Caustics

Question 1

List 8 factors that influence extent of injury from caustic exposure

Answer 1

1. Type of agent
2. concentration
3. volume
4. viscosity
5. duration of contact
6. pH/pKa
7. titratable alkali (acid) reserve)
8. presence/absence of food in tomach

Question 2

what are the 4 classic phases of caustic damage

Answer 2

1. necrosis, invasion by bacteria and PMNs
2. vascular thrombosis
3. sloughing of superficial layers over 2-5d
4. granulation formation, collagen deposition and reepithelialisation (1wk to months)

Question 3

how do strictures form after caustic injury

Answer 3

contraction of scarred mucosa

Question 4

what are the endoscopy grades of caustic injury

Answer 4

1st degree: edema/hyperemia
2nd degree: superficial ulcers/whitish membranes, exudates, friability, hemorrhage
IIa: not circufrential
iib: almost circumfrential
3rd degree: full thickness, necrotic mucosa, frank perforation

Question 5

risk of stricture with grades of caustic injury

Answer 5

1st: none
2nd: 15-30% (circumfrential 75%)
3rd : 90%

Question 6

when should endoscopy be performed? and why

Answer 6

less than 24hr. longer than that and the risk of perforation increases

Question 7

indications for endoscopy

Answer 7

1. intentional ingestion

2. S/S: vomiting, drooling, dysphonia

Question 8

How are phenol and formaldehyde caustic

Answer 8

protoplasmic poisons cause protein denaturation, coagulation necrosis

Question 9

what are the manifestations of phenol and formaldehyde poisoning

Answer 9

dysrhythmias, seizures, coma hypotension

Question 10

how do you treat topical phenol exposure and why

Answer 10

irrigate with PEG, if you irrigate with water the phenol may penetrate deeper.

Question 11

define caustic

Answer 11

an agent capable of causing tissue injury on contac

acid pH less than 3, alkali pH greater than 11

Question 12

household alkali examples

Answer 12

liquid drain cleaner (KOH, NaOH)
crystal drain cleaners (NaOH)
oven cleaners (NaOH)
rust remover (NaOH)

Question 13

household acid examples

Answer 13

Liquid drain cleaners (H2SO4)
rust remover (HF)
Toilet bowl/swimming pool cleaner (HCl)

Question 14

Differentiate types of injuries caused by acids/alkalis

Answer 14

acids: coagulation necrosis
aklali: liquefication necrosis

Question 15

what is the risk and treatment of hydrogen peroxide ingestion

Answer 15

gas emboli, need to image to look for these in chest, abdo and portal system–>Tx: hyperbaric O2

Question 16

how is dermal HF acid exposure result in marked toxicity

Answer 16

permeable, dissociates, causes hypoCa, hyperk causing dysrhythmias and death. concentrated 2%TBSA can be fatal

Question 17

List systemic complications of HF exposure

Answer 17

cardiac: prolonged QT, Hypo Mg, HypoCa, VF/VT
hemorrhage: hypoCa disrupts coagulation cascade
opthalmic: corneal ulcers, edema, necrosis
inhalational exposure: mucosa and pulmonary irritant,

Question 18

List 5 injuries related to disc battery ingestion:

Answer 18

1. pressure necrosis: from obstruction
2. caustic injury: leaking of alkaline medium
3. electrical injury
4. heavy metal toxicity
5. ulceration, perforation, fistulas

Question 19

What is the evaluation and management of button disc battery ingestion?

Answer 19

• Radiography for position of battery
  o Airway or Esophageal: Immediate emoval
  o Gastric or intestinal: Stool monitoring and repeat radiography 1 weekif it does not pass

Question 20

What are your steps for mgmt of Severe Systemic HF toxicity: IF signs of severe toxicity develop (arrhythmias),

Answer 20

need rapid IV infusion
– CaCl or Ca-gluconate à May need several grams
– 4 g IV MgSO4 over 20min
– Treat hyperK and acidosis
– Aggressive monitoring of Mg, K, Ca
\+/- HD if renal function compromised