Introduction to Herpesvirus 6 Infection

Infectious Diseases No Responses »
Dec 032011

Like other herpesviruses, human herpesvirus 6 causes an initial infection, a life-long latency, and a clinical reactivation, especially in hosts who are immunocompromised

Pathophysiology

The infectious agent in roseola infantum/exanthem subitum was demonstrated to be present in blood by inoculating healthy infants with serum from ill infants, a procedure considered very dangerous by today’s standards.

Clinical Presentation

Human herpesvirus 6 (HHV-6) is the single most common cause of hospital visits in infants with fever.

Roseola is characterized by an initial febrile phase of 3-5 days, with temperatures reaching 40°C.

With the fever, some children exhibit bilateral periorbital edema in the prodrome.

At or near the period of defervescence, a maculopapular rash is observed on the infant’s trunk and neck; however, this rash is found in the minority of patients (10%).

Children can contract primary human herpesvirus 6 without manifesting a rash.

Human herpesvirus 6 can be isolated from the blood for the first 5 days and later is found intermittently or persistently in saliva, stool, and, rarely, urine.

Physical Examination

High-grade fever higher than 39.5°C (103°F) persists for 3-5 days and then resolves abruptly.

Rash appears after 12-24 hours of resolution of fever. In many incidents of human herpesvirus 6, rash appears during defervescence or within a few hours.

Rash of roseola is erythematous, nonpruritic, mildly elevated, and consists of rosepink papules (roseola meaning pink-colored rash). The rash blanches on pressure and mainly is distributed on the trunk, arms, and neck.

The rash fades in 1-2 days.

Most children are playful despite high-grade fever; however, anorexia, irritability, and listlessness Continue reading »

VN:F [1.9.2_1090]
Rating: 10.0/10 (1 vote cast)
VN:F [1.9.2_1090]
Rating: +1 (from 1 vote)
  • Share/Bookmark
Posted by admin at 1:53 pm Tagged with:

Introduction to Rabies

Infectious Diseases No Responses »
Jan 112011
Epidemiology
  • Animals most commonly associated with the transmission of rabies infection include bats, skunks, raccoons, and foxes.
  • Rabies is rarely or never transmitted by squirrels, chipmunks, rats, mice, guinea pigs, gerbils, hamsters, or rabbits.
Clinical Presentation
  • Prodromal phase (2–10 days): fever, headache, photophobia, anorexia, sore throat, musculoskeletal pain, itching, pain, and tingling at the site of the bite
  • Acute neurologic phase (2–30 days): delirium, paralysis, hydrophobia, coma, and respiratory arrest
Laboratory Studies
  • The virus may be isolated from the saliva, and viral nucleic acid may be detected in infected tissues.
  • Antibody may be detected in the serum or CSF.
  • Diagnosis may also be based on fluorescent microscopy on a skin biopsy specimen from the nape of the neck.
Treatment
  • Scratches or bites should be thoroughly irrigated with soap and water.
  • Postexposure prophylaxis should ideally be given within 24 hours of the exposure.
    • Rabies vaccine is given intramuscularly (1.0 mL) in the deltoid area or anterolateral aspect of the thigh, on day 0 and repeated on days 3, 7, 14, and 28.
    • Rabies immune globulin (RIG) should be given concurrently with the first dose of vaccine. The recommended dose is 20 IU/kg; as much of the dose as possible should be used to infiltrate the wound and the remainder should be given intramuscularly. Continue reading »
VN:F [1.9.2_1090]
Rating: 10.0/10 (1 vote cast)
VN:F [1.9.2_1090]
Rating: +1 (from 1 vote)
  • Share/Bookmark
Posted by admin at 7:06 am Tagged with:

Introduction to Bacterial Tracheitis

Infectious Diseases, Respiratory System No Responses »
Jan 042011
Definition and Epidemiology
  • This acute bacterial infection of the trachea often also involves the larynx and bronchi. It has been called bacterial laryngotracheobronchitis and pseudomembranous croup.
  • A cause of acute airway obstruction, this condition may potentially be life threatening.
  • Most patients are <3 years of age (usually 3 months to 2 years), although older children may be affected. There are no clear sex differences in incidence or severity.
  • There seems to be no seasonal preferences.

Etiology and Pathophysiology
  • The most common cause is Staphylococcus aureus, but other encountered agents are H. influenzae, S. pneumoniae, and Moraxella catarrhalis. Anaerobic organisms have also been reported.
  • Invasion of opportunistic bacterial organisms, often following an upper airway viral infection, causes subglottic edema with ulcerations, copious and purulent secretions, and pseudomembrane formation.
Clinical Presentation
  • The typical presentation involves a history of an upper respiratory infection (URI) for approximately 3 days characterized by a low-grade fever and a “brassy” cough. The illness then evolves rapidly with high fever and onset of stridor, resulting in progressive deterioration and development of acute respiratory distress.
  • Patients generally appear toxic. Continue reading »
VN:F [1.9.2_1090]
Rating: 10.0/10 (1 vote cast)
VN:F [1.9.2_1090]
Rating: +1 (from 1 vote)
  • Share/Bookmark
Posted by admin at 6:50 am Tagged with: ,
Page 1 of 912345...Last »
© 2012 Easy Pediatrics Suffusion WordPress theme by Sayontan Sinha