You are in: eMedicine Specialties > Pediatrics: General Medicine > Infectious Disease Herpesvirus 6 InfectionArticle Last Updated: Jun 23, 2006AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Ruchir Agrawal, MD, Consulting Staff, Allergy Specialists MD SC, Children's Hospital of Wisconsin Ruchir Agrawal is a member of the following medical societies: American Academy of Allergy Asthma and Immunology, American Academy of Pediatrics, American College of Allergy, Asthma and Immunology, and American Medical Association Coauthor(s): Raghu Kolluri, MD, Research Assistant, Department of Physiology, Pennsylvania State University Editors: Leonard R Krilov, MD, Chief of Pediatric Infectious Diseases, Vice Chair, Department of Pediatrics, Professor of Pediatrics, Winthrop University Hospital; Mary L Windle, PharmD, Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine.com, Inc; Larry I Lutwick, MD, Professor of Medicine, State University of New York, Downstate Medical School; Director, Infectious Diseases, Veterans Affairs New York Harbor Health Care System, Brooklyn Campus; Robert W Tolan Jr, MD, Chief of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine; Russell W Steele, MD, Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine Author and Editor Disclosure Synonyms and related keywords: herpesvirus 6 infection, HHV-6, exanthem subitum, roseola infantum, sixth disease INTRODUCTIONSection 2 of 12
  BackgroundAfter the discovery of HIV 1, HIV 2, and human T-cell lymphotrophic viruses (HTLV) I and II, an enhanced interest arose in the scientific community to isolate novel viruses from cultured lymphocytes of patients with HIV and other patients who are immunocompromised. The discovery of human herpesvirus 6 (HHV-6) is a result of this pursuit. HH-6 was isolated from interleukin-2–stimulated peripheral leukocytes of HIV and lymphoproliferative disorders. Initially named human B-cell lymphotropic virus (HBLV), the virus later was designated HHV-6. Later, several strains of HHV-6 were isolated from the lymphocytes of children with exanthem subitum and patients with chronic fatigue syndrome and from the saliva of patients with HIV and healthy individuals. HHV-6 now is recognized to have an extremely widespread distribution. Like other herpesviruses, HHV-6 causes an initial infection, a life-long latency, and a clinical reactivation, especially in hosts who are immunocompromised. HHV-6 may be involved in the pathogenesis of multiple sclerosis; however, further studies are required to establish this association. PathophysiologyThe 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. Later, Yamashi et al isolated the virus from blood and demonstrated seroconversion to HHV-6 in infected infants. HHV-6 belongs to the Betaherpesvirinae subfamily and to the Roseolovirus genus. HHV-6 is divided further into variants A and B. The virion particle has a typical structure of a herpesvirus with a central core containing the viral DNA, a capsid, and a tegument layer that in turn is surrounded by a membrane. At the molecular level, HHV-6 encodes proteins similar to immune mediators in the chemokine family. The functional chemokine is encoded by an open reading frame U83; U12 and U51 encode the 7 transmembrane proteins analogous to the chemokine receptors. This molecular mimicry seems to help HHV-6 in immune invasion and long latency in the host cells. FrequencyUnited StatesSeroprevalence is almost 100%. The virus is shed in and probably spread through saliva of asymptomatic seropositive children. HHV-6B is the cause of most symptomatic infections of HHV-6. InternationalAlmost 100% in Europe, seroprevalence in the rest of the world also is close to 100% with certain exceptions, such as Morocco, which has 20% seroprevalence. Mortality/MorbidityHHV-6 infections are mainly uncomplicated infections, having a self-limited course. Rarely, HHV-6 can be associated with fatal dissemination and death; 8 fatal cases have been reported. The causes of death were encephalitis, hepatitis, sudden death in infancy, hemophagocytic lymphocytosis, and disseminated infections. In studies by Prezioso et al and Hoang et al, atypical monocyte infiltrate was found in multiple organs, including the brain, spleen, lungs, liver, heart, renal cortex, lymph nodes, and intestine. AgePossibly due to maternal antibody protection before this age, seropositivity is at its peak in infants aged 6-12 months. The virus is shed in and probably spread through saliva of asymptomatic seropositive children. Most children contract HHV-6 before they are aged 5 years. CLINICALSection 3 of 12
History
Physical
DIFFERENTIALSSection 4 of 12
Enteroviral Infections Fever in the Toddler Fever in the Young Infant Fever Without a Focus Measles Meningitis, Aseptic Mononucleosis and Epstein-Barr Virus Infection Rubella
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| Drug Name | Acetaminophen (Tylenol, Feverall, Tempra) |
|---|---|
| Description | Used as an antipyretic and analgesic. |
| Adult Dose | 325-1000 mg PO/PR q4-6h; not to exceed 1 g/dose or 4 g/d |
| Pediatric Dose | Neonates: 10-15 mg/kg PO/PR q6-8h prn Infants and children: 10-15 mg/kg PO/PR q4-6h prn; not to exceed 2.6 g/d >12 years: 325-650 mg PO/PR q4-6h prn; not to exceed 4 g/d |
| Contraindications | Documented hypersensitivity; G-6-PD deficiency |
| Interactions | Rifampin can reduce analgesic effects of acetaminophen; coadministration with barbiturates, carbamazepine, hydantoins, and isoniazid may increase hepatotoxicity |
| Pregnancy | B - Usually safe but benefits must outweigh the risks. |
| Precautions | Hepatotoxicity possible with poisonings or chronic high doses; severe or recurrent pain or high or continued fever may indicate a serious illness; contained in many OTC products, and combined use with these products may result in cumulative doses exceeding recommended maximum dose |
| Drug Name | Ibuprofen (Motrin, Ibuprin) |
|---|---|
| Description | Used as an antipyretic and analgesic. Not recommended for ages <6 mo. Inhibits inflammatory reactions, fever, and pain by decreasing prostaglandin synthesis. |
| Adult Dose | 200-400 mg PO q4-6h prn; not to exceed 1200 mg/d |
| Pediatric Dose | <6 months: Not recommended >6 months: 5-10 mg/kg PO q6-8h prn; not to exceed 50 mg/kg/d |
| Contraindications | Documented hypersensitivity; peptic ulcer disease, recent GI bleeding or perforation, renal insufficiency, or high risk of bleeding |
| Interactions | Coadministration with aspirin increases risk of inducing serious NSAID-related adverse effects; probenecid may increase concentrations and possibly toxicity of NSAIDs; may decrease effects of hydralazine, captopril, and beta-blockers; may decrease diuretic effects of furosemide and thiazides; may increase PT when taking anticoagulants (instruct patients to watch for signs of bleeding); may increase risk of methotrexate toxicity; phenytoin levels may be increased when administered concurrently |
| Pregnancy | B - Usually safe but benefits must outweigh the risks. |
| Precautions | Category D in third trimester of pregnancy; caution in congestive heart failure, hypertension, and decreased renal and hepatic function; caution in anticoagulation abnormalities or during anticoagulant therapy |
The authors and editors of eMedicine gratefully acknowledge the contributions of previous author Sue Jue, MD to the development and writing of this article.
| Media file 1: A 9-month-old infant boy presented with a 1-day history of high-grade fever and irritability. In the emergency department, the patient had a septic workup including lumbar puncture (adhesive bandage) with normal cerebrospinal fluid analysis results. He was admitted to the hospital. | |
 | View Full Size Image | Media type: Photo |
| Media file 2: A 9-month-old infant boy presented with a 1-day history of high-grade fever and irritability. In the emergency department, the patient had a septic workup including lumbar puncture with normal cerebrospinal fluid analysis results. He was admitted to the hospital. High-grade fever abruptly resolved on the third day of hospitalization. Within a few hours, an erythematous, pink papular (roseola), nonpruritic rash appeared, mainly on the trunk. | |
 | View Full Size Image | Media type: Photo |
| Media file 3: A 9-month-old infant boy presented with a 1-day history of high-grade fever and irritability. In the emergency department, the patient had septic workup including lumbar puncture with normal cerebrospinal fluid analysis results. He was admitted to the hospital. High-grade fever abruptly resolved on the third day of hospitalization. Within a few hours, an erythematous, pink papular (roseola), nonpruritic rash appeared mainly on the trunk. Patient was playful after supportive therapy. Antibiotics discontinued after 2 days of negative culture. Rash is distributed mainly over the trunk. | |
 | View Full Size Image | Media type: Photo |
Herpesvirus 6 Infection excerpt
Article Last Updated: Jun 23, 2006
