CONFIRMING DIAGNOSIS Lung biopsy is helpful in the diagnosis of IPF. In the past, an open lung biopsy was the only acceptable procedure, but now biopsies may be done through a thoracoscope or bronchoscope.
Histologic features of the biopsy tissue vary, depending on the stage of the disease and other factors that aren’t yet completely understood. The alveolar walls are swollen with chronic inflammatory cellular infiltrate composed of mononuclear cells and polymorphonuclear leukocytes. Intra-alveolar inflammatory cells may be found in early stages. As the disease progresses, excessive collagen and fibroblasts fill the interstitium. In advanced stages, alveolar walls are destroyed and are replaced by honeycombing cysts.
Chest X-rays may show one of four distinct patterns: interstitial, reticulonodular, ground-glass, or honeycomb. Although chest X-rays are helpful in identifying the presence of an abnormality, they don’t correlate well with histologic findings or pulmonary function tests (PFTs) in determining the severity of the disease. They also don’t help distinguish inflammation from fibrosis. However, serial X-rays may help track the progression of the disease.
High-resolution computed tomography scans provide superior views of the four patterns seen on routine X-ray film and are used routinely to help establish the diagnosis of IPF. Research is currently under way to determine whether the four patterns of abnormality seen on these scans correlate with responsiveness to treatment.
PFTs show reductions in vital capacity and total lung capacity and impaired diffusing capacity for carbon monoxide. Arterial blood gas (ABG) analysis and pulse oximetry reveal hypoxemia, which may be mild when the patient is at rest early in the disease but may become severe later in the disease. Oxygenation will always deteriorate, usually to a severe level, with exertion. Serial PFTs (especially carbon monoxide diffusing capacity) and ABG values may help track the course of the disease and the patient’s response to treatment.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Pneumocystis carinii pneumonia:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
CONFIRMING DIAGNOSIS Histologic studies confirm P. carinii in all patients. Fiber-optic bronchoscopy remains the most commonly used study to confirm PCP. Invasive procedures, such as transbronchial biopsy and open-lung biopsy, are performed less commonly.
In patients with HIV infection, initial examination of a first-morning sputum specimen (induced by inhaling an ultrasonically dispersed saline mist) may be sufficient; however, this technique usually is ineffective in patients without HIV infection.
Chest X-rays may show slowly progressing, fluffy infiltrates and, occasionally, nodular lesions or a spontaneous pneumothorax, but these findings must be differentiated from findings in other types of pneumonia or acute respiratory distress syndrome.
Gallium scan may show increased uptake over the lungs even when the chest X-ray appears relatively normal. Arterial blood gas (ABG) studies detect hypoxia and an increased A-a gradient.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Idiopathic bronchiolitis obliterans with organizing pneumonia:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Diagnosis begins with a thorough patient history meant to exclude any known cause of bronchiolitis obliterans or diseases with a pathology that includes an organizing pneumonia pattern.
❑ Chest X-ray usually shows patchy, diffuse airspace opacities with a ground-glass appearance that may migrate from one location to another. High-resolution computed tomography scans show areas of consolidation. Except for the migrating opacities, these findings are nonspecific and present in many other respiratory disorders.
❑ Pulmonary function tests may be normal or show reduced capacities. The diffusing capacity for carbon monoxide is generally low.
❑ Arterial blood gas analysis usually shows mild to moderate hypoxemia at rest, which worsens with exercise.
❑ Blood tests reveal an increased erythrocyte sedimentation rate, an increased C-reactive protein level, an increased white blood cell count with a somewhat an increased proportion of neutrophils, and a minor rise in eosinophils. Immunoglobulin (Ig) G and IgM levels are normal or slightly increased, and the IgE level is normal.
❑ Bronchoscopy reveals normal or slightly inflamed airways. Bronchoalveolar lavage fluid obtained during bronchoscopy shows a moderate elevation in lymphocytes and, sometimes, elevated neutrophil and eosinophil levels. Foamy-looking alveolar macrophages may also be found.
CONFIRMING DIAGNOSIS Lung biopsy, thoracoscopy, or bronchoscopy is required to confirm the diagnosis of BOOP. Pathologic changes in lung tissue include plugs of connective tissue in the lumen of the bronchioles, alveolar ducts, and alveolar spaces.
These changes may occur in other types of bronchiolitis and in other diseases that cause organizing pneumonia. They also differentiate BOOP from constrictive bronchiolitis (characterized by inflammation and fibrosis that surrounds and may narrow or completely obliterate the bronchiolar airways). Although the pathologic findings in proliferative and constrictive bronchiolitis are different, the causes and presentations may overlap. Any known cause of bronchiolitis obliterans or organizing pneumonia must be ruled out before the diagnosis of BOOP is made.
» READ BOOK EXCERPT ONLINE »
Source: Professional Guide to Diseases (Eighth Edition), 2005
Pneumonia Variants:
Differential Overview
(Field Guide to Bedside Diagnosis)
❑ Streptococcus pneumoniae
❑ Mycoplasma pneumoniae
❑ Haemophilus influenzae
❑ Chlamydia pneumoniae
❑ Influenza virus
❑ Staphylococcus aureus
❑ Mycobacterium tuberculosis
❑ Legionella pneumophila
❑ Klebsiella pneumoniae
❑ Pneumocystis carinii
❑ Chlamydia psittaci
❑ Severe Acute Respiratory Syndrome (SARS)
❑ Hantavirus
Diagnostic Approach
Although the current consensus recommendations call for the use of broad spectrum empiric antibiotics without determining the cause of the pneumonia, clinical findings combined with low-tech bedside diagnostics, such as sputum Gram stain, can be surprisingly informative. As an example, in smokers with chronic bronchitis consider H. influenzae, S. pneumoniae, and
B. catarrhalis.
» READ BOOK EXCERPT ONLINE »
Source: Field Guide to Bedside Diagnosis, 2007
Pneumonia:
Diagnosis
(Handbook of Diseases)
Clinical features, chest X-ray film showing infiltrates, and sputum smear demonstrating acute inflammatory cells support this diagnosis. Positive blood cultures in patients with pulmonary infiltrates strongly suggest pneumonia produced by the organisms isolated from the blood cultures.
Pleural effusions, if present, should be tapped and the fluid analyzed for evidence of infection in the pleural space. Occasionally, a transtracheal aspirate of tracheobronchial secretions or bronchoscopy with brushings or washings may be done to obtain material for smear and culture. The patient’s response to antimicrobial therapy also provides important evidence of the presence of pneumonia.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Pneumocystis carinii pneumonia:
Diagnosis
(Handbook of Diseases)
❑ Histologic studies confirm P. carinii. In patients with HIV infection, initial examination of a first-morning sputum specimen (induced by inhaling an ultrasonically dispersed saline mist) may be sufficient; however, this technique usually is ineffective in patients without HIV infection.
❑ Fiber-optic bronchoscopy remains the most commonly used study to confirm PCP. Invasive procedures, such as transbronchial biopsy and open-lung biopsy, are less common.
❑ Chest X-ray may show slowly progressing, fluffy infiltrates and, occasionally, nodular lesions or a spontaneous pneumothorax. However, these findings must be differentiated from findings in other types of pneumonia or adult respiratory distress syndrome.
❑ Gallium scan may show increased uptake over the lungs even, when the chest X-ray appears relatively normal.
❑ Arterial blood gas (ABG) studies detect hypoxia and an increased alveolar-arterial gradient.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
Bronchiolitis obliterans with organizing pneumonia, idiopathic:
Diagnosis
(Handbook of Diseases)
Diagnosis begins with a thorough patient history meant to exclude any known cause of bronchiolitis obliterans or diseases with a pathology that includes an organizing pneumonia pattern.
❑ Chest X-ray usually shows patchy, diffuse airspace opacities with a ground-glass appearance that may migrate from one location to another. High-resolution computed tomography scans show areas of consolidation. Except for the migrating opacities, these findings are nonspecific and present in many other respiratory disorders.
❑ Pulmonary function tests may be normal or show reduced capacities. The diffusing capacity for carbon monoxide is generally low.
❑ Arterial blood gas analysis usually shows mild to moderate hypoxemia at rest, which worsens with exercise.
❑ Blood tests reveal an increased erythrocyte sedimentation rate, increased C-reactive protein level, and increased white blood cell count with a somewhat increased proportion of neutrophils and a minor rise in eosinophils. Immunoglobulin (Ig) G and IgM levels are normal or slightly increased, and the IgE level is normal.
❑ Bronchoscopy reveals normal or slightly inflamed airways. Bronchoalveolar lavage fluid obtained during bronchoscopy shows a moderate elevation in lymphocyte levels and, sometimes, elevated neutrophil and eosinophil levels. Foamy-looking alveolar macrophages may also be found.
Lung biopsy, thoracoscopy, or bronchoscopy is required to confirm the diagnosis of BOOP. Pathologic changes in lung tissue include plugs of connective tissue in the lumen of the bronchioles, alveolar ducts, and alveolar spaces.
These changes may occur in other types of bronchiolitis and in other diseases that cause organizing pneumonia. They also differentiate BOOP from constrictive bronchiolitis, characterized by inflammation and fibrosis that surround and may narrow or completely obliterate the bronchiolar airways. Although the pathologic findings in proliferative and constrictive bronchiolitis are different, the causes and presentations may overlap. Any known cause of bronchiolitis obliterans or organizing pneumonia must be ruled out before the diagnosis of BOOP is made.
» READ BOOK EXCERPT ONLINE »
Source: Handbook of Diseases, 2003
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