Sjogren's Syndrome

 

• Background

  Pathophysiology

  • Autoimmune disease characterised by lymphocytic infiltration of exocrine glands, especially salivary and lacrimal.
  • Extraglandular manifestations also occur, due to vasculitis and lymphocytic infiltration of other organs.

  Classification

  • Primary Sjögren's syndrome: standalone condition.
  • Secondary Sjögren's syndrome: SS in the presence of another (usually autoimmune) disease, most commonly RA (30% of RA patients), SLE (20%), systemic sclerosis (50%), or primary biliary cirrhosis (10%).

  Epidemiology

  • Primary SS: 1/200 prevalence.
  • Like many autoimmune conditions, it is commoner in women (x10) and middle age.

• Presentation

  Sicca symptoms (Latin siccus = dry) are the commonest manifestation:

  • Dry eyes ('keratoconjunctivitis sicca' or 'xerophthalmia'), often described as 'gritty'.
  • Dry mouth ('xerostomia'). Can lead to eating difficulty, salivary stones, dental caries, and candidiasis.

  Other features:

  • Parotid enlargement.
  • Dryness of other mucous membranes: respiratory tract (→cough), GI tract (→dysphagia), vagina (→dyspareunia).
  • Extraglandular presentations: arthralgia, fatigue, lymphadenopathy, interstitial lung disease, polyneuropathy, renal tubular acidosis, thyroid disease, pancreatitis.
  • Skin features: dryness ('xerosis'), purpuric rash, Raynaud's, annular erythema.
  • Non-Hodgkin's lymphoma: >10x commoner than general population.

• DDx: Sicca symptoms

  • Age-related gland atrophy. Commonest cause.
  • Drugs: anticholinergics, antihistamines, sympathomimetics, benzodiazepines, antidepressants, opioids.
  • Sjogren's syndrome.
  • Parotid infiltration: sarcoidosis, lymphoma/leukaemia.
  • Infection: hepatitis C, HIV.

• Diagnosis and investigations

  Diagnosis requires all 3 of:

  1. Subjective dry eyes and/or mouth.
  2. Objective evidence of dry eyes and/or mouth. Tests of dry eyes include Schirmer's test of tear function (filter strip under eyes), or ocular surface staining (Rose Bengal, lissamine green, or fluorescein). Tests of ↓salivary production include whole sialometry (spit into test tube), parotid sialography, or salivary scintigraphy.
  3. Serological or histopathological evidence of SS. Diagnostic autoantibodies are anti-Ro/SS-A (50%) and anti-La/SS-B (35%). Biopsy of minor salivary glands may show focal lymphocytic sialoadenitis.

  Other investigations:

  • Basic bloods: ↓Hb (20%), ↑ESR/CRP (30%).
  • Non-diagnostic autoantibodies: ANA (70%), RF (50%).
  • Others immunological features: ↑gammaglobulins, ↑cryoglobulins, ↓complement.

• Management

  Lifestyle and preventative:

  • Regular fluid sips and chewing gum.
  • Good oral hygiene.
  • Avoid exacerbating drugs, including smoking and alcohol.

  Medical:

  • Moisture replacement e.g. hypromellose eye drops, saliva substitute mouth rinse.
  • Muscarinic agonists PO: pilocarpine, cevimeline
  • Hydroxychloroquine for arthralgia.
  • Steroids and immunomodulators if there is severe, systemic involvement.