Description

A congenital blockage identified in infants from failure of canalization, most commonly at the distal portion, of the nasolacrimal duct. Epiphora (constant tearing) is the most common presentation followed by discharge unresponsive to treatment. Less commonly, the blockage is an acquired condition.

Epidemiology

• Most common lacrimal system abnormality
• Affects up to 6% of newborns
• Spontaneous resolution occurs in 80–90% of cases within 1 year.
• Most common cause of pediatric epiphora

Risk Factors

Incidence is higher in infants with craniofacial malformations and Down syndrome.

Pathophysiology

• Congenital obstruction most commonly occurs at the caudal end of the duct at the level of the valve of Hasner where there is an imperforate membrane as it enters the nose.
• Obstruction is usually due to a persistence of a membrane but can also be a bony obstruction or narrowing of the inferior meatus abutting the nasal mucosa.
• Acquired obstructions are rare in children but do occur as a result of chronic inflammation and scar tissue occluding the duct. Causes include infection (i.e., ethmoidal sinusitis), inflammation, malignancy, and trauma.

Etiology

Canalization of the duct is usually complete by the 7th month of gestation, but a persistent membrane can remain and may represent the embryologic basis of lacrimal duct obstruction.

Commonly Associated Conditions

• Acute dacryocystitis
  • Strongly suggestive of the presence of obstruction
  • Unclear whether obstruction is the primary cause leading to secondary infection from accumulation of tears and cellular debris or that dacryocystitis is the primary event with an acquired obstruction from fibrosis and inflammation
• Dacryocystocele (distention of the lacrimal sac)
  • A rare variant of lacrimal duct obstruction seen in 0.1% of infants with the disorder
  • There is the typical distal obstruction as well as a proximal obstruction at the junction of the common canaliculus and the lacrimal sac presenting as a bluish mass.
  • Can be associated with infection (i.e., dacryocystitis) as well as respiratory distress because of cystic expansion protruding into the nose
• Anisometropic amblyopia and refractive error have been found to have a higher incidence in those with lacrimal duct obstruction.
• Craniofacial malformations or Down syndrome