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Saturday, December 25, 2010

Giant Papillary Conjunctivitis

Signs and Symptoms
Giant papillary conjunctivitis (GPC) is a common condition frequently seen in soft contact lens patients, patients with exposed suture knots, and patients with prostheses. Patients with asthma, hay fever or animal allergies may be at greater risk. The etiology of GPC may be immunological, where contact lens deposits act as allergens.

Initial presentation may occur months or even years after lens wear has been initiated. The papillae in GPC can be observed on the superior tarsus and (by definition) measure 1mm in diameter. Ocular itching after lens removal, increased mucus discharge in the morning, photophobia and decreased lens tolerance are all initial symptoms. Vision can be affected either as an artifact of the deposits on the lens, due to lens displacement secondary to superior lid papillary hypertrophy, or repetitive mechanical corneal abrasion with infiltration (shield ulceration).

Pathophysiology
The allergic response is considered to be an over-reaction of the body’s immune system to immunogens or allergens. This response can be innate or acquired after multiple exposures to a particular antigen.

The GPC response has no seasonal variation. While the histamine level of tears is increased in vernal keratoconjunctivitis (VKC), it remains level in GPC. Despite this difference, VKC and GPC are pathophysiologically similar. Cytologic scrapings from the conjunctiva of patients with GPC exhibit an immunologic response containing lymphocytes, plasma cells, mast cells, eosinophils and basophils suggesting an antigen-antibody mechanism. The action of phospholipase A2 secondary to the allergic response causes the release of histamines via the degranulation of mast cells. This increases capillary permeability, produces lymphocyte circulation (T-cells, eosinophils, and monocytes) and initiates the liberation of arachidonic acid, which is a catalyst for the cyclooxygenase and lipoxygenase pathways. These pathways produce inflammatory mediators such as thromboxanes, leukotrienes and prostaglandins that cause the discomfort and formation of the papillae.

Management
Management is primarily aimed at reducing symptoms. In more serious cases, aggressive management may be required to prevent ocular tissue damage. The type and frequency of medications depends upon the severity of the condition. Topical supportive therapies act to supplement the biological tears, to wash away debris and environmental allergies. The flushing away of allergens and other debris plays an obvious role in reducing or even canceling the GPC response. Examples of such products include Bion Tears, Tears Naturale Free, Refresh Plus, Ocucoat PF and Dry Eye Therapy.

Topical mast cell stabilizers are a tested and proven modality for treating GPC. Topical mast cell stabilizers are the treatment of choice for chronic GPC. They work by stabilizing the receptors on mast cell vesicles before they can degranulate, beginning the cycle of the allergic response. VKC, atopic keratoconjunctivitis (AKC), and GPC all respond well. If the patient’s history is well known for GPC, a 10-day loading period preceding the onset of symptoms with a preparation like cromolyn sodium (Opticrom, Crolom), at a dosage of four to six times daily, is usually effective in stalling or preventing the initial stages of the disease. Following this, you may need to continue therapy for four to six weeks or until the end of the episode. Another mast cell stabilizer made available in recent years is lodoxamide (Alomide). Like cromolyn sodium, it is a safe drug and is used in the same manner for a wide variety of allergic conditions, at a dosage of two to four times a day. Olopatadine (Patanol) combines mast cell stabilization with antihistamine properties and may be the best therapy due to its dual role. Another advantage of Patanol is its twice daily dosing.

Mast cell stabilizers have been shown to deliver significant therapeutic impact on the GPC reaction. However, to ease chronic irritations of this type, the most effective method remains eradication of the antigen.

In recalcitrant cases, topical corticosteroids function to deliver potent, palliative mediation by reducing the inflammatory response. Topical corticosteroids reduce capillary permeability, suppress lymphocyte circulation, inhibit the degranulation of mast cells, reduce the numbers of basophils and neutrophils, and decrease the production of prostaglandins, thromboxanes and leukotrienes. GPC resistant to standard therapies may respond to topical steroids. Excellent choices of steroids for management of GPC include Vexol, Lotemax, and Alrex.

Clinical Pearls:

Patients with allergic symptoms often have dry eyes as their primary problem. Make sure to rule out tear deficiency in chronic GPC conditions.
When topical steroids are required, you can typically prescribe them four and six times a day for up to seven days to achieve control and then taper off.
The final alternative may entail fitting susceptible patients with daily disposable or rigid gas-permeable lenses, or even discontinuing contact lens wear altogether.
Daily disposable soft contact lenses in combination with medical therapy are an excellent compromise for the patient who absolutely cannot discontinue lens wear for any reason.

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