Canaliculitis

What is Canaliculitis?

Canaliculitis is a medical term for inflammation of the lacrimal canaliculus, a small drainage duct in our eyes. This condition is not very common and can often be misdiagnosed by eye doctors. Because of this, it can be a tricky condition to get rid of. Sometimes, it’s mistaken for other eye conditions such as conjunctivitis (eye infection), blepharitis (eyelid inflammation), dacryocystitis (tear duct infection), mucocele (mucus-filled cyst), and chalazion (small lump on the eyelid) which can end up causing more trouble for patients over time. In fact, it is described as the “most misdiagnosed disease” in a widely respected book in medicine by Harrison.

Canaliculitis can be either primary, appearing on its own, or secondary, appearing as a consequence of other procedures. It often happens as a side effect when small plugs are inserted into the tear ducts — a common treatment for dry eye.

The canaliculi are small channels in the eyelid, essential to the functioning of the tear drainage system. They start at a small opening on the edge of the eyelid, known as the lacrimal puncta, and for most people, merge together to form a single channel known as the common canaliculus. This structure runs through the eyelids for roughly 8 millimeters. The upper channel is shorter, narrower and angled sharply than the lower channel before they merge together. The lower channel runs almost completely horizontally.

What Causes Canaliculitis?

In the past, it was believed that a type of bacteria called Actinomyces israelii was the main cause of a condition called canaliculitis, leading to it being called streptothrix canaliculitis or streptothricosis. Actinomyces israelii was initially classified as a fungus, but it is now understood to be a certain type of bacteria that doesn’t need air to grow.

Recent research, though, is showing that there’s an increase in the number of Staphylococcus and Streptococcus infections involved in causing canaliculitis. Besides these, other bacteria like Eikenella, Lactococcus, Nocardia and even some fungi have also been found in patients with canaliculitis.

Certain studies have found that a bacteria called Pseudomonas aeruginosa is the most common one found in canaliculitis cases when canalicular plugs are used, while other studies are showing that Hemophilus species, Actinomyces species along with Pseudomonas can also be involved.

Risk Factors and Frequency for Canaliculitis

Canaliculitis is a rare condition, making up just 2% to 4% of diseases affecting the lacrimal system (the body’s tear system). People of any age can get it, from as young as 5 to as old as 90, but it’s most typically found in people around 59 years old. This condition seems to be more common in women, which might be due to hormones affecting tear production and making the tear ducts more prone to infection. Cosmetics could also potentially block the tear ducts and lead to canaliculitis. Furthermore, women tend to have more treatment for dry eyes, which includes placing plugs in the tear ducts – this could also increase their risk of developing canaliculitis. More cases seem to involve the lower tear duct rather than the upper one.

Signs and Symptoms of Canaliculitis

Canaliculitis is a medical condition that can be difficult to diagnose correctly and promptly due to its various symptoms. People with this condition tend to experience symptoms like tearing, eye discharge, swelling of a part of the eye (medial canthus), or pouted punctum – a part of the tear duct. Because these symptoms can often be confused with other eye conditions like chronic conjunctivitis or inflamed chalazion, the correct diagnosis can be delayed. Another common symptom is the production of yellowish granules through eye massage. These granules, called sulfur granules, are believed to be caused by certain bacterial species like Actinomyces. Other common symptoms include ocular discomfort and blood-stained tears or blood-tinged eye discharge. Some people may even have a mass coming out from the punctum.

As a result of the varying symptoms, doctors have to do a thorough examination to correctly diagnose canaliculitis. The presence of concretions – hard, compact masses – was traditionally considered as solid proof of canaliculitis. Over time, this evidence expanded to include inflammation around the canaliculi and pouting puncta. Generally, swelling of the punctum, swelling of the eyelid, and the discharge or formation of concretions from the punctum are key signs of primary canaliculitis. Surgical removal of these concretions is often necessary to prevent recurring episodes. Secondary canaliculitis could involve additional signs like an inflammatory mass protruding from the punctum, granuloma formation, blood-stained discharge, and eyelid swelling. Even with these symptoms, the tear duct system’s normal functioning (lacrimal patency) is still usually intact in canaliculitis patients.

Testing for Canaliculitis

In the instance of canaliculitis, a condition where the small tear drainage channels in your eyes are inflamed, your doctor will look closely at various parts of your eye, including the tear duct openings, the area inside the corner of your eye, and the folds of your conjunctiva. This physical exam is usually enough for the doctor to diagnose canaliculitis, but there are also some tests that can provide additional confirmation if your symptoms are unclear.

A range of tests may be carried out if you have canaliculitis. These tests include:

Microbiological Culture: Your doctor may gather samples from your tear duct discharge, lumps and bumps that form around your eyes, abscesses, or a swab from your conjunctiva. These samples can be checked for bacteria (aerobic and anaerobic) and, in certain recurrent or unusual cases, for fungal or mycobacterial infections.

Histopathology: This is a type of test that looks at the tissue under a microscope. In this case, lumps and bumps that form around your eyes are typically examined. These tested tissues can show the presence of certain bacteria, such as actinomyces, or they may just be dead tissues. Sometimes it may show signs of a foreign body with inflammation around it if the canaliculitis is caused by something foreign in your eye.

Ultrasound Biomicroscopy (UBM): UBM is a type of high-resolution eye ultrasound. This non-invasive procedure is quite effective for examining your tear duct system. It can show changes in the tear drainage channels and detect solid bread-crumb-like lumps.

Dacryoendoscopy: During a dacryoendoscopy, a mini camera inspects your tear duct system. This test is particularly valuable in detecting any misplaced punctal plugs (a treatment for dry eyes where a tiny plug is inserted in the tear duct), especially in cases of secondary canaliculitis, where the condition occurs as a result of another issue.

Dacryocystography: This test uses imaging to evaluate the tear drainage system. It can show specific symptoms related to canaliculitis, like filling defects, widening, irregular margins, rounded protrusions, and formation of pouch-like structures.

Treatment Options for Canaliculitis

When it comes to treating new-onset primary canaliculitis – a condition that affects the eyes’ tear ducts – medical treatment can work well if the patient seeks help early on. This mainstream medical treatment can include methods like antibiotics, warm compresses, local massage, and rinsing the area. However, research shows that in many cases, up to 80%, this approach doesn’t work effectively. This could be because small hard deposits (concretions) protect the bacteria from the antibiotics, leading to resistance and an inadequate response to treatment. Therefore, many experts now highlight the importance of detecting and swiftly starting surgical treatment for canaliculitis.

There are several surgical options available such as punctual dilation or punctoplasty with curettage (clearing of the area), canaliculotomy, canaliculoplasty with intubation (inserting a tube), and punctum-sparing canaliculotomy with monocanalicular intubation. The procedure most often deemed safe and effective in studies is canaliculotomy. This involves making a cut at the back part of the canaliculus (the tear duct), removing any stones, concretions, dead skin cells and other debris, and then cleaning the area with an antibiotic solution. The cut can be left as it is or stitched up, with or without a stent, which is a tiny tube that can help the area to heal.

For secondary canaliculitis, that is usually resistant to medical treatment. Canaliculotomy, paired with the removal of the offending plug, is considered the best course of action for this type of canaliculitis. Complicated or repeated cases might need more intrusive procedures, such as dacryocystorhinostomy (a surgery to create a new tear drain between your eyes and your nose), the removal of any foreign bodies or debris within the tear duct, and stent placement.

What else can Canaliculitis be?

Some conditions that could be confused with each other include:

• Cancer of the lacrimal canaliculus, a small drainage tube in the eye
• Chronic conjunctivitis, a long term inflammation of the eye
• Dacryocystitis, an infection in the tear duct
• Migrated punctal plug, a situation where a device inserted into the tear duct moves from its intended position