CT is helpful for the detection and presurgical planning of lung perforation in dogs with spontaneous pneumothorax induced by grass awn migration: 22 cases

Abstract

Spontaneous pneumothorax induced by grass awns accounts for 5% of spontaneous pneumothorax and 22.5% of thoracic grass awn cases. Previous studies report limited interest of CT for spontaneous pneumothorax. Aims of this retrospective case series were to describe CT features of this condition and determine if CT features can efficiently localize the perforation site. Dogs that had a spontaneous pneumothorax, CT examination, thoracic surgery, and confirmed lung perforation due to a grass awn were included. Computed tomography studies were reviewed and compared to the surgical findings. In 19 of 22 (86.4%) dogs, the pneumothorax or its recurrence were ipsilateral to the perforation site. The perforation site was identified in 21 of 22 (95.5%) dogs and involved the caudal lobes in 20 of 22 (90.9%) cases. The lateralization and the involved lung lobe corresponded to surgical findings in 21 of 22(95.5%) dogs. The perforation site was characterized as a soft tissue attenuating focus lying against an extensive pleural thickening in 21 of 22(95.5%) dogs. An adjacent defect in the visceral pleura was seen in 13 of 22(59.1%) dogs. A grass awn was seen in 11 of 22(50%) dogs. The pneumothorax distribution and grass awn position consistently indicated the perforation side in this sample of dogs. The comparison with surgical findings suggests CT might be helpful for future presurgical planning of this etiology for pneumothorax.

Treatment and outcome of spontaneous pneumothorax secondary to suspected migrating vegetal foreign body in 37 dogs

“…Spikelets have a sharp point with backward pointing barbs preventing retrograde movement 24 . Then, they may migrate through the diaphragm, to the retroperitoneal space, and within the sublumbar muscles where they may create abscesses, discospondylitis and recurrent abdominal draining tracts 1,27,29–34 . Small remnants of the MVFB may also be left in their migrating path, causing signs of recurrence.…”

“…Lateralization of pneumothorax, affected lung lobe and location of MVFB are valuable clinical information to choose the correct treatment options and reduce the risk of recurrence of pneumothorax or occurrence of delayed draining tract. CT description of MVFB and their migration pathway were reported in another study of SP cases with confirmed MVFB upon surgery 27 . CT also correctly identified the lateralization of the perforated lung lobe in 100% of the cases and the actual perforated lung lobe in 95.5% of the cases, 27 which could allow lateral thoracotomies to be done.…”

“…Some reports also described migrating vegetal foreign bodies (MVFBs) as a cause of SP in dogs, especially plant awns, also named spikelets. [23][24][25][26][27][28] Ruptured bullae or blebs account for 33-68% of cases in dogs while lung lobe perforation secondary to plant migration is only reported in 5% of cases. 1,14 Active and hunting dogs such as Springer Spaniel, Golden Retriever and Brittany Spaniel have been reported to have an increased prevalence of SP due to grass awn foreign bodies.…”

Arthroscopic Removal of an Intra-Articular Migrating Plant Awn Associated with Septic Shoulder Joint Arthritis in a Dog

“…19,20 Computed tomography has been reported to be useful as a method for localizing lesions produced by the passage of migrating plant parts. 1,[21][22][23] However, vegetal foreign bodies are difficult to see, because they typically show attenuation similar to the surrounding soft tissues when they absorb body fluid. Secondary signs such as soft tissue inflammation, gas-containing elongated structures or slightly hyperattenuating tracts may be used to estimate the position of the foreign material within the soft tissues.…”

Pneumotórax espontâneo primário devido bolha pulmonar em cão

“…O seu diagnóstico é firmado com base no histórico, exame físico, toracocentese e exames de imagem, onde devem ser descartadas causas traumáticas e constatada a presença das vesículas e bolhas. As radiografias não apresentam uma boa acurácia para a detecção das vesículas e bolhas, já a tomografia costuma possibilitar a confirmação do diagnóstico, (AU et al, 2006;REETZ et al, 2013;TRÉHIOU et al, 2020).…”