Parainfluenza Virus Case Study # 2 Galarah D Golanbar Christopher Kwon Vanessa Munoz
Case study • A 13 month old child has a runny nose, mild cough, and a low grade fever for several days. The cough got worse and sounded like “barking”. The child made a wheezing sound when agitated. The child appeared well except for the cough. A lateral X-ray examination of the neck showed a subglottic narrowing.
Background information • Parainfluenza virus (PIV) • Negative sense, single-stranded RNA virus • Varies in size and shape • Averaging in diameters of 150-300 nm • Account for a large percentage of pediatric respiratory infections, second to respiratory syncitial virus. • Major cause of croup • Divided into 4 types • Type 1 is the most frequent in children, followed by type 3 and type 2. • Type 4 is less likely to cause a severe illness. • Self- limited infection • Can manifest repeatedly throughout life
Described Symptoms • Coryza • Symptoms of a common head cold • nasal congestion • runny nose • Sore throat • cough • Inflammation of nasal cavity mucous membrane, affecting upper respiratory tract • Viral croup • Inflammation of the larynx and upper airway • Results in narrowing of the airway • Characterized by a barking cough, inspiratory stridor, and a variable amount of respiratory distress that develops over a brief period. • Stridor • A high pitched, breathing sound caused by turbulent flow of air, usually caused by a blockage in breathing • Inspiratory stridor (a sound heard in inspiration through a spasmodically closed glottis)
Described Symptoms • Retractions • Intercostal retractions: retractions of the chest cavity • The inward movement of the chest due to decreased pressure in the chest cavity. • Usually an indicator for difficulty in breathing • The virus will cause a diffused inflammationwith erythema and edema in the tracheal walls that will affect the mobility of the vocal cords. • The subglottic region of the child’s upper airway is narrow. So, a small amount of edema will significantly restrict airflow.
Other causative agents • Viruses from the Paramyxoviridae family • Mumps, measles, and respiratory syncitial virus (RSV) • Can also cause sporadic cases of croup • Adenovirus • Infection of the respiratory tract, as well as eyes, intestines, and urinary tract • Pneumonia • Inflammation of the lungs caused by bacteria, viruses, or other microorganisms • Leading cause of death in children worldwide • Influenza A and B • Both caused by viruses in the family Orthomyxoviridae
Differential Diagnosis • There are several differential diagnoses listed:
Parainfluenza virus : Current Diagnosis • Pulse Oximetry • Monitors oxygen saturation in the blood. • Used to evaluate the severity of the illness. • Laryngoscopy • Direct: An examination used to look inside the throat with a small camera. • Used in severe cases of parainfluenza virus infection. • Indirect: done with a small handheld mirror to look at the back of the throat.
Techniques and Tests for Diagnosis • Diagnostic Techniques: • Radiographic Studies • Posteroanterior (PA) radiography of the neck • Only confirms 50% of cases http://aapredbook.aappublications.org/week/iotw092004.shtml -->
Parainfluenza virus : Current Diagnosis • Lab tests: • Viral cultures • Requires several days to see the results. More helpful epidemiologically than clinically. • Immunofluorescence and enzyme immunoassay methods • Done in vitro and tests the nasopharyngeal washings of infected patients. • CBC: • Complete Blood Count measures: • Red blood cell (RBC), white blood cell (WBC), total hemoglobin in blood, hematocrit (fraction of blood composed of RBCs), and mean corpusular volume (MCV, which measures size of RBCs) • RNA amplification • Hemadsorption
Treatment • No vaccine or direct treatment for the virus. Instead, treatment is focused on managing the symptoms. • Based on the severity of symptoms, mainly of croup: • Croup severity ranges from mild or moderate, to severe • Severity of the infection is based upon five factors: • Level of consciousness, Cyanosis, Stridor, Air Entry and Retractions
Treatment • Analgesics • Ribavirin • Cool mist and oral intake of fluids • Common types of treatment, as can be done at home • Cool mist helps to soothe inflamed mucosa • Nebulized epinephrine • Used for moderate to severe croup patients to alleviate symptoms • Corticosteroids • Orally administered • To treat airway inflammation and edema • Heliox • Breathing gas composed of a mixture of helium and oxygen • Intubation • Rare, done only in severe cases
References • 1.Viral Croup: A Current Perspective. Leung, A.K.C., Kellner, J.D., Johnson, D.W. Journal of Pediatric Health Care November/December (2004): 297-301. • 2.Infections: Croup. Dowshen, S., Homeier, B.P. Nemours Foundation. May, 2005. • 3.Parainfluenza virus infections. Vega, R.M. eMedicine from WebMD. Sept. 24, 2007. • 4.Evaluation of Stridor and Wheezing. Holinger, L.D. Journal of Children’s Memorial Hospital, Chicago. Spring, 1998. • 5.Definition of Human Parainfluenza Virus. (http://www.medterms.com/script/main/art.asp?articlekey=31631) • 6.Viral Croup: A Current Perspective. Leung, A.K.C., Kellner, J.D., Johnson, D.W. Journal of Pediatric Health Care November/December (2004): 297-301. • 7.Human Parainfluenza Virus Type 4 Infections: A report of 20 cases from 1998 to 2002. Billaud et al. Journal of Clinical Virology 34 (2005) 48–51. • 8.Clinical courses of croup caused by influenza and parainfluenza virus. Peltola, V., Heikkinen, T., & Ruuskanen, O. The Pediatric Infectious Disease Journal 21 (2002) • 9.Acute Epiglottitis. Jaffe, J.E. eMedicine.com by WebMD. (http://www.emedicine.com/Radio/topic263.htm) • 10.Parainfluenza Virus. Parija, S.C., Marrie, T.J. eMedicine.com by WebMD. (http://www.emedicine.com/MED/topic1733.htm)
References 1. 11.Concise Review for Primary-Care Physicians-Viral Croup: Current Diagnosis and Treatment by Julia Rosekranse, MD (http://www.mayoclinicproceedings.com/inside.asp?AID=3078&UID) 2. 12.Quest Diagnosis Laboratories test guide (2006). 3. 13. Fan J, Henrickson KJ: Rapid diagnosis of human parainfluenza virus type 1 infection by quantitative reverse transcription-pcr-enzyme hybridization assay. Journal of Clinical Microbiology 34:1914-1917, 1996. 4. 14. Gilbert LL, Dakhama A, Bone BM, et al: Diagnosis of viral respiratory tract infections in children by using a reverse transcription-pcr panel. Journal of Clinical Microbiology 34:140-143, 1996. 5. 15.Steele RW: Pneumonia in children: Current status of diagnosis and treatment. Journal of Respiratory Diseases 8:63-73, 1987. 6. 16.Sidwell RW, Huffman JH, Khare GP, et al: Broad-spectrum antiviral activity of virazole 1-b-d-ribofuranosyl-1,2,4-triazole-3-carcoxamide. Science 177:705-706, 1972. 7. 17.Steele RW: Antiviral agents for respiratory infections. Pediatric Infectious Diseases Journal 7:457-461, 1988. 8. 18. Cobian L, Houston S, Greene J, et al: Parainfluenza virus respiratory infection after heart transplantation: Successful treatment with ribavirin. CID 21:1040-1041, 1995. 9. 19.Gilbert B, Knight V: Biochemistry and clinical applications of ribavirin. Antimicrob Agents Chemother 30:201-205, 1986. 10. 20. Gelfand E: Ribavirin treatment of viral pneumonia in severe combined immunodeficiency. Lancet 1:732-733, 1983. 11. 21.Kairys SW, Olmstead EM, O'Connor GT: Steroid treatment of laryngotracheitis: A meta-analysis of the evidence from randomized trials. Pediatrics 83:683-693, 1989. 12. 22.Klassen TP, Feldman ME, Watters LK, et al: Nebulized budesonide for children with mild-to-moderate croup. N Engl J Med 331:285-289, 1994.