Sjogren's Syndrome, Cause, Types, Pathogenesis, Clinical Signs and Complications.

Sjogren's syndrome:
Sjogren's syndrome (Sjogren's syndrome) refers to a pathological condition, characterized by:
1. Dry eyes,
2. Dry mouth
3. Lack of moisture at sites where it normally present

Cause:
Dry eyes occur due to the autoimmune destruction of Lacrimal glands and dry mouth occurs due to the autoimmune destruction of salivary glands.
Autoimmune destruction means the immune system of the body kills its own cells instead of killing only foreign cells.

Lacrimal glands are responsible for tear secretion and Salivary glands secrete saliva, destruction of these glands result in symptoms like dry eyes and dry mouth.

Aetiology:
a) Hyperactivity of B cells leading to autoantibodies formation, these antibodies combine with the receptors present of the salivary and lacrimal glands and result in their destruction
b) Hyperactivity of helper T cells and Cytotoxic T cells.
c) Genetic factors also contribute to the Sjogren's syndrome, it is associated with HLA-DR3 and HLA DR4. any abnormality in these genes is a predisposing factor to Sjogren's syndrome.

Pathogenesis:
1. Role Of B cells:
B cells hyperactivity leads to the formation of autoantibodies, that is antinuclear antibodies and rheumatoid factor, this leads to the formation of immune complexes which will finally result in the destruction of lacrimal and salivary glands.

2. Role of T cells.
a) Helper T cells aid the local formation of antibodies and activation of cytotoxic T cells,
b) Cytotoxic T cells may cause tissue destruction but the firm evidence is lacking regarding the role of helper T cells and Cytotoxic cells in the pathogenesis of Sjogren's syndrome.

Organs Involved:
Lacrimal and salivary glands are most affected, but this syndrome also affects glands of respiratory tract and vagina, CNS, Skin, kidney and muscles.

Types:
Primary Sjogren's syndrome:
It refers to Sjogren's syndrome that occurs as an isolated disorder.

Secondary Sjogren's syndrome.
It refers to "Sjogren's syndrome that occurs in association with other autoimmune diseases such as rheumatoid arthritis.
Predisposing factors:
1. Age: More common over 40 years of age.
2. Sex: more common in females.

Clinical Manifestations and signs:

1. Primary Manifestations and signs:
a) dry eye
b) Dry mouth
c) Lack of moisture where it is normally present.

2. Secondary Manifestations:
a) dryness of eye leads to corneal inflammation, erosion and ulceration.
b) Dryness of mouth leads to atrophy, inflammatory fissuring and ulceration of oral mucosa.
c) Dryness and crusting of nose lead to ulceration and perforation of the nasal septum.
d) Respiratory tract involvement leads to secondary laryngitis, bronchitis, and pneumonitis.
e) Renal involvement leads to renal tubular acidosis, uricosuria, phosphaturia and generalized aminoaciduria (Fanconi's syndrome)

Complications:
All the secondary manifestations are the complications of Sjogren's syndrome. moreover, a neoplastic transformation may also occur.
1. B cell lymphomas develop in one per cent of patients.
2. Pseudo-lymphomas develop in 10 per cent of patients, these comprise inflammatory hyper-plastic changes within salivary glands.
3. True malignant lymphoid tumours develop in some patients.