Stridor

# Overview
Stridor is a high pitched sound resulting from turbulent gas flow in the upper airway. It may be inspiratory, expiratory or present on both inspiration and expiration. 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.

# Causes

## Common Causes

### Inspiratory stridor
- Allergy
- Anaphylaxis
- Angioneurotic edema
- Aortic aneurysm
- Aspiration
- Bacterial tracheitis
- Choanal atresia
- Diptheria
- Enlarged tonsils/adnoids
- Epiglottitis
- Facial fracture
- Foreign body aspiration
- Goiter
- Hemangioma
- Inhalation injury
- Laryngeal or tracheal abnormalities
- Laryngomalacia
- Larynx Carcinoma
- Laryngo-tracheal bronchitis
- Laryngeal fracture
- Maxillo-facial dysplasis
- Mandibular fracture
- Medastinal tumor
- Nasal polyp
- Nasal septum deviation
- Neck or facial swelling
- Nerve paresis
- Neck surgery
- Prolonged intubation
- Post-radiation
- Psychogenic
- Retropharyngeal abscess
- Scar stenosis
- Secretions
- Spasmodic croup
- Subglottic stenosis
- Tonsillitis
- Trauma
- Vocal cord cancer
- Vocal cord paralysis

### Expiratory stridor
- Bronchitis
- Bronchial asthma
- Cardiac Failure
- Compression of the bronchii due to lymph node enlargement
- COPD
- Foreign body aspiration
- Pleura process
- Pneumonia
- Pneumothorax
- Trachiobronchitis
- Tumor infiltration

## Causes by Organ System

## Causes in Alphabetical Order
- Aberrant subclavian artery abnormality
- Acenaphthene
- Acetic acid
- Acrylic acid
- Acute diphtheria
- Acute epiglottitis
- Acute laryngitis
- Acute laryngotracheobronchitis
- Acute lymphoblastic leukemia
- Acute pseudo-membranous croup
- Adenoid cystic carcinoma
- Adenovirus
- Airway edema
- Airway obstruction
- Airway trauma
- Alanycarb
- Aldicarb
- Aldoxycarb
- Allergic reaction
- Allyxycarb
- Amidithion
- Aminocarb
- Amiton
- Ammonia
- Anaphylaxis
- Angioedema
- Angioneurotic edema
- Ankylosis of crico-arytenoid joint in rheumatoid arthritis
- Aortic aneurysm
- Arizona bark scorpion poisoning
- Arnold-chiari malformation type 2
- Aromatic amino acid decarboxylase deficiency
- Aspiration
- Asthma-like conditions
- Athyl-gusathion
- Azinfosethyl
- Azinphos
- Azinphosmetile
- Azothoate
- Bacterial tracheitis
- Barium
- Bendiocarb
- Benfuracarb
- Benign tumor of larynx
- Benign tumor of trachea
- Benoxafos
- Bromophos
- Bronchial carcinoma
- Bronchial asthma
- Bronchiolitis obliterans
- Bronchitis
- Bronchogenic carcinoma
- Bronchogenic cyst
- Bronchomalacia
- Bronchopathia osteoplastica
- Bronchopulmonary dysplasia
- Bronchoscopy
- Browntail moth caterpillar poisoning
- Bufencarb
- Bulbar palsy
- Burn injuries
- Butacarb
- Butocarboxim
- Byssinosis
- C1 esterase inhibitor (c1-inh) deficiency
- Cadusafos
- Calcium hypochlorite
- Captafol
- Carbanolate
- Carbaryl
- Carbofuran
- Carbophenothion
- Carbosulfan
- Carcinoid
- Carcinoma of larynx
- Carcinoma of the esophagus
- Carcinoma of the thryoid
- Carcinoma of trachea
- Cardiac failure
- Caustic ingestion
- Cellulitis of neck
- Chlorfenvinphos
- Chlorine dioxide
- Chlorine
- Chloropyrifos
- Choanal atresia
- Chronic lower respiratory diseases
- Chronic obstructive pulmonary disease
- Chronic tuberculous laryngitis
- Classical hodgkin disease
- Cloethocarb
- Common cold
- Compression of bronchii
- Congenital bronchial anomalies
- Congenital laryngeal anomalies
- Congenital laryngeal paralysis in newborns
- Congenital laryngeal stridor
- Congenital subglottic narrowing
- Congenital tracheal anomalies
- Craniofacial anomaly
- Cricoarytenoid ankylosis
- Croup
- Cyanthoate
- Decarbofuran
- Demeton
- Deviated septum
- Dialifos
- Diazinon
- Dichlorvos
- Dicresyl
- Dicrotophos
- Diffuse leiomyomatosis with alport syndrome
- Dimetan
- Dimethoate
- Dimetilan
- Dioxacarb
- Dioxathion
- Diptheria
- Dislocated cricothyroid or cricoarytenoid articulation
- Disulfoton
- Double aortic arch
- Down's syndrome
- Drug allergies
- Edema of the glottis
- Empc
- Endothion
- Enlarged adenoids
- Enlarged tonsils
- Epidermoid carcinoma
- Epiglottitis
- Estrogen dependent hereditary angioedema
- Ethiofencarb
- Ethion
- Ethoate-methyl
- Ethoprophos
- Ethylenediamine
- Ethyl-guthion
- Etrimfos
- Facial fracture
- Fenchlorphos
- Fenethacarb
- Fenitrothion
- Fenobucarb
- Fensulfothion
- Fenthion
- Fonophos
- Food additive allergy
- Food allergies
- Food allergy related asthma
- Foreign body aspiration
- Formaldehyde
- Formothion
- Fresh mangrove caterpillar poisoning
- Furathiocarb
- Gastroesophageal reflux disease
- Gay-feinmesser-cohen syndrome
- Gerhardt syndrome
- Glutaraldehyde
- Goiter
- Granulomatosis with polyangiitis
- Grapeleaf skeletonizer caterpillar poisoning
- Guthion (ethyl)
- Hashimoto's disease
- Hemangioma
- Heptenophos
- Hexamethylene diisocyanate
- Hodgkin's disease
- Hodgkin's lymphoma
- Hydrocephalus
- Hyquincarb
- Idiopathic subglottic tracheal stenosis
- Infectious conditions
- Infectious mononucleosis
- Inhalant abuse
- Inhalation injury
- Inhaled foreign body
- Injury to larynx
- Injury to trachea
- Insect allergy
- Internal laryngeal trauma
- Intrathoracic goitre
- Iodofenphos
- Isoprocarb
- Laryngeal carcinoma
- Laryngeal cleft
- Laryngeal cyst
- Laryngeal fracture
- Laryngeal inflammation
- Laryngeal nerve palsy
- Laryngeal or tracheal abnormalities
- Laryngeal papilloma
- Laryngeal papillomatosis
- Laryngeal stenosis
- Laryngeal web
- Laryngitis
- Laryngocele
- Laryngomalacia
- Laryngoscopy
- Laryngospasm
- Laryngotracheitis
- Laryngotracheobronchitis
- Larynx atresia
- Larynx carcinoma
- Larynx condition
- Latex catheters induced allergies
- Lepidopterism
- Lingual cyst
- Linguinal angioedema
- Local anaesthetic allergy
- Ludwig's angina
- Lung cancer
- Lymphocyte depletion hodgkin's disease
- Macroglossia
- Malathion
- Malignant disease of lower cervical lymph nodes
- Malignant germ cell tumor
- Mandibular fracture
- Mastocytosis
- Maxillo-facial dysplasis
- Mecarbam
- Mediastinal hodgkin's disease
- Mediastinal tumors
- Mesothelioma
- Metabolic disorders
- Metapneumovirus
- Methacrifos
- Methamidophos
- Methidathion
- Methiocarb
- Methomyl
- Metiltriazotion
- Metolcarb
- Mevinphos
- Mexacarbate
- Mixed cellularity hodgkin's disease
- Mixed type non small cell carcinoma
- Monocrotophos
- Morphine allergy
- Nasal polyp
- Nasal septum deviation
- Nasopharyngeal mass
- Neck or facial swelling
- Nerve paresis
- Neural tube defect
- Nickel
- Nitrilacarb
- Nodular goiter
- Nodular sclerosing hodgkin's lymphoma
- Non-small cell lung cancer
- Novacaine drug allergy
- Occupational asthma
- Omethoate
- Osmium
- Oxamyl
- Oxydeprofos
- Oxydisulfoton
- Palladium
- Paragonimiases
- Parathion methyl
- Partial atrioventricular canal
- Peanut allergy
- Penicillin allergy
- Pepper spray
- Peritonsillar abscess
- Phenkapton
- Phorate
- Phosalone
- Phosdrin
- Phosgene oxime
- Phosmet
- Phosphamidon
- Phoxim
- Piriform aperture stenosis
- Pirimicarb
- Pirimiphos-methyl
- Platinum
- Pleura process
- Pneumonia
- Pneumothorax
- Polychondritis
- Post-radiation
- Post-traumatic stenosis of larynx
- Post-traumatic stenosis of the trachea
- Potassium permanganate
- Primary ciliary dyskinesia
- Primiphos methyl
- Profenofos
- Prolonged intubation
- Promacyl
- Promecarb
- Propoxur
- Prothidathion
- Prothoate
- Pseudobulbar palsy
- Psychogenic
- Pulmonary cystic lymphangiectasis
- Pulmonary lymphangiectasia
- Pulmonary pseudolymphoma
- Pyrimitate
- Quinalphos
- Quintiofos
- Recurrent respiratory papillomatosis
- Respiratory tract cancer
- Retropharyngeal abscess
- Retrosternal thyroid
- Rheumatoid disease
- Rhinosinusitis
- Riedel's thyroiditis
- Sarcoidosis
- Satin moth caterpillar poisoning
- Scar stenosis
- Seafood allergy
- Secretions
- Shy-drager syndrome
- Silver
- Small cell lung cancer
- Small jaw
- Smokers throat
- Smoking cessation
- Sophamide
- Spasmodic croup
- Spice allergy
- Sputum
- Squamous cell carcinoma
- Stinging bark caterpillar poisoning
- Stinging nettle caterpillar poisoning
- Stinging rose caterpillar poisoning
- Strictures of main bronchi in sarcoidosis
- Subglottic hemangioma
- Subglottic stenosis
- Sulfa antibiotics allergy
- Sulfotep
- Sulfur trioxide
- Supraglottic webs
- Syphilis
- Syphilitic laryngitis with stenosis
- Tacrine toxicity
- Tazimcarb
- Terbufos
- Tetraethyl pyrophosphate
- Thiocarboxime
- Thiodicarb
- Thiofanox
- Thiometon
- Thoracic aortic aneurysm
- Thymic epithelial tumor
- Thyroglossic cyst
- Thyroidectomy
- Tolclofos methyl
- Tonsillitis
- Tracheal cancer
- Tracheal intubation
- Tracheal stenosis
- Tracheobronchomalacia
- Tracheobronchopathia osteoplastica
- Tracheolaryngobronchitis
- Tracheomalacia
- Tracheopathia osteoplastica
- Tracheostomy
- Trachiobronchitis
- Transfusion reaction
- Trauma
- Triazophos
- Triazotion
- Trifenfos
- Trimellitic anhydride
- Trimethacarb
- Tuberculin
- Tuberculosis
- Tuberculous nodes in mediastinum
- Tuberculous strictures of main bronchi
- Tumor infiltration
- Upper airway burns
- Uranium
- Vamidothion
- Vanadium toxicity
- Vanadium
- Vascular rings
- Vasculitis
- Vocal cord cancer
- Vocal cord paralysis
- Weeping fig poisoning
- Wegener's granulomatosis
- Xmc
- Xylylcarb

# 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 epinephrine (0.5 to 0.75 ml of 2.25% racemic epinephrine added to 2.5 to 3 ml of normal saline) in cases where airway edema 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 epinephrine .)
- Use of dexamethasone (Decadron) 4-8 mg IV q 8 - 12 h in cases where airway edema may be the cause of the stridor; note that some time (in the range of hours) may be need for dexamethasone to work fully.
- Use of inhaled Heliox (70% helium, 30% oxygen); the effect is almost instantaneous

# 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, CT-scans, and / or MRIs may reveal structural pathology.
Flexible fiberoptic bronchoscopy can also be very helpful, especially in assessing vocal cord function of in looking for signs of compression or infection.