Professional Guide to Signs and Symptoms
5th Edition

Stridor
A loud, harsh, musical respiratory sound, stridor results from an obstruction in the trachea or larynx. Usually heard during inspiration, this sign may also occur during expiration in severe upper airway obstruction. It may begin as low-pitched “croaking” and progress to high-pitched “crowing” as respirations become more vigorous.
Life-threatening upper airway obstruction can stem from foreign-body aspiration, increased secretions, intraluminal tumor, localized edema or muscle spasms, and external compression by a tumor or aneurysm.
HISTORY AND PHYSICAL EXAMINATION
When the patient’s condition permits, obtain a patient history from him or a family member. First, find out when the stridor began. Has he had it before? Does he have an upper respiratory tract infection? If so, how long has he had it?
Ask about a history of allergies, tumors, and respiratory and vascular disorders. Note recent exposure to smoke or noxious fumes or gases. Next, explore associated signs and symptoms. Does stridor occur with pain or a cough?
Then examine the patient’s mouth for excessive secretions, foreign matter, inflammation, and swelling. Assess his neck for swelling, masses, subcutaneous crepitation, and scars. Observe the patient’s chest for delayed, decreased, or asymmetrical chest expansion. Auscultate for wheezes, rhonchi, crackles, rubs, and other abnormal breath sounds. Percuss for dullness, tympany, or flatness. Finally, note any burns or signs of trauma, such as ecchymoses and lacerations.
MEDICAL CAUSES
  • Airway trauma. Local trauma to the upper airway commonly causes acute obstruction, resulting in the sudden onset of stridor. Accompanying this sign are dysphonia, dysphagia, hemoptysis, cyanosis, accessory muscle use, intercostal retractions, nasal flaring, tachypnea, progressive dyspnea, and shallow respirations. Palpation may reveal subcutaneous crepitation in the neck or upper chest.
  • Anaphylaxis. With a severe allergic reaction, upper airway edema and laryngospasm cause stridor and other signs and symptoms of respiratory distress: nasal flaring, wheezing, accessory muscle use, intercostal retractions, and dyspnea. The patient may also develop nasal congestion and profuse, watery rhinorrhea. Typically, these respiratory effects are preceded by a feeling of impending doom or fear, weakness, diaphoresis, sneezing, nasal pruritus, urticaria, erythema, and angioedema. Common associated findings include chest or throat tightness, dysphagia and, possibly, signs of shock, such as hypotension, tachycardia, and cool, clammy skin.
  • Anthrax, inhalation. Initial signs and symptoms are flulike and include fever, chills, weakness, cough, and chest pain. The disease generally occurs in two stages with a period of recovery after the initial symptoms. The second stage develops
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    abruptly with rapid deterioration marked by stridor, fever, dyspnea, and hypotension generally leading to death within 24 hours. Radiologic findings include mediastinitis and symmetric mediastinal widening.
  • Aspiration of a foreign body. Sudden stridor is characteristic in this life-threatening situation. Related findings include abrupt onset of dry, paroxysmal coughing, gagging or choking, hoarseness, tachycardia, wheezing, dyspnea, tachypnea, intercostal muscle retractions, diminished
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    breath sounds, cyanosis, and shallow respirations. The patient typically appears anxious and distressed.
  • Epiglottiditis. With this inflammatory condition, stridor is caused by an erythematous, edematous epiglottis that obstructs the upper airway. Stridor occurs along with fever, sore throat, and a croupy cough.
  • Hypocalcemia. With this disorder, laryngospasm can cause stridor. Other findings include paresthesia, carpopedal spasm, and positive Chvostek’s and Trousseau’s signs.
  • Inhalation injury. Within 48 hours after inhalation of smoke or noxious fumes, the patient may develop laryngeal edema and bronchospasms, resulting in stridor. Associated signs and symptoms include singed nasal hairs, orofacial burns, coughing, hoarseness, sooty sputum, crackles, rhonchi, wheezes, and other signs and symptoms of respiratory distress, such as dyspnea, accessory muscle use, intercostal retractions, and nasal flaring.
  • Laryngeal tumor. Stridor is a late sign and may be accompanied by dysphagia, dyspnea, enlarged cervical nodes, and pain that radiates to the ear. Typically, stridor is preceded by hoarseness, minor throat pain, and a mild, dry cough.
  • Laryngitis (acute). This disorder may cause severe laryngeal edema, resulting in stridor and dyspnea. Its chief sign, however, is mild to severe hoarseness, perhaps with transient voice loss. Other findings include sore throat, dysphagia, dry cough, malaise, and fever.
  • Mediastinal tumor. Commonly producing no symptoms at first, this type of tumor may eventually compress the trachea and bronchi, resulting in stridor. Its other effects include hoarseness, brassy cough, tracheal shift or tug, dilated neck veins, swelling of the face and neck, stertorous respirations, and suprasternal retractions on inspiration. The patient may also report dyspnea, dysphagia, and pain in the chest, shoulder, or arm.
  • Retrosternal thyroid. This anatomic abnormality causes stridor, dysphagia, cough, hoarseness, and tracheal deviation. It can also cause signs of thyrotoxicosis.
  • Thoracic aortic aneurysm. If this aneurysm compresses the trachea, it may cause stridor accompanied by dyspnea, wheezing, and a brassy cough. Other findings include hoarseness or complete voice loss, dysphagia, jugular vein distention, prominent chest veins, tracheal tug, paresthesia or neuralgia, and edema of the face, neck, and arms. The patient may also complain of substernal, lower back, abdominal, or shoulder pain.
OTHER CAUSES
  • Diagnostic tests. Bronchoscopy or laryngoscopy may precipitate laryngospasm and stridor.
  • Treatments. After prolonged intubation, the patient may exhibit laryngeal edema and stridor when the tube is removed. Aerosol therapy with epinephrine may reduce stridor. Reintubation may be necessary in some cases. Neck surgery, such as thyroidectomy, may cause laryngeal paralysis and stridor.
SPECIAL CONSIDERATIONS
Continue to monitor the patient’s vital signs closely. Prepare him for diagnostic tests, such as arterial blood gas analysis and chest X-rays.
PEDIATRIC POINTERS
Stridor is a major sign of airway obstruction in children. When you hear this sign, you must intervene quickly to prevent total airway obstruction. This emergency can happen more rapidly in a child because his airway is narrower than an adult’s.
Causes of stridor include foreign-body aspiration, croup syndrome, laryngeal diphtheria, pertussis, retropharyngeal abscess, and congenital abnormalities of the larynx.
Therapy for partial airway obstruction typically involves hot or cold steam in a mist tent or hood, parenteral fluids and electrolytes, and plenty of rest.