Sjögren Syndrome

Introduction And Epidemiology

Chronic, inflammatory autoimmune disease.
Characterized by progressive lymphocytic and plasma cell infiltration of exocrine glands.
Affects primarily salivary and lacrimal glands.
Rare in children.
Mean age at diagnosis spans 9 to 10 years.
Demonstrates strong female predominance approaching 75%.
Classified as primary (isolated sicca complex) or secondary.
Secondary disease occurs in association with systemic lupus erythematosus, scleroderma, or mixed connective tissue disease.

Results from complex interaction of genetic predisposition and potential infectious triggers.
Autoantibodies (Anti-Ro/SSA, Anti-La/SSB) produced via B-cell activation.
Features marked overproduction of interferons.
Lymphocytes and plasma cells infiltrate salivary glands.
Infiltration forms distinct periductal and periacinar foci.
Foci become confluent, eventually replacing normal epithelial glandular structure.
Regulated by apoptosis genes influencing chronicity of lymphocytic infiltration.

Recurrent parotid gland enlargement or parotitis represents the most common presentation in children (>70%).
Painful or painless parotid swelling observed.
Classic sicca symptoms include dry eyes (keratoconjunctivitis sicca) and dry mouth (xerostomia).
Sicca symptoms often less prominent or underreported in pediatric populations compared to adults.
Widespread dental caries common secondary to xerostomia.
Other exocrine features include decreased sense of smell and hoarseness.

Systemic symptoms more prevalent in children than adults.
Fever and lymphadenopathy occur in approximately 8% of cases.
Polyarthritis or arthralgia noted in 18% of pediatric patients.
Renal disease typically manifests as distal renal tubular acidosis or tubulointerstitial nephritis.
Renal tubular acidosis presents clinically with polyuria, polydipsia, and hypokalemic paralysis.
Medullary nephrocalcinosis visible on renal ultrasound.
Pulmonary involvement includes diffuse interstitial lymphocytosis or interstitial lung disease.
Neurological features encompass sensory/autonomic neuropathy and central nervous system involvement.
Hematologic features include autoimmune hemolytic anemia and leukopenia.

Domain	Specific Criteria
Clinical Symptoms	Recurrent parotitis, recurrent nonallergic/noninfectious conjunctivitis, recurrent vaginitis, systemic features (fever, arthralgia, hypokalemic paralysis, abdominal pain).
Objective Findings	Ocular dryness (Schirmer test), abnormal sialography, elevated serum amylase, leukopenia/elevated ESR, polyclonal hyperimmunoglobulinemia, renal tubular acidosis.
Serology	Anti-SSA (Ro), Anti-SSB (La), high titer ANA (speckled pattern), positive Rheumatoid Factor.
Histopathology	Lymphocytic infiltration of salivary glands or other organs.

Markedly raised polyclonal hypergammaglobulinemia constitutes an important diagnostic marker.
Complete blood count reveals leukopenia or anemia.
Antinuclear antibody (ANA) positive in 40-70% of cases, typically exhibiting speckled pattern.
Rheumatoid factor positive in up to 67% of cases.
Specific autoantibodies include Anti-SSA (Ro) and Anti-SSB (La).

Schirmer test quantifies tear production. Utilizes Whatman filter paper No. 41 (5 mm x 35 mm). Wetting ≤5 mm in 5 minutes indicates positive result.
Ocular surface damage detected via special dyes (fluorescein, Lissamine green).
Salivary gland scintigraphy demonstrates reduced or delayed uptake.
Salivary gland ultrasonography reveals characteristic cystic lesions.

Minor salivary gland (labial) biopsy serves as gold standard.
Pathological hallmark requires demonstration of focal lymphocytic sialadenitis.
Focus score >1 per 4 mm² area (defined as cluster of >50 lymphocytes) confirms diagnosis.
Children typically exhibit normal minor salivary gland biopsies but abnormal parotid biopsies.

Juvenile recurrent parotitis: Features intermittent unilateral swelling, younger age onset (3-6 years), male predominance, and lacks focal lymphocytic infiltrates on biopsy.
Infectious parotitis: Includes mumps, Epstein-Barr virus, cytomegalovirus, and HIV.
Structural/Traumatic: Polycystic parotid disease, salivary duct calculi, local trauma.
Other etiologies: Sarcoidosis, eating disorders, tumors.
Sicca symptoms, specific autoantibodies, and rash remain absent in these differential conditions.

Requires tailored multidisciplinary intervention.
Symptomatic Relief: Artificial tears, parotid massage, oral lozenges, and adequate hydration.
Dental Care: Regular dental hygiene checks mandatory to prevent caries.
Secretagogues: Pilocarpine hydrochloride utilized to increase salivary flow.
Renal Management: Urinary alkalinizing agents indicated for renal tubular acidosis.
Pharmacotherapy: Nonsteroidal anti-inflammatory drugs and hydroxychloroquine utilized for mild systemic symptoms.
Corticosteroids: Administered for moderate systemic involvement.
Immunosuppressants: Methotrexate or etanercept indicated for arthritis. Azathioprine utilized for progressive disease.
Severe Disease: Cyclophosphamide, cyclosporine, or Rituximab reserved for life-threatening complications or severe visceral involvement, such as interstitial lung disease.

Disease typically follows indolent, slowly progressive course.
Overall 10-year survival rate exceeds 90% in pediatric patients.
Diminished salivary flow persists indefinitely.
Corneal damage represents significant morbidity if keratoconjunctivitis sicca remains untreated.
Carries increased risk for mucosa-associated lymphoid tissue lymphoma, although incidence is significantly lower in children compared to adults.
Maternal Sjögren syndrome strongly associated with risk of neonatal lupus and congenital heart block in offspring due to transplacental transfer of Anti-Ro/La antibodies.