Nasolacrimal duct obstruction (NLDO) results from any impedance of flow from the puncta within the eyelids to the nares. NLDO may be due to acquired etiologies or congenital anomalies.

Acquired NLDO:
Acquired causes may be primary or secondary. Primary acquired nasolacrimal duct obstruction (PANDO) results from idiopathic inflammation and resulting fibrosis. Secondary acquired nasolacrimal duct obstruction (SANDO) etiologies can include inflammatory, infectious, neoplastic, or traumatic causes. The pathophysiology of the obstruction depends upon the etiology.

Inflammatory causes can be due to autoimmune diseases, most commonly granulomatosis with polyangiitis, Stevens-Johnson syndrome, and sarcoidosis. Exogenous inflammation can result from pharmacotherapy (eg, topical ocular medications, chemotherapy drugs), burns, allergies, or radiotherapy. Regardless, both endogenous and exogenous inflammation result in vasodilation and mucosal swelling, leading to obstruction.

Infectious etiologies cause obstruction in a similar process. Infection can be a cause or a complication of NLDO. Infectious agents can cause NLDO by entering the duct and replicating, which results in obstruction. Conversely, NLDO can cause infection by creating a stagnant flow, thereby producing a perfect environment for infectious agents to thrive, resulting in infection. In either case, viral, fungal, and bacterial agents can be responsible for infection, although gram-positive bacteria are the most commonly observed microorganisms. The most common bacterial pathogens are those that typically colonize the nasal mucosa including Staphylococcus epidermidis, Streptococcus pneumoniae, Pseudomonas aeruginosa, Actincomyces israelii, and Haemophilus influenzae.

Neoplasms can lead to mass obstruction. Neoplasms due to primary growth within the nasolacrimal system are of epithelial origin and include squamous cell carcinoma, adenocarcinoma, adenoid cystic carcinoma, and transitional cell carcinoma. Neoplasms of nonepithelial origin include lymphomas, melanomas, and sarcomas. Obstruction due to secondary spread is most likely as a result of basal cell carcinoma or squamous cell carcinoma of the head and neck. The most common sources of metastatic spread include uterine carcinoma, colorectal carcinoma, and lung carcinoma.

Traumatic etiologies of NLDO include lacerations, blunt trauma, and iatrogenic trauma. The most common traumatic cause of SANDO is naso-orbital-ethmoid fractures resulting from blunt trauma. Iatrogenic causes include trauma after nasolacrimal probing, endoscopic sinus surgery, and craniomaxillofacial surgical procedures.

Acquired NLDO has an incidence of 20.24 per 100 000 and is the most common cause of epiphora in adults. Likely attributable to anatomical differences, NLDO is more common in female patients.

Predisposing medical conditions include glaucoma, dry eyes, cataracts, diabetes mellitus, systemic malignancy, cigarette smoking, and hypertension.

Congenital NLDO:
In infants, NLDO may be due to incomplete development of drainage canalization. Embryologically, the nasolacrimal apparatus appears between the third and fifth week of gestation. First, a crease forms between the frontonasal and maxillary processes. Ectodermal tissue then enters the crease, and a cord of epithelium extends from the puncta to the nose. Tissue canalization occurs during the eighth week of gestation and proceeds from the punctum to the nares. The last portion to complete canalization is at the distal opening within the nares, near the valve of Hasner. Persistence of a membrane at the valve of Hasner is the most common location of NLDO.

Congenital NLDO occurs in 6% of newborns, without sex predilection, and with a median age of diagnosis of 5 weeks. The incidence in stillborn is higher at 73%. NLDO is the most common cause of epiphora and recurrent eye infection in young children. Spontaneous resolution typically occurs by 6 months; persistence beyond 12 months indicates a less likely chance of spontaneous resolution.

Acquired and Congenital:
Patients typically present with epiphora or discharge. Symptoms of epiphora may increase during environmental conditions such as wind and cold air. Patients may have a history of recurrent conjunctivitis or dacryocystitis. Symptoms of dacryocystitis include pain, redness, swelling, periocular mattering, and discharge; it can be unilateral or bilateral. Raw, red, and irritated skin around the eyes, as well as continuous or intermittent discharge presenting with sticky matter on the eyelashes, are signs and symptoms of concern.

Variants of NLDO include neonatal dacryocystocele and diffuse stenosis of the distal duct. Neonatal dacryocystocele appears as a periocular bluish bulge that occurs due to a cystic lesion as a result of a membrane distension near the valve of Hasner; this is observed in only 3% of NLDO patients. Possible complications of neonatal dacryocystoceles include respiratory distress and infection.

Complications of NLDO include acute dacryocystitis, chronic dacryocystitis, chronic canaliculitis, preseptal cellulitis, orbital cellulitis, sepsis, and meningitis.