It is presented Clinically by protracted barking cough and inspiratory stridor due to tracheal narrowing that is caused by mucosal oedema .
X-ray finding :
On Plain film
The diagnosis of acute laryngotracheobronchitis or Croup is usually made clinically
and no need for doing x-ray.you may do it just for excluding other causes of same presentation like:
- foreign body aspiration.........tracheal or oesophageal.
- angioneurotic edema
- epiglottitis and epiglottic-cysts
- congenital subglottic stenosis
However there are some typical radiographic findings :
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgL6XJVEqCC8lMKffauhbV1GbI2Hm_Ii7eenjV05HhgC5by1UlpYQumSwDo7iwkOwK0nozhGKFijr4R4GauPhCtdXYUld35O6M3uFwM3IhuDG9RZzBHr8FJdkLRSMafHNZ2WzfFEtybuoCh/s400/steeple+sign.jpg)
1- steeple sign (the image above): seen on AP radiographs of the neck or chest and neck demonstrates uniform narrowing of the subglottic airway
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlTos8jDBRmmoPwREiLmART4l0UiBtNGTvO6GsLLoGT8H_-mlEBZnk4nOfNylXqZkp-Pm4CnBNpVrMwRcMSkh_YBm4MmLlBxFn3dmXNbrHPqyyRwVu0kNzAH9LY4UkHYt4R2lckoBLhW_S/s200/24323_gallery.jpg)
But What is steeple sign ??
The steeple sign refers to superior tapering of the trachea on a frontal chest radiograph. It is remaniscient of a church steeple and is suggestive of croup.
2- distension of the hypopharynx is also seen due to the patient's attempt at decreasing airway resistance (the image below)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoNx2PSEoYGgk3QbSNBDfTF6M7nFPmbOwO4gYdq0DV3tSbMwKJtgYxIv3HyQfjGjCjAcwikJR5xzWNYpMR84cJv4mFl_9Gp0Gn4wJeAC58ibvj4EuKAuIckBQVsin-YVj6ztgZJH0slOK5/s400/Distended+hypopharynx.jpg)