Imaging Pearls ❯ Chest ❯ Infection
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- Sarcoidosis: Facts
- Multisystem, autoimmune disorder with formation of noncaseous granulomas. Pulmonary involvement is seen in 90% of patients and accounts for a majority of the morbidity and mortality of the disease
- Common presenting symptoms include cough, dyspnea, and fatigue although many patients with sarcoidosis are asymptomatic.
- More than half of patients experience minimal consequences from the disease but around one fifth of patients can develop pulmonary fibrosis. - Tuberculosis: Facts
- Initial infection with Mycobacterium tuberculosis is referred to as primary tuberculosis and can appear radiographically as mediastinal and hilar lymphadenopathy, consolidation, pleural effusion, or nodules.
- Following resolution of the primary infection, tuberculosis can appear as upper lung consolidations and cavitations.
- Both primary and post-primary disease can affect the bronchial wall and manifests as bronchial wall involvement and bronchial stenosis due to lymphadenitis. - Nontuberculous Mycobacterial Infection: Facts
- Typically occurs in older women (Lady Windermere Syndrome) and presents with chronic cough
- CT imaging usually shows peripheral bronchiectasis, bronchial wall thickening, tree-in-bud nodules, and larger random nodules that may cavitate
- Usually spares the upper lungs; classic location is in the right middle lobe and lingula - Allergic Bronchopulmonary Aspergillosis: Facts
- Typically occurs in patients with long standing asthma or cystic fibrosis
- Presents with wheezing and pneumonia-like symptoms of productive cough and fever
- Imaging classically shows the "finger-in-glove" sign of dilated tubular branching opacities which demonstrates mucus plugging
- Attenuation of the mucus plug will exceed that of skeletal muscle on noncontrast CT - Tracheobronchial Amyloidosis: Facts
- Amyloidosis is a multisystem disorder of abnormal protein deposition. Tracheobronchial manifestations include airway wall thickening and intramural nodules that can be complicated by airway obstruction
- Airway involvement can be circumferential including the posterior membrane unlike cartilaginous disorders (ie. relapsing polychondritis and tracheobronchopathia osteochondroplastica)
- Disease of the upper airway presents with typical upper airway symptoms while disease of the lower airways presents with recurrent pneumonia and lobar collapse - Risk factors for primary spontaneous pneumothorax
- Smoking
- Tall thin body habitus in an otherwise healthy person
- Pregnancy
- Marfan syndrome
- Familial pneumothorax - Diseases associated with secondary spontaneous pneumothorax
- COPD
- Asthma
- HIV with pneumocystis pneumonia
- Necrotizing pneumonia
- Tuberculosis
- Sarcoidosis
- Cystic fibrosis
- Bronchogenic carcinoma
- Idiopathic pulmonary fibrosis - Causes of tension pneumothorax
- Penetrating or blunt trauma
- Barotrauma due to positive pressure ventilation
- Percutaneous tracheostomy
- Conversion of spontaneous pneumothorax to tension
- Open pneumothorax when occlusive dressing work as one way valve
- “The hallmark of esophageal disorders with regard to recurrent lung infection is spillage of gastroesophageal contents into the lungs due to alterations in esophageal structure or physiology. In achalasia, dysfunction of the esophageal myenteric plexus results in aperistalsis of the lower esophagus and defective relaxation of the lower esophageal sphincter. A Zenker diverticulum can be a reservoir for ingested contents. Systemic sclerosis causes atrophy of the esophageal smooth muscles with subsequent esophageal dysmotility, dilatation, and gastroesophageal reflux. Tracheoesophageal fistulas are serious complications that may develop from various underlying causes, including congenital disorders, iatrogenic factors, radiation, trauma, and neoplasm.”
Anatomic and Pathologic Causes of Recurrent Pulmonary Infections.
Harowicz MR, Al Khalifah A, Cohen KA, DeMaio A, Illei PB, Fishman EK, Lin CT.
Radiographics. 2023 Jun;43(6):e220106. doi: 10.1148/rg.220106. PMID: 37261962. - “Among congenital disorders, proximal interruption of the pulmonary artery and pulmonary sequestration are both characterized by an abnormal pulmonary arterial supply. Diseases with variant pulmonary blood flow can result in poor delivery of inflammatory cells, which weakens the immune response. Congenital causes of bronchiectasis result in airway collapse and impaired airway clearance; for example, bronchial atresia (focal bronchial interruption associated with distal mucus impaction) and Williams-Campbell syndrome (deficient cartilage in the fourth- to sixth-order bronchi).”
Anatomic and Pathologic Causes of Recurrent Pulmonary Infections.
Harowicz MR, Al Khalifah A, Cohen KA, DeMaio A, Illei PB, Fishman EK, Lin CT.
Radiographics. 2023 Jun;43(6):e220106. doi: 10.1148/rg.220106. PMID: 37261962. - “The lungs’ immunologic defense against infections is impaired by immunodeficiency syndromes, including common variable immunodeficiency (deficiencies in B cells), Good syndrome (associated with thymomas and B- or T-cell abnormalities), and secondary immunodeficiencies. Immunocompetentpatients with asthma or cystic fibrosis are susceptible to allergic bronchopulmonary aspergillosis, caused by Aspergillus organisms in the bronchial mucosa causing excessive immune system activation, repeated bronchospasm, bronchial wall edema, and resultant bronchiectasis.”
Anatomic and Pathologic Causes of Recurrent Pulmonary Infections.
Harowicz MR, Al Khalifah A, Cohen KA, DeMaio A, Illei PB, Fishman EK, Lin CT.
Radiographics. 2023 Jun;43(6):e220106. doi: 10.1148/rg.220106. PMID: 37261962. - “Tracheobronchial variants include single or multiple tracheal outpouchings (diverticuli); accessory airways, particularly cardiac bronchi; and tracheobronchomalacia. Recurrent airway injury and chronic inflammation are typical for several conditions owing to ineffective airway clearance. Thick mucus in cystic fibrosis alters bacterial killing, and repeated infections lead to bronchiectasis. Nontuberculous mycobacterial infection can have a chronic indolent or progressive course and tends to occur in the setting of structural lung disease or bronchiectasis. Right middle lobe atelectasis due to extrinsic airway compression or nonobstructive causes results in chronic inflammation and/or infection, predisposing to bronchiectasis.”
Anatomic and Pathologic Causes of Recurrent Pulmonary Infections.
Harowicz MR, Al Khalifah A, Cohen KA, DeMaio A, Illei PB, Fishman EK, Lin CT.
Radiographics. 2023 Jun;43(6):e220106. doi: 10.1148/rg.220106. PMID: 37261962. - TEACHING POINTS
* The hallmark of esophageal disorders with regard to recurrent lung infection is spillage of gastroesophageal contents into the lungs due to alterations in esophageal structure or physiology.
* Diseases with variant pulmonary blood flow can result in poor delivery of inflammatory cells, which weakens the immune response.
* Immune cell deficiency, impaired or excessive immune system reaction, and variations in mucociliary clearance blunt the immune response and predispose to lung infections.
Anatomic and Pathologic Causes of Recurrent Pulmonary Infections.
Harowicz MR, Al Khalifah A, Cohen KA, DeMaio A, Illei PB, Fishman EK, Lin CT.
Radiographics. 2023 Jun;43(6):e220106. doi: 10.1148/rg.220106. PMID: 37261962.