Internal medicine is a vast and complicated field that is based on strong scientific and clinicalfoundations. Moreover it is rapidly evolving and one needs periodic updating and catching up with thestate of the art knowledge.Providing a comprehensive review of internal medicine is not only difficult but almost impossible, asthe field is vast and extensive. Despite this limitation, the authors have tried to provide a basicframework for working knowledge of Internal medicine. Essential topics are included as much aspossible, and some chapters and topics are dealt extensively, such as Infectious diseases in generaland Acute febrile illnesses, Tuberculosis, and HIV/AIDS in particular, as these are known to be thecommonest causes of morbidity and mortality in developing countries, like ours.Even though a number of individuals have contributed in the original document of this lecture note, asmore than 3 years have elapsed, most of the topics are reviewed, and some topics are completelyrewritten, to include new developments and the state of the art scientific knowledge.This lecture note has been written primarily for Health officer students; however it can also be used bymedical students and all other health science students who deal with patients, who have medicalillnesses.
Arrhythmias: Lethal ventricular arrhythmias are the commonest cause of death in the first hour. This may include ventricular tachycardias and ventricular fibrillation Atrial arrhythmias ; atrial fibrillation and atrial flutter Acute conduction system abnormality The conduction system may be part of the myocardium affected during infarction. This may lead to bradycardia and heart block Inferior wall MI occurs when the right coronary artery is occluded. Since it supplies the AV node, Sinus bradycardia and varying degree of AV block occur during inferior myocardial infarction. 279 Internal Medicine Anterior myocardial infarction may lead to Right or left bundle branch blocks
id: e998696a8afe03f6d6841a4631d6d8e0 - page: 295
Pump failure Congestive heart failure is most likely to occur, when 30 % of the myocardium is infracted , Cardiogenic shock, defined as Systolic BP < 90 mmHg: occurs if more than 40% of the myocardium is affected by infarction. Mitral regurgitation: may occur if the papillary muscles are affected by infarction. Ventricular septal defect: The left ventricular septum may become infracted either in anterior or inferior AMI. , leading to rapture of the septum. Cardiac rapture: Myocardial infarction of the free wall may lead to eventual perforation of the heart. This complication, which results overwhelmingly cardiac tamponade, is nearly always fatal. Left ventricular aneurysm: The infracted myocardium may evaginate and heal with fibrous connective tissue. It may be a source for cardiac emboli. Pericarditis: post AMI pericarditis (Dresslers Syndrome) which is believed to be autoimmune in origin.
id: 4693ccb4fd6d1c8359f1c31e27dbe8ae - page: 296
Diagnostic work up 1. ECG: is diagnostic in approximately 85% of cases. Transmural MI/Q-wave MI : ST segment elevation in those leads reflecting the area of myocardial infarction ,As ST segments fall , Q waves appear and T waves become inverted Subendocadial infarction/Non Q wave MI; ECG findings are less certain and ST segment depression may be the only finding 2. Cardiac enzymes : as myocardial necrosis occurs , the myocardium releases cardiac enzymes Creatine phospho kinase ( CPK ) elevation appears 6 hours after infarction Aspartate aminotransfarase ( AAST or SGOT ) elevates 12 hrs after infarction Lactate dehydrogenase (LDH): starts to elevate 24 hrs after infarction. 280
id: 469d29a21107f77e961df7c8874d3a0e - page: 296
Internal Medicine Cardiac specific troponin-T and cardiac specific troponinI, are also elevated and they are very specific to cardiac muscles. (So this is the preferred biomedical test in Developed countries.). These proteins are not normally detectable in the blood of healthy individuals , but rise > 20 X in patients with AMI. 3. Cardiac Imaging Echo: Decrease myocardial function ( decrease ejection fraction ) and significant wall motion abnormality may be detected Radionuclide imaging techniques Management of patients with acute myocardial infarction Management of AMI is beyond your capacity and immediate referral to hospitals with intensive care unit (ICU) facility is mandatory. However, the management of acute MI is outlined as follows A. Emergency management :Management of patients should start before they reach
id: 91787c6c3ba8f47bccf556f2d2163dee - page: 297