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Toxicity, Ammonia: Treatment & Medication
Updated: Oct 8, 2009
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Prehospital Care
- Immediately remove the patient from the contaminated environment.
- Remove all the patient's clothing.
- Support airway, breathing, and circulation (ABCs) as per advanced cardiac life support (ACLS) and advanced trauma life support (ATLS) guidelines. (ACLS and ATLS guidelines may vary by region, according to training and legal responsibilities of prehospital care providers.)
- If the patient is sufficiently stable, begin copious skin and eye irrigation immediately following exposure. Continue irrigation for at least 20 minutes. Patients then can be covered with a dry, clean dressing and sheet.
- Provide a container for patients with ingestion exposure.
Emergency Department Care
- Decontaminate the patient (if not previously performed) and support ABCs as necessary. Provide warmed humidified oxygen.
- As with all burns, patients with facial or oral lesions are at high risk for developing laryngeal edema. Airway intervention should be aggressive.
- Indications for intubation include severe respiratory distress (hypoxemia, hypercapnia), stridor, hoarseness, deep facial burns, burns identified by bronchoscopy or endoscopy, and depressed mental status.
- If intubation is necessary, use large size tube to prevent plugging by sloughed mucosa.
- Some consider procedural sedation preferable to rapid sequence intubation (RSI) because paralysis is risky with a difficult and edematous airway. Furthermore, ventilation cannot be predicted as successful if intubation fails in this context. Positive end respiratory pressure (PEEP) generally is useful (5 cm water minimum).
- Beware of fluid over-resuscitation. Patients may have or may be developing acute lung injury (ALI).
- Follow standard initial burn management. (Discussion is beyond the scope of this article.)
- Once the patient is adequately stable, irrigate skin with tepid water for at least 15 minutes. Continue frequent regular irrigation for the first 24 hours, in addition to conventional burn management.
- Debride wounds and dress with 1% silver sulfadiazine (avoid using on face).
- Administer tetanus prophylaxis.
- Irrigate eye injuries with copious amounts of tepid water for at least 30 minutes or until conjunctival pH is 6.8-7.4; use pH indicator paper to monitor. Examine eye with slit-lamp and fluorescein staining.
- Perform tonometry to determine if intraocular pressure is elevated.
- Consult ophthalmology promptly because of risk of perforation and/or permanent eye damage.
- Treat ingestions using the following steps:
- Rinse mouth and dilute ingestion with approximately 250 mL of water or milk.
- Do not induce emesis, so as not to reproduce injury with a second pass of toxin.
- Consult gastroenterology promptly for subsequent endoscopic evaluation (not often performed before 12 hours postingestion).
Consultations
When appropriate, immediately consult an intensivist, medical toxicologist, ophthalmologist (all eye injuries), gastroenterologist, and general and plastic surgeons.
Medication
Management of toxic exposure to ammonia is largely supportive, and medical therapy is directed at hypoxia, bronchospasm, acute lung injury (ALI), hypovolemia, and burns of the skin and eyes.
Antibiotics and corticosteroids are controversial therapies following ammonia inhalation and ingestion exposures.
Although antibiotics and corticosteroids are often used in the acute treatment of patients with inhalation injury, neither has been shown to improve outcome and many believe that corticosteroids may actually increase morbidity. Corticosteroids are recommended to treat bronchospasm in patients with underlying reactive airways disease and acute inhalation injury or for chronic respiratory complications that follow an acute inhalation injury. Patients experiencing signs of airway edema after caustic exposure may benefit from IV administration of dexamethasone (adults: 10 mg; children: 0.6 mg/kg up to 10 mg max).
Use of steroids for the treatment of caustic injuries after caustic ingestion is still very controversial.Intravenous corticosteroids and antibiotics administration can be considered in symptomatic patients following ammonia ingestion with grade IIb (near-circumferential) caustic injuries. Presumably, corticosteroids are administered in order to decrease the incidence and severity of esophageal strictures that occur during healing from significant alkaline injuries. Antibiotics are given because of increased risk of mediastinitis associated with full-thickness esophageal alkaline corrosive burns and steroid use. Although controlled animal studies do support the use of these therapies, no well-controlled human trials have been performed; thus, corticosteroids and antibiotics should be administered in consultation with a GI specialist and surgeon.
If steroids are administered, the recommended dose is 1-2 mg/kg/d of methylprednisolone for 3 weeks followed by gradual tapering. If antibiotics are administered, a broad-spectrum antibiotic (eg, second-generation cephalosporins) is appropriate.
The decision to continue or stop corticosteroid and antibiotic therapy is based on endoscopic findings. Discontinue steroid and antibiotic therapies for patients with no injury or mild mucosal inflammation or ulceration, as they are not at risk for stricture formation. Furthermore, patients with severe transmural burns are at risk for stricture formation, but steroid therapy will not alter their risk. Thus, antibiotic therapy alone is recommended for this group to diminish their risk of mediastinitis. Patients with extensive superficial ulceration or deep discrete or circumferential ulcerations are at risk for stricture formation and may benefit from steroid administration. Consider administering corticosteroids and antibiotics to this group of patients.
Bronchodilators
Bronchodilators selectively stimulate beta 2-adrenergic receptors of the bronchial tree and lungs. Bronchodilation results from relaxation of bronchial smooth muscle, which relieves bronchospasm and reduces airway resistance.
Albuterol, salbutamol (Proventil, Ventolin)
Beta 2-agonist is used for the treatment of bronchospasm. Relaxes bronchial smooth muscle by action on beta 2-receptors with little effect on cardiac muscle contractility.
Adult
5 mg/mL of solution for nebulization, mixed as 0.5-1 mL with 2.5 mL of water and nebulized prn
Pediatric
0.2 mg/kg/dose = 0.03 mL/kg/dose (standard solution), prepared as above
Beta-adrenergic blockers antagonize effects; inhaled ipratropium may increase duration of bronchodilatation by albuterol; cardiovascular effects may increase with MAOIs, inhaled anesthetics, tricyclic antidepressants, and sympathomimetic agents; interactions are of relative importance when dealing with life-threatening toxicity
Documented hypersensitivity; tachydysrhythmias
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hyperthyroidism, diabetes mellitus, and cardiovascular disorders
Diuretics
Are sometimes considered for the treatment of acute lung injury (ALI). However, positive end-expiratory pressure (PEEP) may be much more useful than diuretics for optimizing oxygenation because ALI is secondary to alveolar capillary injury, not excess fluid. Nonetheless, a trial of diuretics can be considered in patients with evidence of concomitant fluid overload.
Furosemide (Lasix)
Loop diuretic; inhibits sodium chloride reabsorption in the ascending loop of Henle. Administer IV because this allows for superior potency and a higher peak concentration, despite an increased incidence of adverse effects, particularly ototoxicity (rare).
Adult
20 mg IV for patients not regularly using furosemide
40-80 mg IV for patients regularly using furosemide
80-120 mg IV for patients with symptoms refractory to the initial dose at up to 1 h
Higher doses and more rapid redosing for patients in severe distress
If minimal or no response with initial dose, double next dose
Pediatric
Not established
Metformin decreases furosemide concentrations;
furosemide interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle relaxing effect of tubocurarine; coadministration with aminoglycosides appears to increase auditory toxicity; hearing loss of varying degrees may occur; may enhance anticoagulant activity of warfarin when taken concurrently; increased plasma lithium levels and toxicity are possible when taken concurrently
Documented hypersensitivity; hepatic coma; anuria; severe electrolyte depletion
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Perform frequent serum electrolyte, carbon dioxide, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter; may induce prerenal failure
Antibiotics
Although expensive, topical Silvadene has antipseudomonal properties in addition to coverage for most gram-positive organisms.
For eye exposures, antibiotic eye preparations will reduce risk of infection secondary to tissue injury.
Silver sulfadiazine 1% (Silvadene)
Useful in prevention of infections from second- or third-degree burns. Has bactericidal activity against many gram-positive and gram-negative bacteria including yeast.
Wash burn before application to remove previously applied agent.
Not for ophthalmic and facial use.
Other products may be used instead of silver sulfadiazine for partial thickness burns; these include TransCyte, Acticoat, or Biobrane.
Adult
Apply using sterile technique to affected areas qd/bid
Pediatric
<2 years: Do not administer (risk of kernicterus)
>2 years: Apply as in adults
Effect of proteolytic enzymes is reduced when used concomitantly
Documented hypersensitivity; late pregnancy (risk of kernicterus); facial burns (use Bacitracin instead)
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in G-6-PD deficiency and renal insufficiency
Ciprofloxacin (Ciloxan)
Fluoroquinolone with activity against pseudomonads, streptococci, MRSA, S epidermidis, and most gram-negative organisms, but no activity against anaerobes. Inhibits bacterial DNA synthesis and growth.
Neomycin 5% is described in much of the literature on ammonia-related eye injury; however, newer broad-spectrum antibiotics have fewer adverse effects
Adult
1 gtt qid (prophylaxis)
Pediatric
<12 years: Not recommended
>12 years: Administer as in adults
Antacids, iron salts, and zinc salts may reduce serum levels; administer antacids 2-4 h before or after taking fluoroquinolones; cimetidine may interfere with metabolism of fluoroquinolones; ciprofloxacin reduces therapeutic effects of phenytoin; probenecid may increase ciprofloxacin serum concentrations; may increase toxicity of theophylline, caffeine, cyclosporine, and digoxin (monitor digoxin levels); may increase effects of anticoagulants (monitor PT)
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Prolonged use may result in overgrowth of nonsusceptible organisms, including fungi
Erythromycin (E-Mycin)
Indicated for infections caused by susceptible strains of microorganisms and for prevention of corneal and conjunctival infections
Adult
Apply 1-cm ribbon 4-8 times/d depending on severity of infection
Pediatric
Apply as in adults
None reported
Documented hypersensitivity; viral, mycobacterial, or fungal infections of eye; patients using steroid combinations after uncomplicated removal of a foreign body from cornea also should avoid using this product
Pregnancy
B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals
Precautions
Do not use topical antibiotics to treat ocular infections that may become systemic; prolonged or repeated antibiotic therapy may result in bacterial or fungal overgrowth of nonsusceptible organisms and may lead to a secondary infection (take appropriate measures if superinfection occurs)
Anticholinergic agents
Induces cycloplegia by blocking the body's parasympathetic (cholinergic) effects in the eye. This is beneficial to prevent ciliary spasm. Should be used in consultation with the ophthalmology service.
Cyclopentolate (AK-Pentolate)
Blocks muscle of ciliary body and sphincter muscle of iris from responding to cholinergic stimulation, thus causing mydriasis and cycloplegia.
Induces mydriasis in 30-60 min and cycloplegia in 25-75 min; these effects last up to 24 hours
Adult
1 gtt into affected eye(s) once; may repeat in 24-48 h prn
Pediatric
Administer as in adults
Decreases effects of carbachol and cholinesterase inhibitors
Documented hypersensitivity; narrow-angle glaucoma
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in patients (eg, elderly patients) in whom increased intraocular pressure may be present; can cause toxic anticholinergic systemic adverse effects (common in children especially infants), but incidence is rare when used sparingly; compressing lacrimal sac by digital pressure for 1-3 min following application may minimize systemic absorption
Homatropine (Isopto Homatropine)
Blocks responses of sphincter muscle of iris and muscle of ciliary body to cholinergic stimulation, producing pupillary dilation (mydriasis) and paralysis of accommodation (cycloplegia).
Induces mydriasis in 10-30 min and cycloplegia in 30-90 min; these effects last up to 48 h.
Adult
1 gtt into affected eye(s) once; may repeat in 24-48 h prn
Pediatric
1 gtt into affected eye(s) once; may repeat in 24-48 h prn
None reported
Documented hypersensitivity; narrow-angle glaucoma
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in patients (eg, elderly patients) in whom increased intraocular pressure may be present; toxic anticholinergic systemic adverse effects can occur, but incidence is rare when used sparingly; adverse effects are more common in children, especially infants; compressing lacrimal sac by digital pressure for 1-3 min following instillation minimizes systemic absorption
Tropicamide (Mydriacyl)
Blocks sphincter muscle of iris and muscle of ciliary body from responding to cholinergic stimulation
Adult
1 gtt into affected eye(s) once
Pediatric
Administer as in adults
None reported
Documented hypersensitivity
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in patients (eg, elderly patients) in whom increased intraocular pressure may be present; toxic anticholinergic systemic adverse effects can occur, but incidence is rare when used sparingly; adverse effects are more common in children, especially infants; compressing lacrimal sac by digital pressure for 1-3 min following instillation minimizes systemic absorption
Corticosteroids
Decrease the formation of fibroblasts on the cornea and may limit intraocular inflammation. However, may potentiate infection. Should be administered only in consultation with the ophthalmology service.
Prednisolone (Pred Forte)
Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Note that ophthalmologic steroids are controversial; discuss their use with ophthalmology. Also, steroid-antibiotic combination may be useful.
Adult
1 gtt q1-6h based on severity of inflammation for 7-10 d
Pediatric
Administer as in adults
Effects may decrease in patients taking phenytoin, barbiturates, and rifampin
Documented hypersensitivity; viral, fungal, or tubercular infections
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hypertension; known to cause cataract formation with chronic use; in prolonged use, withdraw treatment by gradually decreasing frequency of applications to avoid adrenal insufficiency; may increase corneal thinning and melting; risk of globe perforation; discontinue if acute rise in intraocular pressure or ocular infection
Fluorometholone (FML)
Suppresses migration of polymorphonuclear leukocytes and reverses capillary permeability
Adult
1 gtt q1-6h based on severity of inflammation for 7-10 d
Pediatric
<2 years: Not established
> 2 years: Administer as in adults
None reported
Documented hypersensitivity; herpes simplex; keratitis; viral and fungal diseases of the ocular structure
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Prolonged use my result in elevated intraocular pressure or glaucoma
Rimexolone (Vexol)
Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Adult
1 gtt q1-6h based on severity of inflammation for 7-10 d
Pediatric
Not established
None reported
Documented hypersensitivity; viral, fungal, bacterial ocular infections
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in corneal or scleral perforation and posterior subcapsular cataracts
Local anesthetics
Used primarily for pain relief. Duration of action is relatively short-lived, limiting usefulness of local anesthetics outside of the hospital or clinic setting.
Proparacaine 0.5% (Alcaine)
Has rapid onset of anesthesia that begins within 13-30 sec after instillation. However, has short duration of action of about 15-20 min.
Least irritating of all topical anesthetics. Prevents initiation and transmission of impulse at nerve cell membrane by stabilizing and decreasing ion permeability.
Onset of action occurs within 20 s of application.
Anesthetic effect may last up to 10-15 min
Adult
Instill 1-2 gtt into affected eye; may repeat if desired
Pediatric
Administer as in adults
Increases effects of phenylephrine and tropicamide
Documented hypersensitivity; prolonged use
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in cardiac disease or hyperthyroidism and those with abnormal or reduced levels of plasma esterases
Do not use outside the ED because prolonged eye anesthesia can eliminate patient's awareness of mechanical damage to cornea; frequent use of anesthetics may retard healing
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References
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Further Reading
Keywords
anhydrous ammonia, NH3, liquid ammonia, ammonia exposure, ammonia exposure symptoms, ammonia ingestion, ammonia inhalation, ammonium hydroxide, liquid anhydrous ammonia, toxic ammonia exposure, ammonia toxicity, ammonia poisoning, fertilizer
