• SOM 4th Yr Curriculum

• CLERKSHIP INFORMATION
• Introduction / Goals and Objectives
• Rotations
  • HMC
  • UWMC
  • VAMC
• Seminars
• Faculty Only
• PULMONARY EDUCATION
• Pulmonary Med Library
• Arterial Blood Gases
• Cardiopulmonary Exercise Testing
• Mechanical Ventilation
• Pulmonary Function Testing
• Pleural Effusion
• Radiology

Pulmonary Function Testing

Case 5 Answer

A 41 year-old woman presents to the General Internal Medicine Clinic at Harborview Medical Center complaining of dyspnea with mild exertion. She has a 10 pack-year history of smoking and a history of using intravenous drugs including heroin and ritalin.

Her pulmonary function testing is as follows:

His flow volume loops is as follows:

Case 5 Interpretation

This patient has evidence of air-flow obstruction, as her FEV₁, FVC and her FEV₁/FVC are all decreased. Her flow volume demonstrates the characteristic scooped-out appearance seen in obstructive lung disease and also demonstrates markedly reduced peak expiratory flows. Based on her FEV₁ of 19% predicted this would be classified as “very severe” obstructive lung disease. The patient also has evidence of air-trapping, as her RV is 257% predicted. She would not be classified as being hyper-inflated because her TLC is only 108% predicted.  There is no evidence of a bronchodilator response as her FVC and FEV₁ both decline following bronchodilator administration. Her DLCO is also decreased, indicating a loss of alveolar-capillary surface area for gas exchange.

It is highly unlikely for a 41 year-old person to have obstructive lung disease with only a 10-pack year history of smoking. Asthma is an unlikely diagnosis given the absence of reversibility with bronchodilator administration.  Her chest x-ray provides some clues to the diagnosis, however. There is marked hyper-lucency at the bases, suggesting that this is a basilar-predominant form of emphysema. The minor fissure (arrow) is also shifted upward on the right side, indicating that the lower lobes are over-inflated. Two disorders can give you early-onset emphysema with a basilar predominance: alpha-one anti-trypsin deficiency (it is usually only seen this early if the person also smokes) and ritalin lung. The latter is an uncommon form of the severe basilar-predominant emphysema seen in people who previously used intravenous injections of ritalin (methylphenidate).

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