Ammonia Toxicity Treatment & Management

Updated: Apr 11, 2022
  • Author: Steven Issley, MD, FRCPC; Chief Editor: Sage W Wiener, MD  more...
  • Print
Treatment

Approach Considerations

Management of toxic exposure to ammonia is largely supportive. Decontaminate the patient (if that was not done at the site of exposure) and support airway, breathing, and circulation (ABCs) as necessary. Provide warmed humidified oxygen.

Patients with facial or oral lesions from ammonia, like all patients with burns in these areas, are at high risk for developing laryngeal edema. Airway intervention should be aggressive. Indications for tracheal intubation include the following:

  • Severe respiratory distress (hypoxemia, hypercapnia)
  • Stridor
  • Hoarseness
  • Deep facial burns or burns identified by bronchoscopy or endoscopy
  • Depressed mental status

If intubation is necessary, use a large-size tube to prevent plugging by sloughed mucosa. Some experts consider procedural sedation preferable to rapid sequence intubation (RSI) because paralysis is risky in patients with a difficult and edematous airway. Furthermore, ventilation cannot be predicted to be successful if intubation fails in this context. [15] 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; see Thermal Burns. Once the patient is adequately stable, irrigate the involved skin with tepid water for at least 15 minutes. Continue frequent regular irrigation for the first 24 hours, in addition to conventional burn management. No salves, creams, ointments, or jellies should be applied to the skin during a 24-hour period following the injury since this will prevent natural elimination of the ammonia from the skin. [16]  Administer tetanus prophylaxis.

Irrigate eye injuries with copious amounts of tepid water for at least 30 minutes or until the conjunctival pH is 6.8-7.4; use pH indicator paper to monitor. 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 worsen injury with a second pass of toxin
  • Promptly arrange a gastroenterology consultation for subsequent endoscopic evaluation 

Corticosteroids are controversial therapies for ammonia inhalation injury. Many experts believe that corticosteroids may actually increase morbidity in these cases. However, corticosteroids are recommended to treat acute bronchospasm in patients with underlying reactive airways disease, and to treat chronic respiratory complications from acute inhalation injury.

Use of steroids for the treatment of caustic injuries after caustic ingestion is also controversial. However, patients exhibiting signs of airway edema after caustic exposure may benefit from intravenous (IV) dexamethasone (adults, 10 mg; children, 0.6 mg/kg up to a maximum of 10 mg). In addition, use of IV corticosteroids can be considered in symptomatic patients with grade IIb (near-circumferential) caustic injuries, to reduce the formation of esophageal strictures. 

Next:

Prehospital Care

Prehospital care for patients exposed to ammonia begins with immediate removal of the patient from the contaminated environment and removal of all clothing. In the case of industrial accidents, clothes that have been saturated by liquid ammonia may freeze to the skin. The patient, still clothed, should get immediately under a shower, if available, or jump into a stock tank, pond, or into any other source of water. Remove clothes only after they are thawed and they can be freely removed from frozen areas. If the clothing is removed incorrectly, whole sections of skin can be torn off. A physician should view any second- or third-degree freeze burns of the skin. [16]

If the patient is sufficiently stable, begin copious skin and eye irrigation immediately. Continue irrigation for at least 20 minutes. Patients then can be covered with a dry, clean dressing and sheet. 

If ammonia is ingested, do not induce vomiting. If vomiting begins, place the patient face down with head lower than hips to prevent vomitus from entering the lungs. [16]

Support 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). In severe inhalation exposure to higher concentrations, administer oxygen. Patients should be kept warm (but not hot) and rested until transported to the hospital. [16]

 

Previous
Next:

Hospital Admission

The majority of patients with unintentional household ammonia exposure will have very mild symptoms and can be discharged safely if asymptomatic and able to tolerate oral intake. Admit patients to observation for at least 24 hours if they show significant and persistent signs, symptoms, or abnormalities in laboratory findings attributable to ammonia exposure. Admit unstable or potentially unstable patients to the intensive care unit.

Patients with ammonia ingestion may be discharged if endoscopy results are normal and oral intake is tolerated. Intentional ingestions require psychiatric evaluation.

Previous
Next:

Corticosteroids and Antibiotics

The rationale for corticosteroid use after ammonia ingestion is that these agents may decrease the incidence and severity of esophageal strictures that occur during healing from significant alkaline injuries.

The use of corticosteroids remains controversial, but the best recent evidence suggests that they are helpful for grade IIB (circumferential partial thickness) esophageal injuries. [17]  Steroid therapy will not alter the risk of stricture formation in patients with severe transmural burns. If steroids are given, the recommended dose is 1-2 mg/kg/d of methylprednisolone for 3 weeks followed by gradual tapering. 

The decision to continue or stop corticosteroid therapy is based on endoscopic findings. Discontinue steroids for patients with no injury or mild mucosal inflammation or ulceration, as they are not at risk for stricture formation.

Antibiotic use is also controversial. They may be considered because of the increased risk of mediastinitis associated with steroid use in patients with full-thickness esophageal alkaline corrosive burns, but no well-controlled human trials have been performed. Consequently, prophylactic antibiotics should not be administered unless recommended after consultation with a toxicologist, gastroenterologist, and surgeon. If antibiotics are given, a broad-spectrum antibiotic (eg, a second-generation cephalosporin) is appropriate.

Previous
Next:

Prevention

According to the U.S. Environmental Protection Agency (EPA), 72% of all reported chemical accidents from 2004-2014 in Iowa, Kansas, Missouri, and Nebraska involved anhydrous ammonia and up to 96% were preventable through increased operator training, improved procedures, and better communication of lessons learned. All commercial facilities with anhydrous ammonia refrigeration systems are required by the EPA to develop and implement recognized and generally accepted good engineering practices which includes adherence to a program like the International Institute of Ammonia Refrigeration (IIAR) Ammonia Refrigeration Management (ARM). [2] ​ 

Previous