exposure and the symptoms appear more
insidiously. Chronic HP occurs with prolonged low level exposure to the
antigens which lead to irreversible pulmonary damage without acute attacks 8.
and sub acute form of disease most of the time resolve by the avoidance of
exposure. Chronic HP is a potentially serious disease which may be progressive,
irreversible, and result in debilitating fibrotic lung disease 9.It may lead
to respiratory failure.
Prompt diagnosis of HP is important, as the disease
is reversible when diagnosed early in its course.
of HP is heavily dependent on clinical judgment and there is no specific immunological,
radiological or physiological diagnostic test for HP.
Diagnosis is based upon exposure history, clinical evaluation,
radiographic and physiologic finding and in certain instances, the result of avoidance
the suspected etiologic exposure would help. Other tests, such as
bronchoalveolar lavage (BAL) and lung biopsy, are helpful in excluding other
potential diagnoses and in lending further support to the diagnosis of HP.
characteristic BAL found in hypersensitivity pneumonitis (HP) is a
lymphocytosis, though we did not have facility to perform BAL full report on
HRCT is useful in diagnosing and separating the
clinical forms of HP. HRCT may be normal in patients with symptomatic acute HP 10.
When abnormal, more frequent findings are ground-glass opacities or poorly
defined small nodules 1112.Diffuse areas of dense air-space consolidation
may be associated with ground-glass opacities12.
Because of the significant overlap in clinical cases
of sub acute and chronic HP, the HRCT patterns are more variable.
Ground-glass opacities or poorly defined small nodules are common in sub acute
HP. In fact, HRCT of our patient does not reveal
typical features of sub acute hypersensitivity pneumonitis which are ground-glass opacities, air trapping, and
centrilobular ground-glass opacities.
HRCT evidence in chronic HP are the
combination of reticular, ground-glass, and centrilobular nodular opacities
associated with features of “fibrosis” including
interlobular septal thickening, traction bronchiectasis, volume loss, , and
strategies include environmental control and medical therapy. Antigen avoidance
and removal is the single most important fact in the treatment of BFL and is
crucial in its management 15. Persistent exposure leads to persistent
symptoms and progressive lung damage. Acute & sub acute form of disease may
improve by the avoidance of exposure. Corticosteroids are indicated
for the treatment of severe acute and sub-acute HP and for chronic HP that is
severe or progressive.