LV
Hamman, Amer. Physician, 1877-1946; AR Rich, Amer. Physician, was born in 1893;
synonyms: idiopathic
pulmonary fibrosis) - a progressive inflammatory lung lesion of unknown nature,
which leads to the development of diffuse fibrosis, chronic respiratory and
cardiopulmonary failure.
Hamman-Rich syndrome is a rare disease characterized by rapidly
progressive diffuse pulmonary fibrosis with the development of respiratory
failure, pulmonary hypertension and cor pulmonale.
Etiology. Hereditary disease with
autosomal dominant type of inheritance.
Pathogenesis. Previously in the development of syndrome there was attached
importance of auto-sensitization in connection with which diseases was entered
to a group of connective tissue disease. Now there is considered that the
syndrome occurs as the result of repeated inflammatory bronchopulmonary diseases.
Morphological substrate is perialveolar fibrosis, which reduces the elasticity
and pliability of lung tissue and thus worsens the excursion of the lungs. Due
to the thickening of the interalveolar septa diffusion of gases in the blood is
damaged, which leads to hypoxemia and hypoxia, hypercapnia.
Clinic
The disease manifests
itself mainly in school age children and adolescents, but the first signs of it
(on history) almost half of the patients are detected in pre-school age. The
disease begins gradually after an attack of influenza, repeated pneumonia,
bronchitis and often measles. There are a spastic, dry cough, shortness of
breath and cyanosis during physical exertion, sometimes chest pain, feeling of
tightness in the chest.
Percussion defines an
insignificant shortening of sound in the basal zones or no change, decrease of
excursion of lungs, reducing difference of lung volume during inspiration and
expiration. Auscultation reveals inconstant fine bubbling or crepitation moist
rales, sometimes may be weakening of breathing in the lower areas.
Further there are increasing
of cyanosis around the mouth, acrocyanosis, fingers take the form
"drumsticks". The child retards in weight and growth. Thorax is flattened,
circumference of the neck disproportionately increases (due to increased
contractility of the neck muscles that perform the role of auxiliary
respiratory muscles during difficult breathing). Pulmonary heart syndrome is developing
with the expansion of the cardiac dullness, signs of cardiovascular failure.
In the blood – polycythemia, may be polyglobulinemia,
ESR is increased, especially in acute periods, concentrations of gamma-globulin
is elevated.
The study of respiratory function reveal the
decline of lung volumes, reduced lung compliance and difficulty in passing the
oxygen through the alveolar-capillary membrane, and therefore change in the gas
composition of the blood (hypoxemia, then hypercapnia) and indicators of
acid-base status.
After treatment with corticosteroids LVC, total lung
capacity, the inspiratory volume is practically unchanged. Radiological investigation
in the initial period reveals that the interstitial pattern is enhanced, later nodular
formation appear on its background. In periods of exacerbations there is determined
multiple shadowing, alternating with areas of particularly clear lung fields. Shadowing
is usually localized in the roots and lower parts. Pneumothorax may be possible
complication.
Representative
CT scan image from a person with
idiopathic pulmonary fibrosis.
Idiopathic fibrosing alveolitis.
Detail of chest radiograph with interstitial pneumosclerosis
with a primary lesion
of the alveolar connective tissue (fibrosing alveolitis): small meshy pattern of lung.
Micropreparations of lung at diffuse interstitial pneumosclerosis: interseptums
are extremely thickened and sclerotic; coloured by Van Gieson; × 24.
A. Lung showing extensive interstitial and alveolar fibrosis.
Note the increased
interstitial cellularity with numerous fibroblasts.
B. Patchy areas of alveolar septal thickening and prominent hyaline
membranes.
C. Higher magnification showing typical dense laminated hyaline
membranes.
D. Alveolar septum showing prominent type II pneumocyte proliferation.
E. Abundant polymorphonuclear leukocytes fill alveolar spaces with focal
destruction of alveolar septa.
F. Higher power magnification showing the antraalveolar exudate
composed mainly of polymorphonuclear leukocytes, red blood cells, and
fibrin.
Original magnifications: A & B, x 50; C, x 100; D, x 158; E, x 50;
F, x 158.
Electron-microscopic picture of fibrosed alveoli.
CT-image of
meshy lung
Vacuolization of macrophages in amiodarone alveolitis. Materials
obtained through bronchoalveolar lavage.
The disease is undulating with periods of
exacerbation and remission. However, remission time zone fibrotic changes do
not disappear, and rates of respiratory still significantly reduced. Depending
on the frequency and duration of periods of exacerbation, some authors
distinguish subacute and chronic forms of course. In subacute form periods of
exacerbation are more frequent, accompanied by fever reaction, while at chronic
progression of pulmonary fibrosis occurs gradually and manifests the growth of
respiratory failure. At present, long-term treatment of patients with
corticosteroid differences within these two forms have become less pronounced. There
are two clinical forms of idiopathic diffuse pulmonary fibrosis depending on diffusion
of gases in the lungs. In most cases diffusion capacity is decreased, but in 10-15%
of patients it is within normal limits. In such patients the process is easier,
retarded growth and weight are insignificant or absent.
Diagnosis is mainly based on typical
clinical signs of disease.
Diagnostic criteria of IFA
Clinical
·
progressive dyspnea
·
cyanosis
·
dry cough
·
progressive loss of weight
·
tender crepitation wheezing
·
thickening of hand phalanges nails
Radiographic
·
diffuse fibrosis
·
deformation of the pulmonary pattern
·
presence of focal shadows
Indicators of
external respiration
·
decrease of lung volumes
·
hypoxemia
Indicators of
regional lung function
·
diffuse irregular distribution of radionucleids
·
regional lung volume reduction
·
smoothing apex-basal ingredients
.
Differential diagnose.
Differential diagnosis should be carried out with
exogenous allergic alveolitis caused by the inhalation of various organic
antigens. Such condition is observed in children with close and prolonged
contact with animals and birds. Clinically, the disease is very similar
to idiopathic diffuse pulmonary fibrosis. Exogenous allergic alveolitis is
diagnosed based on the detection of precipital antibodies against animal serum
and excrements. Excluding the effects of antigen in combination with
corticosteroid therapy in such patients may lead to recovery. In idiopathic
pulmonary fibrosis diffused all lung volumes, lung elasticity during therapy
with corticosteroids did not decreased even at satisfactory state of health of
patients and the absence of exacerbations process.
Treatment.
Corticosteroid therapy is used.
Originally prednisolone is prescribed at a dose of 1 mg / kg per day. The dose
is gradually reducing, but maintenance therapy (5-10 mg prednisolone per day),
continue for many months. In severe progressive course corticosteroids are combined
with cytostatic drugs (azathioprine, etc.). During exacerbations, the accession
of pneumonia, bronchitis, corticosteroids are combined with antibiotics. In
addition, antihistamines, vitamins, symptomatic treatment is used.
Prognosis
is unfavorable.
No comments:
Post a Comment