stridor

Definition

Stridor is a term used to describe noisy breathing in general, and to refer specifically to a high-pitched crowing sound associated with croup, respiratory infection, and airway obstruction.

Description

Stridor occurs when erratic air currents attempt to force their way through breathing passages narrowed by:

• illness
• infection
• the presence of foreign objects
• throat abnormalities

Stridor can usually be heard from a distance but is sometimes audible only during deep breathing. Someone who has stridor may crow and wheeze when:

• inhaling
• exhaling
• inhaling and exhaling

Most common in young children, whose naturally small airways are easily obstructed, stridor can be a symptom of a life-threatening respiratory emergency.

— Maureen Haggerty

1. A harsh, shrill, grating, or creaking sound.
2. Pathology. A harsh, high-pitched sound in inhalation or exhalation.

[Latin strīdor, from strīdēre, to make harsh sounds, ultimately of imitative origin.]

A peculiar, harsh, vibrating sound produced during respiration.

Definition

Stridor is a term used to describe noisy breathing in general and to refer specifically to a high-pitched crowing sound associated with croup, respiratory infection, and airway obstruction.

Description

Stridor is a symptom, not a disease. It occurs when air is forced through breathing passages narrowed by the following:

• illness
• infection
• the presence of foreign objects
• congenital throat abnormalities

The sound is usually loud enough to be heard at a distance, although sometimes only during deep breathing and can occur on inhaling, exhaling, or both. It can be a symptom of a life-threatening respiratory emergency.

Demographics

Stridor is most common in children. Croup, an inflammation of the trachea (windpipe) and larynx (voice box), is the most common cause of stridor in children under age two. Young children also frequently develop acute stridor by inhaling a foreign object, often food such as hot dogs, popcorn, or hard candy. Stridor as a complication of bacterial infections is also common in children under age eight.

Congenital stridor is caused by abnormalities in the airways that cause them to partially collapse when the child breathes. It is present at birth and usually becomes obvious within the first six weeks of life.

Causes and Symptoms

During childhood, stridor is usually caused by infection of the cartilage flap (epiglottis) that covers the opening of the trachea to prevent material from entering the lungs and choking a person during swallowing. It can also be caused by foreign objects, such as a food or a coin, that a child has tried to swallow.

Laryngomalacia is the most common cause of congenital stridor, accounting for 75 percent of stridor in newborns. It seems to be caused by a collapse of tissue around the larynx and usually occurs in newborns that have no other health problems. It produces a rapid, low-pitched form of stridor that may be heard when a baby inhales. This condition develops soon after birth and usually does not require medical attention. It normally disappears as the child matures and almost always by the time the child is 18 months old.

Causes of stridor in adolescents and adults include the following:

• abscess or swelling of the upper airway
• paralysis or malfunction of the vocal cords
• tumor
• enlargement of the thyroid gland goiter
• swelling of the voice box (laryngeal edema)
• narrowing of the windpipe (tracheal stenosis)

When to Call the Doctor

Acute stridor, especially when caused by inhaling a foreign object, can be a life-threatening emergency. Emergency medical care should be sought immediately if the individual is showing any signs of difficulty breathing or is turning blue, is unconscious, or is thought to have inhaled a foreign object. In other cases, a doctor should be consulted on a non-emergency basis whenever stridor develops in a newborn or when stridor accompanies other signs of illness such as a fever.

Diagnosis

When stridor is present in a newborn, pediatricians and neonatologists also look for evidence of heart defects or neurological disorders that may cause paralysis of the vocal cords. Paralysis of the vocal cords can be life threatening. If examinations do not reveal other reasons for the baby's noisy breathing, the air passages are assumed to be the cause of the problem.

Listening to an older child or adult breathe usually enables pediatricians, family physicians, and pulmonary specialists to estimate where an airway obstruction is located. The timing and location of the noisy breathing, whether the sound is intermittent, occurs during eating, is better or worse when lying or standing, as well as the presence or absence of fever or other signs of infection and similar information help in determining the cause of stridor. It is sometimes difficult in children for doctors to differentiate between stridor and wheezing caused by asthma. However, a history of the breathing problem and careful examination can usually help them make the distinction.

The extent of the obstruction can be calculated by assessing several features in the patient:

• complexion
• chest movements
• breathing rate
• level of consciousness

X rays and direct examination of the voice box (larynx) and breathing passages using a laryngoscope or bronchoscope indicate the exact location of the obstruction or inflammation. Computed tomography (CT) scans and magnetic resonance imaging (MRI) scans also may be useful, especially if surgery is needed.

Flow-volume loops and pulse oximetry are diagnostic tools used to measure how much air flows through the breathing passages and how much oxygen is available. Pulmonary function tests may also be performed.

Treatment

Treatment of stridor depends on the underlying cause of the breathing difficulty. Life-threatening emergencies may require the insertion of a breathing tube through the mouth and nose (tracheal intubation) or the insertion of a breathing tube directly into the windpipe (tracheotomy) and surgery to remove a foreign object. Bacterial infections are treated with antibiotics. Congenital stridor is usually left untreated and resolves on its own.

Prognosis

The outcome of stridor depends on its cause. Death by suffocation may occur when a foreign object blocks the airway. Otherwise the outcome for most cases of stridor is good to excellent, depending on the cause.

Prevention

Adults must keep small, easily swallowed objects such as coins, beads, and hard, round candies away from young children so that they do not try to swallow them. Taking precautions against colds and bronchial infections (washing hands, not sharing dishes, avoiding sick people) can cut down on stridor from infective causes. Congenital stridor is not preventable.

Parental Concerns

Congenital stridor in a newborn can sound frightening to parents, but it is rarely a cause for concern or medical intervention.

See also Croup; Foreign objects; Vocal cord dysfunction.

Resources

Books

Wyka, Kenneth, et al. Foundations of Respiratory Care. Albany, NY: Delmar Learning, 2002.

Organizations

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007–1098. Web site: www.aap.org.

Web Sites

Kumar, Murda, and Deandra Clark. "Stridor." eMedicine Medical Library, January 3, 2003. Available online at www.emedicine.com/ped/topic2159.htm (accessed November 30, 2004).

Ren, Clement L. "Congenital Stridor." eMedicine Medical Library, February 28, 2003. Available online at www.emedicine.com/ped/topic2624.htm (accessed November 30, 2004).

[Article by: Tish Davidson, A.M. Maureen Haggerty]

A high-pitched noisy sound, or wheezing, occurring during inhalation or exhalation. It is a sign of respiratory obstruction. See also inspiratory stridor.

A shrill, harsh sound, especially the respiratory sound heard during inspiration in laryngeal obstruction.

• laryngeal s. — that due to laryngeal obstruction. See also roaring.

Stridor

ICD-10	R06.1
ICD-9	786.1

This article needs additional citations for verification. Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (June 2008)

Stridor is a high pitched sound resulting from turbulent air flow in the upper airway. It is primarily inspiratory.^[1] It can be indicative of serious airway obstruction from severe conditions such as epiglottitis, a foreign body lodged in the airway, or a laryngeal tumor. Stridor is indicative of a potential medical emergency and should always command attention. Wherever possible, attempts should be made to immediately establish the cause of the stridor (e.g., foreign body, vocal cord edema, tracheal compression by tumor, functional laryngeal dyskinesia, etc.) That examination requires visualization of the airway by a team of medical experts equipped to control the airway.

A reduction in oxygen saturation is considered a late sign of airways obstruction, particularly in a child with healthy lungs and normal gas exchange.

Contents 1 Treatments 2 Causes 3 Diagnosis 4 References 5 External links

Treatments

The first issue of clinical concern in the setting of stridor is whether or not tracheal intubation or tracheostomy is immediately necessary. Some patients will need immediate tracheal intubation. If intubation can be delayed for a period, a number of other potential options can be considered, depending on the severity of the situation and other clinical details. These include:

• Expectant management with full monitoring, oxygen by face mask, and positioning the head of the bed for optimum conditions (e.g., 45 - 90 degrees)
• Use of nebulized racemic adrenaline (0.5 to 0.75 ml of 2.25% racemic adrenaline added to 2.5 to 3 ml of normal saline) in cases where airway oedema may be the cause of the stridor. ( Nebulized Cocaine in a dose not exceeding 3 mg/kg may also be used, but not together with racemic adrenaline [because of the risk of ventricular arrhythmias].)
• Use of dexamethasone (Decadron) 4-8 mg IV q 8 - 12 h in cases where airway oedema may be the cause of the stridor; note that some time (in the range of hours) may be needed for dexamethasone to work fully.
• Use of inhaled Heliox (70% helium, 30% oxygen); the effect is almost instantaneous. Helium, being a less dense gas than nitrogen, reduces turbulent flow through the airways.

Causes

Stridor may occur as a result of:

• foreign bodies (e.g., aspirated peanut, aspirated food bolus),
• tumor (e.g., laryngeal papillomatosis, squamous cell carcinoma of larynx, trachea or esophagus),
• infections (e.g., epiglottitis, retropharyngeal abscess, croup),
• subglottic stenosis (e.g., following prolonged intubation or congenital),
• airway edema (e.g., following instrumentation of the airway intubation, drug side effect, allergic reaction),
• subglottic hemangioma (rare),
• vascular rings compressing the trachea
• Many thyroiditis such as Riedel's thyroiditis
• vocal cord palsy
• Tracheomalacia or Tracheobronchomalacia (e.g., collapsed trachea)
• Congenital anomalies of the airway are present in 87% of all cases of stridor in infants and children.^[2]
• Patients with enlarged oral and laryngeal anatomy have a close correlation to parents who tested positive for cannabis during pregnancy.

Diagnosis

Stridor is usually diagnosed the basis of history and physical examination, with a view to revealing the underlying problem or condition.

Chest and neck x-rays, bronchoscopy, CT-scans, and / or MRIs may reveal structural pathology.

Flexible fiberoptic bronchoscopy can also be very helpful, especially in assessing vocal cord function or in looking for signs of compression or infection.

References

1. ^ stridor at Dorland's Medical Dictionary
2. ^ Holinger LD (1980). "Etiology of stridor in the neonate, infant and child". Ann. Otol. Rhinol. Laryngol. 89 (5 Pt 1): 397–400. PMID 7436240. 

External links

Look up stridor in Wiktionary, the free dictionary.

• Stridor at eMedicine
• Congenital stridor at eMedicine
• MedlinePlus Encyclopedia Breathing sounds - abnormal (stridor)
• DDB 27190
• Stridor sounds at R.A.L.E. Lung Sounds

v • d • e Symptoms and signs: respiratory system (R04-R07, 786) Hemorrhage Epistaxis · Hemoptysis Abnormalities of breathing Respiratory sounds: Stridor · Wheeze · Rales · Rhonchi · Hamman's sign Dyspnea · Hyperventilation/Hypoventilation · Hyperpnea/Tachypnea/Bradypnea · Orthopnea/Platypnea Biot's respiration · Cheyne-Stokes respiration · Kussmaul breathing Hiccup · Mouth breathing/Snoring Other Asphyxia · Cough · Pleurisy · Sputum Respiratory arrest · Hypercapnia/Hypocapnia Pectoriloquy: Whispered pectoriloquy · Egophony · Bronchophony Pleural friction rub Fremitus Chest, general Chest pain respiratory system navs: anat nose,larynx/lower+thoracic cavity/physio/dev, noncongen/congen/tumors, symptoms+signs/eponymous, proc

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