Some Causes of Stridor

Cause

Suggestive Findings

Diagnostic Approach

Acute stridor

Allergic reaction (severe)

Sudden onset after exposure to an allergen

Usually accompanied by wheezing and sometimes orofacial edema; itching

No fever or sore throat; cough rare

Clinical evaluation

Angioedema

Often swelling of the face, lips, and/or tongue

Often in people at risk (eg, exposure to an allergen, use of an ACE inhibitor, personal or family history of hereditary angioedema)

Clinical evaluation

Sometimes indirect laryngoscopy

Bacterial tracheitis (rare)

Barking cough that is worse at night, high fever, and respiratory distress

Toxic appearance

Neck x-rays

Sometimes direct or indirect laryngoscopy with visualization and culture of purulent tracheal secretions

Croup

Age 6–36 months

Barking cough that is worse at night, URI symptoms, no difficulty swallowing, low-grade fever

Clinical evaluation

Sometimes anteroposterior neck x-ray showing subglottic narrowing (steeple sign)

Epiglottitis

Mainly adults, as well as children who missed HiB vaccination

Abrupt onset of high fever, sore throat, drooling, and often respiratory distress and marked anxiety

Toxic appearance

Lateral neck x-ray if the patient is stable

Examination in operating room if any signs of distress

Foreign body aspiration

Sudden onset in a toddler or young child who has no URI or constitutional symptoms

In adults, foreign body in upper airway typically apparent by history

Direct or indirect laryngoscopy or bronchoscopy

Inhalation injury (eg, due to cleaning agents, smoke inhalation)

Clinically apparent recent toxic inhalation

Clinical evaluation

Sometimes bronchoscopy

Laryngospasm

Recurrent episodes, associated with gastroesophageal reflux or recent drug use or occurring after endotracheal intubation

Direct or indirect laryngoscopy

Postextubation complications (eg, laryngeal edema, laryngospasm, arytenoid dislocation)

Recent intubation and respiratory distress

Clinical evaluation

Sometimes direct laryngoscopy

Retropharyngeal abscess

Mainly in children < 4 years

High fevers, severe throat pain, drooling, trouble swallowing, sometimes respiratory distress

Swelling that may or may not be visible in the pharynx

Lateral neck x-ray

Sometimes neck CT with contrast

Vocal cord dysfunction

Recurrent episodes of unexplained stridor often with hoarseness, throat tightness, a choking sensation, and/or cough

Direct laryngoscopy

Chronic stridor

Bilateral vocal cord paralysis or dysfunction

Recent trauma (eg, during birth, thyroid or other neck surgery, intubation, or deep airway suctioning)

Various neurodegenerative or neuromuscular disorders present

Good voice quality but limited intensity

Direct or indirect laryngoscopy

Congenital anomalies (numerous; laryngomalacia most common)

Usually in neonates or infants

Sometimes other congenital anomalies present

Sometimes trouble feeding or sleeping

Sometimes worse with URI

CT of neck and chest

Direct laryngoscopy

Spirometry with flow-volume loops

Congenital tracheomalacia

Chronic symptoms

Stridor or barky cough during coughing, crying, or feeding

May worsen in the supine position

CT or MRI

Spirometry with flow-volume loops

Sometimes bronchoscopy

External compression

History of head and neck cancer or obvious mass, night sweats, and weight loss

X-ray of neck and chest

CT of neck and chest

Direct or indirect laryngoscopy

Laryngeal tumors (eg, squamous cell carcinoma, hemangiomas, small cell carcinoma)

Inspiratory or biphasic stridor that may progressively worsen as tumor enlarges

Direct or indirect laryngoscopy

Spirometry with flow-volume loops

ACE = angiotensin-converting enzyme; HiB =Haemophilus influenzae type B; URI = upper respiratory infection.

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