These tend to be more numerous and severe in those with high
titres of rheumatoid factor in blood. Three major pathological phenomena
dominate the disease.
1. Inflammation of membranes
2. Nodule formation
i) Rheumatoid Nodules:
Subcutaneous and intracutaneous nodules are the hall mark of the
disease in ¼ th of patients. They are firm, non-tender swellings that
occur on the extensor surface of the fore arm and olecranon sites, where
repeated minor trauma could initiate their formation. They may also
develop in many other tissues including eye (Scleromalacia), pleura,
pericardium, parenchyma of lungs and heart.
ii) Haematological manifestation:
Moderate normochromic normocytic anaemia is a finding in active
RA. Factors that are related to the inflammatory process probably
contribute to this anaemia. There may be ineffective erythropoiesis and
red blood cell survival is reduced. Iron binding capacity is typically
reduced in active rheumatoid arthritis.
2. Thrombocytosis, Leukopenia is a finding in patients with Felty’s
Intimal hyperplasia of the small terminal digital vessels causes very
limited cutaneous lesions (Nail fold infarcts, rashes, splinter
haemorrhages). In contrast severe life threatening tissue infection may
develop when there is involvement of large blood vessels by
leucocytoclastic or necrotizing vasculitis.
iv) Lung involvement:
The fluid has more protein, low glucose, low complement levels
and is typically positive for RA factor.
2. Nodules (Caplan syndrome):
More in upper than lower zones. Cavitation may occasionally lead
3. Pulmonary fibrosis:
It causes progressive dyspnoea, clubbing of fingers, fine late
4. Obliterative Bronchiolitis:
Manifesting with an acute onset of breathlessness. Many patients
have evidence of airway obstruction. Bronchiectasis also appears to
be more common.
v) Cardiac involvement:
1. Pericardial effusion can be found by ultra-sonography in
patients with seropositive nodular disease. Constrictive
pericarditis is more common and presents with dyspnoea, right
sided heart failure, peripheral oedema.
2. Valvulitis: Granulomatous thickening of the cusps of the aortic
valve occurs more frequently than in the mitral valve, rarely
vi) Eye involvement:
Common in RA and may be due to localized tissue
Appears as a raised lesion in the anterior sclera with
hyperaemia of the deeper layers.
Is less common and may lead to progressive thinning of the
sclera (scleromalacia) and even perforation.
3. Keratoconjunctivitis sicca (dry eyes) due to secondary
4. Corneal melting is a rare manifestation. Clinical features are
pain, redness and blurred vision with corneal thinning.
vii) Peripheral Nerve involvement:
Peripheral neuropathies can be produced by proliferating
synovium causing compression of nerves. A mild glove and
stocking sensory neuropathy is relatively common in RA.
viii) Muscle involvement:
Is attributed to the reflex inhibition and wasting resulting
from severe joint pain.
ix) Liver pain:
There may be mild hepatosplenomegaly and asymptomatic
elevation of the serum alkaline phosphatase.
x) Bone involvement:
Juxta – articular osteoporosis is an early feature. A small
proportion of patients may develop osteomalacia.
xi) Felty’s syndrome:
Lymphadenopathy is common. It is more obvious in
patients with Felty syndrome (Rheumatoid arthritis, Splenomegaly,
Leucopenia). Other features include anaemia, thrombocytopenia,
persistent vasculitic leg ulceration, cutaneous pigmentation, weight
loss and recurrent infection.