Differentiating the Opacities of Hemitorak

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  • Differentiating theCauses of an OpacifiedHemithorax

    William Hering 2002

  • Three Major Causes + 1Atelectasis of an entire lungA large pleural effusionPneumonia of an entire lungAnd a fourth cause: n Post-pneumonectomy removal of an entire lung

  • Atelectasis of the LungAtelectasis of an entire lung = loss of volume of the affected lungVisceral and parietal pleura do NOT separate from each otherThere is a shift of heart and hemidiaphragm toward side of opacification (toward side of volume loss)

  • Atelectasis of the right lungThe right hemithorak is opaque.

    The shift of trachea & heart toward the side of opasification

  • Pleural EffusionIf an effusion (whatever the fluid is) fills the entire hemithorax

    It acts like a mass

    Pushing the heart and trachea away from the side of opacification

  • PneumoniaThe hemithorax is opaque and there is no shift of the heart or trachea

    There may be an air bronchogram sign present

  • Post-PneumonectomyWhen the entire lung is removed, there is volume loss on the pneumonectomized sideThe hemithorax eventually fibroses and becomes opaqueClues: There is frequently a resected fifth rib and/or surgical clips

  • Important PointsIn atelectasis, there is s shift toward the side of the opacification In pleural effusion, there is a shift away from the side of the opacificationIn pneumonia, there is no shift In pneumonectomy, the 5th rib is usually absent

  • Which is this?

  • Which is this?

  • Which is this?

  • Recognizing A Pleural Effusion

  • Normal AnatomyVisceral pleura is adherent to the lung

    Space between visceral and parietal pleura is a potential space

    Infoldings of visceral pleura form fissures

    Loose connective tissue beneath visceral pleura = subpleural space

  • Normal PhysiologyNormally there are 2-10 cc of fluid in the pleural space

    Each hour, as much as 100cc of fluid is produced, mostly at parietal pleura

    Fluid drains mostly to visceral pleura and via lymphatics

  • Abnormal PhysiologyPleural effusions may form when n hydrostatic pressure n colloid osmotic pressure n capillary permeability n absorption of fluid by lymphatics n pressure in pleural space n Transport of peritoneal fluid through diaphragm or via lymphatics

  • Pleural Effusion-TypesTransudate

    Exudate n Empyema n Hemothorax n Chylothorax

  • Transudate capillary hydrostatic pressure or osmostic pressure n CHF n Hypoalbuminemia n Cirrhosis n Nephrotic syndrome

  • ExudateUsually 2 neoplastic or inflammatory dzs involving pleura

    [Fluid Protein] :[serum protein] > 0.5

    [Fluid LDH] : [serum LDH] >0.6

    Fluid LDH > 2/3 highest normal serum LDH

  • Specific Types of EffusionsHemothorax n Fluid hematocrit > 50% blood hematocrit

    Empyema = exudate containing pus.

    Chylothorax = triglycerides or cholesterol n Obstruction or rupture of lymphatic vessels

  • Side-specificityMostly left-sided n Pancreatitis n Dresslers syndrome n Distal thoracic duct obstruction

    Mostly right-sided n Heart failure n Abdominal disease related to liver or ovary n Proximal thoracic duct obstruction

  • Appearances of Pleural EffusionsSubpulmonic effusion Blunting of Costophrenic angleMeniscus signLayeringLoculatedLaminar effusionOpacified hemithoraxAir-fluid levels

  • Subpulmonic EffusionUsually less than 300-350cc

    Accumulates at base of lung between visceral and parietal pleura

    Causes apparent lateral displacement of highest part of hemidiaphragm

    Flat-edge sign on lateral

    Increased distance between stomach bubble and base of lung

  • Subpulmonic Pleural EffusionOn the frontal film, the highest point of the apparent right hemidiaphragmis displaced laterally (it is usually in the center). On the lateral film, thereis a flat edge where the effusion meets the major fissure

  • Blunting of the CP AngleNormally there are 2-10cc of fluid in the pleural space

    When >75cc accumulate, the posterior costophrenic (CP) sulci, seen on the lateral film, become blunted

    When 200-300cc accumulate, the CP sulci on the frontal film become blunted

  • Normal costophrenic angle BluntingWhen 200 300 cc of fluid accumulate in the pleural space, usually costophrnenic angle become blunted ( the same person )

  • Meniscus SignPleural fluid tends to rise higher along its edge producing a meniscus shape medially and laterally

    Usually only lateral meniscus can be seen

    The meniscus is a good indicator of the presence of a pleural effusion

  • Meniscus Sign

  • Effect of Position - Layering Supine Erect

  • Loculated EffusionOccurs 2 adhesions which form between visceral and parietal pleura

    Adhesions more common with blood (hemothorax) and pus (empyema)

    Loculated effusions have unusual shapes or positions in thorax n E.g. remain at apex on erect films

  • Loculated EffusionA loculated effusin (lenticular form )in the thoracic cavity.Loculated empyema

  • Laminar EffusionA laminar effusion collects in the loose connective tissue between the lung and the visceral pleura

    It is not usually free-flowing

    It usually occurs with CHF or lymphangitic spread of malignancy

  • A laminar effusion collects between the lung and the visceral pleura in the loose connective tissue of the subpleural space Laminar effusions are usually seen with CHF or lymphangitic spread of tumor

  • Opacified HemithoraxIf an effusion fills the entire hemithorax, it acts like a mass

    There is displacement of the heart and trachea away from the side of opacification

    In atelectasis of an entire lung, the heart and trachea are pulled toward the side of opacification

  • HydropneumothoraxIf both a pneumothorax and a pleural effusion occur together, it is called a hydropneumothorax

    A hydropneumothorax is usually due to trauma, surgery, bronchopleural fistula

    It is characterized by an air-fluid level in the hemithorax

  • A straight edge, indicative of a fluid interface, in this case an air-fluid interface, is seen on the right. In order to have an air-fluid level in the pleural space, there must be a pneumothorax present.

  • Important PointsPleural effusions are transudates or exudates

    It takes from 200-300cc to blunt the costophrenic sulcus on the frontal view

    The meniscus is the classic shape of an effusion on a frontal film

    Pleural effusions shift the mediastinal structures away from the side opacified