Surgical Anatomy of the Gastrointestinal Tract in Cats

In cats, the gastrointestinal tract is one of the regions in which surgical procedures are most frequently performed by veterinary surgeons; therefore, knowledge of the surgical anatomy of the feline gastrointestinal tract is of high importance. The main surgical procedures performed include gastrotomy, gastrectomy, enterotomy, and enterectomy, as well as procedures in the liver and pancreas. There are also anatomical differences between dogs and cats, increasing the need for deep knowledge of the anatomy treated in the different surgical approaches. The aim of the present review is to describe in detail the anatomy of the gastrointestinal tract in cats highlighting the anatomical regions of significant importance in different surgical procedures.

Chios ram testicular blood flow and echotexture changes depending on age, season and ejaculation process

The present study aimed to investigate the impact of age, season and ejaculation on ram testicular blood flow and echotexture. The survey was conducted biweekly on 7 Chios rams for one year, including breeding and non-breeding periods. The rams were divided into 2 age groups: 3 rams 2-6 years old (mature) and 4 rams 9-13 years old (old). Hemodynamic indices [Pulsatility index (PI), Resistive index (RI), End-diastolic velocity (EDV), testicular artery Diameter (D), Time-averaged maximum velocity (TAVM), Blood flow volume (BFV)] and echotexture parameters [Mean value (MV), Contrast (Con), Gray value distribution (GVD), Run length distribution (RunLD), Long run emphasis (LRunEm), Entropy (Ent), Correlation (Cor), Standard deviation (StD), Gray variance (GV) and Gradient mean value (GMV)] were evaluated in each testis before and after ejaculation. Ejaculation did not affect testes blood flow or echotexture (p>0.05). PI and RI were higher in the breeding period compared to the non-breeding period, for both testes (p⟨0.001). Left testis GV and Cor before ejaculation were lower (p=0.01) and higher (p=0.03), respectively, in the breeding compared to the non-breeding period. Left testis D (p=0.005) and BFV (p⟨0.001) were higher in old compared to mature rams after ejaculation. Right testis Con (p=0.03) and Cor (p=0.05) before ejaculation were higher in old rams, whereas right testis Ent after ejaculation was higher in mature rams (p=0.05). In conclusion, testicular blood flow and echotexture are affected by season and ram age, but not by ejaculation.

Brainstem phaeohyphomycosis due to Curvularia lunata (Cochliobolus lunatus) in a cat

A 13-year-old female neutered domestic short-hair cat was presented with chronic progressive vestibular ataxia, lethargy and anorexia. Clinical examination revealed bilateral mucopurulent nasal discharge. Neurological examination revealed obtundation, a right head tilt, ambulatory tetraparesis, generalised vestibular ataxia, decreased postural reactions in all limbs, right Horner's syndrome, spontaneous conjugate jerk rotatory nystagmus and right positional ventral strabismus. Neuroanatomical localisation was observed in the right central vestibular system. Computed tomography revealed a solitary ill-defined contrast-enhancing mass lesion at the level of the right cerebellopontine angle. Cerebrospinal fluid (CSF) analysis revealed mild mononuclear pleocytosis and fungal elements. CSF culture was positive for Curvularia spp. Further tests for underlying diseases were all negative. The cat was treated with antibiotic and antifungal treatment, but it deteriorated rapidly and was euthanased. Necropsy of the brainstem mass lesion revealed pyogranulomatous inflammation. Panfungal polymerase chain reaction (PCR) targeting the internal transcribed spacer (ITS) region and subsequent sequencing identified Curvularia lunata in the formalin fixed brain tissue. This is the first report of brainstem phaeohyphomycosis by Curvularia lunata (Pleosporales) in a cat. In addition, this is the first report among animal and humans where fungal elements of Curvularia lunata were found in the CSF cytology. Opportunistic fungal pathogens should be always considered within the differential diagnoses list in cats with neurological signs and advanced imaging findings compatible with solitary mass lesions in the brain. In feline patients with pyogranulomatous meningoencephalitis and a suspicion of a fungal aetiology, panfungal PCR for the ITS region and sequencing should be performed regardless of the absence of fungal elements in histopathology.

Contrast-enhanced voiding urosonography: A new, radiation-free, alternative method for imaging of urinary bladder and urethra in healthy dogs

Contrast-enhanced voiding urosonography (CE-VUS) has been generally considered as a promising tool to diagnose vesicoureteral reflux and abnormalities in lower urinary tract in human patients, especially in children. The purpose of this prospective study is to evaluate the quality of images of the urinary bladder and urethra obtained by CE-VUS using a second-generation ultrasound contrast agent (SonoVue®) in healthy dogs and to investigate the safety profile of SonoVue® after intravesical administration. Eighty-four CE-VUS examinations with SonoVue® were successfully performed in both unsedated (39/84) and sedated (45/84) dogs. Contrast-enhanced voiding urosonography examination of urinary bladder was technically successful in all (84/84) dogs. The image quality was not considered adequate in five (5/84) dogs including three dogs in whom layering of contrast media during filling phase was observed and two dogs with premature destruction of microbubbles. In these five dogs, the problem was readily recognized and corrected such that the procedure was still successfully undertaken. The assessment of the urethra during spontaneous micturition was successfully performed in all (84/84) dogs in whom voiding was elicited during the examination. No side effects were observed after intravesical application of SonoVue®. This study demonstrates that CE-VUS is a feasible and valuable technique to evaluate low urinary tract morphology and function in dogs. Based on our review of the literature, there are no published reports about the use of this method in dogs.

Colonic impaction in dogs: a retrospective study of 58 cases (1996 to 2014)

OBJECTIVES

To describe the clinical findings, management and outcome of colonic impaction in dogs and report the effectiveness of medical treatment.

MATERIALS AND METHODS

Case records of 58 dogs with colonic impaction were reviewed. Telephone contact with the owners was used to obtain long-term outcome.

RESULTS

Twenty-nine dogs (50%) were mixed-breed, and 45 (78%) were entire males. Median age at presentation was 7 years, and median bodyweight was 22 kg. The degree of radiographic colonic distension did not appear to be related to long-term outcome. Fifty-five dogs (95%) received medical treatment including enemas alone, hyperosmotic and/or bulk-forming and/or lubricant laxatives, enemas combined with laxatives or enemas and/or laxatives combined with manual evacuation of faecal material under anaesthesia. Median survival time of the 58 dogs was 2 years. Overall, 36 of 41 dogs with available long-term follow-up had a favourable outcome.

CLINICAL SIGNIFICANCE

Medical treatment of colonic impaction in dogs with a single agent or a combination of agents has a high success rate. Marked colonic dilation is not necessarily indicative of megacolon in dogs.

Pre- and post-treatment computed tomographic findings of a primary intranasal transmissible venereal tumor in a canine patient

A two-year-old, female intact, cross-breed dog presented with a two-month history of nasal discharge. Computed tomography (CT) demonstrated obliteration of both nasal cavities by soft tissue density, destruction of the nasal and ethmoidal turbinates, and lysis of the frontal and palatine bones and maxilla. Frontal sinuses and maxillary recesses were obscured by soft tissue/fluid density. Histopathological examination of the mass was diagnostic of transmissible venereal tumor. The dog was clinically normal 3 months after treatment initiation with vincristine sulphate and amoxicillin/clavulanate. Six months after the completion of treatment no mass-like lesion was demonstrated in CT sections. Nasal cavities, maxillary recesses and frontal sinuses were filled with air. The reticular turbinate nasal plexus appeared atrophic with focal loss of the nasal turbinates on both sides. The ethmoidal turbinates were well-defined; however, focal loss of turbinates was also seen. Lysis of the frontal and palatine bones were still evident.

Effect of intrafragmentary bupivacaine (haematoma block) on analgesic requirements in dogs undergoing fracture repair

OBJECTIVE

To test the efficacy of intraoperative intrafragmentary administration of bupivacaine (haematoma block) in controlling postoperative pain in dogs undergoing osteosynthesis of long-bone isolated diaphyseal fractures.

STUDY DESIGN

Randomized, 'blinded', placebo-controlled, prospective study.

ANIMALS

A total of 23 client-owned dogs with isolated long-bone fractures.

METHODS

Dogs were allocated randomly to two groups: bupivacaine group (B) or placebo group (P). Group B dogs (n = 11) were administered an intraoperative intrafragmentary injection of 0.5% bupivacaine (1.1 mg kg^-1) just before fracture fixation, whereas group P dogs (n = 12) were administered normal saline. Postoperative pain evaluations using the University of Melbourne Pain Scale (UMPS) and algometer were performed upon arrival to the recovery room and 1, 2, 4, 6, 8, 20 and 32 hours later. Algometer measurements were performed on: the incision site, a healthy region near the fracture line and the contralateral healthy limb. When the pain score exceeded 14 points in the UMPS, rescue analgesia was administered. The time-standardised area under the curve (AUCst) was used to compare UMPS scores and mechanical pain thresholds between the two groups.

RESULTS

None of the group B dogs required rescue analgesia, whereas eight of the 12 group P dogs did (p = 0.001). The pain threshold AUCst at the incision line was higher in group B [16.3 (2.9-41.6) N] than in group P [5.6 (2.5-17.4) N] (p = 0.029). The mean UMPS score AUCst was lower in group B (3.7 ± 1.8) than in group P (9.4 ± 4.6) (p = 0.016). In a small number of animals of both groups that were evaluated radiologically, adequate bone healing was noted.

CONCLUSIONS AND CLINICAL RELEVANCE

An intraoperative bupivacaine haematoma block is a simple, quick and effective method that can be used to aid in postoperative pain control in dogs submitted to long-bone osteosynthesis.

Magnetic resonance imaging features of cerebellar vermis medulloblastoma in an adult canine patient

A seven-year-old, not-castrated male, Airedale Terrier presented with a history of ataxia and intention tremor of the head of three-week duration. Neurologic examination demonstrated severe hypermetria, intention tremor of the head and a bilateral menace response deficit. Magnetic resonance imaging revealed a well demarcated cerebellar vermis mass, hypointense on T1-weighted images, hyperintense on T2-weighted images, with multiple small foci of high signal similar to that of CSF. Foci dispersed in the mass creating a speckled appearance. Homogeneous faint, wispy post-contrast enhancement of the mass was noted; as a result the tumor became isointense to gray matter and was not clearly evident in post contrast images. The histopathological diagnosis of the excised tumor was cerebellar medulloblastoma.

Evaluation of a proposed therapeutic protocol in 12 dogs with tentative degenerative myelopathy

The objective of this work was to evaluate the long-term efficacy of a proposed therapeutic protocol in 12 dogs with a tentative diagnosis of degenerative myelopathy, followed-up for a 6-month period. Twelve dogs fulfilling the antemortem inclusion criteria (breed, age, adequate vaccination, history of progressive posterior ataxia and/or paraparesis, no radiographic and myelographic abnormalities in the spinal cord and vertebral column) were allocated. All these dogs presented signs of thoracolumbar syndrome (T3-L3), scored as grade I (mild to moderate ataxia and paraparesis) in 10 and grade II (severe ataxia and ambulatory paraparesis) in 2 cases. Treatment included the use of epsilon-aminocaproic acid and N-acetylcysteine, supplemented with vitamins B, C and E. Prednisolone was given for the first two weeks and upon worsening of neurological signs. Daily exercise, performed as walking or swimming, was strongly recommended. Clinicopathological evaluation was normal in all 12 dogs, and survey radiographs and myelograms did not show spinal cord compression. Magnetic resonance imaging (MRI), performed only in 4 dogs, did not disclose compressive disorders or intramedullary lesions. Neurological signs were progressively worsening in all 12 animals, eventually resulting in severe paraparesis (grade III) or paraplegia (grade IV). The applied medications do not appear to be an attractive alternative to conservative management (physiotherapy) or euthanasia in canine degenerative myelopathy, irrespective of its chronicity.

Vertebral telangiectatic osteosarcoma in a dog

Telangiectatic osteosarcoma (TOS) affecting the seventh cervical vertebra (C7) was diagnosed in a 4-year-old male dog with signs of locomotor dysfunction. Bone lysis and an extradural-extramedullary mass were observed in radiographs and occipital myelograms. The diagnosis was confirmed by histopathologic and immunohistochemical examination of the mass. The tumor was composed of large blood-filled cavities lined by anaplastic stromal cells (malignant osteoblasts). Around the cavities were characteristic tumor giant cells ("bizarre cells"). Immunohistochemically the tumor cells were positive for proliferating cell nuclear antigen. The lining cells of the cysts were negative for von Willebrand factor. The histologic findings in this case of TOS involving C7 were similar to those seen in other cases of TOS in dogs and in people. Immunohistochemistry was a useful tool for assessing malignancy and for ruling out other differential diagnoses.