Medical Pharmacology Chapter 49: Overview of Chronic Obstructive Pulmonary Diseases


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18Bullous emphysema


  • 18"Emphysema is an enlargement of air spaces caused by destruction of alveolar walls. Air spaces greater than one cm are bullae. This photo shows apical bullous disease with relatively little involvement of the rest of the lung."


18Centriacinar emphysema/distal acinar emphysema


  • 18"This lung shows centriacinar emphysema with holes located around the terminal bronchioles and preservation of more distal air spaces. The parenchyma along the major fissure shows some distal acinar emphysema. Panacinar emphysema involves the entire acinus."



18Centriacinar emphysema
  • 18"This section of centriacinar emphysema shows the enlarged air spaces around a small airway.

  • Respiratory epithelium remains at the arrow. The more peripheral alveoli are normal."


19Normal Chest X-Ray & X-Ray from Emphysema Patient
  • 19Normal lung chest X-ray (left) compared to chest X-ray from a patient with emphysema:

  •  "The findings of hyperinflated lungs, flattened diaphragms, diminshed vascular markings suggest emphysema. 

    • Emphysema destroys alveoli and results in obstruction of small airways leading to air trapping - increased lung volumes. 

    • On lateral film there may be increased retrosternal space. 

    • However, thin individuals with good inspiratory effort may have flattened diaphragms and hyperinflated lungs that could mimic emphysema on Chest X-Ray."


20Classic Emphysema on CXR

  •  20"PA (left) and lateral (right) radiographs of a young woman with alpha-1-antitrypsin deficiency and typical changes of severe obstructive lung disease.

  • There is diminished vascularity (arterial deficiency pattern) along with flattened diaphragms and an increase in the AP dimension of the chest."

21Goblet Cells

  • Goblet cells secret mucus, which mainly consists of highly glycosylated proteins (proteins with sugars bound) called mucins in a viscous electrolyte solution.  Functions of mucus include protection against both stear stress and chemical damage, particularly in the respiratory tree as well as trapping particular matter and bacteria.

  • Goblet cells are commonly found in the epithelium of a number of organs, but predominately in the GI and respiratory tract.  The "goblet" shape of this cell type is clear in the two images below which are from intestinal sections.  Also, the "goblet" shape itself is due to an artifact associated with tissue fixation, as opposed to being a correct morphological description in vivo.

21Goblet Cells in Thin Section



24Functional Right to Left Shunting

  • 24Patient History:  41 year old male with a history of subarachnoid hemorrhage and seizure approximately two weeks ago who developed tachycardia, tachypnea and hypoxia. 

    • A chest X-ray was obtained. 

    • 24The patient was intubated and evaluated for pulmonary embolism with lung scintigraphy. {"Tc-99m DTPA aerosol by inhalation and Tc-99m MAA i.v.")

    • 24"The aerosol ventilation images demonstrate markedly decreased ventilation of the left lung. 

      • The perfusion images are nearly normal in this region, with mild heterogeneity elsewhere. 

      • The chest radiograph shows marked volume loss on the left with retrocardiac opacity probably representing left lower lobe collapse."

    • 24A reverse mismatch (decreased ventilation with normal perfusion) defines functional right to left shunting. 

      • Blood passes through the pulmonary capillary bed without being adequately oxygenated. This event may be commonly observed in intubated, intensive care unit patients, often occuring secondary to mucous plugging and can be associated with significant hypoxia. 

      • 24Therapeutic Intervention:   

        • 1.  "Putting the patient in the decubitus position with the mismatched side up (in this case left side up) will decrease blood flow to the area. 

        • 2. If PEEP is being used to help ventilate the patient, this can exacerbate the problem by relatively decreasing flow to ventilated lung, while the poorly ventilated area receives a greater portion of the total pulmonary flow (since the PEEP pressures are transmitted slightly less efficiently to the obstructed region). 

        • 3. If possible, positive end-expiratory pressure should be turned off in patients with evidence of functional right to left shunting. 

        • 4. Finally, the primary problem should be directly addressed. Sometimes bronchoscopy is necessary to clear the mucous plug.


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