);
tumor (e.g., laryngeal papillomatosis, squamous cell carcinoma of larynx, trachea or esophagus);
ALL (T-cell ALL can present with mediastinal mass that compresses the trachea and causes inspiratory stridor)

Diagnosis
Stridor is mainly diagnosed on 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. Treatments
The first issue of clinical concern in the setting of stridor is whether or not tracheal intubation or tracheostomy is immediately necessary. A reduction in oxygen saturation is considered a late sign of airway obstruction, particularly in a child with healthy lungs and normal gas exchange. 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 on the bed for optimum conditions (e.g., 45 - 90 degrees). Use of nebulized racemic adrenaline 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 Codeine 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].)
Risk scores
The Global Registry of Acute Coronary Events score and the Thrombosis in Myocardial Infarction performed at time of admission may help stratify persons into low, intermediate and high risk groups for acute coronary syndrome. However these scores do not provide management guidelines for risk-stratified persons. The HEART score, stratifies persons into low-risk and high-risk groups, and recommends either discharge or admission based upon the score. Cumulative score:

0-3: 2.5% risk of adverse cardiac event. Patients can be discharged with follow-up. 4-6: 20.3% risk of adverse cardiac event. Patients should be admitted to the hospital for trending of troponin and provocative testing. ≥7: 72.7% risk of adverse cardiac event, suggesting early invasive measures with these patients and close coordination with inpatient cardiology.If acute coronary syndrome ("heart attack") is suspected, many people are admitted briefly for observation, sequential ECGs, and measurement of cardiac enzymes in the blood over time. On occasion, further tests on follow up may determine the cause.