Rosen & Barkin's 5-Minute Emergency Medicine Consult (327 page)

CODES

• 466.0 Acute bronchitis
  
• 491.9 Unspecified chronic bronchitis
  
• 786.30 Hemoptysis, unspecified
  

BASICS

Hemorrhagic fever
describes a multisystem syndrome of vasocapillary permeability and/or organ dysfunction. Viral hemorrhagic fever (VHF) is caused by a distinct group of viruses, but the initial phase resembles influenza-like illness. Hemorrhagic stages typify the minority of patients and the later phases of disease.

• Travel in endemic region
  
• Biologic warfare
  
• Close animal contact, insect bite or ingestion
  

• VHF causes endothelial damage and increase vascular permeability, hemorrhage, and may proceed to shock
  
• VHF shock state is both hypovolemic and distributive, and is often very difficult to reverse. Hypotension can progress swiftly, and indicates very high mortality.
  
• DIC appears to be a regular feature of Marburg and Crimean-Congo hemorrhagic fever but is less frequent with Arenavirus infections.
  
• Dengue hemorrhagic fever is immune mediated and is usually the result of secondary infection. It is among the most common causes for VHF.
  

• RNA viruses that have zoonotic life cycles in specific geographic areas
  
• Short incubation period (<10–21 days)
  
• More common VHF vectors:
  
  • Filoviruses: Fruit bat reservoir, unclear mode of transmission (sub-Saharan Africa)
    
    • Ebola
      
    • Marburg
      
  • Arenaviruses: Rodent reservoir, aerosolized rodent excreta (sub-Saharan Africa).
    
    • Lassa
      
    • South American hemorrhagic fevers
      
  • Flaviviruses: Human reservoir, via mosquito (tropics, increasingly worldwide)
    
    • Dengue (common cause of VHF)
      
    • Yellow fever
      
  • Bunyaviridae: Rodent reservoir, via tick or mosquito (Europe, South Asia, Africa)
    
    • Rift Valley fever
      
    • Crimean-Congo hemorrhagic fever
      
  • Hantaviridae: Rodent reservoir, aerosolized rodent excreta (Southwest USA)
    
    • Hemorrhagic fever with renal syndrome
      
    • Hantavirus pulmonary syndrome
      

DIAGNOSIS

• Most common (>50%) symptoms:
  
  • Acute febrile illness
    
  • Malaise
    
  • Headache
    
  • Nausea/vomiting
    
  • Flushing
    
  • Diarrhea (nonbloody)
    
  • Abdominal pain
    
  • Myalgias
    
• Less common (<30%) symptoms:
  
  • Gingival hemorrhage
    
  • Conjunctival injection/hemorrhage
    
  • Petechia
    
  • Hematemesis
    
  • Melena
    
  • Epistaxis
    
  • Ecchymoses
    
• Hemorrhagic presentations >3 days into disease
  
  • Skin, IV sites, gums, nose, lungs, GI tract, or uterus
    
  • Diffuse alveolar hemorrhage or ARDS
    
  • More common in CCHF, Lassa, Marburg, Ebola, Hantavirus
    
• Exanthems
  
  • Marburg and Ebola: Nonpruritic centripetal, papular, erythematous eruption appearing between days 5 and 7, which then coalesce into well-demarcated macules that may be hemorrhagic
    
  • Yellow fever: Jaundice
    
  • Dengue: Bright maculopapular truncal erythroderma that blanches dramatically under light pressure (often on lower extremities)
    
• Hemodynamic collapse, shock, seizures, coma, death.
  
  • Late stage of disease, often irreversible
    

• Travel to endemic regions
  
• Sick contacts
  
• Clustering of cases should raise concerns of a bioweapon attack or outbreak
  

• Protection of health care workers:
  
  • Universal blood and body precautions
    
• Vital signs: Monitor BP, fever, tachycardia
  
  • Narrowed pulse pressure (<20 mm Hg) may signal imminent cardiovascular collapse
    
• Hemorrhage (see Signs and Symptoms)
  
• Exanthems (see Signs and Symptoms)
  
• RUQ tenderness or hepatomegaly
  
  • Hepatitis
    
• Adventitious lung sounds
  

• Focus on differentiating from other acute febrile illnesses, especially in the traveler.
  
• Investigate lung involvement, as it can indicate systemic disease and worse outcome
  
• Recognize possible biologic attack when unusual number of patients present with similar and/or unusual findings.
  
• History to identify potential pathogen:
  
  • Include recent travel, illnesses, or other sources of exposure.
    
  • Often patients are unaware of animal contacts
    

• CBC:
  
  • May see leukocytosis, leukopenia, thrombocytopenia, or pancytopenia
    
  • Abnormally high hematocrit can signify hemoconcentration; may indicate increased 3rd spacing impending shock/cardiovascular collapse.
    
• Electrolytes, BUN, creatinine, and glucose levels:
  
  • Consider renal failure
    
• Liver function tests:
  
  • Hepatic involvement is common, but jaundice occurs mainly with yellow fever.
    
• Type and screen, prothrombin time, partial thromboplastin time, and
  d
  -dimer tests:
  
  • Look for coagulopathy and DIC (seen in Crimean-Congo hemorrhagic fever, Ebola, and Marburg)
    
• Special lab test:
  
  • In specialized labs (biohazard level 4), definitive diagnosis can be made by viral isolation, real-time reverse transcriptase polymerase chain reaction (RT-PCR), and immunohistochemistry techniques:
    
    • Coordinated with CDC
      
    • Thick and thin smears to help differentiate from malaria
      

CXR, head, and abdominal CT scanning:

• Rule out pneumonia or ARDS
  
• Intracranial and intra-abdominal bleeding
  

Serum and saliva can be analyzed by RT-PCR in specialized labs.

• Malaria:
  
  • A concern for traveler with fever
    
• Dengue fever:
  
  • Common source of fever in traveler
    
• Rickettsial:
  
  • Rocky Mountain spotted fever
    
  • Typhus
    
• Bacterial:
  
  • Meningococcemia
    
  • Sepsis
    
  • EHEC (Escherichia coli O157:H7)
    
• Systemic disease:
  
  • Leukemia
    
  • TTP, ITTP
    
• Pit viper envenomation
  

TREATMENT

Protection of health care workers:

• Universal blood and body precautions
  
• Isolation of patient
  
• Use of protective clothing plus HEPA-filtered respirators to minimize exposure to aerosols for those involved in procedures such as suctioning, catheter placement, and wound dressing
  

• Supportive therapy
  
• Empiric therapy with antimalarial regimens until definitive diagnosis is obtained
  
• Aggressive treatment of secondary infections
  
• Bleeding is usually mild, and life-threatening blood loss is rare:
  
  • If indicated, hemorrhage can be managed by replacement of blood, platelets, and clotting factors.
    
• Fluid support
  
  • Patients are prone to 3rd spacing and can go into flash pulmonary edema; be judicious with crystalloids.
    
  • Reserve colloids/blood products for impending shock/cardiovascular collapse.
    
• Ribavirin—a synthetic nucleoside:
  
  • Useful for Lassa, South American hemorrhagic fever, Crimean-Congo hemorrhagic fever, and hemorrhagic fever with renal syndrome; ineffective against filoviruses
    
  • Causes a reversible hemolytic anemia
    
• Transfusion of immune plasma (convalescent plasma therapy) for South American hemorrhagic fever within 1st week of symptoms