Idiopathic granulomatous pneumonia in seven horses

Abstract

The history, clinical signs and pathological findings in seven adult horses with histologically confirmed idiopathic granulomatous disease, primarily of the lungs, are reviewed. They ranged in age from eight to 21 years, five were geldings and two were females, they belonged to five breeds and there were no seasonal or geographical associations. The primary clinical signs were chronic weight loss, exercise intolerance and respiratory distress which did not respond to conventional treatment. The most consistent physical findings were depression, anorexia, tachycardia, tachypnoea and adventitious lung sounds. Thoracic radiographs revealed a diffuse, structured, nodular, interstitial pulmonary pattern in each horse. Haematological measurements suggested a chronic inflammatory process and the cytology of transtracheal washes was consistent with a mild suppurative inflammation. Idiopathic granulomatous pneumonia was confirmed histologically in each of the horses, either postmortem or by a lung biopsy. The horses responded poorly to medical treatment and only one of three treated horses is still alive.

Technique and diagnostic value of percutaneous lung biopsy in 66 horses with diffuse pulmonary diseases using an automated biopsy device

“…Although the assessment of predisposing factors for diffuse pulmonary diseases was not part of this study, most of the affected horses were middle-aged. This is in agreement with previous published case series reporting pneumoconiosis and idiopathic granulomatous pneumonia in horses (Berry et al 1991;Pusterla et al 2003). While no breed predilection was found, geldings were overrepresented in this study when compared to the general population of horses referred to our hospital.…”

“…In this study we reviewed the technique and demonstrated the diagnostic value of lung biopsy performed on 66 equine cases with diffuse pulmonary manifestations using an automated biopsy device that has been used at our clinic since 1990. A percutaneous lung biopsy is a reliable and definitive test for diagnosing diffuse pulmonary diseases, such as interstitial pneumonia, neoplasia, RAO and diffuse infectious pneumonia (Shively et al 1973;Berry et al 1991;Naylor et al 1992;Savage et al 1998;Pusterla et al 2002Pusterla et al , 2003. However, this procedure is not commonly performed, probably due to the lack of data evaluating the safety and usefulness of the lung biopsy technique.…”

“…Further, for the biopsy specimen to be diagnostic, the disease concerned has to be one where a specific histological diagnosis is possible. Percutaneous lung biopsy has been successfully used in horses with diffuse pulmonary diseases such as fungal pneumonia, granulomatous pneumonia, pneumoconiosis and recurrent airway obstruction (Shively et al 1973;Berry et al 1991;Naylor et al 1992;Savage et al 1998;Pusterla et al 2002Pusterla et al , 2003. Complications observed with lung biopsy in horses include epistaxis, pulmonary haemorrhage, tachypnoea, respiratory distress, and less commonly, pneumothorax, haemothorax, collapse and death (Raphel and Gunson 1981;Naylor et al 1992;Savage et al 1998;Perkins et al 1999).…”

Granulomatous Pneumonia, Lymphadenopathy, and Hepatopathy in an Adult Horse with Repeated Injection of BCG

“…The findings in the present patient are essentially the same as those described in 7 horses and termed idiopathic granulomatous pneumonia 18 . Those authors point out that the pulmonary lesions seen in their equine patients are very similar to those described in human sarcoidosis, and in recent studies of human sarcoidosis mycobacterial DNA has indeed been detected in lung tissue and blood 19,20–22 .…”

“…The diagnosis of equine idiopathic granulomatous pneumonia depends on histological confirmation and exclusion of known etiological agents 18 . The histological findings in the horse in the present report confirmed granulomatous pneumonia, and it was only when smears from a large surface area of the lung were stained that mycobacteria were found.…”