustic injuries but may still cause harm and should prompt further investigation and referral include:
• Paraffin
• Petroleum
• Organophosphates and other pesticides
• Household bleach

Question 11

What factors influence the degree and extent of caustic injury after ingestion?

Answer 11

The degree and extent of caustic injury depend on:
• Physical form of the substance (crystal, liquid, powder)
• pH and concentration of the substance
• Quantity swallowed
• Contact time with tissues

Question 12

What pH values are associated with severe caustic injury?

Answer 12

Severe caustic injury is associated with substances having a pH greater than 12 (alkali) or less than 1.5 (acid).

Question 13

How do different forms of caustic substances affect injury severity?

Answer 13

• Crystalline substances tend to lodge in the proximal oesophagus.
• Caustic alkaline liquids pass quickly through the oropharynx, causing injury to the upper, middle, and lower oesophagus.
• Powder forms can be inhaled, leading to acute respiratory symptoms.

Question 14

What is the difference between injury caused by alkaline and acidic substances?

Answer 14

• Alkaline substances:
• Cause liquefactive necrosis of tissues, particularly in the pharyngo-oesophageal region.
• Lead to deeper injury, higher perforation risk, and worse scarring and fibrosis.
• Acidic substances:
• Cause coagulative necrosis on contact.
• Typically cause less damage in the oesophagus, often seen in the antrum of the stomach.
• Duodenum is usually protected due to pyloric spasm.
• Sour taste may cause the child to swallow less, reducing injury.

Question 15

What factors influence the severity of caustic injury after ingestion?

Answer 15

The severity depends on:
• The physical form of the substance
• The pH and concentration of the substance
• The quantity swallowed
• The contact time with tissues

Question 16

What pH values are associated with severe caustic injury?

Answer 16

Severe injury occurs with substances having a pH greater than 12 (alkali) or less than 1.5 (acid).

Question 17

How does the physical form of caustic substances affect injury?

Answer 17

• Crystals often lodge in the proximal oesophagus.
• Alkaline liquids pass quickly through the oropharynx, causing injuries in the upper, middle, and lower oesophagus.
• Powders can be inhaled, causing respiratory symptoms.

Question 18

What type of necrosis does an alkaline substance cause?

Answer 18

Alkaline substances cause liquefactive necrosis, particularly in the pharyngo-oesophageal region.

Question 19

What is the risk associated with alkaline substances?

Answer 19

Alkaline substances can cause deeper injury, increase the risk of perforation, and lead to scarring and fibrosis.

Question 20

How does acid cause injury after ingestion

Answer 20

Acid causes coagulative necrosis on contact and typically glides down the oesophagus without causing severe damage.

Question 21

Where is the pathological effect of acid usually seen?

Answer 21

The antrum of the stomach is typically where the pathological effects of acid ingestion are observed.

Question 22

Why is the duodenum usually protected from injury by acid?

Answer 22

The pyloric spasm protects the duodenum from acid injury.

Question 23

How does the taste of acid influence ingestion in children?

Answer 23

Acid tastes sour, and children may be reluctant to swallow more, resulting in less damage.

Question 24

What is a common history in children with caustic ingestion?

Answer 24

There may be a history of witnessed ingestion, but patients can also be asymptomatic with no oral injury, though distal injury may still occur.

Question 25

What symptoms indicate possible airway injury in caustic ingestion?

Answer 25

Airway injury symptoms include: • Hoarseness • Stridor • Dyspnoea • Tachypnoea

Question 26

What are the symptoms of oesophageal injury after caustic ingestion?

Answer 26

Oesophageal injury symptoms include: • Drooling • Dysphagia • Reluctance to eat or drink

Question 27

What signs suggest mediastinitis due to perforation from caustic ingestion?

Answer 27

Symptoms of mediastinitis include: • Retrosternal or abdominal pain • Fever, tachycardia, and signs of severe sepsis • Hypovolaemic or septic shock

Question 28

What are the signs of distal GIT or gastric injury from caustic ingestion?

Answer 28

Symptoms of distal GIT/gastric injury include: • Epigastric pain and/or tenderness • Peritonism • Sepsis • Haematemesis

Question 29

How long should a patient be observed after caustic ingestion, even if asymptomatic?

Answer 29

Observation for 12 to 24 hours is mandatory, even in asymptomatic patients.

Question 30

What is the first step in managing children with complications of caustic ingestion?

Answer 30

Immediate resuscitation is required, which includes: • Airway management for respiratory complications • Fluid & blood product administration if the patient is dehydrated or haemodynamically unstable due to blood loss • Initiation of antibiotic therapy if there is established sepsis

Question 31

What should not be done in cases of caustic ingestion and why?

Answer 31

Do not induce vomiting because it can worsen the burn as the caustic substance is brought back into contact with the tissues.

Question 32

Which patients require referral and investigation for caustic ingestion?

Answer 32

Referral and investigation are required for: • All patients with a history of witnessed caustic ingestion • All patients with oropharyngeal burns suggesting possible caustic injury • All patients with respiratory, GIT, or systemic symptoms after suspected caustic ingestion

Question 33

What type of X-ray is needed to assess for complications like pneumo-mediastinum or aspiration after caustic ingestion?

Answer 33

Erect chest X-ray is required to screen for: • Pneumo-mediastinum • Pneumoperitoneum • Assess the lung fields for evidence of aspiration

Question 34

What is a 99mTc Sucralfate scan, and when is it useful?

Answer 34

A 99mTc Sucralfate scan is a non-invasive screening tool used to exclude oesophageal injury. It is helpful in institutions with nuclear medicine facilities. • Negative result (no adherence of sucralfate to oesophageal mucosa) means the patient does not require endoscopic assessment.

Question 35

When should flexible endoscopy be performed in cases of caustic ingestion?

Answer 35

Flexible endoscopy should be performed at an appropriate referral centre: • For patients with a positive sucralfate scan • In centres where the sucralfate scan is not available Endoscopy is the gold standard for establishing the presence and grading of injury.

Question 36

What does further management of caustic ingestion depend on?

Answer 36

Further management depends on the severity and grading of the oesophageal burn, which is determined through endoscopic assessment.

Question 37

What are the grades of oesophageal burns based on endoscopic necrosis appearance?

Answer 37

The grading system for oesophageal burns based on endoscopic necrosis appearance is: • Grade 0: No evidence of injury • Grade I: Mucosal injury • Grade IIa: Superficial, non-circumferential ulceration • Grade IIb: Deep or circumferential ulceration • Grade IIIa: Multiple scattered ulcerations • Grade IIIb: Extensive necrosis

Question 38

What is the risk of stricture formation based on endoscopic grading?

Answer 38

The risk of stricture formation associated with each grade is: • Grade 0: 0% • Grade I: <5% • Grade IIa: <5% • Grade IIb: 71.4% • Grade IIIa: ~100% • Grade IIIb: ~100%

Question 39

What is the gold standard for assessing oesophageal injury after caustic ingestion?

Answer 39

Endoscopy.

Question 40

What does management depend on

Answer 40

Management depends on the severity and grading of the oesophageal burn.

Question 41

What is the general medical management for caustic ingestion?

Answer 41

Proton pump inhibitors, oral anti-fungal preparations, and intravenous or NGT feeds until the patient tolerates oral feeds.

Question 42

When is a contrast meal performed after caustic ingestion?

Answer 42

At 3 weeks after injury to assess the degree of oesophageal stricturing.

Question 43

What are the long-term sequelae of severe oesophageal injury?

Answer 43

Stricture formation, growth retardation, recurrent aspiration pneumonia, possible perforations, and increased risk of oesophageal malignancy.

Question 44

What are the prognostic indicators for stricture dilation after oesophageal injury?

Answer 44

Early oesophagoscopy findings of grade IIb or III injury, oesophageal stenosis on contrast oesophagogram, and persistent dysphagia at 3 weeks.

Question 45

When does stricture dilation typically start and how often is it repeated?

Answer 45

Stricture dilation starts at 3 weeks post-injury and is repeated weekly or every second week until healing is achieved.

Question 46

What adjunct therapies may be used to modulate scar formation?

Answer 46

Topical or intra-lesion steroids or Mitomycin C.

Question 47

What is the surgical option for refractory oesophageal strictures?

Answer 47

Oesophageal replacement with a gastric tube, small bowel, or colonic interposition.