Comprehensive Guide to Secondary Acquired Lacrimal Duct Obstruction

Definition of Secondary Acquired Lacrimal Duct Obstruction

Secondary acquired lacrimal duct obstruction (SALDO) is a condition in which the lacrimal drainage system becomes clogged due to external factors such as trauma, surgery, inflammation, infection, or tumors. In contrast to primary acquired nasolacrimal duct obstruction (PANDO), which develops without an identifiable external cause, SALDO is always associated with a specific antecedent event or condition that disrupts the normal functioning of the lacrimal drainage system.

Anatomy of the Lacrimal System

To understand the implications of SALDO, we must first understand the anatomy of the lacrimal system. The lacrimal system consists of structures that generate, distribute, and drain tears. The lacrimal gland, which is located in the orbit’s upper outer quadrant, produces tears. Tears are secreted and spread across the ocular surface during blinking before draining into the lacrimal puncta, which are tiny openings on the medial aspect of the upper and lower eyelids.

Tears flow from the lacrimal puncta into the canaliculi, which are small channels that connect to the common canaliculus and eventually to the lacrimal sac. The lacrimal sac, located in the lacrimal fossa near the nasal bone, serves as a reservoir for tears before they drain into the nasolacrimal duct. The nasolacrimal duct then transports the tears to the nasal cavity’s inferior meatus, where they are either absorbed or evaporated. Any obstruction in this pathway can cause improper tear drainage, resulting in tear overflow (epiphora) and complications such as infections.

Causes of Secondary Acquired Lacrimal Duct Obstruction

SALDO can occur due to a variety of causes, each of which disrupts the normal tear drainage process. The pathogenesis of SALDO is largely dependent on the underlying cause:

1. Trauma: Physical injuries to the face, particularly those involving the medial canthal region, can directly harm the lacrimal drainage system. Fractures in the nasal bones or maxilla can disrupt the nasolacrimal duct, whereas lacerations or blunt trauma can harm the canaliculi or lacrimal sac. Scar tissue formation after trauma can result in a permanent ductal obstruction.
2. Surgical Procedures: Iatrogenic causes of SALDO include surgeries on the nasal cavity, sinuses, or orbital structures. Rhinoplasty, endoscopic sinus surgery, and dacryocystorhinostomy (DCR) are some procedures that can inadvertently harm the lacrimal drainage system, resulting in obstruction. Postoperative adhesions, scarring, or unintentional injury to the nasolacrimal duct are common causes.
3. Inflammatory Conditions: Chronic inflammation, whether from autoimmune diseases like sarcoidosis or chronic sinusitis, can cause the nasolacrimal duct to narrow and eventually become obstructed. The inflammatory process can cause thickening of the ductal walls, fibrosis, and eventual occlusion. Inflammatory conditions can also increase the patient’s susceptibility to secondary infections, complicating the situation.
4. Infections: Recurrent or chronic infections of the lacrimal sac (dacryocystitis) or sinuses can cause strictures in the nasolacrimal duct. These infections’ inflammation frequently causes scarring, which can permanently narrow or obstruct the duct. Infections can also result from nasolacrimal duct stones (dacryoliths), which can clog the duct and cause secondary infections.
5. Tumors: Both benign and malignant tumors can cause SALDO by compressing the lacrimal duct externally or infiltrating the ductal structures. Nasal and sinus tumors, lacrimal sac tumors, and metastatic lesions can block the normal flow of tears, resulting in epiphora. Tumors can also alter the anatomy of the lacrimal system, necessitating complex treatment strategies.
6. Medications: Certain medications, particularly chemotherapy drugs, can cause fibrosis and scarring of the lacrimal ducts. This is frequently a delayed effect, with chronic use causing gradual obstruction of the duct. Medications such as 5-fluorouracil and docetaxel are known to cause such effects.
7. Radiation Therapy: Patients who have received radiation therapy for head and neck cancers may experience SALDO as a late complication. Radiation can cause fibrosis and scarring in the lacrimal drainage system, gradually narrowing and eventually blocking the duct.

Clinical Features of Secondary Acquired Lacrimal Duct Obstruction

The clinical presentation of SALDO is primarily defined by symptoms associated with impaired tear drainage. The most common symptom is epiphora, which refers to excessive tearing or tear overflow. This can be especially bothersome because it impairs vision, causes skin irritation, and raises the risk of infections. Patients may also report blurred vision as a result of tear film instability.

In addition to epiphora, patients with SALDO may exhibit signs and symptoms of recurrent dacryocystitis. Dacryocystitis is a lacrimal sac infection that is commonly caused by tear stasis within the obstructed lacrimal system. Patients with dacryocystitis typically complain of pain, redness, and swelling in the lacrimal sac area, which is frequently accompanied by purulent discharge from the puncta. In chronic cases, a mucocele or pyogenic granuloma may form at the site of obstruction.

Pain in the medial canthal area may also be a presenting symptom, especially if the obstruction is associated with trauma or a tumor. Patients with underlying inflammatory conditions, such as sarcoidosis, may experience additional systemic symptoms associated with their primary disease, such as fatigue, joint pain, and respiratory problems.

Physical examination typically reveals tearing and discharge, and palpation over the lacrimal sac may produce pain or pus in cases of dacryocystitis. A palpable mass in the medial canthal region should raise suspicion of a tumor or mucocele. In cases where SALDO is suspected, a thorough history and examination are required to determine the underlying cause, which will guide subsequent diagnostic and therapeutic measures.

Differential Diagnosis

When evaluating a patient with symptoms of SALDO, it is critical to distinguish this condition from other causes of epiphora and lacrimal duct obstruction. Differential diagnosis includes:

1. Primary Acquired Nasolacrimal Duct Obstruction (PANDO): Unlike SALDO, PANDO has no known external cause and is thought to be caused by idiopathic nasolacrimal duct stenosis. PANDO is common in middle-aged or older adults, particularly women, and is usually bilateral.
2. Congenital Nasolacrimal Duct Obstruction: This condition occurs at birth due to incomplete canalization of the nasolacrimal duct. It typically manifests in infants as tearing and discharge and is usually self-limiting.
3. Functional Lacrimal Outflow Obstruction: Although there is no physical blockage of the lacrimal duct, normal tear drainage is impaired due to functional abnormalities. This could be due to poor eyelid positioning, lacrimal pump dysfunction, or an underlying neurological condition.
4. Dry Eye Disease: Surprisingly, dry eye disease can cause excessive tearing, especially when the ocular surface is irritated and compensatory reflex tearing takes place. Assessing tear production and ocular surface health can help distinguish this condition from SALDO.
5. Allergic Conjunctivitis: Patients with allergic conjunctivitis may have excessive tearing, itching, or redness. However, these symptoms are usually caused by seasonal or environmental allergens, and they are accompanied by other allergic symptoms like sneezing and nasal congestion.
6. Blepharitis: Inflammation of the eyelid margins can cause secondary obstruction of the lacrimal puncta, resulting in tears. However, this condition is frequently associated with other symptoms of eyelid inflammation, such as crusting, redness, and irritation.

A thorough history and clinical examination, accompanied by appropriate diagnostic tests, are required to distinguish SALDO from these other conditions.

Epidemiology and Risk Factors

SALDO is less common than primary acquired nasolacrimal duct obstruction, but the exact prevalence is difficult to estimate due to the variety of underlying causes. The condition can affect people of all ages, but it is more common in adults, especially those who have had facial trauma, surgery, or radiation therapy.

Certain populations are more likely to develop SALDO, including:

• Individuals with a history of facial trauma or surgery: Those who have suffered significant facial trauma or have had surgeries on the nasal cavity, sinuses, or orbits are more likely to develop SALDO due to the possibility of lacrimal drainage system injury.
• Patients with chronic inflammatory diseases: Conditions such as sarcoidosis, granulomatosis with polyangiitis (formerly known as Wegener’s granulomatosis), and chronic sinusitis are associated with an increased risk of SALDO due to chronic inflammation and scarring in the lacrimal ducts.
• Individuals undergoing radiation therapy: Radiation to the head and neck area can cause fibrosis and scarring of the lacrimal drainage system, resulting in SALDO.
• Patients with a history of recurrent dacryocystitis: Chronic infections of the lacrimal sac can cause scarring and stricture formation, putting individuals at risk for secondary acquired lacrimal duct obstruction. Recurrent dacryocystitis, if not treated properly, can cause chronic inflammation and fibrosis, resulting in permanent blockage of the lacrimal duct.
• Elderly patients: While SALDO can occur at any age, older adults are more vulnerable due to the cumulative effects of aging, chronic inflammation, and prior medical interventions, all of which can contribute to lacrimal duct obstruction.

Effects on Quality of Life

SALDO can have a significant impact on a patient’s quality of life, primarily because of the discomfort and social inconvenience caused by persistent tearing. Patients may feel embarrassed or frustrated by the constant need to wipe their eyes, which can cause skin irritation and secondary infections. The chronic nature of the condition can also contribute to a decline in visual function, especially if recurrent dacryocystitis causes corneal involvement or if epiphora significantly impairs daily activities like reading or driving.

Chronic conditions that affect facial appearance and comfort can cause anxiety and depression in some patients. Furthermore, patients with severe SALDO may require multiple surgical procedures, which can be physically and emotionally taxing.

Diagnostic methods

Secondary acquired lacrimal duct obstruction (SALDO) requires a combination of clinical evaluation, imaging studies, and, in some cases, diagnostic procedures to confirm the presence and extent of the obstruction. The diagnostic approach is required not only to identify the blockage but also to determine its underlying cause, which is critical for effective management planning.

Clinical Evaluation

The first step in diagnosing SALDO is to conduct a detailed clinical history and physical examination. The clinical evaluation contains:

1. History Taking: A detailed history should be obtained in order to identify potential etiological factors. Previous facial trauma, surgical history (particularly rhinologic or orbital surgeries), episodes of dacryocystitis, chronic sinusitis, radiation therapy, or systemic inflammatory conditions should all be considered. The onset, duration, and progression of symptoms, particularly epiphora, are important because they can reveal information about the nature of the obstruction.
2. Physical Examination: A thorough examination of the lacrimal system is required. The examination should include an examination of the eyelids and puncta, palpation of the lacrimal sac area, and evaluation of tear drainage. The presence of swelling, tenderness, or discharge in the lacrimal sac area may indicate dacryocystitis. Furthermore, any mass or irregularity in the medial canthal area should raise concerns about tumors or mucoceles.
3. Tear Drainage Tests: Simple in-office tests, such as the dye disappearance test (DDT) or the Jones test, can provide early indications of lacrimal outflow obstruction. The DDT procedure entails injecting fluorescein dye into the conjunctival sac and measuring how quickly it disappears, which reflects the efficiency of the tear drainage system. The Jones test, which can be performed as a primary or secondary test, involves recovering fluorescein dye from the nasal cavity after instilling it into the conjunctival sac, which aids in localizing the source of obstruction.

Imaging Studies

Imaging is critical in the diagnosis of SALDO, especially when the obstruction is suspected to be due to trauma, tumors, or extensive scarring. The key imaging modalities are:

1. Dacryocystography (DCG) is a specialized imaging technique that involves injecting a contrast medium into the lacrimal system and then imaging it with radiography. This method visualizes the entire lacrimal drainage system and can precisely locate the source of obstruction. DCG is especially useful in cases of complex or uncertain obstruction, and it can help distinguish between complete and partial blockages.
2. Computed Tomography (CT) Scan: A CT scan is especially useful in cases where SALDO is suspected to be caused by trauma, tumors, or bony abnormalities. CT imaging allows for detailed views of the bony structures surrounding the lacrimal system and can detect fractures, bone erosion, and masses compressing the nasolacrimal duct.
3. Magnetic Resonance Imaging (MRI): MRI is less commonly used than CT in evaluating SALDO, but it may be necessary in cases where soft tissue masses or tumors are suspected. MRI provides superior soft tissue contrast and can aid in determining the extent of tumors or inflammatory lesions affecting the lacrimal sac or duct.
4. Nuclear Medicine Scintigraphy: This imaging technique, also known as dacryoscintigraphy, involves the injection of a radiolabeled tracer into the conjunctival sac. A gamma camera then monitors the tracer’s passage through the lacrimal system. This method is especially useful for detecting functional obstructions, which cause a delay in tear drainage rather than an anatomical blockage.

Diagnostic Procedures

In some cases, additional diagnostic procedures may be required to confirm the diagnosis or to further evaluate the cause of obstruction.

1. Probing and Irrigation: This simple but informative procedure involves inserting a fine probe through the lacrimal puncta and canaliculi into the nasolacrimal duct. The duct’s patency is then determined using saline irrigation. The procedure can help identify the source of the obstruction and determine whether it is complete or partial.
2. Endoscopic Dacryocystorhinostomy (DCR) Evaluation: For patients with suspected SALDO who may require surgical intervention, an endoscopic examination of the nasal cavity and lacrimal system is possible. This procedure allows for direct visualization of the nasolacrimal duct and any associated nasal pathology, such as polyps, septal deviations, or tumors, which may be contributing to the obstruction.
3. Biopsy: If a tumour or granulomatous disease is suspected, a biopsy of the affected tissue may be necessary. The histopathological examination of the biopsy can confirm the diagnosis and guide future treatment.

Secondary Acquired Lacrimal Duct Obstruction Management

Secondary acquired lacrimal duct obstruction (SALDO) is treated based on the underlying cause, the extent of the obstruction, and the severity of the symptoms. The primary goals of treatment are to restore the patency of the lacrimal drainage system, relieve epiphora symptoms, and avoid complications such as recurrent infections. Depending on the circumstances, treatment options include conservative management and surgical intervention.

Conservative Management

Conservative treatment is frequently the first line of management for mild cases of SALDO, especially when the obstruction is partial or the patient’s symptoms are manageable.

1. Lacrimal System Irrigation: When the obstruction is partial or functional, lacrimal system irrigation can serve as both a diagnostic and therapeutic measure. This procedure involves flushing the lacrimal drainage system with saline or antibiotic solution to remove any debris, mucus, or minor blockages. It is frequently combined with probing to mechanically open ducts.
2. Topical Medications: Patients who have inflammation-related obstructions, such as those caused by chronic sinusitis or allergic reactions, may benefit from topical anti-inflammatory medications such as corticosteroids or antihistamines. These medications can help reduce swelling and inflammation around the lacrimal ducts, resulting in better tear drainage.
3. Warm Compresses and Massage: In cases where mild inflammation or dacryocystitis contribute to the obstruction, warm compresses and lacrimal sac massage may be prescribed. These measures can help to reduce pain, promote drainage, and relieve minor obstructions.
4. Systemic Antibiotics: When dacryocystitis is present, systemic antibiotics are required to control the infection. The antibiotic used depends on the severity of the infection and the pathogens, which are typically gram-positive bacteria. In some cases, broad-spectrum antibiotics are started while culture results are pending.

Minimal Invasive Procedures

Minimally invasive procedures may be used for patients with more severe obstructions or who do not respond to conservative treatment.

1. Probing and Dilation: A common procedure for treating partial obstructions is to probe the nasolacrimal duct and then dilate it. This outpatient procedure is frequently effective in restoring tear flow. Probing entails inserting a fine metal probe into the duct to mechanically open any blockages, then dilation with a small balloon catheter to widen the duct.
2. Lacrimal Stenting: If probing alone is insufficient or there is a risk of re-occlusion, a temporary lacrimal stent or silicone tube may be inserted into the nasolacrimal duct. The stent maintains the duct’s patency while the tissues heal and can be left in place for weeks or months.
3. Endoscopic Procedures: Endoscopic techniques, such as endoscopic dacryocystorhinostomy (DCR), can be used in cases where the obstruction is in the nasolacrimal duct or nasal pathology is causing the obstruction. This procedure involves creating a new passageway for tear drainage into the nasal cavity, which bypasses the blocked segment. It is performed with a nasal endoscope, allowing for a less invasive approach with less scarring and a faster recovery time than traditional open surgery.

Surgical Management

Patients with complete obstructions, those with significant symptoms that do not respond to conservative or minimally invasive treatments, or when the obstruction is secondary to tumors or severe scarring should undergo surgery.

1. Dacryocystorhinostomy (DCR): DCR is the most effective surgical treatment for nasolacrimal duct obstruction, especially in cases of SALDO. The procedure entails creating a new drainage pathway from the lacrimal sac to the nasal cavity, which avoids the obstructed nasolacrimal duct. DCR can be done externally with a small incision near the nose or endoscopically through the nasal cavity. Both techniques are extremely effective, with success rates that exceed 90%. Endoscopic DCR is preferred in many cases due to its minimal invasiveness and low scarring.
2. Canaliculodacryocystorhinostomy (CDCR): In cases where the canaliculi are obstructed, CDCR may be required. This procedure involves using a glass or silicone tube (Jones tube) to bypass the entire lacrimal drainage system and connect the tear lake directly to the nasal cavity. CDCR is usually reserved for severe cases in which other treatments have failed.
3. Tumor Resection: If a tumor is causing the obstruction, surgical resection is required. The approach is determined by the tumor’s size, location, and whether it is benign or malignant. Tumor resection can be combined with DCR to improve tear drainage.
4. Reconstruction Procedures: Reconstructive surgery may be required for patients who have suffered extensive trauma or surgery that has caused significant damage to their lacrimal system. This could include grafting tissue to rebuild the lacrimal ducts or creating new drainage pathways.
5. Radiation Therapy and Chemotherapy: In cases where the obstruction is caused by a malignant tumor, radiation therapy and/or chemotherapy may be required as part of the overall treatment. These treatments are typically coordinated with oncologists and may be used in addition to surgical management.

Follow-Up and Monitoring

Following any intervention, close follow-up is required to monitor for symptom recurrence, ensure proper healing, and assess the treatment’s long-term success. Patients may require additional procedures or ongoing treatment, especially if they have chronic inflammation or recurring infections.

Trusted Resources and Support

Books

1. “Diseases of the Lacrimal System” by John H. Dartt: This book provides comprehensive coverage of lacrimal system disorders, including secondary acquired lacrimal duct obstruction, with detailed discussions on anatomy, pathophysiology, and treatment options.
2. “Oculoplastic Surgery: The Essentials” by William B. Stewart and William R. Nunery: A practical guide for clinicians, this book covers the surgical management of lacrimal duct obstructions, including step-by-step techniques and case studies.

Organizations

1. American Academy of Ophthalmology (AAO): The AAO offers extensive resources, including clinical guidelines and patient education materials on lacrimal duct obstructions and related conditions.
2. International Society of Ocular Oncology and Oculoplasty (ISOOO): This organization provides a platform for professionals specializing in lacrimal system disorders, offering research updates, conferences, and collaboration opportunities.
3. The Tear Film and Ocular Surface Society (TFOS): TFOS focuses on research and education related to tear film and ocular surface disorders, providing valuable information for both professionals and patients dealing with lacrimal system issues.