Rosen & Barkin's 5-Minute Emergency Medicine Consult (241 page)

FOLLOW-UP

All patients

Empiric treatment for HSV-1 infection with acyclovir should always be initiated as soon as possible if the patient has encephalitis without apparent explanation to decrease morbidity/mortality

• Fitch MT, Abrahamian FM, Moran GJ, et al. Emergency department management of meningitis and encephalitis.
  Infect Dis Clin North Am.
  2008;22(1):33–52.
  
• Long SS. Encephalitis diagnosis and management in the real world.
  Adv Exp Med Biol.
  2011;697:153–173.
  
• Mandell G.
  Mandell, Douglas, and Bennett’s Principles and Practice of Infectious Diseases
  . 7th ed. Philadelphia, PA: Churchill Livingstone; 2010.
  
• Wingfield T, McHugh C, Vas A, et al. Autoimmune encephalitis: A case series and comprehensive review of the literature.
  QJM.
  2011;104:921–931.
  
• Ziai WC, Lewin JJ 3rd. Update in the diagnosis and management of central nervous system infections.
  Neurol Clin.
  2008;26(2):427–468.
  

See Also (Topic, Algorithm, Electronic Media Element)

Meningitis

CODES

• 049.9 Unspecified non-arthropod-borne viral diseases of central nervous system
  
• 058.29 Other human herpesvirus encephalitis
  
• 323.9 Unspecified causes of encephalitis, myelitis, and encephalomyelitis
  

BASICS

An inflammation of the endothelial surface of the heart

• Various cardiac structures may be involved:
  
  • Native heart valves (most common)
    
  • Prosthetic valves
    
  • Interventricular septum
    
  • Chordae tendineae
    
  • Mural endocardium
    
  • Intracardiac devices
    
• Characterized by a vegetation (a thrombus with superimposed microorganisms)
  
  • Bacterial colonization of the initially sterile vegetation composed of fibrin and platelets
    
  • Bacterial growth enlarges the vegetation, further impeding blood flow and inciting inflammation.
    
  • Propagation of the infection through systemic emboli
    
• Almost always secondary to bacterial infection
  
• Rare noninfectious causes
  
  • Nonbacterial thrombic endocarditis or marantic endocarditis
    
    • Often due to a hypercoagulable state
      
    • Small sterile vegetations
      
  • Libman–Sacks endocarditis
    
    • Complications of lupus erythematosus
      
    • Due to the deposition of immune complexes that cause an inflammatory reaction
      
    • Small vegetations
      

• More common in men (ratios from 3.2 to 9.1)
  
  • M: 8.6–12.7 cases/100,000 person-yr
    
  • F: 1.4–6.7 cases/100,000 person-yr
    
• Risk factors:
  
  • Older patients
    
  • Poor dental hygiene
    
  • Comorbidities
    
    • Rheumatic heart disease
      
    • Prosthetic valve
      
    • Hemodialysis
      
    • Diabetes
      
  • IV drug abuse (IVDA):
    
    • Greater risk than rheumatic heart disease or prosthetic valves
      
    • Predilection for right-sided heart valves
      
• Septic embolization
  
  • Cerebral complications
    
    • Cerebral embolism
      
    • Intracranial hemorrhage
      
    • Cerebral abscess
      
  • Extracerebral embolic events
    
    • Pulmonary
      
    • Splenic
      
    • Renal
      
    • Mycotic aneurysms (aorta, renal artery, splenic artery, hepatic artery, mesenteric arteries, etc.)
      
    • Hepatic
      
    • Coronary
      
• Risk factor for recurrent endocarditis:
  
  • Structural heart disease serves as common vegetative site due to altered intracardiac flow:
    
    • Mitral valve prolapse
      
    • Aortic valve dysfunction
      
  • Congenital heart disorders in the pediatric populations:
    
    • Tetralogy of Fallot
      
    • Aortic stenosis
      
    • Patent ductus arteriosus
      
    • Ventricular septal defects
      
    • Aortic coarctation
      
  • Prosthetic valves
    
  • Indwelling catheters
    
  • Any mechanical device may serve as a portal of entry or attachment for microorganisms.
    

• Major categories:
  
  • Bacterial endocarditis
    
  • Prosthetic valve endocarditis
    
  • Nonbacterial thrombotic endocarditis:
    
    • Malignancy
      
    • Uremia
      
    • Burns
      
    • Systemic lupus erythematosus
      
• Common organisms:
  
  • Staphylococcus aureus
    (most common pathogen):
    
    • Seen in all populations, especially IVDA and toxic illness
      
    • Sometimes metastatic
      
  • Streptococcus viridans
    :
    
    • Found in oropharynx, common agent in native valve endocarditis
      
  • Streptococcus bovis
    :
    
    • Common association with colonic polyps or GI malignancy
      
  • Streptococcus pneumoniae
    :
    
    • Causes rapid valvular destruction, abscess, and CHF
      
    • Risk factor: Alcoholism
      
  • Staphylococcus epidermidis
    
  • Enterococci:
    
    • Seen in young women and old men following instrumentation or infection
      
  • Candida and Aspergillus:
    
    • Found in IVDA, prosthetic valves, or immunocompromised patients
      
  • HACEK (Haemophilus sp.)
    
  • Culture-negative endocarditis (Q fever, psittacosis, Bartonella, brucellosis)
    

DIAGNOSIS

• Fever:
  
  • Present in 86% of patients
    
  • May be absent in certain settings:
    
    • Elderly
      
    • CHF
      
    • Severe debility
      
    • Chronic renal failure
      
    • Flulike illness
      
    • Chills
      
    • Sweats
      
    • Rigors
      
    • Malaise
      
• Head, eyes, ears, nose, and throat:
  
  • Retinal hemorrhages or Roth spots
    
• Respiratory:
  
  • Dyspnea
    
  • Cough
    
  • Heart failure
    
• Cardiac:
  
  • A new or changing murmur in 80–85% of patients
    
• Abdominal:
  
  • Abdominal or back pain
    
  • Splenomegaly (15–50%)
    
• Extremities:
  
  • Myalgias
    
  • Arthralgias
    
  • Digital clubbing
    
• Neurologic:
  
  • Altered mental status
    
  • Septic embolization (stroke or mycotic aneurysm)
    
• Skin:
  
  • Cutaneous vasculitic lesions:
    
    • Mucosal and conjunctival petechiae
      
    • Splinter hemorrhages
      
    • Osler nodes: Erythematous, painful tender nodules
      
    • Janeway lesions: Erythematous or hemorrhagic, macular or nodular lesions, a few millimeters in diameter on the hands and feet
      

• Fever duration and pattern
  
• Risk factors:
  
  • Prior cardiac disease
    
  • Source of bacteremia:
    
    • Indwelling intravascular catheters
      
    • IV drug use
      
    • Poor dental hygiene
      

• Heart and lung exam:
  
  • New cardiac regurgitant murmur
    
  • Heart failure
    
• Assess for splenomegaly.
  
• Assess for septic emboli:
  
  • Fundi, skin, nail beds
    
  • Careful neurologic exam for small focal deficits