Caustic Ingestion Flashcards
What is caustic ingestion, and what can it lead to?
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.
What substances commonly cause caustic ingestion in children?
Common substances involved in caustic ingestion include household cleaning products, hair relaxers, and dyes. In children, the ingestion is typically accidental and unwitnessed.
What is the clinical challenge with caustic ingestion?
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.
What are the major causes of morbidity and mortality in caustic ingestion?
Ingestion of highly acidic or alkaline substances can cause severe aerodigestive and proximal GIT injuries, leading to significant morbidity and mortality.
How should children with suspected caustic ingestion be managed?
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.
What is the primary cause of accidental caustic ingestion in children?
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.
How should all caustic ingestions be initially assumed to affect the child?
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.
What types of agents typically cause caustic injuries?
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
What substances do not typically cause caustic injuries but can still cause harm?
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
What factors influence the degree and extent of caustic injury after ingestion?
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
What pH values are associated with severe caustic injury?
Severe caustic injury is associated with substances having a pH greater than 12 (alkali) or less than 1.5 (acid).
How do different forms of caustic substances affect injury severity?
• 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.
What is the difference between injury caused by alkaline and acidic substances?
• 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.
What factors influence the severity of caustic injury after ingestion?
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
What pH values are associated with severe caustic injury?
Severe injury occurs with substances having a pH greater than 12 (alkali) or less than 1.5 (acid).
How does the physical form of caustic substances affect injury?
• 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.
What type of necrosis does an alkaline substance cause?
Alkaline substances cause liquefactive necrosis, particularly in the pharyngo-oesophageal region.
What is the risk associated with alkaline substances?
Alkaline substances can cause deeper injury, increase the risk of perforation, and lead to scarring and fibrosis.
How does acid cause injury after ingestion
Acid causes coagulative necrosis on contact and typically glides down the oesophagus without causing severe damage.
Where is the pathological effect of acid usually seen?
The antrum of the stomach is typically where the pathological effects of acid ingestion are observed.
Why is the duodenum usually protected from injury by acid?
The pyloric spasm protects the duodenum from acid injury.
How does the taste of acid influence ingestion in children?
Acid tastes sour, and children may be reluctant to swallow more, resulting in less damage.
What is a common history in children with caustic ingestion?
There may be a history of witnessed ingestion, but patients can also be asymptomatic with no oral injury, though distal injury may still occur.
What symptoms indicate possible airway injury in caustic ingestion?
Airway injury symptoms include:
• Hoarseness
• Stridor
• Dyspnoea
• Tachypnoea
What are the symptoms of oesophageal injury after caustic ingestion?
Oesophageal injury symptoms include:
• Drooling
• Dysphagia
• Reluctance to eat or drink
What signs suggest mediastinitis due to perforation from caustic ingestion?
Symptoms of mediastinitis include:
• Retrosternal or abdominal pain
• Fever, tachycardia, and signs of severe sepsis
• Hypovolaemic or septic shock
What are the signs of distal GIT or gastric injury from caustic ingestion?
Symptoms of distal GIT/gastric injury include:
• Epigastric pain and/or tenderness
• Peritonism
• Sepsis
• Haematemesis
How long should a patient be observed after caustic ingestion, even if asymptomatic?
Observation for 12 to 24 hours is mandatory, even in asymptomatic patients.
What is the first step in managing children with complications of caustic ingestion?
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
What should not be done in cases of caustic ingestion and why?
Do not induce vomiting because it can worsen the burn as the caustic substance is brought back into contact with the tissues.
Which patients require referral and investigation for caustic ingestion?
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
What type of X-ray is needed to assess for complications like pneumo-mediastinum or aspiration after caustic ingestion?
Erect chest X-ray is required to screen for:
• Pneumo-mediastinum
• Pneumoperitoneum
• Assess the lung fields for evidence of aspiration
What is a 99mTc Sucralfate scan, and when is it useful?
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.
When should flexible endoscopy be performed in cases of caustic ingestion?
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.
What does further management of caustic ingestion depend on?
Further management depends on the severity and grading of the oesophageal burn, which is determined through endoscopic assessment.
What are the grades of oesophageal burns based on endoscopic necrosis appearance?
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
What is the risk of stricture formation based on endoscopic grading?
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%
What is the gold standard for assessing oesophageal injury after caustic ingestion?
Endoscopy.
What does management depend on
Management depends on the severity and grading of the oesophageal burn.
What is the general medical management for caustic ingestion?
Proton pump inhibitors, oral anti-fungal preparations, and intravenous or NGT feeds until the patient tolerates oral feeds.
When is a contrast meal performed after caustic ingestion?
At 3 weeks after injury to assess the degree of oesophageal stricturing.
What are the long-term sequelae of severe oesophageal injury?
Stricture formation, growth retardation, recurrent aspiration pneumonia, possible perforations, and increased risk of oesophageal malignancy.
What are the prognostic indicators for stricture dilation after oesophageal injury?
Early oesophagoscopy findings of grade IIb or III injury, oesophageal stenosis on contrast oesophagogram, and persistent dysphagia at 3 weeks.
When does stricture dilation typically start and how often is it repeated?
Stricture dilation starts at 3 weeks post-injury and is repeated weekly or every second week until healing is achieved.
What adjunct therapies may be used to modulate scar formation?
Topical or intra-lesion steroids or Mitomycin C.
What is the surgical option for refractory oesophageal strictures?
Oesophageal replacement with a gastric tube, small bowel, or colonic interposition.
