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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 inflammation with
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:
Acute
Spasmodic croup
laryngotracheobronc
hitis
Epiglottitis
Bacterial tracheitis
Peritonsillar abscess Retropharyngeal
abscess
Diphtheria
Angioneurotic
edema
Burns or thermal
injury
Smoke inhalation
Neoplasm or
hemangioma
Foreign body
Acute laryngeal
fracture
Arnold-Chiari
malformation
Dandy-Walker
malformation
Laryngomalacia
Subglottic stenosis
Laryngeal
papillomatosis
Extrinsic obstruction
by a vascular ring
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
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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
Final Diagnosis
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.
2.
3.
4.
5.
6.
7.
8.
9.
10.
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
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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).
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quantitative reverse transcription-pcr-enzyme hybridization assay. Journal of Clinical Microbiology
34:1914-1917, 1996.
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11. 21.Kairys SW, Olmstead EM, O'Connor GT: Steroid treatment of laryngotracheitis: A meta-analysis
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