Parainfluenza Virus Infections
Roy M Vega, MD, Assistant Professor of Pediatrics, Albert Einstein College of Medicine;
Director, Pediatric Emergency Services, Department of Emergency Medicine, Bronx Lebanon Hospital Center, Bronx, NY
Updated: Aug 28, 2009
Introduction
Background
Human parainfluenza viruses (PIVs) account for a large percentage of pediatric respiratory infections, including upper respiratory tract infections (URTIs), laryngotracheobronchitis (croup), bronchiolitis, and pneumonia. Human parainfluenza viruses is the major cause of croup (type 1 is most frequent, followed by type 3 and type 2). Human parainfluenza viruses are divided into 4 types, all of which are classified as paramyxoviruses. Infections from types 1 and 3 account for most disease.
Transmission electron micrograph of parainfluenza virus. Transmission electron micrograph of parainfluenza virus. Two intact particles and free filamentous nucleocapsid.
In 2005, a previously unidentified human parvovirus was identified.1 The virus was named human bocavirus. It resembles 2 other parvoviruses that belong to the Bocavirus genus. Human bocavirus resembles respiratory syncytial virus (RSV) in its clinical manifestations. Similar age profiles were noted in a study evaluating the epidemiological profile of human bocavirus, with infections predominantly limited to infants and young children.2 Clinical manifestations of human bocavirus include bronchiolitis, pneumonia, bronchitis, and exacerbations of asthma.
Pathophysiology
The virus colonizes the nose and the nasopharynx; then, it invades the epithelium, resulting in cell damage, edema, and loss of cilia. A fibrinous exudate develops with downward spread of cell damage and edema. The resulting airway obstruction and laryngeal muscle spasm account for the typical symptoms of croup. The incubation period is 1-7 days.
Frequency
United States
Outbreaks of parainfluenza disease occur regularly throughout fall and mid winter. Parainfluenza virus type 1 causes biennial epidemics in the United States.
Mortality/Morbidity
Most children with croup have mild infections that are usually managed on an outpatient basis. Approximately 41,000 individuals per year are admitted to the hospital for parainfluenza virus infections. Precautions are necessary within hospitals to prevent further spread.3 Only 1-5% of patients admitted to the hospital need artificial airway support.
Age
Parainfluenza-related laryngotracheobronchitis commonly affects children aged 3 months to 3 years. Parainfluenza virus infection can also account for bronchiolitis in infants and children younger than 2 years.
Clinical
History
Patients with parainfluenza virus (PIV) infection typically present with a history of coryza and low-grade fever. They then develop the classic barking cough associated with croup.
Symptoms of croup include the following:
Fever
Barking cough
Coryza
Stridor
Retractions
Tachypnea (when lower airways become involved)
Irritability
Children with croup are usually more symptomatic at night. Coughing often awakens them from sleep. The reasons for worsening of symptoms at night are unknown.
Parainfluenza infections can also present as bronchiolitis. The typical presentation includes fever, coryza, tachypnea, coughing, and wheezing.4
Physical
Croup scoring systems have been developed to aid in grading the severity of infection.
Factors in such scoring systems include stridor, retractions, air entry, color, and level of consciousness.
Croup scoring systems were developed prior to the advent of pulse oximetry. Pulse oximetry may be beneficial in grading severity of illness, response to management, and disposition.
Differential Diagnoses
Epiglottitis
Retropharyngeal Abscess
Other Problems to Be Considered
Tracheitis
Pneumonia
Workup
Laboratory Studies
Viral cultures in patients with parainfluenza virus (PIV) infection usually require 4-7 days to yield results, which limits their clinical applicability in the acute setting. Cultures can be helpful from an epidemiological standpoint.
Immunofluorescent and enzyme immunoassay methods can be performed to test nasopharyngeal washings; however, they are not readily available and vary in sensitivity.
The WBC count on CBC count samples is usually normal; however, lymphocytosis may be noted.
Imaging Studies
Posteroanterior (PA) radiography of the neck may reveal the classic steeple sign (ie, narrowing of the proximal portion of the trachea, indicative of subglottic edema); however, this finding is absent in approximately 50% of cases.
Lateral soft tissue films of the neck are normal in most cases. Lateral neck films can be useful if the diagnosis is unclear, especially if conditions such as foreign body aspiration, retropharyngeal abscess, or epiglottitis are in the differential diagnosis.
Treatment
Medical Care
Management of croup caused by parainfluenza virus (PIV) infection depends on the severity of disease.
Prehospital care
Prehospital care includes fever control and attempts to alleviate respiratory symptoms and patient anxiety.
Respiratory symptoms commonly improve with benign measures such as sitting in a bathroom with a steaming shower and allowing vapor droplets to soothe inflamed airways. Another option includes exposing the child to the cool night air. Often, the patient's symptoms resolve en route to the hospital. Attempts at calming or distracting the child can be beneficial.
Antipyretics may assist with fever control. Moderate or severe croup requires medical evaluation in the office or emergency department.
Emergency department care
Mild croup: Management of mild croup consists of cool blow-by oxygen mist, fever control, and observation to determine whether the airway appears compromised.
Moderate croup
Cool oxygen mist and steroids are common therapies. Controlled trials for the palliation of croup symptoms have yielded conflicting results, and routine use of dexamethasone in this disease remains controversial. Dexamethasone was traditionally intramuscularly administered; however, recent studies have documented the use of oral steroids.
In patients who fail to improve, administration of racemic epinephrine with a nebulizer has been beneficial. If racemic epinephrine alleviates symptoms, observe the patient for a minimum of 3 hours to ensure the patient's condition does not worsen (eg, due to possible rebound laryngospasm as the racemic epinephrine dose wears off). If asymptomatic at this time, the patient can be discharged with proper follow-up care.
In patients with moderate croup, oral intake may be lacking; therefore, evaluate the patient's hydration status. Intravenous fluids may be required.
Severe croup
Perform the same measures as in moderate croup. Observe for signs of impending respiratory failure.
Repeat racemic epinephrine nebulization may be needed, in addition to intensive care monitoring. Racemic epinephrine nebulizations can be repeated at 1-hour to 2-hour intervals as needed. Fortunately, fewer than 5% of patients who are admitted require artificial airway support (endotracheal intubation).
Medication
No specific antiviral agents are available for treating parainfluenza virus (PIV) infections; however, medications are available to treat the respiratory symptoms associated with croup. The medications include corticosteroids and nebulized epinephrine to treat airway inflammation and edema.
Glucocorticoids
These agents have anti-inflammatory properties and cause profound and varied metabolic effects. They modify the body's immune response to diverse stimuli. Anti-inflammatory drugs (specifically dexamethasone) help reduce the inflammation and subglottic edema of croup. Despite delayed onset of action, the high potency and prolonged intramuscular half-life of dexamethasone make it the preferred corticosteroid for croup.
Dexamethasone (Decadron)
Criterion standard anti-inflammatory drug for reducing airway edema that occurs in croup. Other glucocorticoids have been used, including prednisone and prednisolone. Dexamethasone is thought to decrease inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Dosing
Adult
10 mg PO/IV/IM qd
Pediatric
0.6 mg/kg PO/IM qd prn; not to exceed 10 mg/d
Interactions
Possible decreased effects with coadministration of barbiturates, phenytoin, or rifampin; decreases effect of salicylates and vaccines
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hyperthyroidism, osteoporosis, cirrhosis, nonspecific ulcerative colitis, peptic ulcer, diabetes, and myasthenia gravis; tuberculosis; untreated systemic infections; ocular herpes simplex virus
Budesonide (Pulmicort Respules)
Nebulized budesonide has been found to be beneficial in treating croup.
Dosing
Adult
Not applicable
Pediatric
2-4 mg/d inhaled via nebulizer divided qd/bid
Interactions
Ketoconazole may increase plasma levels of budesonide; cimetidine may increase bioavailability of budesonide
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella; patients may develop PO thrush
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tuberculosis, untreated systemic infections, ocular herpes simplex virus
Prednisolone (Delta-Cortef, Pediapred)
Many practitioners administer liquid prednisolone for patients with croup in lieu of dexamethasone. Prednisolone has not been proven superior to dexamethasone.
Dosing
Adult
Not applicable
Pediatric
1-2 mg/kg/d PO qd or divided bid
Interactions
Decreases effects of salicylates and toxoids (for immunizations); phenytoin, carbamazepine, barbiturates, and rifampin decrease effects of corticosteroids
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hyperthyroidism, osteoporosis, cirrhosis, nonspecific ulcerative colitis, peptic ulcer, diabetes, and myasthenia gravis; tuberculosis; untreated systemic infections; ocular herpes simplex virus
Bronchodilators
When delivered by air or oxygen-powered devices, epinephrine is directly delivered to respiratory mucosal surfaces and smooth muscle. Because nebulizers deliver the medication directly to the target organ, fewer systemic adverse effects are encountered in comparison with oral or parenteral administration.
Epinephrine, racemic solution (Vaponefrin, microNefrin)
Very effective in reversing upper airway edema when administered with a nebulizer. Proposed mechanism of action is alpha-adrenergic receptor-mediated vasoconstriction of edematous tissues.
Dosing
Adult
Mix 0.5 mL with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer q1-2h prn
Pediatric
Mix 0.05 mL/kg with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer q1-2h prn; not to exceed 0.5 mL/dose
Interactions
Inhaled anesthetics may enhance cardiac irritability; nonselective beta-blockers block the beta effects of epinephrine leaving unopposed alpha effects (eg, hypertension)
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tachycardia, especially with HR >200 BPM; consider cardiac monitoring if multiple doses required
L-epinephrine (Adrenalin)
In concentrations of 1:1000, may be substituted for racemic epinephrine for nebulized administration.
Dosing
Adult
5 mL nebulized q1-2h prn; mix with 3 mL 0.9% NaCl
Pediatric
<4 years: Mix 2.5 mL with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer
>4 years: Administer as in adults
Interactions
Inhaled anesthetics may enhance cardiac irritability; nonselective beta-blockers block the beta effects of epinephrine leaving unopposed alpha effects (eg, hypertension)
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tachycardia, especially with HR >200 BPM, consider cardiac monitoring if multiple doses required
Follow-up
Further Inpatient Care
Indications for hospitalization in patients with parainfluenza virus (PIV) infection include the following:
Stridor or retractions present at rest despite therapy
Need for repeated doses of racemic epinephrine
Rebound laryngospasm in patients who receive racemic epinephrine
Signs of respiratory distress
Inadequate oral intake or dehydration
Further Outpatient Care
Use cool mist vaporizers.
Administer acetaminophen or ibuprofen for fever.
Increase oral fluid intake.
Deterrence/Prevention
No vaccine is currently available for parainfluenza virus.
Passively acquired maternal antibodies from breast feeding may be protective in the first few months of life.
Handwashing and contact precautions can limit the spread of disease to others.
Complications
Posttransplant parainfluenza virus infection is a cause of serious lower respiratory tract involvement in both adults and children who undergo bone marrow transplantation.
Long-term ribavirin therapy has been helpful in case reports.5
Prognosis
Patients with parainfluenza infections generally do well, with resolution of symptoms in 7-10 days.
On occasion, the infection spreads to the lower respiratory tract, causing bronchiolitis or viral pneumonia.
Denudation of respiratory epithelium places patients at a slightly increased risk of bacterial superinfection. Evaluate any patient recovering from croup who deteriorates suddenly for possible bacterial tracheitis.
Patient Education
For excellent patient education resources, visit eMedicine's Lung and Airway Center. Also, see eMedicine's patient education article Croup.
Miscellaneous
Medicolegal Pitfalls
A common occurrence in pediatric emergency department charts concerns varied assessment of the patient. All notes on the chart (eg, triage, nursing, resident) should be examined. If the assessments differ from the physician's assessment, the physician should address said differences in his or her notes. At discharge, ensure that proper discharge instructions, both written and oral, are given to the patient.
Document an examination at time of discharge. For example, "Patient is breathing comfortably, is alert, consolable, without tachypnea, stridor, or retractions." A pulse oximetry reading can also be included if available.
If the patient has a pediatrician or other primary care provider, attempt to contact them to ensure proper follow-up care. The pediatrician can also be consulted on management issues if the physician has concerns or doubts.
For any concerns about stability for discharge, always err on the side of admission.
http://emedicine.medscape.com/article/967189-print
Roy M Vega, MD, Assistant Professor of Pediatrics, Albert Einstein College of Medicine;
Director, Pediatric Emergency Services, Department of Emergency Medicine, Bronx Lebanon Hospital Center, Bronx, NY
Updated: Aug 28, 2009
Introduction
Background
Human parainfluenza viruses (PIVs) account for a large percentage of pediatric respiratory infections, including upper respiratory tract infections (URTIs), laryngotracheobronchitis (croup), bronchiolitis, and pneumonia. Human parainfluenza viruses is the major cause of croup (type 1 is most frequent, followed by type 3 and type 2). Human parainfluenza viruses are divided into 4 types, all of which are classified as paramyxoviruses. Infections from types 1 and 3 account for most disease.
Transmission electron micrograph of parainfluenza virus. Transmission electron micrograph of parainfluenza virus. Two intact particles and free filamentous nucleocapsid.
In 2005, a previously unidentified human parvovirus was identified.1 The virus was named human bocavirus. It resembles 2 other parvoviruses that belong to the Bocavirus genus. Human bocavirus resembles respiratory syncytial virus (RSV) in its clinical manifestations. Similar age profiles were noted in a study evaluating the epidemiological profile of human bocavirus, with infections predominantly limited to infants and young children.2 Clinical manifestations of human bocavirus include bronchiolitis, pneumonia, bronchitis, and exacerbations of asthma.
Pathophysiology
The virus colonizes the nose and the nasopharynx; then, it invades the epithelium, resulting in cell damage, edema, and loss of cilia. A fibrinous exudate develops with downward spread of cell damage and edema. The resulting airway obstruction and laryngeal muscle spasm account for the typical symptoms of croup. The incubation period is 1-7 days.
Frequency
United States
Outbreaks of parainfluenza disease occur regularly throughout fall and mid winter. Parainfluenza virus type 1 causes biennial epidemics in the United States.
Mortality/Morbidity
Most children with croup have mild infections that are usually managed on an outpatient basis. Approximately 41,000 individuals per year are admitted to the hospital for parainfluenza virus infections. Precautions are necessary within hospitals to prevent further spread.3 Only 1-5% of patients admitted to the hospital need artificial airway support.
Age
Parainfluenza-related laryngotracheobronchitis commonly affects children aged 3 months to 3 years. Parainfluenza virus infection can also account for bronchiolitis in infants and children younger than 2 years.
Clinical
History
Patients with parainfluenza virus (PIV) infection typically present with a history of coryza and low-grade fever. They then develop the classic barking cough associated with croup.
Symptoms of croup include the following:
Fever
Barking cough
Coryza
Stridor
Retractions
Tachypnea (when lower airways become involved)
Irritability
Children with croup are usually more symptomatic at night. Coughing often awakens them from sleep. The reasons for worsening of symptoms at night are unknown.
Parainfluenza infections can also present as bronchiolitis. The typical presentation includes fever, coryza, tachypnea, coughing, and wheezing.4
Physical
Croup scoring systems have been developed to aid in grading the severity of infection.
Factors in such scoring systems include stridor, retractions, air entry, color, and level of consciousness.
Croup scoring systems were developed prior to the advent of pulse oximetry. Pulse oximetry may be beneficial in grading severity of illness, response to management, and disposition.
Differential Diagnoses
Epiglottitis
Retropharyngeal Abscess
Other Problems to Be Considered
Tracheitis
Pneumonia
Workup
Laboratory Studies
Viral cultures in patients with parainfluenza virus (PIV) infection usually require 4-7 days to yield results, which limits their clinical applicability in the acute setting. Cultures can be helpful from an epidemiological standpoint.
Immunofluorescent and enzyme immunoassay methods can be performed to test nasopharyngeal washings; however, they are not readily available and vary in sensitivity.
The WBC count on CBC count samples is usually normal; however, lymphocytosis may be noted.
Imaging Studies
Posteroanterior (PA) radiography of the neck may reveal the classic steeple sign (ie, narrowing of the proximal portion of the trachea, indicative of subglottic edema); however, this finding is absent in approximately 50% of cases.
Lateral soft tissue films of the neck are normal in most cases. Lateral neck films can be useful if the diagnosis is unclear, especially if conditions such as foreign body aspiration, retropharyngeal abscess, or epiglottitis are in the differential diagnosis.
Treatment
Medical Care
Management of croup caused by parainfluenza virus (PIV) infection depends on the severity of disease.
Prehospital care
Prehospital care includes fever control and attempts to alleviate respiratory symptoms and patient anxiety.
Respiratory symptoms commonly improve with benign measures such as sitting in a bathroom with a steaming shower and allowing vapor droplets to soothe inflamed airways. Another option includes exposing the child to the cool night air. Often, the patient's symptoms resolve en route to the hospital. Attempts at calming or distracting the child can be beneficial.
Antipyretics may assist with fever control. Moderate or severe croup requires medical evaluation in the office or emergency department.
Emergency department care
Mild croup: Management of mild croup consists of cool blow-by oxygen mist, fever control, and observation to determine whether the airway appears compromised.
Moderate croup
Cool oxygen mist and steroids are common therapies. Controlled trials for the palliation of croup symptoms have yielded conflicting results, and routine use of dexamethasone in this disease remains controversial. Dexamethasone was traditionally intramuscularly administered; however, recent studies have documented the use of oral steroids.
In patients who fail to improve, administration of racemic epinephrine with a nebulizer has been beneficial. If racemic epinephrine alleviates symptoms, observe the patient for a minimum of 3 hours to ensure the patient's condition does not worsen (eg, due to possible rebound laryngospasm as the racemic epinephrine dose wears off). If asymptomatic at this time, the patient can be discharged with proper follow-up care.
In patients with moderate croup, oral intake may be lacking; therefore, evaluate the patient's hydration status. Intravenous fluids may be required.
Severe croup
Perform the same measures as in moderate croup. Observe for signs of impending respiratory failure.
Repeat racemic epinephrine nebulization may be needed, in addition to intensive care monitoring. Racemic epinephrine nebulizations can be repeated at 1-hour to 2-hour intervals as needed. Fortunately, fewer than 5% of patients who are admitted require artificial airway support (endotracheal intubation).
Medication
No specific antiviral agents are available for treating parainfluenza virus (PIV) infections; however, medications are available to treat the respiratory symptoms associated with croup. The medications include corticosteroids and nebulized epinephrine to treat airway inflammation and edema.
Glucocorticoids
These agents have anti-inflammatory properties and cause profound and varied metabolic effects. They modify the body's immune response to diverse stimuli. Anti-inflammatory drugs (specifically dexamethasone) help reduce the inflammation and subglottic edema of croup. Despite delayed onset of action, the high potency and prolonged intramuscular half-life of dexamethasone make it the preferred corticosteroid for croup.
Dexamethasone (Decadron)
Criterion standard anti-inflammatory drug for reducing airway edema that occurs in croup. Other glucocorticoids have been used, including prednisone and prednisolone. Dexamethasone is thought to decrease inflammation by suppressing migration of polymorphonuclear leukocytes and reversing increased capillary permeability.
Dosing
Adult
10 mg PO/IV/IM qd
Pediatric
0.6 mg/kg PO/IM qd prn; not to exceed 10 mg/d
Interactions
Possible decreased effects with coadministration of barbiturates, phenytoin, or rifampin; decreases effect of salicylates and vaccines
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hyperthyroidism, osteoporosis, cirrhosis, nonspecific ulcerative colitis, peptic ulcer, diabetes, and myasthenia gravis; tuberculosis; untreated systemic infections; ocular herpes simplex virus
Budesonide (Pulmicort Respules)
Nebulized budesonide has been found to be beneficial in treating croup.
Dosing
Adult
Not applicable
Pediatric
2-4 mg/d inhaled via nebulizer divided qd/bid
Interactions
Ketoconazole may increase plasma levels of budesonide; cimetidine may increase bioavailability of budesonide
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella; patients may develop PO thrush
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tuberculosis, untreated systemic infections, ocular herpes simplex virus
Prednisolone (Delta-Cortef, Pediapred)
Many practitioners administer liquid prednisolone for patients with croup in lieu of dexamethasone. Prednisolone has not been proven superior to dexamethasone.
Dosing
Adult
Not applicable
Pediatric
1-2 mg/kg/d PO qd or divided bid
Interactions
Decreases effects of salicylates and toxoids (for immunizations); phenytoin, carbamazepine, barbiturates, and rifampin decrease effects of corticosteroids
Contraindications
Documented hypersensitivity; immunosuppressed patients receiving corticosteroids; varicella
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in hyperthyroidism, osteoporosis, cirrhosis, nonspecific ulcerative colitis, peptic ulcer, diabetes, and myasthenia gravis; tuberculosis; untreated systemic infections; ocular herpes simplex virus
Bronchodilators
When delivered by air or oxygen-powered devices, epinephrine is directly delivered to respiratory mucosal surfaces and smooth muscle. Because nebulizers deliver the medication directly to the target organ, fewer systemic adverse effects are encountered in comparison with oral or parenteral administration.
Epinephrine, racemic solution (Vaponefrin, microNefrin)
Very effective in reversing upper airway edema when administered with a nebulizer. Proposed mechanism of action is alpha-adrenergic receptor-mediated vasoconstriction of edematous tissues.
Dosing
Adult
Mix 0.5 mL with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer q1-2h prn
Pediatric
Mix 0.05 mL/kg with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer q1-2h prn; not to exceed 0.5 mL/dose
Interactions
Inhaled anesthetics may enhance cardiac irritability; nonselective beta-blockers block the beta effects of epinephrine leaving unopposed alpha effects (eg, hypertension)
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tachycardia, especially with HR >200 BPM; consider cardiac monitoring if multiple doses required
L-epinephrine (Adrenalin)
In concentrations of 1:1000, may be substituted for racemic epinephrine for nebulized administration.
Dosing
Adult
5 mL nebulized q1-2h prn; mix with 3 mL 0.9% NaCl
Pediatric
<4 years: Mix 2.5 mL with 3 mL 0.9% NaCl (normal saline) and inhale via nebulizer
>4 years: Administer as in adults
Interactions
Inhaled anesthetics may enhance cardiac irritability; nonselective beta-blockers block the beta effects of epinephrine leaving unopposed alpha effects (eg, hypertension)
Contraindications
Documented hypersensitivity
Precautions
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Tachycardia, especially with HR >200 BPM, consider cardiac monitoring if multiple doses required
Follow-up
Further Inpatient Care
Indications for hospitalization in patients with parainfluenza virus (PIV) infection include the following:
Stridor or retractions present at rest despite therapy
Need for repeated doses of racemic epinephrine
Rebound laryngospasm in patients who receive racemic epinephrine
Signs of respiratory distress
Inadequate oral intake or dehydration
Further Outpatient Care
Use cool mist vaporizers.
Administer acetaminophen or ibuprofen for fever.
Increase oral fluid intake.
Deterrence/Prevention
No vaccine is currently available for parainfluenza virus.
Passively acquired maternal antibodies from breast feeding may be protective in the first few months of life.
Handwashing and contact precautions can limit the spread of disease to others.
Complications
Posttransplant parainfluenza virus infection is a cause of serious lower respiratory tract involvement in both adults and children who undergo bone marrow transplantation.
Long-term ribavirin therapy has been helpful in case reports.5
Prognosis
Patients with parainfluenza infections generally do well, with resolution of symptoms in 7-10 days.
On occasion, the infection spreads to the lower respiratory tract, causing bronchiolitis or viral pneumonia.
Denudation of respiratory epithelium places patients at a slightly increased risk of bacterial superinfection. Evaluate any patient recovering from croup who deteriorates suddenly for possible bacterial tracheitis.
Patient Education
For excellent patient education resources, visit eMedicine's Lung and Airway Center. Also, see eMedicine's patient education article Croup.
Miscellaneous
Medicolegal Pitfalls
A common occurrence in pediatric emergency department charts concerns varied assessment of the patient. All notes on the chart (eg, triage, nursing, resident) should be examined. If the assessments differ from the physician's assessment, the physician should address said differences in his or her notes. At discharge, ensure that proper discharge instructions, both written and oral, are given to the patient.
Document an examination at time of discharge. For example, "Patient is breathing comfortably, is alert, consolable, without tachypnea, stridor, or retractions." A pulse oximetry reading can also be included if available.
If the patient has a pediatrician or other primary care provider, attempt to contact them to ensure proper follow-up care. The pediatrician can also be consulted on management issues if the physician has concerns or doubts.
For any concerns about stability for discharge, always err on the side of admission.
http://emedicine.medscape.com/article/967189-print
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