http://ebook2book.ir/ USMLE® STEP 2 CK SURGERY Lecture Notes http://ebook2book.ir/ 2019 http://ebook2book.ir/ Table of Contents USMLE Step 2 CK Lecture Notes 2018: Surgery Cover Title Page Copyright Editors Feedback Page Part I: Surgery Chapter 1: Trauma Primary Survey: The ABCs A Review from Head to Toe Burns Bites and Stings Chapter 2: Orthopedics Pediatric Orthopedics Adult Orthopedics Tumors Chapter 3: Pre-Op and Post-Op Care Preoperative Assessment Postoperative Complications Chapter 4: General Surgery Diseases of the Gastrointestinal System Diseases of the Breast Diseases of the Endocrine System Surgical Hypertension Chapter 5: Pediatric Surgery Birth—First 24 Hours A Few Days Old—First 2 Months of Life Later in Infancy Chapter 6: Cardiothoracic Surgery Congenital Heart Problems Acquired Heart Disease Lung Chapter 7: Vascular Surgery Chapter 8: Skin Surgery http://ebook2book.ir/ Chapter 9: Ophthalmology Children Adults Chapter 10: Otolaryngology (ENT) Neck Masses Other Tumors Pediatric ENT ENT Emergencies and Miscellaneous Chapter 11: Neurosurgery Differential Diagnosis Based on Patient History Vascular Occlusive Disease Brain Tumor Pain Syndromes Chapter 12: Urology Urologic Emergencies Congenital Urologic Disease Tumors Retention and Incontinence Stones Miscellaneous Chapter 13: Organ Transplantation Part II: Surgical Vignettes Chapter 1: Trauma Primary Survey: The ABCs A Review from Head to Toe Burns Bites and Stings Chapter 2: Orthopedics Pediatric Orthopedics Adult Orthopedics Tumors Chapter 3: Pre-Op and Post-Op Care Preoperative Assessment Postoperative Complications Chapter 4: General Surgery Diseases of the Gastrointestinal System Diseases of the Breast Diseases of the Endocrine System Surgical Hypertension http://ebook2book.ir/ Chapter 5: Pediatric Surgery At Birth—The First 24 Hours A Few Days Old—The First 2 Months of Life Later in Infancy Chapter 6: Cardiothoracic Surgery Congenital Heart Problems Acquired Heart Disease Lung Chapter 7: Vascular Surgery Chapter 8: Skin Surgery Chapter 9: Ophthalmology Children Adults Chapter 10: Otolaryngology (ENT) Neck Masses Other Tumors Pediatric ENT ENT Emergencies and Miscellaneous Chapter 11: Neurosurgery Vascular Occlusive Disease Brain Tumor Spinal Cord Pain Syndromes Chapter 12: Urology Urologic Emergencies Congenital Urologic Disease Tumors Retention and Incontinence Stones Miscellaneous Chapter 13: Organ Transplantation http://ebook2book.ir/ USMLE® is a joint program of the Federation of State Medical Boards (FSMB) and the National Board of Medical Examiners (NBME), neither of which sponsors or endorses this product. This publication is designed to provide accurate information in regard to the subject matter covered as of its publication date, with the understanding that knowledge and best practice constantly evolve. The publisher is not engaged in rendering medical, legal, accounting, or other professional service. If medical or legal advice or other expert assistance is required, the services of a competent professional should be sought.
This publication is not intended for use in clinical practice or the delivery of medical care. To the fullest extent of the law, neither the Publisher nor the Editors assume any liability for any injury and/or damage to persons or property arising out of or related to any use of the material contained in this book. © 2018 by Kaplan, Inc. Published by Kaplan Medical, a division of Kaplan, Inc.
750 Third Avenue New York, NY 10017 All rights reserved under International and Pan-American Copyright Conventions. By payment of the required fees, you have been granted the non-exclusive, non-transferable right to access and read the text of this eBook on screen. No part of this text may be reproduced, transmitted, downloaded, decompiled, reverse engineered, or stored in or introduced into any information storage and retrieval system, in any form or by any means, whether electronic or mechanical, now known or hereinafter invented, without the express written permission of the publisher. ISBN-13: 978-1-5062-3633-9 http://ebook2book.ir/ EDITORS Carlos Pestana, MD, PhD Emeritus Professor of Surgery University of Texas Medical School at San Antonio San Antonio, TX Adil Farooqui, MD, FRCS Clinical Assistant Professor of Surgery Keck School of Medicine, University of Southern California Kaiser Permanente, West Los Angeles Medical Center Los Angeles, CA Mark Nolan Hill, MD, FACS Professor of Surgery Chicago Medical School Chicago, IL http://ebook2book.ir/ CONTRIBUTOR Ted A.
James, MD, MS, FACS Chief, Breast Surgical Oncology Vice Chair, Academic Affairs Department of Surgery Beth Israel Deaconess Medical Center Harvard Medical School Boston, MA The editors would like to acknowledge Michaela West, MD, PhD, FACS, North Memorial Health/University of Minnesota and Gary Schwartz, MD, Baylor University Medical Center. http://ebook2book.ir/ We want to hear what you think. What do you like or not like about the Notes? Please email us at medfeedback@kaplan. http://ebook2book.ir/ Part I http://ebook2book.ir/ SURGERY http://ebook2book.ir/ TRAUMA http://ebook2book.ir/ LEARNING OBJECTIVES Describe the ABCs of evaluating a trauma patient Discuss the importance of the Secondary Survey and a complete head-to- toe review of a trauma patient Provide basic information about treatment of burns, bites, and stings http://ebook2book.ir/ PRIMARY SURVEY: THE ABCs The initial evaluation of a trauma patient requires a systematic approach to identify life threatening and potentially life-threating injuries.
This typically involves a brief “Primary Survey” to assess airway (A), breathing (B), circulation (C), disability (D, neuro exam), and exposure (E) of the patient, so that all potential injuries can be seen (ABCDE mnemonic). Needed interventions should be immediately addressed as the examiner proceeds through ABCDE. After the Primary Survey is complete, and if the patient is stable, then a Secondary Survey, involving a complete head to toe examination and evaluation of all organ systems should be performed. http://ebook2book.ir/ AIRWAY (A) The first step in the evaluation of trauma is airway assessment and protection.
The airway is considered intact if the patient is conscious and speaking in a normal tone of voice. An airway is considered unprotected and/or compromised if there is an expanding hematoma or subcutaneous emphysema in the neck, noisy or “gurgly” breathing, or a Glasgow Coma Scale <8. An airway should be secured before the situation becomes critical. In the field or in the ED, a definitive airway can be secured by intubation or cricothyroidotomy.
Emergent airway control is best done by rapid sequence induction and orotracheal intubation, monitoring oxygen saturation with pulse oximetry. In the presence of a cervical spine injury, orotracheal intubation can still be done if the head is secured and in-line stabilization is maintained during the procedure. If severe maxillofacial injuries preclude the use of intubation or intubation is unsuccessful, cricothyroidotomy may become necessary. In the pediatric patient population (age <8), tracheostomy is preferred over cricothyroidotomy due to the high risk of airway stenosis, as the cricoid is much smaller than in the adult.
http://ebook2book.ir/ BREATHING (B) The presence of symmetrical breath sounds indicate satisfactory ventilation; an absence or decrease of breath sounds may indicate a pneumothorax and/or hemothorax and necessitate chest tube placement. Pulse oximetry can be used to determine if oxygenation is satisfactory (O2 saturation >90-95%); hypoxia may be secondary to airway compromise, pulmonary contusion, or neurological injury impairing respiratory drive and necessitate intubation. Measurement of end tidal CO2 (capnography) is also very useful. http://ebook2book.ir/ CIRCULATION (C) AND SHOCK Clinical signs of shock are seen only if >25% of blood volume (>1500-2000 mL) has been lost and include the following: Low BP (<90 mm Hg systolic) Tachycardia (heart rate >100 bpm) Low urinary output (<0.5 ml/kg/h) Patients in shock will be pale, cold, shivering, sweating, thirsty, and apprehensive.
In the most severe cases, impaired perfusion of the brain may render patients unconscious. In the trauma setting, shock is generally hypovolemic (secondary to hemorrhage and the most common scenario) or rarely cardiogenic (secondary to pericardial tamponade or tension pneumothorax due to chest trauma). http://ebook2book.ir/ NOTE Many consider the chest x-ray and pelvis to be part of Primary Survey, along with FAST, looking for abdominal or pericardial fluid. Hemorrhagic shock is accompanied by collapsed neck veins due to low central venous pressure (CVP), while cardiogenic shock tends to cause elevated CVP with jugular venous distention.
Both processes may occur simultaneously, that is, a patient could be hemorrhaging (hypovolemic) and have a tension pneumothorax (with distended neck veins). In pericardial tamponade, there is shock without respiratory distress. With tension pneumothorax, there is significant dyspnea, absent breath sounds and hyperresonance on the side of the tension pneumothorax, diminished breath sounds on the opposite side (due to mediastinal shift and compression of the lung), accompanied by, tracheal deviation. Treatment of hemorrhagic shock includes volume resuscitation and control of bleeding, in the OR or ED depending on the injury and available resources.
Volume resuscitation is initially with 2L of lactated Ringer’s solution unless blood products are immediately available. In the setting of trauma, transfusion of blood products should be in a 1:1:1 ratio between packed RBCs, fresh frozen plasma, and platelets. Resuscitation should be continued until BP and heart rate normalize and urine output reaches 0.0 ml/kg/hr. In the setting of uncontrolled hemorrhage, permissive hypotension is recommended to prevent further blood loss while awaiting definitive surgical http://ebook2book.ir/ repair, but a mean arterial pressure >60 mm Hg should be maintained to ensure adequate cerebral perfusion.
The preferred route of fluid resuscitation in the trauma setting is 2 large bore peripheral IV lines, 16-gauge or greater. If this cannot be obtained, percutaneous femoral vein catheters should be inserted; saphenous vein cutdown and placement of ≥1 intraosseous cannulas are acceptable alternatives. In children age <6, intraosseous cannulation of the proximal tibia or femur is the alternate route. Pericardial tamponade is generally a clinical diagnosis that can be confirmed with U/S.
Management requires evacuation of the pericardial space by pericardiocentesis, subxiphoid pericardial window, or thoracotomy. Fluid and blood administration while evacuation is being set up is helpful to maintain an adequate cardiac output. Tension pneumothorax is a clinical diagnosis based on physical exam. Signs include absent breath sounds, tracheal deviation, “hyperresonance,” and distended neck veins.
May also be hypotension and shock. Management requires immediate decompression of the pleural space, initially with a large-bore needle (needle thoracostomy) which converts the tension to a simple pneumothorax and followed by chest tube placement. In the non-trauma setting, hypovolemic shock can also arise because of massive fluid loss such as bleeding, burns, peritonitis, pancreatitis, or massive diarrhea. The clinical picture is similar to trauma, with hypotension, tachycardia, and oliguria with a low CVP.
Stop the bleeding and replace the blood volume. Non-traumatic (intrinsic) cardiogenic shock is caused by myocardial damage (e. myocardial infarction or fulminant myocarditis). The clinical picture is http://ebook2book.ir/ hypotension, tachycardia, and oliguria with a high CVP (presenting as distended neck veins).
Treat ment acutely consists of pharmacologic circulatory support, followed by attempts to restore perfusion and/or cardiac function. Differential diagnosis is essential, because additional fluid and blood administration in this setting could be lethal, as the failing heart becomes easily overloaded. Neurogenic/spinal shock is often associated with low BP and bradycardia. It can also result in circulatory collapse.
Patients are flushed, “pink and warm” with a low CVP. Treatment with phenylephrine and fluids is aimed at filling dilated veins and restoring peripheral resistance. http://ebook2book.ir/ DISABILITY (D) Neurologic evaluation (disability) is also an important component of the Primary Survey. Key points include assessing for the patient's ability to move all extremities, looking for gross defects.
Level of consciousness, usually graded by the Glasgow Coma Score (GCS) is also performed and documented. http://ebook2book.ir/ EXPOSURE (E) Staying aware of modesty at all times, remove the patient's clothing to allow for a thorough physical examination. Check for signs of trauma, bleeding, skin irritations, needle marks, and warm body temperature. http://ebook2book.ir/ SECONDARY SURVEY After the ABCs have been evaluated and any immediate life-threatening emergencies addressed, trauma evaluation continues with the secondary survey which is composed of a complete physical exam to evaluate for occult injuries followed by chest x-ray and pelvic x-ray (although many include chest x-ray, pelvis x-ray, and FAST as part of the primary survey under “C,” to identify location of hemorrhage).
The secondary survey may be augmented with further imaging studies depending on the mechanism of injury and findings on examination. Any change that occurs requires complete re-evaluation, including rechecking that there has not been a change in the ABCs. http://ebook2book.ir/ A REVIEW FROM HEAD TO TOE HEAD TRAUMA Penetrating head trauma as a rule requires surgical intervention and repair of the damage, although brain gunshot wound (especially transcranial gunshot wounds) are frequently lethal.