Skip to Main Content

INTRODUCTION

DEFINITION

Shock is a condition of severe impairment of tissue perfusion leading to cellular injury and dysfunction. Rapid recognition and treatment are essential to prevent irreversible organ damage and death. Common causes are listed in Table 12-1.

TABLE 12-1Categories of Shock

CLINICAL MANIFESTATIONS

  • Hypotension (mean arterial bp <60 mmHg), tachycardia, tachypnea, pallor, restlessness, and altered sensorium.

  • Signs of intense peripheral vasoconstriction, with weak pulses and cold clammy extremities. In distributive (e.g., septic) shock, vasodilation predominates and extremities are warm.

  • Oliguria (<20 mL/h) and metabolic acidosis common.

  • Acute lung injury and acute respiratory distress syndrome (ARDS; see Chap. 16) with noncardiogenic pulmonary edema, hypoxemia, and diffuse pulmonary infiltrates.

APPROACH TO THE PATIENT

APPROACH TO THE PATIENT Shock

Obtain history for underlying causes, including cardiac disease (coronary disease, heart failure, pericardial disease), recent fever or infection leading to sepsis, drug effects (e.g., excess diuretics or antihypertensives), conditions leading to pulmonary embolism (Chap. 135), and potential sources of bleeding.

PHYSICAL EXAMINATION

Jugular veins are flat in oligemic or distributive (septic) shock; jugular venous distention (JVD) is typical in cardiogenic shock; JVD in presence of paradoxical pulse (Chap. 112) suggests cardiac tamponade (Chap. 118). Check for asymmetry of pulses (aortic dissection—Chap. 127). Assess for evidence of heart failure (Chap. 126), murmurs of aortic stenosis, acute mitral or aortic regurgitation, and ventricular septal defect. Tenderness or rebound in abdomen may indicate peritonitis or pancreatitis; high-pitched bowel sounds suggest intestinal obstruction. Assess stool for GI bleeding.

Fever and chills typically accompany septic shock. Sepsis may not cause fever in elderly, uremic, or alcoholic pts. Skin lesions may suggest specific pathogens in septic shock (see Chap. 14).

LABORATORY

Obtain lactate, CBC, renal and liver function tests, PT, PTT, and cardiac troponin if myocardial ischemia, myocarditis, or pulmonary embolism is suspected. Arterial blood gas usually shows metabolic acidosis (in septic shock, respiratory alkalosis precedes metabolic acidosis). If sepsis is suspected, draw blood cultures, perform urinalysis, and obtain cultures of sputum, urine, and other suspected sites.

Obtain ECG (myocardial ischemia/infarction or acute arrhythmia) and chest x-ray (heart failure, tension pneumothorax, pneumonia). Echocardiography is often ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.