Brief notes on diseases Flashcards
Goodpastures
ANTI-GLOMERULAR BASEMENT MEMBRANE ANTIBODY DISEASE
utoimmune disease characterized by(1) glomerulonephritis(2) circulating antibodies against glomerular + alveolar basement membrane(3) pulmonary hemorrhage
symmetric consolidation of perihilar area + lung bases with sparing of lung apices√ air bronchogram√ consolidation replaced by interstitial pattern within 2–3 days (due to organization of hemorrhage resulting in interlobular septal thickening)√ hilar lymph nodes may be enlarged during acute episodes
eosinophilic granuloma
SPARING OF CPA DIFFERENTIATES PULMONARY EG FROM LYMPHANGIOMYOMATOSIS
Also know as Langerhans’ cell histiocytosis
Patients with isolated pulmonary involvement are usually young adults (age 20 to 40 years), Caucasian, and there is an equal frequency in men and women (although young men appear to have the worst prognosis) [20]. The disorder is rare in blacks. There is a strong association with smoking (90-95% of cases occur in smokers) and symptoms often improve with cessation of smoking.
There are no known genetic factors that predispose persons to pulmonary LCH [13]. Between one-quarter and one-third of patients are asymptomatic at presentation. Symptomatic patients may present with cough (66%), progressive dyspnea, weight loss, fever, or diabetes insipidus (25%). Pneumothorax occurs in 10-25% of patients and will recur on the ipsilateral side in up to 58% of patients [16]. Hemoptysis occurs in less than 5% of patients [13]. There
Computed tomography: On HRCT the distribution of the disease is similar to that on CXR with an upper lobe predominance with sparing of the costophrenic recesses (likely related to the inhalational component of the disorder) [18,20]. In the early stages, findings include centrilobular opacities and small nodules (1 to 5 mm, but up to 1.5 cm) [17]. The nodules may be few or innumerable and typically have irregular margins [17]. Later in the disorder there is cystic cavitation of small nodules, and cysts- initially thick walled and later thin walled (typically lesions progress in this fashion) [17]. Some authors feel that the nodules do not cavitate and that the cysts represent paracicatrical emphysematous change adjacent to the nodules. The cysts are usually less than 10 mm in size, although cysts larger than 10 mm are found in over half the cases. The walls of the cysts are usually thin (1mm or less), but can be variable, and the cysts are not necessarily round (they may be bilobed or branching). The intervening lung parenchyma appears normal. In the late stage, there may be diffuse cysts, with no nodules evident (about 20% of cases [6]), while in the early stages, only nodules may be seen [3]. In the late stages, the disorder may be indistinguishable from lymphangiomyomatosis- but sparing of the costophrenic angles suggests the diagnosis of histiocytosis X [6]. Mediastinal adenopathy has been described in some series, but is usually uncommon [2]. Other authors report medistinal adenopathy in up to 30% of EG patients [10].
CYSTIC ADENOMATOID MALFORMATION
CYSTIC ADENOMATOID MALFORMATION= CAM = congenital cystic abnormality of the lung characterized by an intralobar mass of disorganized pulmonary tissue communicating with bronchial tree + having normal vascular supply + drainage but delayed clearance of fetal lung fl uid TYPE I (50%):Histo: single / multiple large cyst(s) >20 mm lined by ciliated pseudostratifi ed columnar epithelium, mucus-producing cells in 1/3Prognosis: excellent following resectionTYPE II (40%):Histo: multiple cysts 5–12 mm lined by ciliated cuboidal / columnar epitheliumPrognosis: poor secondary to associated abnormalitiesTYPE III (10%):Histo: solitary large bulky fi rm mass of bronchuslike structures lined by ciliated cuboidal epithelium with 3–5-mm small microcystsPrognosis: poor secondary to pulmonary hypoplasia / hydrops
Age of detection: children, neonates, fetus; M÷F = 1÷1
Location: equal frequency in all lobes (middle lobe rarely affected); more than one lobe involved in 20%;mostly unilateral without side preferenceCXR:√ almost always unilateral expansile mass with well-defi ned margins (80%) (due to retained fetal lung fl uid / type III lesion)√ multiple air- / occasionally fl uid-fi lled cysts√ compression of adjacent lung√ contralateral shift of mediastinum (87%)√ hypoplastic ipsilateral lung√ proper position of abdominal viscera√ spontaneous pneumothorax (late sign)CT:◊ Postnatally becoming obstructed and fi lled with air√ solitary / multiple fl uid or air-fl uid fi lled cysts with thin walls√ surrounding focal emphysematous changes
Prognosis: 50% premature, 25% stillborn
Sequestration
BRONCHOPULMONARY SEQUESTRATION
Bronchopulmonary sequestration (BPS) is a rare congenital malformation of the lower respiratory tract.
It consists of a nonfunctioning mass of normal lung tissue that lacks normal communication with the tracheobronchial tree, and that receives its arterial blood supply from the systemic circulation.
BPS is estimated to comprise 0.15 to 6.4 percent of all congenital pulmonary malformations, making it an extremely rare disorder.
Sequestrations are classified anatomically.
Intralobar sequestration (ILS) in which the lesion is located within a normal lobe and lacks its own visceral pleura.
Extralobar sequestration (ELS) in which the mass is located outside the normal lung and has its own visceral pleura
The blood supply of 75% of pulmonary sequestrations is derived from the thoracic or abdominal aorta.
The remaining 25% of sequestrations receive their blood flow from the subclavian, intercostal, pulmonary, pericardiophrenic, innominate, internal mammary, celiac, splenic, or renal arteries.
INTRALOBAR SEQUESTRATION
· The intralobar variety accounts for 75 percent of all sequestrations.
· Usually presents in adolescence or adulthood as recurrent pneumonias.
· Lies within the same visceral pleura as the lobe in which it occurs.
· Males and females are equally affected with ILS.
· In ILS, the arterial supply usually is derived from the lower thoracic or upper abdominal aorta.
· Venous drainage is usually to the left atrium via pulmonary veins establishing a left to right shunt.
o Abnormal connections to the vena cava, azygous vein, or right atrium may occur.
· Two thirds of the time, the sequestration is located in the paravertebral gutter in the posterior segment of the left lower lobe.
· Unlike extralobar sequestration, it is rarely associated with other developmental abnormalities.
· Patients present with signs and symptoms of pulmonary infection of a lower lobe mass.
o It is believed that sequestrations become infected when bacteria migrate through the pores of Kohn or if the sequestration is incomplete.
EXTRALOBAR SEQUESTRATION
· The extralobar variety accounts for 25 percent of all sequestrations.
· ELS usually presents in infancy with respiratory compromise.
· Develops as an accessory lung contained within its own pleura.
· ELS has a male predominance (80%).
· Related to the left hemidiaphragm in 90% of cases.
o ELS may present as a subdiaphragmatic or retroperitoneal mass.
· In general, the arterial supply of ELS comes from an aberrant vessel arising from the thoracic aorta.
· It usually drains via the systemic venous system to the right atrium, vena cava, or azygous systems.
· Congenital anomalies occur more frequently in patients with ELS than ILS.
o Associated anomalies include Congenital cystic adenomatoid malformation (CCAM), congenital diaphragmatic hernia, vertebral anomalies, congenital heart disease, pulmonary hypoplasia, and colonic duplication
· Since it is enveloped in its own pleural sac, it rarely gets infected so almost always presents as a homogeneous soft tissue mass.
· The mass may be closely associated with the esophagus, and fistulae may develop.
IMAGING
· An arteriogram has been considered vital in documenting the systemic blood supply, allowing definitive diagnosis as well as preoperative planning.
· The advent of new noninvasive imaging techniques has changed this thinking.
CHEST RADIOGRAPH
· Sequestrations typically appear as a uniformly dense mass within the thoracic cavity or pulmonary parenchyma.
· Recurrent infection can lead to the development of cystic areas within the mass.
· Air-fluid levels due to bronchial communication can be seen.
ULTRASOUND
· The typical sonographic appearance of BPS is an echogenic homogeneous mass that may be well defined or irregular.
· Some lesions have a cystic or more complex appearance.
· Doppler studies are helpful to identify the characteristic aberrant systemic artery that arises from the aorta and to delineate venous drainage.
CT
· CT scans have 90% accuracy in the diagnosis of pulmonary sequestration.
· The most common appearance is a solid mass that may be homogeneous or heterogeneous, sometimes with cystic changes.
· Less frequent findings include a large cavitary lesion with an air-fluid level, a collection of many small cystic lesions containing air or fluid, or a well-defined cystic mass.
· Emphysematous changes at the margin of the lesion are characteristic and may not be visible on the chest radiograph.
· CT technique for optimal depiction of lesions by using state-of-the-art volumetric scanning requires a fast intravenous (IV) contrast injection rate and appropriate volume and delay based upon size.
· Multiplanar and 3D reconstructions are helpful.
MRI
· Contrast-enhanced MRA or even conventional T1-weighted spin-echo (SE) images may help in the diagnosis of pulmonary sequestration by demonstrating a systemic blood supply, particularly from the aorta, to a basal lung mass.
· In addition, MRA may demonstrate venous drainage of the mass and may obviate more invasivey investigations.
· However, CT allows sharper delineation of thin-walled cysts and emphysematous changes than MRI.
CT with IV contrast of the thorax showing an Intralobar Bronchopulmonary Sequestration. The yellow arrow in frames A and B point to a hyperdense region in the left lower lobe of the lung with small cystic lesions containing air within it. The red arrows in frames C and D show a contrast enhanced vessel arising from the aorta and supplying the area of hyperdensity in the lung.
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