What is dacryocystitis causing a six-month history of unilateral watery discharge?

Dacryocystitis: Definition and Clinical Context

Dacryocystitis is an infection of the lacrimal sac caused by obstruction of the nasolacrimal duct, which converts the sac into a reservoir of bacteria and presents with chronic watery discharge (epiphora), often accompanied by mucous discharge and medial canthal swelling. 1, 2

Pathophysiology

• Nasolacrimal duct obstruction is the underlying cause, leading to tear stasis within the lacrimal sac and subsequent bacterial colonization 1, 2
• The obstruction may be primary (acquired) or secondary to anatomical abnormalities, though many "primary" cases likely result from unrecognized low-grade infection 3
• Once established, the infected lacrimal sac becomes a constant threat to the cornea and orbital soft tissues 4

Clinical Presentation in Chronic Cases

• Epiphora (excessive tearing) is the hallmark symptom, typically unilateral and present for months 2, 4
• Mucous or mucopurulent discharge from the medial canthus, often worse in the morning 5
• Lacrimal sac swelling at the medial canthal region, which may be tender on palpation 4
• Reflux of purulent material when pressure is applied over the lacrimal sac (regurgitation test) 4

Associated Conditions and Risk Factors

• Female predominance and left eye more commonly affected than right 4
• Associated nasal pathology in approximately 20% of patients, including deviated nasal septum, hypertrophied inferior turbinate, nasal polyps, and allergic rhinitis 4
• Lower socioeconomic status and pond-bathing habits increase risk 4
• Giant fornix syndrome frequently presents with concomitant nasolacrimal duct obstruction and chronic dacryocystitis 6

Microbiology

• Staphylococcus aureus is the most common pathogen (40% of positive cultures), followed by Staphylococcus epidermidis and Streptococcus pneumoniae 4
• Gram-negative organisms include Pseudomonas aeruginosa (16.6%), Klebsiella pneumoniae, and Haemophilus influenzae 4
• Approximately 54% of lacrimal sac cultures yield bacterial growth 4
• Important caveat: Conjunctival and nasal cultures do not reliably predict lacrimal sac organisms, so direct sac cultures are preferred when planning treatment 3

Potential Complications

• Acute-on-chronic dacryocystitis with severe pain, erythema, and systemic symptoms 4
• Lacrimal abscess formation requiring urgent drainage 4
• Lacrimal fistula to the skin 4
• Corneal ulceration from chronic exposure to infected discharge 4
• Conjunctivitis as a secondary complication 4
• Complications occur in approximately 25% of untreated chronic cases 4

Management Approach

Conservative Trial (Selected Patients)

• Oral broad-spectrum antibiotics plus topical antibiotics with office lacrimal irrigation may be attempted in patients with tearing and mucous discharge without prior acute dacryocystitis 5
• Success rate is low (approximately 9% avoid surgery) in complete nasolacrimal duct obstruction 5
• Patients with lacrimal sac mucocele or history of acute dacryocystitis typically require early surgical intervention, as only 10% respond to conservative management 5

Definitive Surgical Treatment

• Dacryocystorhinostomy (DCR) is the definitive treatment, creating a new drainage pathway from the lacrimal sac into the nasal cavity 1, 2
• Traditional external DCR requires skin incision and drilling through lacrimal bone 1
• Laser-assisted translacrimal DCR offers an incisionless alternative with 85% success rate after one procedure, comparable to standard DCR 1
• Silicon tubes are typically left in place for 6 months post-operatively 1

Antibiotic Selection

• Most organisms show resistance to penicillin 4
• Fluoroquinolones (ciprofloxacin, ofloxacin) are effective against Pseudomonas and Klebsiella 4
• Chloramphenicol is effective against most Gram-positive organisms 4
• Aminoglycosides (tobramycin) are effective against Staphylococcus epidermidis 4

Key Clinical Pitfalls

• Do not rely on conjunctival or nasal cultures to guide antibiotic therapy—they do not correlate with lacrimal sac organisms 3
• Six-month history of unilateral watery discharge strongly suggests chronic dacryocystitis rather than simple conjunctivitis 5, 2
• Always examine for associated nasal pathology that may contribute to obstruction 4
• Conservative management rarely succeeds in complete obstruction; early surgical referral prevents complications 5