Ocular Chemical Burns – Causes, Symptoms, Diagnosis, Treatment and Ongoing care

Basics

Description

Chemical exposure to the eye can result in rapid, devastating, and permanent damage, and is one of the true emergencies in ophthalmology.Separate alkaline from acid chemical exposure: Alkaline burns: More severe—alkali compounds are lipophilic, penetrating rapidly into eye tissue; saponification of cells leads to necrosis and may produce injury to lids, conjunctiva, cornea, sclera, iris, and lens (cataracts).Acid burns: Acid usually does not damage internal structures because protein denatures, creating a barrier to further acid penetration (hydrofluoric and, to a lesser extent, sulfurous acids are an exception to this rule). Injury is often limited to lids, conjunctiva, and cornea.System(s) affected: Nervous; Skin/ExocrineSynonym(s): Chemical Ocular Injuries

Epidemiology

Predominant age: Can occur at any age, peak from 16–25 years of agePredominant sex: Male > Female

Incidence

Estimated 300/100,000 per yearAlkali burns twice as common as acid burns

Risk Factors

Construction work (plaster, cement, whitewash)Use of cleaning agents (drain cleaners, ammonia)Automobile battery explosions (sulfuric acid)Industrial work (many possible agents)AlcoholismAny risk factor for assault (~10% or injuries due to deliberate assault)

General Prevention

Safety glasses to safeguard eyes

Pathophysiology

Hydration of glycosaminoglycans causes corneal opacification.Saponification of cell membranes causes cell death.Cation binding to collagen results in hydration, thickening, and shortening of collagen fibrils. This can mechanically elevate intraocular pressure through distortion of the trabecular meshwork.

Etiology

Sources of alkaline and acidic compounds

Commonly Associated Conditions

Facial cutaneous chemical or thermal burns

Diagnosis

Physical Exam

Mild burns: Pain and blurred visionEyelid skin erythema and edemaCorneal epithelial defects or superficial punctate keratitisConjunctival chemosis, hyperemia, and hemorrhages without perilimbal ischemiaMild anterior chamber reactionModerate-to-severe burns: Severe pain and markedly reduced vision2nd- and 3rd-degree burns of eyelid skinCorneal edema and opacificationCorneal epithelial defectsMarked conjunctival chemosis and perilimbal blanchingModerate anterior chamber reactionIncreased intraocular pressureLocal necrotic retinopathyIn alkaline burns, can have initial pain that later diminishes

Diagnostic Tests & Interpretation

Imaging

Not necessary unless suspicion of intraocular or orbital foreign body is present

Diagnostic Procedures/Surgery

Measure pH of tear film with litmus paper or electronic probe: Irrigating fluid with non-neutral pH (e.g., normal saline has pH of 4.5) may alter results.Careful slit lamp exam, fundus ophthalmoscopy, tonometry, and measurement of visual acuityFull extent of damage from alkaline burns may not be apparent until 48–72 hours after exposure.

Pathological Findings

Corneal epithelial defects or superficial punctate keratitis, edema, opacificationConjunctival chemosis, hyperemia, and hemorrhagesPerilimbal ischemiaAnterior chamber reactionIncreased intraocular pressure

Differential Diagnosis

Thermal burnsOcular cicatricial pemphigoidOther causes of corneal opacificationUltraviolet radiation keratitis

Treatment

Copious irrigation and removal of corneal or conjunctival foreign bodies are always the initial treatment (1,2)[A]:

Passively open patient’s eyelid and have them look in all directions while irrigating.Be sure to remove all reservoirs of chemical from the eyes.Continue irrigation until the tear film and superior/inferior cul-de-sac is of neutral pH and pH is stable (2)[C]: Severe burns should be irrigated for at least 15 minutes to as much as 2–4 hours; this irrigation should not be interrupted during transportation to hospital (2)[C].It is impossible to overirrigate.Initial pH testing should be done on both eyes even if the patient claims to only have unilateral ocular pain/irritation so that a contralateral injury is not neglected.Use whatever nontoxic fluid is available for irrigation on scene. In hospital, sterile water, normal saline, normal saline with bicarbonate, balanced salt solution (BSS) or lactated Ringer’s solution may be used. No therapeutic difference in effectiveness has been noted between types of solutions (1)[C].A topical anesthetic can be used to provide for patient comfort (e.g. proparacaine, tetracaine).Sweep the conjunctival fornices every 12–24 hours to prevent adhesions (2)[C].Eye patching may relieve pain, but has not been shown to improve outcomes (3)[C].

Medication

First Line

Further treatment (depending on severity and associated conditions): Topical prophylactic antibiotics: Any broad-spectrum agent (e.g., bacitracin–polymyxin B[Polysporin] ointment q2–4h, ciprofloxacin [Ciloxan] drops q2–4h, chloramphenicol[Chloroptic] ointment q2–4h) (1)[C]:Some experts suggest that systemic tetracycline derivatives (especially doxycycline) may be beneficial because studies performed in animals have shown an additional anti-inflammatory effect (by inhibiting metalloproteinases) and improved corneal healing in alkali burns (4)[C].Tear substitutes: Hydroxypropyl methylcellulose (HypoTears PF, Refresh Plus) drops q4h, carboxymethylcellulose (Refresh PM) ointment at bedtime (1)[C]: Most beneficial in those with impaired tear production (elderly patients)Cycloplegics for photophobia and/or uveitis: Cyclopentolate 1% t.i.d., or scopolamine 1/4% b.i.d. (1)[C]Antiglaucoma for elevated intraocular pressure (IOP): Latanoprost (Xalatan) 0.005% q24h, or timolol (Timoptic) 0.5% b.i.d., or levobunolol (Betagan) 0.5% b.i.d., and/or acetazolamide (Diamox) 125–250 mg p.o. q6h, or methazolamide (Neptazane) 25–50 mg p.o. b.i.d., and/or IV mannitol 20% 1–2 g/kg as needed (1)[C]Corticosteroids for intraocular inflammation: Prednisolone (Pred-Forte) 1% or equivalent q1–4h for 7–10 days; if severe, prednisone 20–60 mg p.o. daily for 5–7 days. Taper rapidly if epithelium is intact by this time (1)[C]: Use of corticosteroids > 10 days may do harm by inhibiting repair and cause corneoscleral melt (1,5)[C]Consider vitamin C (ascorbic acid) 500 mg p.o. q.i.d. and/or acetylcysteine (Mucomyst) 10–20% topically q4h if corneal melting occurs (1)[C].Precautions: Timolol and levobunolol: History of congestive heart failure (CHF) or chronic obstructive pulmonary disease (COPD)Acetazolamide and methazolamide: History of nephrolithiasis or metabolic acidosisMannitol: History of CHF or renal failureScopolamine: History of urinary retentionTopical corticosteroids must be used with caution in the presence of damaged corneal epithelium because iatrogenic infection can occur. Daily follow-up or consultation with an ophthalmologist is recommended.

Additional Treatment

Issues for Referral

See Medication (Drugs).

Surgery/Other Procedures

Goal of subacute treatment is restoration of the normal ocular surface anatomy, control of glaucoma, and restoration of corneal clarity. Surgical options include:

Debridement of necrotic tissue (1)[C]Conjunctival/tenon advancement (tenoplasty) to restore vascularity in severe burns (1)[C]Tissue adhesive (e.g., isobutyl cyanoacrylate) for impending or actual corneal perforation of <1 mm (1)[C]: Tectonic keratoplasty for acute perforation >1 mm (1)[C]Limbal autograft transplantation for epithelial stem cell restoration (1)[C]Conjunctival or mucosal membrane transplant to restore ocular surface in severe injury (1)[C]Lamellar or penetrating keratoplasty for tectonic stabilization or visual rehabilitation (1)[C]

In-Patient Considerations

Initial Stabilization

Usual for patient

Admission Criteria

Based on ophthalmic consultation and concomitant burn injuries

Discharge Criteria

Emergency department evaluation with inpatient admission and ophthalmology consultation, depending on severity

Ongoing Care

Follow-Up Recommendations

Patient Monitoring

Depending on severity of ocular injury: From daily to weekly visits initiallyMay be inpatientIf on mannitol or prednisone, consider frequent serum electrolytes

Diet

Regular as tolerated

Patient Education

Safety glassesNeed for immediate ocular irrigation with any available water following chemical exposure to the eyes

Prognosis

Depends on severity of initial injury. Increasing amounts of limbal ischemia and corneal opacification correlate with poorer prognosis (Roper-Hall classification system)For mildly injured eyes, complete recovery is the norm.For severely injured eyes, permanent loss of vision is not uncommon.

Complications

Persistent epitheliopathyFibrovascular pannusCorneal ulcer/perforationCorneal scarringProgressive symblepharon and entropionNeurotrophic keratitisLid malposition secondary to cicatricial changesGlaucomaCataractHypotonyPhthisis bulbiBlindness

References

1. Wagoner MD. Chemical injuries of the eye: Current concepts in pathophysiology and therapy. Survey Ophthalmol. 1997;41:275–313.

2. Kuckelkorn R, Schrage N, Keller G, et al. Emergency treatment of chemical and thermal eye burns. Acta Ophthalmol Scand. 2002;80:4–10.

3. Spector J, Fernandez WG et al. Chemical, thermal, and biological ocular exposures. Emerg. Med. Clin. North Am. 2008;26:125–36, vii

4. Ralph RA et al. Tetracyclines and the treatment of corneal stromal ulceration: a review. Cornea. 2000;19:274–7.

5. Fish R, Davidson RS et al. Management of ocular thermal and chemical injuries, including amniotic membrane therapy. Curr Opin Ophthalmol. 2010;21:317–21.

Additional Reading

Rodrigues Z et al. Irrigation of the eye after alkaline and acidic burns. Emerg Nurse. 2009;17:26–9.

See Also (Topic, Algorithm, Electronic Media Element)

Burns

Codes

ICD9

940.0 Chemical burn of eyelids and periocular area940.2 Alkaline chemical burn of cornea and conjunctival sac940.3 Acid chemical burn of cornea and conjunctival sac

Snomed

16096002 Chemical burn of eyelid and/or periocular area (disorder)38916004 Alkaline chemical burn of cornea and/or conjunctival sac (disorder)63542002 Acid chemical burn of cornea and/or conjunctival sac (disorder)231869007 chemical injury to conjunctiva (disorder)231945007 chemical injury to cornea (disorder)

Clinical Pearls

Prompt irrigation of all chemical burns, even prior to arrival to the emergency room, is essential to ensure best outcomes.All patients with chemical injuries to their eyes should be refered to ophthalmology staff for further assessment.