Case reveal » Veterinary Diagnostic Imaging » College of Veterinary Medicine

Radiographic findings:

In the cranial aspect of the trachea, there is a focal region of moderate, heterogeneous, ill-defined soft tissue thickening (yellow arrowheads), associated with focal moderate narrowing of the tracheal lumen (green arrowheads).

Focal, moderate to severe cranial cervical tracheal narrowing, likely due to cicatrix formation. The possibility of mucosal granuloma formation is not excluded.

Endoscopic evaluation revealed bands of scar tissue within the pharynx, extending to and involving the openings of the guttural pouches. The arytenoid cartilages were moderately thickened, resulting in a narrowing of the laryngeal opening (rima glottidis). Additionally, the tracheal walls appeared diffusely thickened and inflamed, with a markedly reduced tracheal diameter in the most cranial cervical region. The findings were consistent with nasopharyngeal cicatrix syndrome.

The single radiographic view was acquired to see the extent of the tracheal narrowing.

Nasopharyngeal cicatrix syndrome (NCS) is a chronic, progressive upper airway disorder primarily affecting horses in central and southeastern Texas. It is characterized by inflammation and subsequent scarring of the nasopharynx, larynx, and occasionally the proximal trachea. The condition has been recognized since the 1970s and is one of the most common indications for permanent tracheostomy in horses (Norman et al., 2012; Chesen & Rakestraw, 2008).

Diagnosis of NCS is primarily based on clinical signs and endoscopic evaluation. Common clinical signs include respiratory noise, nasal discharge, exercise intolerance, and respiratory distress. These signs are associated with specific endoscopic findings such as circumferential pharyngeal scarring, arytenoid chondropathy, epiglottic deformation, and thickening of the vocal cords (Norman et al., 2012). Acute cases may present with erythema, swelling, or diphtheritic membranes, while chronic cases exhibit weblike fibrosis and airway narrowing.
Radiographs are not typically acquired in the diagnostic workup of NCS. The literature emphasizes that endoscopy is the gold standard for diagnosis, as radiographic imaging does not provide sufficient detail of the soft tissue structures involved in the upper airway (Norman et al., 2013). Moreover, radiographs are not routinely mentioned in the diagnostic protocols of the large retrospective studies on NCS, underscoring their limited utility.
Risk factors for NCS include increasing age, exclusive or predominant pasture turnout, and evaluation during warmer months. Horses housed exclusively in stalls were significantly less likely to develop NCS, suggesting an environmental etiology, possibly related to inhaled irritants or allergens present in pasture environments (Norman et al., 2013).

Permanent tracheostomy is often the treatment of choice for horses with severe airway obstruction due to NCS, particularly when circumferential scarring or laryngeal involvement compromises airflow. In a retrospective study of 82 horses undergoing permanent tracheostomy, 72% had NCS as a primary indication (Chesen & Rakestraw, 2008). The procedure was performed in standing horses, minimizing anesthetic risk, and was associated with a high rate of owner satisfaction (98%) and return to previous use (89%).
Short-term complications included incisional swelling, transient fever, and partial dehiscence, while long-term issues were minimal and primarily involved mild coughing or respiratory noise. The 1-year survival rate was 97%, and the estimated failure-free survival time was 9.7 years. Importantly, none of the mares in the study experienced complications during parturition, despite concerns about impaired abdominal press due to the open stoma.
Permanent tracheostomy is not recommended as a first-line treatment for all upper airway conditions but is considered the most effective intervention for advanced NCS cases unresponsive to medical or surgical management. Attempts at laser or bistoury resection of cicatricial tissue have shown only temporary benefits (Norman et al., 2012).

Norman, Tracy E., et al. “Association of clinical signs with endoscopic findings in horses with nasopharyngeal cicatrix syndrome: 118 cases (2003–2008).” Journal of the American Veterinary Medical Association 240.6 (2012): 734-739.
Norman, Tracy E., et al. “Risk factors associated with nasopharyngeal cicatrix syndrome in horses.” Journal of the American Veterinary Medical Association 242.9 (2013): 1267-1270.
Chesen, A. Berkley, and Peter C. Rakestraw. “Indications for and short-and long-term outcome of permanent tracheostomy performed in standing horses: 82 cases (1995–2005).” Journal of the American Veterinary Medical Association 232.9 (2008): 1352-1356.