Introduction

Vegetal foreign bodies (vFBs) are less frequently reported in cats compared with dogs, and no predisposed location has been described in this species.^1–3

The main offending types of vFB are the seeds of Avena spp. (wild oat) and Hordeum spp., usually called “foxtail.”^1,2–7 The sharp anterior end of the awn can penetrate the skin or enter via natural orifices, and the backward-pointing barbs prevent a retrograde migration.^1,2 Their incidence is higher in spring and summer.^2,6 vFBs can cause local infection and inflammation and may migrate into deeper tissues, resulting in swelling, abscess and draining fistulas, or sepsis.^6,8,9 vFBs may also be inhaled, causing intrathoracic abscesses, or they may migrate through the diaphragmatic crura to the iliopsoas muscle.^{2–4,6–8,10,11} The diagnosis and treatment of migrating vFBs can represent a challenge: skin wounds or inhalation may be unnoticed by owners, and the patient can show persistent or intermittent unspecific clinical signs.^6,12 Without removing the vFB, the response to antimicrobials is usually partial and transient.^2,9,12 To the authors’ knowledge, deep vFBs in cats are rarely described in the literature.^2,3,7 The aim of this retrospective study, covering a period of 6 yr (2010–2016), was to investigate if there is a tendency for vFBs to be deeply localized in specific locations, and to report clinical signs, diagnosis and surgical treatments in cats.

Material and Methods

Electronic medical records of cats presented to the Veterinary University Hospital of the Department of Veterinary Medical Sciences (University of Bologna, Italy) and to the Struttura Didattica Speciale (University of Turin, Italy) from 2010 to 2016 regarding deeply located vFBs in cats were retrospectively reviewed. Cats were included if surgery was performed. Cases of cutaneous or subcutaneous vFB localizations were excluded.

For the cases included, the living habit, the season in which the problem presented, clinical signs, physical examination, diagnostic imaging, surgical approach, outcome, and follow-up were reviewed.

Results

Ten cats were included, and 11 surgeries were performed. All the cats were domestic shorthairs. Seven cats were castrated males, and 3 were spayed females. The median age was 3 yr, 11 mo (mean 4 yr, 8 mo; range 1 yr, 11 mo to 10 yr, 7 mo). Cats were living either both outdoors and indoors (6/10) or exclusively outdoors (4/10). Seasonality varied, but cats were mainly presented in summer (7/10) followed by fall (3/10).

The main clinical signs were lethargy (6/10) and decreased appetite (5/10). Other specific signs recorded were related to the anatomical location of the vFB such as dyspnea, flank swelling, dysuria, and refusal to jump (Table 1). Bloodwork revealed moderate anemia in one case (case 6; hematocrit 18.1%, reference range 24–45%) and mild-to-moderate neutrophilic leukocytosis in four cats (cases 2, 6, 7, and 10; mean 41,477/mm³; range 20,440–55,920/mm³; reference range 5,000–19,000/mm³). No relevant biochemical anomalies were detected. Activated partial thromboplastin time (aPTT) was abnormal in three cats (cases 1, 2, and 10; mean 47.4 s; range 20.7–96.9 s; reference range 9–20 s), and cats 1 and 10 received fresh frozen plasma during fluid resuscitation prior to surgery. The vFBs were most frequently found in the thoracic cavity (4/10), followed by the retroperitoneal space (2/10), urethra (2/10), the peritoneal cavity (1/10), and the ventral neck in a paratracheal position (1/10; Table 1). Cultures were performed from the exudate, and they showed a higher presence of Pasteurella (3/10), followed by anaerobic polymicrobism (2/10) and Actinomyces spp. (2/10; Table 1).

TABLE 1 Characteristics, Localization of vFB, Clinical Signs, Surgery, Bacteria Isolated, Antimicrobial Therapy, and Outcome

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Thoracic vFB

Four cats with vFB in the thoracic cavity (Table 1) were presented for dyspnea. In addition to unilateral pleural effusion, thoracic radiographs (left side in cases 1 and 2; right in cases 3 and 4) identified mild pneumothorax in cat 1 and increased radiopacity of left lung lobes in cat 2, but no focal lesions were observed. Ultrasound examination (UE) of the thorax confirmed the presence of pleural effusion and highlighted the presence of atelectasis of the ventral portion of lung lobes of the affected side. Pleural effusion was sampled for cytology and culture. During one cat’s (case 2) first examination, the UE identified the presence of a lanceolate binary structure characterized by two hyperechogenic walls separated by a central hypoechogenic band compatible with a vFB. The remaining three cats were initially treated by thoracostomy tubes and broad-spectrum antibiotics, and their clinical conditions improved in the following days. In addition to clinical improvement, persistent purulent pleural effusion was observed, and multiple UEs (median 3 UE, range 3–5 UE, repeated once daily or every 2 days within 3–14 days, median 6 days) were performed to detect the vFB. The vFBs had an average length of 15.2 mm (minimum–maximum 12–21 mm) on UE (Figure 1). In cases 2 and 4, the vFBs were found inside an abscess capsule.

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In cases 1, 3, and 4, the culture was positive, and the bacteria isolated were sensitive to the broad-spectrum antibiotics empirically administered, such as ampicillin and sulbactam (20 mg/kg q 8 hr). In cat 1, marbofloxacin (3 mg/kg q 24 hr) was also introduced based on sensitivity, as a result of persistent hyperthermia (Table 1). For cat 2, the culture was negative; the cat had received antimicrobial therapy prior to admission and continued using the same antibiotics for 10 days (Table 1). For cat 3, the surgical approach consisted of a video-assisted thoracoscopy (VATS) with the cat in dorsal recumbency. For cat 1, VATS was attempted, but conversion to intercostal thoracotomy was necessary as a result of numerous adhesions between the visceral and parietal pleura. For cats 2 and 4, intercostal thoracotomy was used to reach the mediastinum. In all patients, the vFBs were removed, a copious pleural space lavage was performed using warm sterile 0.9% NaCl, and a thoracostomy tube was reapplied. The thoracostomy tube was removed 1–6 (median 4) days after surgery. Cats were monitored at least 24 hr after removal of the chest tube and were discharged. Cats were hospitalized for a total of 6–17 days (median 11 days) and for 3–6 days after the surgery (median 5 days). Clinical check-ups were performed after 1 and 4 wk postoperatively. Respiratory pattern and lung auscultations were always within normal limits. Chest radiographs were performed at 1 mo check-up, and no abnormalities were observed. One year after surgery, information about clinical conditions was obtained by the referring veterinarians or by phone calls with the owners. All the cats were in good clinical condition with no respiratory clinical signs.

vFBs in the Retroperitoneal Space

Cats 5 and 6 (Table 1) showed lethargy, flank pain on palpation, and swelling, with fistulous tracts in case 5. A UE of the sublumbar region was performed; in both cases, a structure compatible with vFB was detected (length 8.2 and 13 mm) in the right retroperitoneal space, surrounded by fluid. An abscess caudal to the kidney was suspected in all cases (Figure 2A). The effusion around the vFB was aspirated before any treatment, and on cytological examination, it was consistent with purulent exudate. After sampling, broad-spectrum antibiotic treatment was instituted. Culture was positive in both cases, and the antibiotic treatment was continued based on sensitivity (Table 1). Surgical treatment consisted of an inspection of the retroperitoneal space through a ventral midline celiotomy to reach the vFBs. Abscesses reported on preoperative UE were not found, and several attempts to locate and remove the vFB were performed, but in all the cases, an intraoperative UE was needed to find the vFB. The ultrasound probe was covered with a sterile sheath, and the vFB was identified through an intra-abdominal approach in cases 5 (at the first surgery) and 6. In case 5 a second surgery was performed as a result of recurrence of right flank fistula 3 mo apart. During the second surgery for cat 5, the intraoperative, intra-abdominal ultrasound did not aid in vFB localization because of difficulties visualizing the vFB and triangulating instruments within the ultrasound field. A transcutaneous ultrasonographic approach from the flank was chosen as it appeared more similar to preoperative visualization and easily identified the vFB (Figure 2B). Furthermore, this approach facilitated instruments triangulation. Under ultrasound guidance, the peritoneum was incised, and the vFB was successfully extracted using mosquito forceps. In both surgeries in case 5, the vFB was inside an abscess; in case 6, it was in the perinephric fat, caudal to the kidney. After extracting the vFB, intraoperative UE was repeated in all cases to check for additional vFBs. The abscess cavity was widely irrigated with warm sterile saline solution (NaCl 0.9%); the peritoneum was closed with an absorbable monofilament suture (Biosyn 3-0 USP^a). In cases 5 and 6, a percutaneous active drain (Redon drain, 8-French^b) directed toward the retroperitoneal space was applied at the end of procedure and removed 3 and 5 days after surgery, respectively. Cat 5 was checked 14 and 45 days after surgery; he appeared healthy, and UE failed to find further vFB. Ninety days after surgery, the cat exhibited a recurrence of clinical signs (Table 1). At UE, a second vFB was detected, and a second surgery was performed (case 5). No further clinical signs developed for at least 3 yr after the second surgery. In cat 6, no signs of recurrence occurred during the following 12 mo.

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Urethral and Perineal Localization

Cat 7 was presented for dysuria, and a urethral obstruction was suspected; radiographic and ultrasonographic exams could not identify the cause. A urinary tract infection was excluded by urine culture, and a penile urethral obstruction was diagnosed because catheterization was not feasible. The cat underwent orchiectomy and perineal urethrostomy, and during the surgical procedure, a vFB was detected in the penile urethra (Figure 3). The urinary clinical signs resolved after surgery. Cat 8 was presented for dysuria and a large perineal wound characterized by extensive skin necrosis and fistulas. A urethral rupture and urine infiltration of the perineum were suspected. A retrograde, positive-contrast urethrocystography confirmed the suspicion of intrapelvic urethral rupture. The cat underwent a perineal surgical exploration in an attempt to catheterize the urethra and debride the necrotic tissue. Urethral catheterization was not possible, but two vFBs were found close to the pelvic urethra and removed. A caudal celiotomy was performed, and a 1.3 mm catheter was inserted through a cystotomy into the urethra and used as a guide to catheterize the urethra with a 3.5-French urinary catheter^c. After surgery, the urinary catheter was left in place to allow urethral healing, and the perineal wound was topically managed with daily bandage change. After 12 days, the urinary catheter was removed, and a retrograde, positive-contrast urethrocystography showed a complete urethral healing. The cat was discharged 48 hr after urinary catheter removal as urination appeared normal. No clinical signs were reported within the 12 postoperative mo.

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Other Localizations

In case 9, the vFB was found close to the cervical trachea (Table 1). The clinical signs were dysphagia, aphonia, and swelling of the neck. The referring veterinarian had performed a surgical exploration of the ventral cervical region 3 days before presentation and found purulent exudate. After hospitalization, a UE detected a linear and hyperechoic structure (length of 1.5 cm) surrounded by a small amount of dense fluid on the right side of the trachea. In order to rule out a perforating FB or lesion, an endoscopic examination of the esophagus and the upper airways was performed, and no abnormalities were observed. On surgical exploration, reactive fibrous tissue was present, and the fluid was sampled for culture and sensitivity. Intraoperative UE facilitated the location and removal of the vFB (Figure 4). A passive drain (Penrose 6 mm) was placed before reconstruction. The drain was removed 3 days after surgery, and the cat was sent home. No recurrence was recorded during the following 12 mo. Cat 10 was presented with stupor and hypotension. An abdominal ultrasound showed peritoneal effusion and free air. The effusion was sampled, and cytology confirmed the suspicion of septic peritonitis. After initial fluid resuscitation, an emergency exploratory celiotomy was performed. During surgical exploration, effusion and several peritoneal adhesions were observed. After omental adhesion resolution, a jejunal loop was dark and presented a 3 mm perforation on the mesenteric side. A vFB was found in close proximity to the perforated loop surrounded by omental adhesions. Because of the condition of the bowel, an enterectomy (7 cm length) and subsequent end-to-end anastomosis were performed. The abdomen was irrigated with a large amount of sterile warm saline solution (NaCl 0.9%) and routinely closed. The clinical condition remained poor, and 3 days postoperatively, UE revealed the persistence of peritoneal effusion, septic on cytology. A dehisce was suspected, and a second surgery was advised, but it was refused by the owner, electing for euthanasia because of the economic concern. Postmortem examination was declined.

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Discussion

This retrospective study has identified some possible common locations for vFB in cats. The thoracic cavity, retroperitoneal space, and perineal region were particularly represented. The lower frequency of migrating vFBs in cats compared with dogs could be linked to feline behavior such as extensive self-cleaning, closed-mouth breathing, and a lower propensity to swallow FBs.^2,3,7 Nevertheless, outdoor cats may be exposed to vFBs.^2,3,7 In agreement with the literature, our study found that young adult domestic shorthair males are overrepresented, with the highest incidence in summer.^{2,3,6,7,13–15} Deep vFBs must be suspected when cats are presented with nonspecific clinical signs such as decreased appetite, lethargy, reluctance to move, months-long recurring fistulous tracts, or pyothorax, as reported in literature.^5–9,12,13 The bloodwork of our population highlighted slight and/or moderate alterations compatible with an inflammatory state. Three out of 10 cats presented with prolonged aPTT, possibly related to their septic condition as suggested in literature, although a factor XII deficiency could not be completely excluded.^16,17 In domestic shorthairs, the deficiency of the factor XII is a common inherited congenital coagulopathy that might determine an in vitro prolonged aPTT, which is not usually associated with bleeding in vivo.¹⁷ Grass awns were the main vFB found during surgery; these may be aspirated and migrate into the lower airways causing lung abscesses or into the pleural cavity causing pyothorax.^4,6,13,15 Another hypothesis is they migrate into the thorax from the esophagus after swallowing or from a skin wound through the thoracic wall.^5,7,18 Indeed, vFBs in the neck region may have been swallowed or aspirated.^6,7,18 Like in dogs, vFBs may remain in the thoracic cavity or migrate through the diaphragmatic crura toward the iliopsoas muscle, potentially leading to intramuscular or retroperitoneal abscess formation.^{1,2,4,6,8,10,11} In the present study, the right-side localization appeared to be more frequent for both thoracic and iliopsoas vFBs, as already reported in previous studies.^3,15 This may be a result of the anatomical conformation of the right mainstem bronchus in line with the trachea; however, other authors have reported no side predisposition.^3,14,15 In case 7, an ascending migration of a vFB through the penile urethra probably caused urethral obstruction, similar to previous reports in dogs.^19,20 In case 8, the vFB may have been responsible for the urethra rupture as a result of migration inside the urethra, or it may have migrated through the perineal skin or wounds. In case 9, it was unclear whether the vFB had migrated from the oral cavity, pharynx, larynx, esophagus, or from a previous skin wound that had gone unnoticed. In case 10, it is possible that the vFB had been swallowed and carried through the small intestine, causing perforation and septic peritonitis.^1,2,4,5,21 The cultured bacteria from the effusion sampled were consistent with the current literature pertaining to vFBs.^2,13,14 According to the authors’ experience and the literature, UE plays a crucial role in diagnosis, particularly in the case of thoracic and retroperitoneal vFB. The UE is also useful during surgery as it increases the chances of finding the vFB during the first attempt and helps assess the presence of remnants.¹¹ The surgical removal of the vFB represents a challenge, especially if it is located in the retroperitoneal space.¹¹ The position of a vFB may be different during the preoperative UE and surgery in relation to specific anatomical landmarks.^6,11 It is possible that the change in the patient’s recumbency between UE and surgery causes a positional change. Moreover, as the space within a cat’s abdomen is limited and it is difficult to find the appropriate angle between the surgeon’s forceps and ultrasound probe, the authors found using percutaneous intraoperative ultrasonography from the flank as a guide to be useful. Because of the small number of cases of the study, it is not possible to assess the sensitivity and specificity of UE in detecting deep vFB in cats. In this study, repeated UEs permitted the detection of vFBs in the thorax, retroperitoneal space, and neck. For the other locations, UE was not performed or did not identify the vFB. In fact, in case 10, the presence of peritoneal effusion together with air in the bowel loops and peritoneal cavity may have impeded visualization of the vFB. For the perineal region, no UEs were performed, as vFBs were not among the differential diagnosis.

Advanced diagnostic imaging, as reported in the literature, was not undertaken in this study.^{2,8,10,11,13,14} Computed tomography (CT) may be useful in planning the surgical approach, especially when a minimally invasive approach such as VATS is considered.^2,8,14 However, vFBs are not always directly visible using CT, and if a vFB is suspected, ultrasound is usually performed after CT.^2,14 According to the present results, the use of VATS to treat pyothorax and to remove the vFB had some limitations, mainly because of the severe and chronic inflammation that caused pleural adhesion and hindered visualization. In fact, in one cat, it was necessary to convert VATS to open surgery as a result of these difficulties. In this case series, the surgical removal of the vFB was performed in all cases, and resolution of the clinical signs was obtained in 80% of cats. Only one cat had a poor outcome, and one more cat required a second surgery to remove a second vFB in the same location (iliopsoas). It is not clear if the second vFB migrated from a different location during the months following the first surgery or if it was already present and had gone unnoticed. Therefore, when a vFB is diagnosed in a deep location, the potential for multiple vFBs should always be kept in mind.

The low number of cases included in this series may be primarily linked to the infrequent presentation of vFB in cats, and it may represent an important limitation of the study. Another limitation is that both the incidence of the anatomic localization and diagnostic and therapeutic modalities used were retrospectively reviewed, and these may not represent the situation in a larger number of cats.

Conclusion

vFBs may cause deep abscesses or lesions in cats less frequently than in dogs. Thoracic and retroperitoneal locations appear to be common in cats; other locations are possible but less frequent. vFBs should be considered a rare cause of urethral obstruction or perineal lesions in outdoor male cats.

Surgical removal can be easier if associated with intraoperative ultrasonography, and long-term prognosis is more frequently positive.