Sjögren syndrome

Sjögren syndrome, or Sjögren disease, is an autoimmune condition of the exocrine glands that produce tears and saliva.

Epidemiology

Sjögren syndrome is the second most common autoimmune disorder after rheumatoid arthritis. There is a recognized female predilection with F:M ratio of  ≈9:1. Patients typically present around the 4^th to 5^th decades.

Clinical presentation

Clinically, the cardinal features are glandular:

• keratoconjunctivitis sicca (xerophthalmia)
• dryness of the mucous membrane of the mouth (xerostomia)
• bilateral parotid enlargement

Additionally, there may be multi-organ extra-glandular involvement, which can have a wide variety of clinical features.

Pathology

It is a chronic autoimmune disorder involving mainly the salivary and lacrimal glands and is associated with hyperactivity of the B-lymphocytes and with autoantibody and immune complex production. 

Associations

Approximately 40% of cases occur in isolation. Known associations include:

• thoracic changes associated with Sjögren syndrome
  • non-specific interstitial pneumonitis (NSIP): considered the most common pattern ^9,10
  • usual interstitial pneumonitis ¹¹
  • lymphoid interstitial pneumonia (LIP)
  • focal lymphoid hyperplasia of the lung
  • small airways disease ^7,8
  • pulmonary amyloidosis: AL type ¹⁴
• Mikulicz syndrome (sometimes known as Sjögren type 1 ⁶)
• other connective tissue diseases
  • systemic lupus erythematosus (SLE)
  • scleroderma
  • rheumatoid arthritis (RA)
• EBV infection
• Hepatitis C infection
• primary biliary cirrhosis (possible ¹²)
• HTLV infection

Markers

• anti-Ro (SSA) antibody
• anti-La (SSB) antibody

Radiographic features

Ultrasound

Salivary glands

• early stage: the gland can be normal or become enlarged and hyperechoic ⁵ 
• late stages: may characteristically show a multicystic or reticular pattern within an atrophic gland ⁵

MRI 

Salivary glands

Parotid gland involvement may give a salt and pepper appearance or a honeycomb appearance. A change in the size of the lacrimal glands associated with accelerated fat deposition may also be seen ³.

Treatment and prognosis

Complications

One of the complications of this syndrome is the development of malignant lymphoma.

History and etymology

This condition is named after Swedish ophthalmologist Henrik Sjögren (1899-1986) although it was first described by WB Hadden and JW Hutchinson in 1871 ¹³.