The 25 most important concepts from PCM

This page discusses the 25 most important concepts taught in the Principles of Clinical Medicine (and elsewhere) that second year medical students should understand.

Physical Exam

 * 1) Pupillary reflexes of CN II and CN III. Discussed elsewhere. Clinically useful.  Distinguish between afferent (CN2) and efferent defects (CN3).
 * 2) Interpreting the Rinne & Weber tests. Be able to distinguish conductive from neurosensory hearing loss on either side. Discussed elsewhere
 * 3) Know the rules for how to wash your hands. Hand washing prevents disease.  It's especially important to know how to examine patients who are high risk, like those with a surgical wound or who are in isolation.  See Handwashing Vital Signs.  Hint: wash with soap and water for at least 15 seconds, always use gloves when examining a wound, use sanitizer before AND after glove use.  No personal protection is required to examine a person with a fever of unknown origin (use hand hygiene before and after).
 * 4) Interpret the auscultation finds from the lung exam. Distinguish between consolidation, pneumothorax, and pleural effusion.  Know what to expect in terms of tactile fremitis, breath sounds, ratio of aveolar to brochiolar sounds (timing), egophony, and percussion.  Know it cold.  Reviewed in PCM1: Lung Exam
 * 5) * Consolidation (fluid/pus in bronchioles as in pneumonia): dull percussion, decreased breath sounds/crackles, increased tactile fremitus (sound moves faster through solids than air), egophany (pt says E, sounds like A)
 * 6) * Pleural effusion (fluid in pleural space): dull percussion, decreased breath sounds, decreased tactile fremitus; egophony, crackles at edge of effusion.
 * 7) * COPD (hi lung vol): tympanic percussion, decreased breath sounds; wheezes, crackles; PMI moves from axilla to subxiphoid area; tripod posture, pursed lip breathing
 * 8) * Pneumothorax (collapsed area of lung): tympanic/hyperresonant percussion, decreased breath sounds, no tactile fremitus
 * 9) Identify heart murmurs by auscultation characteristics, including radiation, timing between S1/S2, pitch etc. Don't be fooled when asked to identify mitral regurgitation vs. tricuspid regurgitation.
 * 10) Physiologic Splitting of the second heart sound is a normal process (S1--A2P2 sequence). In brief, deep inspiration increases venous return to the RV, thereby delaying the closure of P2.  Further describe here
 * 11) Significance of S3 and S4 heart sounds.
 * 12) *S3 may be heard in athletic young people, but is otherwise pathological.
 * 13) *An abnormal S4 is most frequently observed in patients with decreased left ventricular distensibility [46]. Thus, S4 is common in hypertensive heart disease, aortic stenosis, and hypertrophic cardiomyopathy. Left ventricular hypertrophy, which is present in all these conditions, contributes to decreased left ventricular distensibility.
 * 14) * Both are best heard with the bell of the stethoscope over the cardiac apex.
 * 15) Identify pulse abnormalities. In particular, identify the difference between regularly irregular and irregular, know that S3 comes right after S2 and S4 comes right before S1.
 * 16) Jugulovenous pressure calculations. Understand how to calculate the column of water representing JVP (5 cm from angle of Louis) and the normal range (5 - 9 cm of water).  Canon venous pulses are observed in tricuspid regurgitation.

Issues in Medicine

 * 1) Understand the different levels of housing care options for seniors. Specifically, be able to identify what level of care each facility provides.
 * 2) Sensitivity versus Specificity. high sensitivity rules out, high specificity rule in.
 * 3) Thoroughly understand the meaning of a p-value
 * 4) Distinguish between inductive, deductive, and bayesian clinical reasoning
 * 5) * Deduction works from a list of observations, and tests a hypothesis. follows a algorithm (theory --> hypothesis --> observation --> confirmation)
 * 6) * Induction (observation --> pattern --> tentative hypothesis --> theory)
 * 7) * Bayesian clinical reasoning incorporates the notion of pretest probability, likelihood ratios. Every maneuver is approached as a test with a specificity and sensitivity.
 * 8) The age of consent for Oregon for medical procedures is 15.  Any age can get treatment for venereal disease See complete entry.