Transcript Approach to chronic cough in children

Approach to chronic cough in
children
‫د هالة الرفاعي‬
• INTRODUCTION
• Coughing is an important defensive reflex that
protects from aspiration of foreign
• materials, and enhances clearance of
secretions and particulates from the airways.
Healthy children may
• cough on a daily basis; one study documented
an average of 11 cough episodes every 24
hours
• However, a cough may also be the presenting
symptom of a serious underlying pulmonary or
• extrapulmonary disease. The causes of chronic
cough in children are quite different from that of
adults,
• so evaluation and management of children
should not be based on adult protocols.
Adolescents 15 years
• and older may be evaluated using guidelines for
adults
• The differential diagnosis of chronic cough in
children includes subacute and chronic
infections
• bacterial bronchitis
• pertussis,
• mycoplasma, tuberculosis
• foreign body aspiration, and cough dominant
• asthma
• Gastroesophageal reflux, upper airway cough
syndrome (formerly
• known as postnasal drip syndrome), and
sinusitis are sometimes implicated because of
associations with
• chronic cough in adults, but their role in
causing chronic cough in children is
controversial [
• Less
• common disorders must be excluded if the
cough is unusually severe and/or frequent, or
when there is
• evidence of failure to thrive, growth
retardation, purulent sputum, exertional
dyspnea, hypoxemia, chest
• pain, or hemoptysis
• chronic cough appears to be common, with an
estimated prevalence of 5 to 7
• percent in preschoolers, and 12 to 15 percent in
older children
• Cough is more common among
• boys than girls up to 11 years of age
• and may be less common in developing countries
than in
• affluent countries [
DEFINITION
• There is no consensus as to the length of time in
the definition of chronic cough in
• children. The American College of Chest
Physicians, Thoracic Society of Australia and New
Zealand,
• and many studies have defined chronic cough as
one that lasts more than four weeks, because
most acute
• respiratory infections in children resolve within
this interva
• In comparison, guidelines from the
• British Thoracic Society define chronic cough
as one that lasts more than eight weeks
• However,
• these guidelines also describe a "prolonged
acute cough" as one that lasts at least three
weeks
PHYSIOLOGY
• Each cough occurs through the stimulation of
a complex reflex arc
• This
• is initiated by the irritation of cough receptors
that exist not only in the epithelium of the
upper and lower
• respiratory tracts, but also in the pericardium,
esophagus, diaphragm, stomach, and external
ear
•
•
•
•
Chemical receptors sensitive to acid, heat
mechanical cough receptors can
be triggered by touch or displacement.
The proximal airways (larynx and trachea) are
more sensitive to
• mechanical stimulation, the distal airways more
sensitive to chemical stimulation. Irritation at the
• bronchiolar and alveolar level does not cause
cough
• Impulses from stimulated cough receptors
traverse afferent branches of the vagus nerve to a
"cough
• center" in the medulla and nucleus tractus
solitarius, which itself is under control by higher
cortical
• centers. The cough center generates an efferent
signal that travels down the vagus, phrenic, and
spinal
• motor nerves to expiratory musculature to
produce the cough
• The mechanical events of a cough can be
divided into three phases
• Inspiratory phase: Inhalation, which generates the
volume necessary for an effective cough.
• Compression phase: Closure of the larynx combined
with contraction of muscles of chest wall,
• diaphragm, and abdominal wall result in a rapid rise in
intrathoracic pressure.
• Expiratory phase: The glottis opens, resulting in high
expiratory airflow and the coughing sound.
• Large airway compression occurs. The high flows
dislodge mucus from the airways and allow
• removal from the tracheobronchial tree.
• The specific pattern of the cough depends on the
site and type of stimulation. Mechanical laryngeal
• stimulation results in immediate expiratory
stimulation (sometimes termed the expiratory
reflex),
• probably to protect the airway from aspiration;
stimulation distal to the larynx causes a more
prominent
• inspiratory phase, presumably to generate the
airflow necessary to remove the stimulus
• Cough is an important defensive reflex that is
required to maintain the health of the
• lungs. Children who do not cough effectively
are at risk for atelectasis, recurrent
pneumonia, and chronic
• airways disease from aspiration and retention
of secretions
• Many disorders can impair a child's ability to
• cough effectively, resulting in persistent
cough. Children with neuromuscular disease
and chest wall
• deformities may not generate a deep enough
inspiratory volume or expiratory flow
necessary for
• effective clearance of secretions due to
defective "pump" mechanisms
• Children with reduced
• function of the abdominal wall musculature are particularly
at risk for ineffective cough. Children with
• tracheobronchomalacia
• ("floppy" airways), or with obstructive airways diseases,
often do not generate
• the high flow rates needed for effective clearance of
secretions. Individuals with laryngeal disorders,
• including those with tracheostomies, may not achieve
sufficient laryngeal closure to generate the
• increased intrathoracic pressures necessary for an effective
cough [
DIAGNOSTIC APPROACH
• Children with chronic cough should be
evaluated with a detailed history, physical
examination, chest
• radiograph, and (if the child is able)
spirometry
• This evaluation often provides sufficient
• information to categorize the cough as specific
(ie, caused by an underlying disease) or
nonspecific
• Specific cough — The causes of specific
chronic cough fall into the following general
categories
•
•
•
•
•
•
•
•
Asthma
Persistent bacterial bronchitis
Chronic suppurative lung disease and bronchiectasis
Airway abnormality (congenital, foreign body, or
neoplastic)
Aspiration
Chronic or less common infections
Interstitial lung disease
Extrapulmonary causes: cardiac abnormalities, ear
conditions
• The sequence of evaluation for these
disorders is informed by the age and
presenting features of the
• child. Identification of the presenting features
and cough characteristics is important
because many are
• easily recognizable and strongly suggestive of
a specific cause; this is less true in adults.
• Key symptoms and signs — Certain symptoms
and signs are highly predictive of a specific
cough.
• These signs or symptoms narrow the
diagnostic possibilities and call for further
specific testing or
• referral
• Chronic wet cough
• Wheezing or crepitations
• Onset after an episode of choking, or sudden
onset while eating or playing
• Abnormal chest radiography or spirometry
• Associated cardiac or neurologic abnormalities
• Failure to thrive, feeding difficulties, or
hemoptysis
• the symptom of a chronic wet cough, with or
without production of purulent sputum, is
• always pathologic and warrants investigations
for a persistent endobronchial infection
(persistent
• bacterial bronchitis or chronic suppurative
lung disease), retained airway foreign body, or
• immunodeficiency
• Nonspecific cough — If symptoms suggesting
specific cough are absent and the chest
radiograph and
• spirometry are normal
• the possibility of asthma should be considered
and pursued with an empiric
• trial of bronchodilators and other asthma
medications
• If there is no response, the child should be
considered to have a nonspecific cough, and
the medication
• should be stopped. The child and parents
should be reassured and the patient observed
over time for
• possible emergence of specific symptoms
• HISTORY — The diagnostic approach outlined
above requires a detailed history, which should
focus on
• the following key elements
• Age and circumstances at onset — Neonatal
onset of coughing should prompt consideration
of
• congenital malformations (eg,
tracheobronchomalacia), conditions predisposing
to aspiration
• tracheoesophageal fistula, laryngeal cleft, or a
neurological disorder), or chronic pulmonary
infections
• (eg, cystic fibrosis or ciliary dyskinesia
• A cough that begins suddenly while playing or eating,
especially in the toddler age range, should raise
• suspicion of an aspirated foreign body in the airway.
The physician should specifically ask about a
• history of choking, because this may have occurred
weeks before and the family may not voluntarily
• recall the information. Even if there is no history of
choking, a foreign body remains a diagnostic
• possibility
• An episode of severe pneumonia can damage
the airways, making the child vulnerable to
chronic cough.
• More rarely, severe pneumonia may cause
frank bronchiectasis. A psychogenic or
habitual cough also
• often begins after an upper respiratory
infection.
Nature of the cough
• .
• Chronic paroxysmal cough triggered by
exercise, cold air, sleep, or allergens is
• often seen in patients with asthma.
• Barking or brassy cough suggests a process in
the trachea or more
• proximal airways, such as airway malacia,
laryngotracheobronchitis, spasmodic croup, or
foreign body
• Staccato cough in young infants can be the
result of infection with Chlamydia
trachomatis. Cough that is
• honking ("Canadian Gooselike")
• and disappears at night suggests a
psychogenic or habitual cough.
• A chronic productiv coughe
• suggests a suppurative process, and may require
further
• investigation to exclude
• Bronchiectasis
• cystic fibrosis immune deficiency, or congenital
• malformation
• active infection
• Acute or subacute paroxysmal cough suggests
infection with pertussis or parapertussis; this
characteristic
• cough can be retriggered by subsequent upper
respiratory illness
Timing and triggers
• The timing and triggers associated with cough
can help guide diagnosis
• Cough
• due to asthma typically occurs following
exposure to characteristic asthma triggers (ie,
allergens, smoke,
• exercise, cold air, or viral infection), and
typically worsens during sleep
• Cough associated with nasal
• problems typically is worst during changes of
position,
• while cough due to bronchiectasis typically is
• worst and most productive early in the day.
• Cough that is triggered during swallowing is
suggestive of aspiration, either primary or due
totracheoesophageal fistula or laryngeal
abnormalities
• Cough in the first hour after meals, or which is
• worse while supine, may reflect
gastroesophageal reflux
Associated symptoms
• A history of dyspnea or hemoptysis should trigger
a search for an underlying
• lung disease
• Hemoptysis should also raise concerns of
bronchiectasis, cavitary lung disease (tuberculosis
• or bacterial abscesses), heart failure,
hemosiderosis, neoplasm, foreign bodies,
vascular lesions, endobronchial lesions,
catamenial bleeding, and clotting disorders
• Cough, with or without symptoms of
pancreatic insufficiency, recurrent
endobronchial infection, and/or
• failure to thrive should raise suspicion of cystic
fibrosis
• Cough associated with persistent fever, and/or
• failure to thrive, or weight loss should raise
suspicion of chronic infection and immune
deficiency
• Children with neurologic impairment or
seizures frequently have chronic aspiration
• Anaphylactic reactions to food can include
cough but are unlikely to present with
recurrent cough in the
• absence of other symptoms of anaphylaxis
Past medical history
• The past medical history should include an
account of the pregnancy, labor, and
• delivery, as well as the neonatal course
• Low birth weight and/or premature neonates
are at risk for
• developing atopic sensitization and asthma.
• The past medical history should also include
questions related to eczema and pulmonary
infections. In
• preschool children, a history of infantile
eczema is often associated with inhalant
allergy
Family history
• Family history of atopy or asthma increases
the risk in offspring, and suggests a
• diagnosis of either allergic rhinitis or asthma
in the child with chronic cough
• Family history of
• cystic fibrosis or primary ciliary dyskinesia should raise
suspicion for these disorders.
• A careful history
• should be obtained for current illness in family
members or close contacts; such individuals with
cough,
• weight loss, and night sweats should arouse suspicion
of tuberculosis. In some cases, the possibility of
• HIV transmission from mother to child should be
assessed
• Social history and environmental exposures
• Passive or active exposure to smoke from tobacco
• marijuana, cocaine or other chemical irritants can
result in chronic cough
• In addition, woodburning
• stoves cause indoor air
• pollution and can predispose children to
respiratory infection s Gas stoves are also
associated with
• respiratory symptoms in children
• It is important to elicit any history of contact with
pets or other animals, as cough may be induced
by
• allergy to the animals. Similarly, the location of
the child's home and travel history may be
relevant.
• Local epidemiology can inform the diagnostic
considerations, especially with respect to
endemic fungal
• and parasitic infections
• Histoplasmosis is commonly associated with
exposure to birds and
• bats, and echinococcosis with exposure to
dogs and sheep
• Medications — Response to prior therapy may
yield some diagnostic clues regarding the
cause of
• chronic cough. Previous response to
antihistamines suggests a component of
rhinitis and postnasal drip,
• while a response to inhaled bronchodilators
suggests possible asthma.
• Any medications taken by the patient should
be reviewed carefully; angiotensin converting
enzyme
• (ACE) inhibitors are a wellestablished
• cause of chronic cough. Patients previously
treated with cytotoxic
• drugs or thoracic radiation are at risk of
interstitial lung disease.
PHYSICAL EXAMINATION
• General examination — The physical
examination should pay close attention to the
following signs of
• chronic underlying disease
• General appearance of chronic illness
• Poor growth, thinness, or obesity
• Increased work of breathing, retractions, accessory
muscle use, chest wall hyperinflation or
• deformity, abnormal breath sounds (reduced intensity,
asymmetry, wheezing, stridor, crackles)
• Shiners, swollen nasal turbinates, nasal obstruction,
nasal polyps, allergic nasal crease, halitosis,
• tonsillar hypertrophy, pharyngeal cobblestoning, high
arched or cleft palate, hoarseness
•
•
•
•
Tympanic membrane scarring or frank otorrhea
Abnormal heart sounds, abnormal pulses
Hepatoand/
or splenomegaly, abdominal masses, bloating,
rectal prolapse
• Edema of the extremities, cyanosis and/or
clubbing of the digits
• Rashes and other skin lesions (eg, scars of healed
recurrent impetigo)
Chest examination
• Polyphonic wheezing (ie, many different
pitches) with cough is typical of asthma; the
wheezing occurs
• on expiration and sometimes also on
inspiration
• Many children with asthma are also atopic
and exhibit
• signs of rhinitis, conjunctivitis, and/or eczema
• Other causes of polyphonic wheezing include
viral
• bronchiolitis, obliterative bronchiolitis,
bronchiectasis (cystic fibrosis, allergic
bronchopulmonary
• aspergillosis, primary ciliary dyskinesia),
bronchopulmonary dysplasia, heart failure,
immunodeficiency, bronchomalacia, and
aspiration syndromes.
Monophonic wheezing
• Monophonic wheezing (a single, distinct noise
of one pitch and starting and stopping at one
discrete
• time) and cough should always raise suspicion
of large airway obstruction caused by foreign
body
• aspiration or malacia and/or stenosis of the
central airways
• lymphadenopathy, and mediastinal
• tumors can cause extrinsic large airway
obstruction. Tuberculosis should always be
considered in a child
• with a monophonic wheeze, particularly in
areas where the disease is prevalent
CHEST RADIOGRAPHY
• In addition to a thorough history and physical
examination, a chest
• radiograph should be obtained. If foreign body
aspiration is suspected because of the age, clinical
• presentation or history, frontal films should be
obtained during both inspiration and expiration, to
• evaluate for unilateral lung hyperinflation that would
suggest airway obstruction. Similar information can
• be obtained from the combination of frontal, right
lateral decubitus, and left lateral decubitus
• radiograph
PULMONARY FUNCTION TESTS
• Spirometry will show signs of obstruction in
diseases that
• obstruct the airways, and restriction in
interstitial or chest wall restrictive processes.
Suboptimal effort on
• the part of the child will also result in a
restrictive picture; thus, spirometry should be
conducted by a
• technician proficient in testing children
• If an obstructive pattern is seen on the expiratory
flowvolume
• loop, the reversibility of the obstruction
• can be assessed by measuring FEV1 before and
after inhalation of a bronchodilating agent. A
positive
• response to bronchodilators establishes the
presence of airway reactivity, and is suggestive of
asthma but
• does not rule out other disorders
BRONCHOSCOPY
• The primary indication for urgent
bronchoscopy in children with chronic cough
• is for suspected foreign body aspiration.
• Bronchoscopy is also valuable in the
evaluation of suspected airway malacia,
tracheoesophageal fistula,
• or stenosis
• Patients with presumed infectious etiologies in
whom a sputum sample is not obtained or
• yields negative results can be evaluated with
flexible bronchoscopy to perform
bronchoalveolar lavage
• for bacterial, fungal, and mycobacterial cultures.
Bronchial brushings can also be taken for patients
with
• suspected ciliary dyskinesia, although nasal
brushings also may be used
OTHER TESTS
• Esophageal pH monitoring —
• Whether gastroesophageal reflux disease
(GERD) is an important cause
• of isolated chronic cough in children is
controversial. Most authorities suggest that
this is not a common
• Sinus imaging
• Tuberculin testing
• Allergy testing
SUMMARY AND RECOMMENDATIONS
• There is no consensus definition of the time frame for
chronic cough in children. Chronic cough is
• often defined as a cough lasting more than four weeks,
because most acute respiratory infections in
• children resolve within this interval. Other schemes
define chronic cough as one that last more than
• eight weeks but also recognize that a relentlessly
progressive cough often warrants evaluation prior
• to eight weeks
• Chronic cough can be a symptom of congenital
anomalies, genetic disease, airway
obstruction,
• infection, airway inflammation without
infection (as in asthma), neoplasia, or
psychogenic
• processes
• The evaluation of a child with chronic cough
should include a detailed history, physical
• examination, chest radiograph, and
spirometry (when possible
• Symptoms and signs that are highly predictive of
a specific cough include chronic wet cough,
• wheezing or crepitations, onset after a choking
episode, abnormal chest radiography or
spirometry,
• associated cardiac or neurologic abnormalities,
and failure to thrive, feeding difficulties, or
• hemoptysis. These signs or symptoms narrow the
diagnostic possibilities and call for further
• specific testing or referral
• The symptom of a chronic wet cough in a
young child, usually indicates persistent
bacterial
• sinusitis or retained foreign body
‫شكرا •‬