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Second-Year Medicine

Block 5: Respiratory System

The Respiratory Block is an interdisciplinary course that aims to integrate core information from the basic sciences (with an emphasis on microbiology), pathology, and clinical medicine relevant to the respiratory system. The latter comprises the upper airways (including paranasal sinuses and middle ear), the intrathoracic airways, the lung parenchyma, and the lung’s dual vasculature. The block curriculum encompasses the following broad domains:

  1. pathophysiology of the respiratory system (with reference to the normal state)
  2. the major groups of lung diseases (with associated pathology)
  3. infections of the upper and lower respiratory tract (with related microbiology)
  4. respiratory therapeutics

The block employs several instructional formats: traditional lectures (presented as computerized “slide shows”), case-based learning (CBL), practical laboratory work, and independent study from written course material and assigned textbook sections. Students receive a detailed written syllabus that covers all lectures and several (currently 3) topics for independent study. Some of the course material and a bank of practice exam questions are available to students electronically through the medical school’s network (computer terminals are readily accessible at many sites, including the Education Building’s carrels and the medical library).

Both the lectures and written syllabus are organized by clinical topic or disease, and they weave basic and clinical information together for each subject. The emphasis is on pathophysiology, but reference is made to normal physiology and cell/molecular biology as well — partly to refresh and elaborate on 1st-year material and partly to introduce material new to the class. The major categories of respiratory disease are represented by paradigm diseases, chosen because of their clinical importance and/or because they illustrate important mechanisms of disease. Thus, for example, the diffuse infiltrative (interstitial) lung diseases are represented by idiopathic pulmonary fibrosis (fibrosing alveolitis), sarcoidosis, and hypersensitivity pneumonitis.

Microbiology and infectious diseases receive particular emphasis in this block. This is appropriate given the large interface that the upper and lower respiratory tract present to the environment, the vast number of specific pathogens known to cause respiratory tract infections (e.g., > 100 agents of pneumonia), and the frequency and relative severity of many respiratory tract infections.

The respiratory block uses one case (an actual patient with real data) for its three CBL sessions. The case may vary from year to year, but all represent one of the major obstructive airways diseases (asthma, COPD, bronchiectasis, or a combination thereof). Asthma and COPD are the commonest lung diseases in the general population, and they offer an excellent opportunity to explore the pathophysiology underlying the main respiratory symptoms, to become familiar with spirometry and other lung function tests (PFT), and to broach respiratory therapeutics. The majority of the therapies currently available in respiratory medicine apply to these airways diseases, whereas many other lung diseases currently lack effective treatments. Additionally, the MS2 CBL case complements the sarcoidosis case used in the MS1 respiratory block. Thus over the two years the students encounter the two main paradigms of lung dysfunction (restrictive and obstructive disorders) and study different types of chronic lung inflammation, both immunologic and nonspecific, irritant-induced.

Principles of occupational and environmental medicine are introduced briefly in this block, and major occupational lung diseases are covered in a lecture.

The block includes three types of laboratory practicums for which the class is divided into groups:

  1. The pathology lab presents specimens illustrating gross pathology and microscopy slides illustrating the histopathology of major diseases.
  2. The microbiology lab provides an overview of clinical microbiologic methods. Students perform Gram stains and throat cultures, use a rapid test for streptococcal group antigen, and view cultures (for colonial morphology) and stained specimen slides (for microbial morphology) of representative bacteria, mycobacteria, and fungi. The grade for this lab is based on a multiple-choice quiz.
  3. The PPD lab provides instruction in the use and interpretation of tuberculin skin tests and reviews delayed-type hypersensitivity. Students perform the PPD test on each other and read the results 2 days later.

A lecture on physical diagnosis of the respiratory tract and a practicum on examining the thorax (which the students do in same-sex pairs) take place during the respiratory block, as part of the year-long Essentials of Clinical Medicine II course.

The block concludes with a 2-hour open session at which students can raise any questions or problems they have regarding block content. The block director answers questions and provides impromptu teaching and clarification of certain topics that often prove challenging for the students.