Rosen & Barkin's 5-Minute Emergency Medicine Consult (468 page)

FOLLOW-UP

• Adverse outcomes, particularly dysrhythmias, are uncommon but generally occur within 1st 24 hr.
  
• No single test or combination of tests will accurately predict which patients can be discharged safely from ED:
  
  • All patients in whom diagnosis is seriously being entertained should be admitted to a monitored setting.
    

• EKG abnormalities
  
• Cardiac enzyme abnormalities
  
• Hemodynamic instability
  
• Other studies suggesting cardiac contusion
  
• Admit to monitored unit for close observation.
  

Asymptomatic patients with no EKG abnormalities or dysrhythmia and with normal cardiac enzymes after 6–8 hr period may be discharged.

Immediate surgical consultation:

• Suspected myocardial wall rupture
  
• Suspected valve or papillary muscle rupture
  
• Suspected septal rupture
  
• Coronary artery thrombosis
  
• Pericardial effusion
  
• Cardiac tamponade
  

Discharged patients:

• Should have follow-up within 24 hr of injury
  

• Obtain EKG in patients following chest wall trauma.
  
• Perform FAST exam on all patients to assess pericardium.
  
• External signs of chest wall trauma should increase concern of blunt cardiac injury.
  
• Pediatric patients may have little or no external signs of chest wall trauma.
  
• Do not administer thrombolytics to patients with ST elevation MI following trauma.
  
• Negative troponin I and normal EKG make significant blunt cardiac injury unlikely.
  

• Clancy K, Velopulos C, Bilaniuk JW, et al. Screening for blunt cardiac injury: An Eastern Association for the Surgery of Trauma practice management guideline.
  J Trauma Acute Care Surg
  . 2012;73:S301–S306.
  
• El Chami MF, Nicholson W, Helmy T. Blunt cardiac trauma.
  J Emerg Med
  . 2008;127–133.
  
• Rajan GP, Zellweger R. Cardiac troponin I as a predictor of arrhythmia and ventricular dysfunction in trauma patients with myocardial contusion.
  J Trauma
  . 2004;57:801–808.
  
• Salim A, Velmahos GC, Jindal A, et al. Clinically significant blunt cardiac trauma: Role of serum troponin levels combined with electrocardiographic findings.
  J Trauma
  . 2001;50:237–243.
  
• Sybrandy KC, Cramer MJ, Burgersdijk C. Diagnosing cardiac contusion: Old wisdom and new insights.
  Heart
  . 2003;89(5):485–489.
  

CODES

861.01 Contusion of heart without mention of open wound into thorax

BASICS

• An inflammatory change in the heart muscle characterized by myocyte necrosis and subsequent myocardial destruction
  
• Direct cytotoxic effect of causative agent followed by a secondary immune response
  
• True incidence is unknown because many cases are asymptomatic.
  
• Autopsy studies have demonstrated evidence of myocarditis in 1–7% of cases and >50% in HIV patients.
  
• Male > female (1.5:1)
  
• Average age of patients with myocarditis is 42 yr.
  
• Major cause of unexpected sudden death (15–20% of cases) <40 yr old
  

• Viral:
  
  • Enteroviruses (coxsackie B)
    
  • Adenovirus
    
  • Herpesvirus (including cytomegalovirus [CMV])
    
  • Hepatitis C
    
  • Influenza
    
  • Echovirus
    
  • Herpes simplex virus
    
  • Varicella-zoster
    
  • Epstein–Barr virus
    
  • Cytomegalovirus
    
  • Mumps
    
  • Rubeola
    
  • Variola/vaccinia
    
  • Yellow fever
    
  • Rabies
    
  • HIV
    
• Bacteria:
  
  • Diphtheria
    
  • Tuberculosis
    
  • Brucellosis
    
  • Psittacosis
    
  • Meningococcus
    
  • Mycoplasma
    
  • Group A streptococcus
    
• Protozoa:
  
  • Leishmaniasis
    
  • Malaria
    
  • Toxoplasmosis in the immunocompromised host
    
  • Treponema cruzi
    (Chagas disease):
    
    • Most common cause of heart failure and myocarditis worldwide
      
    • 20 million persons infected in Central and South America
      
  • Trichinosis
    
  • Trypanosomiasis
    
• Spirochetes:
  
  • Borrelia burgdorferi,
    the spirochete agent in Lyme disease
    
  • Syphilis
    
• Rickettsial:
  
  • Scrub typhus
    
  • Rocky Mountain spotted fever
    
  • Q fever
    
• Fungal:
  
  • Candidiasis
    
  • Aspergillosis
    
  • Cryptococcosis
    
  • Histoplasmosis
    
  • Actinomycosis
    
  • Helminthic
    
  • Trichinosis
    
  • Echinococcosis
    
  • Schistosomiasis
    
  • Cysticercosis
    
• Drugs:
  
  • Acetaminophen
    
  • Ampicillin
    
  • Chemotherapeutic agents (anthracyclines)
    
  • Cocaine
    
  • Hydrochlorothiazide
    
  • Lithium
    
  • Methyldopa
    
  • Penicillin
    
  • Sulfamethoxazole
    
  • Sulfonamides
    
  • Zidovudine
    
  • Radiation
    
  • Hypersensitivity
    
  • Heavy metals
    
  • Hydrocarbons
    
  • Carbon monoxide
    
  • Arsenic
    
• Autoimmune disorders:
  
  • Systemic lupus erythematosus (SLE)
    
  • Wegener granulomatosis
    
  • Kawasaki disease
    
  • Giant cell arteritis
    
  • Sarcoidosis
    
• Peripartum cardiomyopathy
  
• Bites/stings:
  
  • Scorpion
    
  • Snake
    
  • Black widow venom
    

DIAGNOSIS

Arrhythmias (18%), dyspnea (72%), and chest pain (35%)

• Fatigue
  
• Myalgias/arthralgias
  
• Malaise
  
• Fever
  
• Chest pain:
  
  • Reported in 35%
    
  • Most commonly pleuritic, sharp, stabbing, precordial
    
• Dyspnea on exertion is common.
  
• Orthopnea and shortness of breath if congestive heart failure (CHF) is present
  
• Palpitations are common
  
• Acute coronary syndrome due to local spasm & inflammation
  
• Syncope:
  
  • May signal high-grade aortic valve block or risk for sudden death from VT/VF
    

• Fever
  
• Tachypnea
  
• Tachycardia:
  
  • Often out of proportion to fever
    
• Cyanosis
  
• Hypotension:
  
  • Due to left ventricular dysfunction
    
  • Uncommon in the acute setting and indicates a poor prognosis when present
    
• Bibasilar crackles
  
• Rales
  
• Jugular venous distention (JVD)
  
• Peripheral edema
  
• Hepatomegaly
  
• Ascites
  
• S
  ₃
  or a summation gallop if significant biventricular involvement
  
• Intensity of S
  ₁
  may be diminished
  
• Murmurs of mitral or tricuspid regurgitation
  
• Pericardial friction rub if associated with pericarditis
  

• Most common cause of heart failure in previously healthy children
  
• Particularly infants, present with nonspecific symptoms:
  
  • Fever
    
  • Respiratory distress
    
  • Poor feeding or, in cases with CHF, sweating while feeding
    
  • New onset murmur
    
  • Cyanosis in severe cases
    

• Physical exam
  
• EKG
  
• CXR
  

• Cardiac enzymes
  
  • Troponin T: Low levels can be used to exclude myocarditis
    
  • Troponin I specificity is 89%; sensitivity is 34%
    
  • Creatinine kinase (elevated MB) may be elevated from myocardial necrosis
    
• Erythrocyte sedimentation rate (ESR) is elevated in 60% during the acute phase.
  
• Leukocytosis is present in 25%.
  
• Viral titers; cultures rarely positive
  
• Mycoplasma, antistreptolysin titers, cold agglutinin titer
  
• Hepatitis panels
  
• Lyme titer
  
• Monospot testing
  
• CMV serology
  
• Blood cultures