Congenital nasolacrimal duct obstruction

The nasolacrimal duct usually canalises at eight months of fetal life but there is commonly a delay in this developmental process which can result in residual membrane tissue or stenosis at any level in the nasolacrimal system - from the canaliculi to the extreme end of the nasolacrimal duct underneath the inferior turbinate.

Congenital nasolacrimal duct obstruction (NLDO) is a common condition causing excessive tearing in the first year of life. The incidence of nasolacrimal duct obstruction in early childhood ranges from 5% to 20%.¹

Congenital nasolacrimal duct obstruction symptoms

Infants present with excessive tearing or mucoid discharge from the eyes due to blockage of the nasolacrimal duct system, which can result in maceration of the skin of the eyelids, sticky eyes, crusting of the eyelids and local infections, such as conjunctivitis.¹

Differential diagnosis

Diagnosis is usually straightforward - but always consider:

• Congenital dacryocystocele (uncommon tense blueish swelling of the lacrimal sac) - acute inflammation occurs commonly and there may be an associated intranasal cyst. Refer to ophthalmology.

• Congenital conjunctivitis (ophthalmia neonatorum) or other conjunctivitis.

• Corneal abrasions.

• Congenital glaucoma - this is another important paediatric childhood condition that may present with epiphora. Photophobia, a difference in eye size (compare the diameter of the cornea of each eye with a simple desk-top clear ruler) and clouding of the cornea suggest congenital glaucoma which needs urgent ophthalmic assessment.²

• Other congenital abnormality - eg, albinism or aniridia.

Investigations

Fluorescein dye disappearance test may be helpful - a small drop of dye is instilled into both eyes and will normally disappear over five minutes if the duct is patent, and may subsequently be visible in the nostril using blue light.

However, this is usually a clinical diagnosis and using dye is often not necessary.

Congenital nasolacrimal duct obstruction treatment and management^{3 4}

Congenital nasolacrimal duct obstruction often resolves without surgery. Treatment options are either conservative, including observation (or deferred probing), massage of the lacrimal sac, and antibiotics, or probing the nasolacrimal duct to open the membranous obstruction at the distal nasolacrimal duct. Probing may not be successful if the obstruction is due to a bony protrusion of the inferior turbinate into the nasolacrimal duct or when the duct is oedematous due to infection. Potential complications with probing include creation of a false passage and injury to the nasolacrimal duct, canaliculi and puncta, bleeding, laryngospasm, or aspiration. The effects and costs of immediate versus deferred probing are uncertain.¹

Conservative

In most cases, simple massaging of the ducts may be enough because of the high rate of spontaneous resolution. Parents should be advised to apply gentle pressure with their finger over the common canaliculus, stroking downwards firmly to raise pressure in the lacrimal sac and encourage opening of the valve. They should perform ten strokes twice daily. They should also be advised to perform regular cleaning of any discharge from the eyelids.⁵

Use topical antibiotics for any episodes of associated conjunctivitis (ie red conjunctiva as opposed to simple discharge).

In infants with nasolacrimal duct obstruction (NLDO) who are aged between 6 and 10 months, non-surgical management will resolve symptoms within six months in over half of cases.⁶

Surgical

Current guidelines are for children with persistent obstruction beyond 1 year of age to be referred for probing as a first-line interventional therapy.⁵ This is usually carried out under a brief general anaesthetic as a day case. However, the optimal timing for probing still remains controversial.⁷ Although there is still a high possibility of spontaneous resolution after 1 year of age, there is actually a reduction in success rates for probing with increasing age.

Surgical treatment is rarely considered before 6 months of age.⁶

One study found that probing was successful in 75% of eyes overall. The procedure was less successful in eyes of children with bilateral NLDO compared with unilateral NLDO.⁸

If symptoms persist after probing then the procedure can be repeated, usually with placement of a silicone stent to hold the passage open whilst it settles from the surgery.⁹ This remains in place for several months before removal, again usually with a brief general anaesthetic. Occasionally a dacryocystorhinostomy (DCR) procedure is required.

Complications

Conjunctivitis is the most common complication. This can be managed with simple topical antibiotics. The baby may also be born with - or develop - a dacryocystocele (mucocele) whereby fluid (eg, amniotic fluid) enters the sac and is retained by the non-patent duct. This may lead to acute dacryocystitis.

The risks of probing include:

• Failure - the risks of this increase exponentially with age and number of probings.

• Creation of a false passage.

• Bleeding (rare).