Back to RHEUMATOLOGYSjögren’s syndrome is a chronic inflammatory disorder of probable autoimmune nature characterized by infiltration of the exocrine glands, particularly the salivary and lacrimal glands, by lymphocytes and plasma cells. The classic signs of the Sjögren’s syndrome, therefore, includes enlargement of the parotid glands with mucosal dryness manifest by dry mouth (xerostomia) and dry eyes (xerophthalmia).
Sjögren’s syndrome exists in both a primary and secondary form. In the absence of other autoimmune disorders, it is classified as primary Sjögren’s syndrome. When occurring with a well-defined connective tissue disease, usually rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis or polymyositis, it is known as secondary.
The disease affects predominantly middle-aged women, in the peri- or post-menopausal period, in a female-to-male ratio of 9:1. However, it can be seen in both sexes and all ages. The prevalence is still unknown. Nevertheless, it is considered to be quite common since in addition to the primary syndrome, 30% of patients with rheumatoid arthritis, systemic lupus erythematosus and systemic sclerosis suffer secondary Sjögren’s syndrome. Besides, 2 to 5 % of people aged 60 and above have primary Sjögren’s syndrome.
The majority of the patients with Sjögren’s syndrome have symptoms related to diminished lacrimal and salivary gland functions. The initial manifestations may be nonspecific, such as arthralgias, Raynaud’s phenomenon and fatigue, and usually 8 to 10 years elapse from the initial symptoms to the full-blown development of the disease. The signs and symptoms may be subtle and therefore require a thoughtful history and careful physical examination.
The patients usually complain of dry eye symptoms, including burning, itching or foreign body (gritty, sandy) sensation and accumulation of thick, ropy secretions along the inner canthus of the eyes . With time conjunctival injection, reduced visual acuity and increased photosensitivity develop. These symptoms, which occur because of the decreased and altered tear production, result in the destruction of corneal and bulbar conjunctival epithelium defined as keratoconjunctivitis sicca.
Drying of the mouth, xerostomia, is frequent but variable in severity. Patients usually complain of difficulty in eating dry food (like trying to eat crackers without water), inability to speak continuously, oral soreness, changes in tasting and smelling and fissures of the tongue and lips (angular queilitis). An increase in dental caries is due to decreased saliva volume and the relative loss of its antibacterial factors. Physical examination shows a dry, erythematous, sticky oral mucosa.
Involvement of other exocrine glands occur less frequently. A decrease in the mucous gland secretions of the upper and lower respiratory tree results in dry nose, throat and trachea. Mucosal gland involvement of gastrointestinal tract can be associated with dysphagia, atrophic gastritis, esophageal mucosal atrophy, constipation and subclinical pancreatic insufficiency. Vulva and vaginal dryness can result in dyspareunia.
Extraglandular (systemic) features can complicate the course of the Sjögren’s syndrome and are seen in one third of the patients. These manifestations are more common in patients with primary rather than secondary Sjögren’s syndrome. The spectrum of extraglandular involvement varies. Most patients complain of easy fatigability, low-grade fever, myalgias and arthralgias. Nonerosive arthritis is also common. Dyspnea may be the presenting symptom of an underlying diffuse interstitial pneumonitis due to lymphocytic infiltration. Renal involvement includes interstitial nephritis, clinically manifested as hypostenuria and renal tubular dysfunction with or without acidosis and Fanconi’s syndrome. Central nervous system involvement has been recognized only over the past decade and reported features include focal and diffuse defects, including multiple sclerosis, progressive dementia cognitive dysfunction and spinal cord involvement similar to transverse mielitis. Vasculitis affects small and medium sized vessels. The most common clinical features are nonthrombocytopenic purpura of the legs, skin ulceration, recurrent urticaria and mononeuritis multiplex. Raynaud’s phenomenon occurs in about 20% of the patients.
Malignant or pseudomalignant lymphoproliferation may be a prominent part of the illness, specially in primary Sjögren’s syndrome. Most lymphomas derive from B cell lineage and may develop into monoclonal gammopathies (as Waldenstron’s macroglobulinemia). Pseudolymphoma or frank lymphoma should always be suspected when persistent major salivary gland enlargement, lymphadenopathy or lung nodules are noted.
Diagnosis of Sjögren’s syndrome is based on the presence of two of the three following manifestations: keratoconjunctivitis sicca, xerostomia and an associated connective tissue or lymphoproliferative disorder. Salivary or lacrimal gland enlargement may or may not be present.
Minor salivary gland biopsy serves as the cornerstone for the diagnosis. Schirmer’s tear test is used for evaluation of tear secretion by the lacrimal glands. The test is performed with strips of filtered paper slipped beneath the inferior lid of an unanesthetized eye. After 5 minutes the wetting length of the paper is measured. Wetting of less than 5 mm is a strong indication for diminished secretion. Keratoconjunctivitis sicca, the sequelae of decreased tear production, is diagnosed with slit-lamp examination after using Rose Bengal staining of the corneal epithelium. Rose Bengal is a dye which stains the devitalized epithelium of both the cornea and conjunctiva.
The differential diagnosis of Sjögren’s syndrome includes other diseases which may cause dry eyes or mouth or parotid salivary gland enlargement (see table below).
| DIFFERENTIAL DIAGNOSIS OF SICCA SYMPTOMS |
1. PAROTID GLAND ENLARGEMENT
2. DRY EYE
Inflammation : Stevens-Johnson syndrome, pemphigoid, chronic conjunctivitis or 3. XEROSTOMIA
Viral infection |
|---|
The ophthalmologic and oral manifestations of Sjögren’s syndrome are generally not progressive. Patients with primary Sjögren’s syndrome are at an increased risk of developing lymphoproliferative disorders, including non-Hodgkin lymphoma. Patients with splenomegaly, bilateral parotid enlargement, and a history of radiation treatment are at especially high risk.
Sjögren’s syndrome remains fundamentally an incurable disease, since no therapeutic modality has been identified that may alter the course of the disease. Hence, the treatment of dry eyes is largely symptomatic and includes artificial tears and lubricant ointments. Occasionally, patients may require surgical punctual occlusions to block tear drainage. Managing the oral component of Sjögren’s syndrome requires the use of saliva substitutes, stimulation of salivary flow from functioning acinar tissue and aggressively fighting dental caries through both prevention and treatment.
Patients with severe extraglandular manifestations are usually treated with systemic corticosteroids and immunosuppressive drugs such as cyclophosphamide.
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