Adenovirus Infections

Adenovirus Infections

Basics

Description

Usually self-limited febrile illnesses characterized by inflammation of conjunctivae and the respiratory tract. Adenovirus infections occur in epidemic and endemic situations.

• Common types:
  • Acute febrile respiratory illness, affecting primarily children
  • Acute respiratory disease, affecting adults
  • Viral pneumonia, affecting children and adults
  • Acute pharyngoconjunctival fever, affecting children, particularly after summer swimming
  • Acute follicular conjunctivitis, affecting all ages
  • Epidemic keratoconjunctivitis, affecting adults
  • Intestinal infections leading to enteritis, mesenteric adenitis, and intussusception
• Conjunctivitis, sometimes called pink eye
• System(s) affected: Cardiovascular; Gastrointestinal; Hemic/Lymphatic/Immunologic; Musculoskeletal; Nervous; Pulmonary; Renal/Urologic

Geriatric Considerations

• Complications more likely

Pediatric Considerations

• Viral pneumonia in infants and neonates may be fatal.

Epidemiology

• Predominant age: All ages
• Predominant sex: Male = Female

Incidence

• Very common infection, estimated at 2–5% of all respiratory infections
• More common in infants and children

Risk Factors

• Large number of people gathered in a small area (e.g., military recruits, college students at the beginning of the school year, day care centers, community swimming pools)
• Immunocompromised at risk for severe disease

General Prevention

• Live type 4 and type 7 adenovirus vaccine orally in enteric-coated capsules reduces incidence of acute respiratory disease.
• Frequent hand washing among office personnel and family members
• 9-valent pneumococcal conjugate vaccine may decrease risk of pneumonia in infants.

Pathophysiology

• Adenovirus (DNA viruses 60–90 nm in size with 47 known serotypes; 3 types cause gastroenteritis); difficult to eliminate from skin and environmental surfaces
• Different serotypes have different epidemiologies.
• Most common known pathogens:
  • Types 1, 2, 3, 5, and 7 cause respiratory illness.
  • Type 3 causes pharyngoconjunctival fever.
  • Types 4, 7, and 21 cause acute respiratory disease.
  • Several other types may cause epidemic keratoconjunctivitis.

Commonly Associated Conditions

• Hemorrhagic cystitis (can be caused by adenovirus)
• Viral enteritis
• Intussusception and mesenteric adenitis

Diagnosis

History

Depends on type (see “Differential Diagnosis”). Common signs and symptoms with most respiratory forms:

• Headache
• Malaise
• Sore throat
• Cough
• Fever (moderate to high)
• Vomiting
• Diarrhea
• Abdominal Pain
• Ear Pain
• Urinary symptoms/hematuria
• Conjunctivitis

Physical Exam

• Mucosa exhibiting patches of white exudates
• Cervical adenitis
• Conjunctivitis

Diagnostic Tests & Interpretation

Cultures and serologic studies, if appropriate

Lab

• Viral cultures from respiratory, ocular, or fecal sources can establish diagnosis:
  • Pharyngeal isolate suggests recent infection.
• Antigen detection in stool for enteric serotypes is available.
• Serologic procedures such as complement fixation with a fourfold rise in serum antibody titer identify recent adenoviral infection.

Imaging

Radiographs: Bronchopneumonia in severe respiratory infections

Diagnostic Procedures/Surgery

Biopsy (lung or other) may be needed in severe or unusual cases.

Pathological Findings

• Varies with each virus:
  • Severe pneumonia may be reflected by extensive intranuclear inclusions.
• Bronchiolitis obliterans may occur.

Differential Diagnosis

Early diagnosis depends on clinical evaluation. The following are the primary characteristics of the major adenovirus infections:

• Acute febrile respiratory illness:
  • Nonspecific coldlike symptoms, similar to other viral respiratory illnesses (e.g., fever, pharyngitis, tracheitis, bronchitis, pneumonitis)
  • Mostly in children
  • Incubation period 2–5 days
  • May be pertussislike syndrome (rarely)
• Acute respiratory disease:
  • Malaise, fever, chills, headache, pharyngitis, hoarseness, dry cough
  • Fever lasting 2–4 days
  • Illness subsiding in 10–14 days
• Viral pneumonia:
  • Sudden onset of high fever, rapid infection of upper and lower respiratory tracts, skin rash, diarrhea
  • Occurs in children aged a few days up to 3 years
  • Common; severe illness occurs in subset.
• Acute pharyngoconjunctival fever:
  • Spiking fever lasting several days, headache, pharyngitis, conjunctivitis, rhinitis, cervical adenitis
  • Conjunctivitis, usually unilateral
  • Subsides in 1 week
• Epidemic keratoconjunctivitis:
  • Usually unilateral onset of ocular redness and edema, periorbital edema, periorbital swelling, local discomfort suggestive of foreign body
  • Lasts 3–4 weeks

Treatment

Medication

• Acetaminophen, 10–15 mg/kg PO, for analgesia (avoid aspirin)
• Cough suppressants and/or expectorants
• Antihistamine/decongestant combos may decrease cough.

Additional Treatment

General Measures

• Treatment is supportive and symptomatic.
• Infections are usually benign and of short duration.

Complementary and Alternative Medicine

Echinacea has not been shown to be better than placebo for treatment of viral upper-respiratory infections.

In-Patient Considerations

Admission Criteria

Severely ill infants or those with epidemic keratoconjunctivitis or infants with severe pneumonia:

• Contact and droplet precautions during hospitalization are indicated.

Ongoing Care

Follow-Up Recommendations

Rest during febrile phases

Patient Monitoring

For severe infantile pneumonia and conjunctivitis, daily physical exam until well

Diet

No special diet

Patient Education

• Avoid aspirin in children.
• Give instructions for nasal spray, cough preparations, frequent hand washing

Prognosis

• Self-limited, usually without sequelae
• Severe illness and death in very young and in immunocompromised hosts

Complications

Few if any recognizable long-term problems