Respiratory System Pathology: Chest Radiographs and Imaging - PDF

**[RESPIRATORY SYSTEM]** Chest radiographs are the most common exams in most Radiology departments. They provide useful information about lungs, soft tissue, bone, pleura, and mediastinum. Inappropriate exposure may hide or mimic pathology. *Standard films of the chest are a PA and lateral. On a r...

**[RESPIRATORY SYSTEM]** Chest radiographs are the most common exams in most Radiology departments. They provide useful information about lungs, soft tissue, bone, pleura, and mediastinum. Inappropriate exposure may hide or mimic pathology. *Standard films of the chest are a PA and lateral. On a routine chest film, the following items are examined:* \- trace the diaphragms \- check the position of the heart and mediastinum \- check the size and shape of the heart \- examine hilar shadows \- check ribs, clavicles, and spine \- assess the technical quality of the film *Extra views which may be taken include:* \- oblique: demonstrate intrathoracic shadows to a better advantage \- lordotic: demonstrates the apices \- lateral decubitus: demonstrates fluid or free air \- expiration film: demonstrates diaphragmatic movement, pneumothorax, and foreign bodies Inspiration and expiration may be performed for these situations. Ribs, sternum, and thoracic spine enclose the thoracic cavity. Rib fractures may be seen with accompanying pneumothorax. *Thymus Gland:* Fully developed around age of puberty. Crying causes the same effect as the Valsalva maneuver, resulting in a distorted thymus (wide). On an AP chest, the thymus resembles a "sail sign". *Pectus excavatum:* A congenital anomaly in which the sternum is greatly depressed, resulting in compression of the heart. *Azygous Lobe Fissure:* A common variant, resulting from the failure of normal migration of the azygous vein from the chest wall to its usual location. *Dextrocardia:* The heart is located on the right side of the chest. *Diaphragmatic dysfunction: Sniff test* - Weakness - Diaphragmatic muscle weakness can impede respiratory function - Results in smaller inspiration and limited expansion of the thorax - Most often involves entire diaphragm - Paralysis - Marked by absence of excursion (superior to inferior diaphragm movement during respiration - The affected hemi diaphragm loses its muscular power and cannot contract - May be unilateral or bilateral - Bilateral may result in disabling dyspnea - May be caused by degeneration of diaphragm or trauma (from spinal cord injury) - Eventration - Uncommon, permanent elevation of one hemi diaphragm - When it is unilateral, more often affects the left side - Acquired or congenital causes **IMAGING MODALITIES\ \ Computed Tomography:** - Method of choice for evaluation of pulmonary adenopathy - Rule of thumb for evaluating the character of a visualized nodule relates to its size: Nodule \< 1cm in size is usually benign and those that are \> 1cm are usually malignant. - Spiral or helical CT offers the advantage of imaging the entire chest with 1 breath hold. **Nuclear Medicine** - Perfusion and ventilation scans are useful in evaluating chest disease, particularly in the case of obstructive disease and pulmonary emboli. - Injection of a radionuclide into the venous system for a perfusion scan causes it to become trapped in the pulmonary circulation. - Ventilation scan: the patient inhales a radioactive gas (Xenon) and holds his or her breath while an image is taken of the gas distribution throughout the lungs. **PET** - Captures information regarding metabolic activity. **CHEST TUBES, VASCULAR ACCESS LINES, AND CATHETERS** - Important to exercise caution when moving a patient with any of these in place - Have assistance - Check with nurse - Cover cassette *Endotracheal tube:* - large plastic tube inserted through patient's nose or mouth, into the trachea - helps to manage the patient's airway - allows suctioning - allows mechanical ventilation - proper position is: below the vocal cords and above the carina *Chest tube:* - large plastic tube inserted into the chest wall between the ribs - allows drainage of air (pneumothorax) from the thoracic cavity - allows drainage of fluid (pleural effusion) from the thoracic cavity - allows the lungs to inflate to help the patient breath easier - usually inserted into the subclavian (may be jugular, antecubital or femoral vein) - Proper placement: Tip of CV line should be in the distal SVC just above the right atrium - Provides alternate injection site to compensate for loss of peripheral infusion sites or to allow massive volumes of fluid - Also allows for measurement of Central venous pressure, which indicates the function of the heart - Chest radiographs are performed to check for proper placement and the presence of a pneumothorax or hemothorax - Swan Ganz catheter - Usually inserted via the subclavian vein - Multiluminal catheter that serves to evaluate cardiac function - Measures pulmonary pressure, which reflects left atrial pressure - Positioned in the pulmonary artery *Access catheters (Hickman Catheter or Port-a-Cath):* - Usually inserted via the subclavian vein - Hickman catheters are open to the outside of the body with the tip of the catheter placed in the SVC - Port-a-Cath access devices are placed under the skin, just below the clavicle. Because they are not open to the outside, there is less chance of infection - Either type are used for chemotherapy in patients with poor peripheral venous access **CONGENITAL / HEREDITARY DISORDERS** *[Cystic Fibrosis:]* **(Destiny)** - Genetic disposition - Excessively viscous mucus; secretion by all exocrine glands - Affects pancreas and digestive organs and lungs - Higher incidence in Caucasians - Newborn (SB ileus) - Failure to gain weight - Diagnosis - Sweat chloride test - Radiographic findings - Hard to penetrate - Generalized irregular thickening of linear markings throughout lungs - Hyperinflation *[Hyaline Membrane Disease /RDS: ]* - Respiratory distress in newborn infant - Most often premature - Lack of surfactant - Radiographic Findings - Air bronchogram - Widespread white opacities (ground glass appearance) **INFLAMMATORY DISORDERS** *[Croup:]* \- Primarily a viral infection of young children that produces inflammatory obstructive swelling in the subglottic part of the trachea. *[Epiglottitis:]* \- Acute infection of the epiglottis. \- Most commonly caused by Haemophilus influenza in children. \- Seen on a lateral soft tissue view of the neck. \- May result in sudden, complete airway obstruction. *[Pneumonia:]* \- **Lobar pneumonia** involves 1 or more lobes of the lungs. \- **Bronchopneumonia** involves bronchioles and has more of a patchy appearance. \- **Alveolar or air space pneumonia** is produced by an organism (staphylococcus) that an inflammatory infiltrate that replaces air sacs. So the affected part appears solid. Often produces an air bronchogram. \- **Aspiration pneumonia** occurs as a result of reflux of esophageal or gastric contents, tumor, strictures, achalasia, Zenker\'s diverticula, or a neuromuscular disorder. \- Hard to penetrate \- Some types of pneumonia occur secondary to diseases like the flu, malignancy, human organ transplants, fractures, and any type of surgery in the elderly. *[Lung Abscess:]* \- A necrotic area of pulmonary parenchyma containing pus like material. \- May occur as a complication of bacterial pneumonia, bronchial obstruction, aspiration, foreign body or other bacterial conditions. \- Symptoms: fever, cough, and foul smelling sputum. \- Complication of a lung abscess is the development of a brain abscess. (Carried through the blood) *[Tuberculosis:]* \- Caused by Mycobacterium tuberculosis (rod shaped bacterium with a protective waxy covering) \- Spreads mainly by droplets in the air. The organisms may be inhaled from sputum that has dried and been changed into dust. They are rapidly killed by sunlight but survive a long time in the dark. May also be acquired by drinking the milk of an infected cow. \- This organism is called \"acid fast\" bacilli. \- Primarily a disease of the lungs, but may spread to the GI, GU, and skeletal systems. \- TB organism is an aerobic organism, likes O2. The apices of the lungs have slightly more oxygen than the other parts of the lungs, so TB often grows in the apices. \- High risk for TB: \- homeless/alcoholics \- diabetes mellitus \- dehabilitation \- Rheumatoid arthritis \- CA \- silicosis \- Immunosuppressive drugs \- Primary TB may be seen as a lobar or segmental air-space consolidation that is usually dense and well defined. Enlargement of hilar or mediastinal lymph nodes is common. \- Miliary TB refers to dissemination of the disease by way of the bloodstream. Radiographically, it produces multiple fine discrete nodules located uniformly throughout both lungs.. \- Active TB is easy to penetrate. \- Latent TB is hard to penetrate. **[*Chronic obstructive pulmonary disease (COPD)*:]** **(Morgan)** Includes several conditions in which chronic obstruction of the airways leads to an ineffective exchange of respiratory gases and difficult breathing. Eventually, emphysema and chronic bronchitis lead to heart failure. - Symptoms - Coughing - Breathlessness - Wheezing - Diagnosis - History - Spirometry test - Blood tests - Chest x-ray - Treatment - Antibiotics - Bronchodilators - Pulmonary rehabilitation - Oxygen - Includes - Emphysema - Chronic bronchitis - Asthma - Prevention - Avoid alcohol - Decrease exposure to environmental irritants - Appropriate protective gear - Physical activity - People with COPD should get annual flu and pneumococcal vaccinations to avoid infections *[Emphysema:]* - Characterized by an increase in the air spaces distal to the terminal bronchioles. - Alveoli become enlarged and lose elasticity. - Caused by cigarette smoke, air pollution, and industrial irritants. - Radiographically characterized by: - flattening of the hemidiaphragms - increase in the retrosternal air space - irregular hyperlucency of the lungs - increased AP diameter of the chest - elongation and narrowing of the heart - Radiographically easy to penetrate. *[Acute Bronchitis]:* *[Chronic Bronchitis]* \- Treatment - Stop smoking - Antibiotics - Bronchodilators *[Asthma:]* **(Abbi)** - Disease in which widespread narrowing of the airways develops because of an increased responsiveness of the tracheobronchial tree to allergens - Early in the disease, no radiographic signs - Patients with a hx of repeated attacks may show prominent interstitial markings - Exercise induced asthma *[Bronchiectasis:]* \- Irreversible dilation of the bronchioles. \- Depending on the extent of the disease, there may be impairment of bronchial secretions. \- Radiographic findings: visible dilated bronchioles \- Persistant consolidation of the affected areas \- Bronchography is the definitive method of making the diagnosis. \- Hard to penetrate. **OTHER PATHOLOGY** *[Pneumoconiosis:]* \- Group of conditions caused by inhalation of dust. \- Caused by prolonged occupational exposure to certain irritating dusts \- Silicosis: silicon dust (mining and sandblasting) \- Asbestosis: asbestos workers \- Anthracosis: coal miners (black lung) \- Hard to penetrate \- Radiographically - Nodules - Cavitation - Pleural thickening *[Bronchogenic Carcinoma]* - Linked to smoking and other carcinogens - May appear as mass or only detectable as bronchial obstruction - Hard to penetrate - Malignant tumors - Irregular or fuzzy border - Benign tumors - Sharp margin - Diagnosis - Lab test on sputum - Bronchoscopy/biopsy - Prognosis - Depends on single lesion or metastasis *[Pulmonary Embolus]* - Potentially fatal - 95% arise from deep venous thrombosis in lower extremity - Most embolic occlusions occur in lower lobes of lungs - Often incorrectly diagnosed - Symptoms: - Sudden onset of dyspnea - Subtle pleuritic and hemoptysis - Predisposing condition - Recent fracture - Surgical procedure - Heart disease - Obesity - Pregnancy - Estrogen therapy - Radiographically - May be normal - Subtle abnormalities - Infarction that appears as an area of lung consolidation - Chest may be normal or inconclusive so, Nuclear Medicine lung scan is also used (Very effective) - Pulmonary Angiogram *[Atelectasis:]* - Complete or partial lung collapse - Results from - Obstruction - Compression - Iatrogenic - Radiographic Findings - Hard to penetrate - Local area of airless lung - Compensation of "good" lung *[Adult Respiratory Distress Syndrome (ARDS)]* - Life threatening acute respiratory distress - May result from: - Trauma - Aspiration - Drug overdose Severe lung pathology *[Empyema]* - Pus in pleural cavity - Hard to penetrate *[Pneumothorax]* - Is air in the potential space between the visceral and parietal pleura of the lung. Air can enter the intrapleural space through a communication from the chest wall or through the lung parenchyma across the visceral pleura.   - Tension pneumothorax - Medical emergency in which air continues to enter the pleural space, and cannot leave it - Lung collapses completely - Heart and mediastinum shift toward the unaffected side, compromising cardiac output - Spontaneous pneumothorax - Air in the intrapleural space without preceding trauma and without underlying clinical or radiologic evidence of lung disease - Typically in patients who are between 18 and 40 years of age - More common in males \- Iatrogenic pneumothorax - Medical procedure resulting in traumatic pneumothorax (usually from a small-bore hollow needle) *[Pleural Effusion]* - Accumulation of fluid in pleural cavity - Hard to penetrate - Cause - - CHF - PE - Pleurisy - CA - Recent surgery - Ascites - Pancreatis *[Subcutaneous Emphysema]* - Air gets trapped under the skin - When moving a patient, a crackling sound can be heard - Many times related to trauma *[Covid]* - Origin and source of the SARS-CoV-2 remains unknown - Declared a pandemic by the World Health Organization on March 11th, 2020 - Transmission - Human to human by respiratory droplets - Close contact with patients that have COVID-19 - Possibly by fecal-oral and aerosol contact - Airborne transmission is highly virulent and represents the dominant route - - Fever or Chills - Cough - SOB - Fatigue or Muscle Aches - Headache - Loss of Taste or Smell - Sore Throat - Congestion or Runny Nose - Nausea or Vomit - Diarrhea *[Whooping Cough:]* **(Karlie)**