Lung - nontumor
Infections
Adenovirus pneumonia

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 22 February 2017, last major update August 2011

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed search: adenovirus pneumonia lungs

Cite this page: Adenovirus pneumonia. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/lungnontumoradenovirus.html. Accessed March 23rd, 2017.
Definition / General
  • Lung disease caused by infection with adenovirus, a nonenveloped, lytic, double stranded DNA virus
Epidemiology
  • At least 51 serotypes of adenovirus have been associated with clinical syndromes; not well understood why specific sterotypes are associated with specific syndromes, but differences in mode of transmission and virus tropism are likely to play a role
  • Seven species are known (groups A - G); respiratory disease is caused by groups C, E and some members of group B
  • Infection is ubiquitous; most individuals have had several infections during childhood
Sites
  • In addition to lung, also occurs in the upper respiratory tract (tonsils, adenoids), liver, GI tract, CNS, heart, kidneys, urinary bladder, ear, eyes
Clinical Features
  • Half of infections are subclinical
  • Represent 5% - 10% of febrile illness in infants and young children
  • Transmission is through respiratory droplets, fomites, or fecal-oral
  • In children, causes 5% of upper respiratory tract infections and 10% of cases of pneumonia; adult infection is less common
  • Can persist as a latent infection for years after primary disease; tonsils and adenoids are likely reservoirs
  • Outbreaks among military recruits have caused epidemics of serious disease at military training centers
  • Certain subgroups are associated with severe pneumonia, especially young children
  • Virulent strains have led to fatalities in previously healthy young adults (Clin Infect Dis 2003;37:e142)
  • Serious disease has occurred in immunocompromised hosts, especially patients with solid organ and hematopoietic stem cell transplants, although infection may be associated only with asymptomatic shedding
  • Adenovirus infections are only rare causes of significant disease in AIDS patients
  • When symptomatic, upper respiratory tract infection causes fever, sore throat, cough, hoarseness, rhinorrhea
  • Disease may mimic tonsillitis with group A streptococcal infection, due to exudative pharyngitis and enlarged cervical lymph nodes
  • Otitis media may occur children under age 1 year
  • Upper respiratory tract infection may progress to involve lower respiratory tract with cough and shortness of breath; often with systemic symptoms of fever, headache, myalgias; abdominal pain may occur
  • May cause a pertussis-like syndrome
  • Chest Xray: bilateral, patchy, ground glass opacities consistent with viral pneumonia
  • In hematopoietic stem cell transplants, the GI tract is more commonly affected than lungs; cold agglutinins are present in 20% of patients with adenovirus pneumonia
  • In solid organ transplants, usually the transplanted organ affected is by adenovirus
  • In lung transplant patients, disease usually occurs in early post-transplant period and is associated with graft failure, bronchiolitis obliterans, and often death
  • Disease in transplant patients may be due to primary infection or reactivation
  • Diagnosis: rountine tissue culture, PCR, serology, or antigen specific assays; in tissue samples, use immunostains
Prognostic Factors
  • In transplant patients, increasing viral load by PCR and greater immunosuppression increases the risk of serious disease
  • Other risk factors are young patient age, graft vs. host disease, unrelated stem cell donor, T cell depletion of graft, cord stem cell transplant, low T cell counts post transplant, total body irradiation, use of antilymphocyte antibodies
Treatment
  • Only supportive care is known to be effective
  • Some studies have shown benefit of ribavirin therapy, but this is not universal
  • Immunotherapy is being investigated
  • Appropriate hand hygiene can reduce transmission
  • In the United States, military recruits formerly received vaccinations against some strains of adenovirus; production of this vaccine stopped, however, efforts to resume production are ongoing
Micro Description
  • Epithelial cells contain smudged nuclei with brick-like, intranuclear inclusions; start as small, eosinophilic inclusions, then briefly appear as basophilic inclusions with a thin halo; then enlarge to obscure the nuclear membrane to take on the typical smudgy appearance
  • Two patterns of disease are commonly encountered that may occur concurrently: diffuse alveolar damage like pattern with interstitial edema, mononuclear cell infiltrates and exudative fluid accumulation in alveoli with hyaline membranes; second pattern is necrosis of bronchi, bronchioles, and alveoli with neutrophilic and histiocytic infiltrates, with interstitial fibrosis and obliterative bronchiolitis as potential sequelae
Micro Images

Images hosted on other servers:

Interstitial inflammation (no inclusions identifiable)

Various images

Adenovirus inclusions
in lung from an infant
chimpanzee

Positive Stains
  • Adenovirus immunohistochemistry
Electron Microscopy Description
  • 60 - 90 nm, icosahedral particles in crystalline array
Differential Diagnosis
  • The diagnosis can be made by rountine tissue culture, PCR, serology, or antigen specific assays
  • In tissue samples, immunohistochemistry can confirm the diagnosis