Karen M. Tobias DVM, DACVS, College of Veterinary Medicine

A new dissection technique for approach to right-sided intrahepatic portosystemic shunts: Anatomic study and use in three dogs

Karen M. Tobias et al. — Tue, 12 Mar 2013 07:30:30 PDT

Objective— To determine the feasibility of indirect suture passage around the right portal vein for attenuation of right-sided intrahepatic portosystemic shunts (IHPSS).

Study Design— Anatomic study of cadavers and prospective evaluation of clinical cases.

Animals— Nine canine cadavers (median weight, 20.5 kg) and 6 client-owned dogs suspected of having right-sided IHPSS.

Methods— Silicone casts of the caudal vena cava and pre- and intrahepatic portal veins were made in fresh canine cadavers. A suture was passed dorsal to the portal vein above and below its bifurcation and pulled laterally so that it surrounded the right portal vein. The number and size of portal and caudal vena cava branches that interfered with the suture passage were recorded. Intra- and postoperative complications were evaluated in 3 dogs with right-sided IHPSS and 3 dogs suspected of having right-sided IHPSS that had right portal vein dissection and occlusion using this technique.

Results— Suture passage and placement around the right portal vein were easily accomplished in all 9 specimens. A 1 mm branch from the dorsal surface of the right portal vein was included in the encircling ligature in 4 specimens. The dissection technique was used successfully in 3 dogs with right-sided IHPSS and 2 other clinical cases. The portal branch to the papillary process of the caudate lobe interfered with suture placement in 1 dog with a central IHPSS.

Conclusions— Indirect suture passage for ligation of the right portal vein can be successfully performed in normal dogs and dogs with congenital portosystemic shunts.

Clinical Relevance— Hemorrhage, vascular trauma, and surgery time may be reduced using this technique for attenuation of right-sided IHPSS.

Atlas of Ear Diseases in the Dog and Cat

Sue Patterson et al. — Tue, 12 Mar 2013 07:27:24 PDT

Evaluation of the feline pancreas using computed tomography and radiolabeled leukocytes.

L. L. Head et al. — Mon, 12 Mar 2012 18:49:24 PDT

This study was designed to test the feasibility and utility of computed tomography and radiolabeled granulocytes in evaluating the feline pancreas in six normal cats. Autologous granulocytes were labeled with 99mTc-hexamethylpropyleneamine oxime (HMPAO) and injected into each cat. Whole body scintigraphic images were acquired at 1, 5, 15, and 30 minutes, and 1, 2, and 4 hours following injection. The following day, each cat was anesthetized and computed tomographic images of the abdomen were acquired both pre- and post-contrast. Following CT, a surgical pancreatic biopsy was collected. Feline granulocytes were successfully labeled with 99mTc-HMPAO with a labeling efficiency of 15-42% (average of 27%). An average of 5.42*10 7 cells in a 2 mL volume were injected into each cat. Less than 1 minute was required to acquire 500 000 count images. Granulocytes distributed predominantly to the lung, spleen and liver in order of decreasing activity. Only background activity was identified in the region of the pancreas. The pancreas was easily identified on CT images of the abdomen. The pancreas was hypoattenuating relative to both the spleen and liver. The pancreas enhanced with the administration of contrast medium, peaking immediately, then gradually clearing over the 30-minute test period. Following contrast medium administration the pancreas remained hypoattenuating relative to the spleen. All biopsies confirmed the absence of pancreatic inflammation in the study cats and no adverse effects were recognized as a result of pancreatic biopsy. Both computed tomography and radiolabeled granulocytes appear to hold promise as imaging procedures for the detection of feline pancreatitis. We predict that these described normal parameters may be altered in the face of inflammation, facilitating detection of feline pancreatitis. Data from cases of suspect feline pancreatitis are needed to evaluate these methods for clinical utility.

Manual of Small Animal Soft Tissue Surgery

Karen M. Tobias — Thu, 02 Feb 2012 11:12:55 PST

Veterinary Surgery: Small Animal

Karen M. Tobias et al. — Thu, 02 Feb 2012 11:11:01 PST

A Comparison of Four Methods of Analgesia In Cats Following Ovariohysterctomy

Karen M. Tobias et al. — Thu, 02 Feb 2012 11:05:36 PST

Objective: To evaluate the effectiveness of preoperative administration of oral carprofen, subcutaneous ketoprofen, and local nerve block with bupivacaine in preventing postoperative pain-associated behavior in cats after ovariohysterectomy.

Animals: Fifty-two female intact cats.

Materials and methods: Cats received butorphanol (0.44 mg kg−1 IM), carprofen (2.2 mg kg−1 PO), ketoprofen (2.2 mg kg−1 SQ), or bupivacaine infiltration block (1.1 mg kg−1 SQ) before surgery. Cortisol and drug concentrations and visual analog scale (VAS) and interactive visual analog scale (IVAS) pain-associated behavior scores were measured 2 hours before and 0, 1, 2, 4, 8, 12, and 24 hours after ovariohysterectomy.

Results: Cats receiving butorphanol had significantly increased IVAS scores 2 hours after surgery compared with baseline measurements. Cats receiving carprofen, ketoprofen, and bupivacaine had significant increases from baseline in VAS and IVAS scores 1 and 2 hours after surgery. VAS and IVAS scores for cats receiving bupivacaine were significantly greater 1 and 2 hours after surgery than for cats that received butorphanol. Cats receiving carprofen had significant increases in cortisol 1 hour after surgery and significant decreases 24 hours after surgery compared with baseline measurements.

Conclusions and clinical relevance: Preoperative carprofen and ketoprofen have effects on pain-associated behavior similar to butorphanol in cats undergoing ovariohysterectomy. Cats receiving bupivacaine blocks may require additional analgesics immediately after surgery.

Carcinoma ex pleomorphic adenoma with sebaceous differentiation in the mandibular salivary gland of a dog

Olga A. Smrkovski et al. — Mon, 16 Jan 2012 20:16:30 PST

A carcinoma ex pleomorphic adenoma was diagnosed in the left mandibular salivary gland of an 8-year-old female spayed dog. The animal presented with a large nonpainful swelling in the left submandibular region. A computed tomography scan detected an irregularly enhancing soft tissue mass that was closely associated with the left external ear canal and extended to the left wing of the atlas. On surgical exploration, the mass was intimately associated with the left mandibular salivary gland. Both the mass and the adjacent gland were removed, and the diagnosis was determined by histopathology. The tumor was comprised of basaloid and low columnar epithelial cells, many glandular units formed by well-differentiated sebocytes, and multifocal regions of necrosis, mineralization, and hemorrhage. Salivary gland tumors with sebaceous differentiation are very rare in animals, with one previously reported case in a cat.

Comparison of trans-splenic and per-rectal portal scintigraphy for diagnosis of congenital portosystemic shunts

Patricia Sura et al. — Fri, 17 Jun 2011 08:58:09 PDT

Objective— To evaluate trans-splenic portal scintigraphy (TSPS) and per-rectal portal scintigraphy (PRPS) for diagnosis of congenital portosystemic shunts (CPSS) in dogs, and compare these results with surgical findings.

Study Design— Prospective, randomized cross over clinical trial.

Animals— Dogs (n=42) with suspected CPSS.

Methods— Dogs had TSPS and PRPS 48 hours apart; quantity of radionuclide administered was recorded. Three independent, blinded reviewers evaluated each scintigraphic study for study quality, shunt presence, number, and location of shunt termination (caudal vena cava, azygos vein). All dogs had exploratory celiotomy. Negative scintigraphic findings were confirmed with intraoperative mesenteric portography. Ameroid constrictors were placed on all extrahepatic CPSS, and hepatic biopsies were obtained.

Results— TSPS was 100% sensitive and specific for diagnosis of CPSS and significantly (P<.05) more likely than PRPS to detect shunt number and termination. Interpretation was consistent between observers, and TSPS required significantly less radionuclide than PRPS.

Conclusion— TSPS was as sensitive as PRPS for detection of shunting vessels, and consistently yielded studies of higher quality, allowing detection of shunt number and location with consistent interpretation among radiologists.

Clinical Relevance— TSPS provides information about shunt number and location, which allows improved surgical planning. Because it requires significantly less radionuclide, TSPS improves safety, allows for more comprehensive patient care, and earlier surgical intervention.

Adrenal response to adrenocorticotropic hormone in dogs before and after surgical attenuation of a single congenital portosystemic shunt

Amy Holford et al. — Fri, 17 Jun 2011 08:53:29 PDT

Background: Dogs with single congenital portosystemic shunts (CPSS) often develop postoperative hypoglycemia and prolonged anesthetic recovery. These abnormalities could be attributable to inadequate adrenal response. However, adequacy of adrenal response after CPSS surgery is unexplored.

Hypothesis: Dogs with CPSS have inadequate postoperative adrenal response.

Animals: Eight nonoperated, 8 ovariohysterectomy (OHE), and 16 CPSS dogs.

Methods: Consecutive day ACTH stimulation tests were performed on nonoperated healthy dogs, healthy dogs before and after OHE, and CPSS dogs before and after surgery. Adequate response was defined as >50% or >30 ng/mL increase in cortisol after ACTH administration. Blood glucose (BG) was monitored before and after surgery. Prolonged anesthetic recovery and refractory hypoglycemia episodes were recorded.

Results: Results of consecutive day ACTH stimulation tests did not vary in normal dogs. Results of preoperative ACTH stimulation tests of CPSS and OHE dogs were not significantly different. Dogs with CPSS had higher postoperative baseline cortisol concentrations (median, 329 ng/mL) than OHE dogs (median, 153 ng/mL). Postoperative cortisol increase after ACTH in CPSS was ≤50% in 10/16 and ≤30 ng/mL in 6/16. After surgery, BG was ≤60 mg/dL in 7/16 CPSS dogs. Cortisol concentrations were not correlated with BG. Two CPSS dogs had refractory hypoglycemia and 4 had delayed recovery; all improved with dexamethasone administration (0.1–0.2 mg/kg/IV).

Conclusions and Clinical Importance: Contrary to previous reports, baseline cortisol concentrations in CPSS and healthy dogs are similar. Many CPSS dogs have postoperative hypercortisolemia. Response to ACTH does not correlate with postoperative hypoglycemia or prolonged anesthetic recovery.

Head and neck swelling due to a circumferential cicatricial scar in a dog

Hans Westermeyer et al. — Fri, 17 Jun 2011 08:49:49 PDT

A 4-year-old, castrated male, mixed-breed dog was evaluated because of progressive head swelling, exercise intolerance, and increasing respiratory effort of 1 month’s duration. Physical examination and radiographs revealed severe edema of the head and face that was cranial to a circumferential, midcervical constriction caused by scarring related to previous removal of a foreign body. Surgical en bloc resection of the cicatricial tissue was performed, and clinical signs resolved completely after 2 months. Histopathology showed ongoing inflammation and hairs within a fibrous band. This case emphasizes that incomplete wound debridement may lead to excessive fibrous tissue proliferation and that thorough wound examination and debridement should be performed after removing circumferential cervical foreign bodies to ensure complete healing.

Septic Peritonitis

Efrat Kelmer et al. — Fri, 17 Jun 2011 08:47:12 PDT

Sepsis is defined as the systemic inflammatory response to infection. Septic peritonitis occurs when infectious organisms are present in the peritoneal cavity. With few exceptions (e.g., feline infectious peritonitis), septic peritonitis represents a surgical emergency; therefore, diagnosis must be prompt and accurate. the most common cause of septic peritonitis in small animals is dehiscence of gastrointestinal (GI) surgical wounds.Other etiologies include penetrating or blunt abdominal trauma, GI perforation secondary to foreign bodies, neoplasia, nSAId or glucocorticoid use resulting in gastric perforation, intestinal ischemia, rupture of infected or abscessed organs (e.g., prostatic abscess, hepatic abscess, pancreatic abscess, pyometra), infected biliary peritonitis or uroperitonitis, dislodgment of intraabdominal feeding tubes (i.e., gastrostomy or jejunostomy tubes), and intraoperative contamination.

Laryngeal paralysis in dogs

R Millard et al. — Fri, 17 Jun 2011 08:44:38 PDT

Laryngeal paralysis can cause progressive upper airway obstruction and ultimately death, usually in older, large-breed dogs. Videos of normal and paralyzed laryngeal abduction are available in this article.

Inflammatory mammary carcinoma in 12 dogs: clinical features, cyclooxygenase-2 expression, and response to piroxicam treatment

Carlos Souza et al. — Fri, 17 Jun 2011 08:40:55 PDT

Canine inflammatory mammary carcinoma (IMC) is a rare, locally aggressive, highly metastatic tumor that is poorly responsive to treatment. The purposes of this study were to retrospectively evaluate the history, signalment, and clinical signs of dogs with IMC; compare the outcome of affected dogs treated with traditional chemotherapy with those treated with piroxicam; evaluate Cox-2 expression of IMC cells; and correlate Cox-2 expression with outcome based on treatment. Strong cyclooxygenase-2 expression was present in all tumors. Improvement in clinical condition and disease stability was achieved in all dogs treated with piroxicam, with mean and median progression-free survival of 171 and 183 days, respectively. Median survival time of 3 dogs treated with doxorubicin-based protocols was 7 days, which was significantly less than that of dogs treated with piroxicam (median, 185 days). In conclusion, piroxicam should be considered as a single agent for the treatment of dogs with inflammatory mammary carcinoma.

Association of breed with the diagnosis of congenital portosystemic shunts in dogs: 2400 cases (1980-2002)

Karen M. Tobias et al. — Fri, 17 Jun 2011 08:33:43 PDT

Objective: To determine the annual and overall proportion of diagnoses of congenital portosystemic shunts (CPSS) in dogs and identify breeds at increased risk for CPSS. Design: Retrospective study. Animals: 2400 dogs with CPSS from veterinary teaching hospitals that reported to the Veterinary Medical Database (VMDB) from 01 January 1980 to 28 February 2002. Procedure: The proportion of diagnoses of CPSS was calculated for all dogs and each breed recorded in the VMDB annually and for the 22.2-year period. Odds ratios and adjusted confidence intervals were calculated for breeds with at least 100 accessions by comparing odds of each breed with a diagnosis of CPSS with that of mixed-breed dogs. Results: Congenital portosystemic shunts were reported in 0.18% of all dogs and 0.05% of mixed-breed dogs. The proportion of diagnoses of CPSS increased from 5 in 10 000 dogs in 1980 to 5 in 1000 dogs in 2001. Yorkshire Terriers had the greatest total number of diagnoses of CPSS. Thirty-three breeds were significantly more likely to have a diagnosis of CPSS, compared with mixed-breed dogs. The greatest proportions of diagnoses were found in Havanese (3.2%), Yorkshire Terriers (2.9%), Maltese (1.6%), Dandie Dinmont Terriers (1.6%), and Pugs (1.3%). Conclusions and Clinical Relevance: Certain breeds appear to be at increased risk for CPSS, compared with mixed-breed dogs. The increased odds ratios among specific breeds support the hypothesis of a genetic predisposition for CPSS. Clients and veterinarians should consider appropriate diagnostic tests for dogs with clinical signs and those used for breeding from breeds with increased risk of CPSS.

Effects of Various Anesthetic Agents on Laryngeal Motion During Laryngoscopy in Normal Dogs

Aaron M. Jackson et al. — Fri, 17 Jun 2011 08:33:42 PDT

Objective— To evaluate the effects of various drugs and drug combinations conventionally used for anesthesia on arytenoid cartilage motion during laryngoscopy in normal dogs.

Study Design— Experimental study.

Animals— Six large breed healthy dogs with no previous history of respiratory dysfunction.

Methods— Each dog was randomly assigned to a different injectable anesthetic protocol once weekly for 6 weeks, then in the 7th week all dogs were anesthetized with isoflurane. Videolaryngoscopy was performed and recorded starting immediately after induction until dogs could no longer be safely restrained for endoscopy. Video was digitized and 3 still images ofmaximalinspiration and expiration from the first 15 seconds (induction) and the last 15 seconds (recovery) were captured and imported into an image analysis software program. The height andarea of the laryngeal ostium were measured in pixels. Normalization of the glottal gap areawasperformed using the formula (normalized glottal gap area (NGGA)=area in pixels/height2). ANOVA was performed on the NGGA of images collected at inspiration and expiration during induction and recovery. Fischer's exact test was performed when significance (P<.05) wasfound.

Results— Within each protocol, laryngeal motion (defined as change in NGGA) at induction was not significantly different from laryngeal motion measured at recovery. Additionally, no significant differences were found in arytenoid motion immediately after induction when anesthetic protocols were compared. Arytenoid motion before recovery was significantly greater with thiopental when compared with propofol (P=.046), ketamine+diazepam (P=.0098), acepromazine+thiopental (P=.0021), and acepromazine+propofol (P=.0065). No significant difference in arytenoid motion was seen immediately after induction or before recovery when acepromazine+butorphanol+ isoflurane and thiopental were compared.

Conclusion— We concluded that intravenous thiopental given to effect is the best choice for assessing laryngeal function in dogs. Dogs premedicated with acepromazine with or without opioids that require further anesthetic restraint for laryngoscopy should be anesthetized with isoflurane administered by mask.

Clinical Relevance— Misdiagnosis of laryngeal paralysis during laryngoscopy can be avoided by selecting the anesthetic regimens with the least effect on arytenoid motion.

Breeds with portosystemic shunts

Karen M. Tobias et al. — Fri, 17 Jun 2011 08:33:40 PDT

In this retrospective university study using data from a central veterinary medical database, the proportion of diagnoses of congenital portosystemic shunts (CPSs) and the breeds at risk during a 22-year period were determined. CPSs were identified in nearly 0.2% of all dogs and in 0.05% of mixed breeds. Most dogs were 2 to 12 months of age at diagnosis. From 1980 to 2001, the proportion of CPS diagnoses increased 10-fold. In 2001, the annual proportion of CPSs compared with all diagnoses was 0.5%. The greatest number of diagnoses was in Yorkshire terriers. The highest percentage of diagnoses were in Havanese (3.2%), Yorkshire terriers (2.9%), Maltese (1.6%), Dandie Dinmont terriers (1.6%), and pugs (1.3%). The authors recommend that owners and breeders be aware of breeds at risk of CPSs and that appropriate diagnostic tests (i.e., bile acid analyses) be instituted if clinical signs exist in these dogs. Furthermore, affected dogs should also be neutered.

Comparison of oral and subcutaneous administration of buprenorphine and meloxicam for preemptive analgesia in cats undergoing ovariohysterectomy

A D. Gassel et al. — Fri, 17 Jun 2011 08:33:38 PDT

Objective - To compare the effectiveness of preoperative PO and SC administration of buprenorphine and meloxicam for prevention of postoperative pain-associated behaviors in cats undergoing ovariohysterectomy. Design - Randomized controlled study. Animals - 51 female cats (4 to 60 months old; weight range, 1.41 to 4.73 kg [3.1 to 10.4 lb]). Procedure - Cats received 1 of 5 treatments at the time of anesthetic induction: buprenorphine PO (0.01 mg/kg [0.0045 mg/lb]; n=10), buprenorphine SC (0.01 mg/kg; 10), meloxicam SC (0.3 mg/kg [0.14 mg/lb]; 10), meloxicam PO (0.3 mg/kg; 10), or 0.3 mL of sterile saline (0.9% NaCl) solution SC (control group; 11). Sedation scores and visual analogue scale and interactive visual analogue scale (IVAS) pain-associated behaviour scores were assigned to each cat 2 hours before and at intervals until 20 hours after surgery. Results - Cats receiving meloxicam PO or SC had significantly lower IVAS scores (2.91 and 2.02, respectively), compared with IVAS scores for cats receiving buprenorphine PO (7.55). Pain-associated behaviour scores for cats administered buprenorphine or meloxicam PO or SC preoperatively did not differ significantly from control group scores. Rescue analgesia was not required by any of the cats receiving meloxicam, whereas 3 of 10 cats receiving buprenorphine PO, 2 of 10 cats receiving buprenorphine SC, and 1 of 11 cats receiving the control treatment required rescue analgesia. Conclusions and Clinical Relevance - On the basis of pain-associated behaviour scores, cats receiving meloxicam PO or SC before ovariohysterectomy appeared to have less pain after surgery than those receiving buprenorphine PO preoperatively.

In vitro efficacy of a polyhexamethylene biguanide-impregnated gauze dressing against bacteria found in veterinary patients

W R. Lee et al. — Fri, 17 Jun 2011 08:33:37 PDT

Objective - To evaluate the in vitro efficacy of polyhexamethylene biguanide (PHMB)-impregnated gauze dressing in limiting the growth of bacteria both within and underneath the dressing. Study Design - In vitro study. Methods - Squares of PHMB-impregnated and control gauze were placed on agar plates inoculated with 1 of 11 bacterial species, including 8 multi-resistant organisms. Growth under the gauze was assessed qualitatively after 24-hour incubation. Repeated use of sponges was used to evaluate residual inhibitory activity against Micrococcus lutea and Staphylococcus schleiferi ss. schleiferi. In a second procedure, PHMB-impregnated and control gauze squares were placed in sterile plastic wells and inoculated with 1 of 5 bacterial species, including Pseudomonas spp. and Klebsiella spp. Inhibition of bacterial growth within and underneath the dressing after 24-hour incubation was evaluated by quantifying the numbers of bacteria on the well floor and within each square. Results - PHMB-impregnated gauze provided greater inhibition of growth of 4/4 Gram-positive species and 2/6 Gram-negative species on inoculated plates compared with control gauze. Residual inhibitory activity of PHMB-impregnated gauze was significantly greater against M. lutea on all days and against S. schleiferi ss. schleiferi on days 1 and 4 compared with control. No bacteria were recovered from inoculated PHMB-impregnated gauze squares placed in sterile wells or from the well floor underneath. More than 9*105 colony-forming units (CFU) were recovered from inoculated control samples placed in sterile wells and more than 8.4*104 CFU were recovered from control well floors. Conclusion - PHMB-impregnated gauze dressing, when placed on inoculated agar plates, reduces growth of underlying bacteria, particularly Gram-positive species. Wet-inoculated PHMB-impregnated dressing prevents growth of Gram-positive and Gram-negative bacteria both within and underneath the dressing. Clinical Relevance - PHMB-impregnated dressings may be useful for reducing contamination of underlying wounds by bacterial pathogens.

Protein C Activity in Dogs: Adaptation of a Commercial Human Colorimetric Assay and Evaluation of Effects of Storage Time and Temperature

Michael M. Fry et al. — Fri, 17 Jun 2011 08:33:34 PDT

Objectives of this study were to adapt a commercial human protein C (PC) colorimetric assay for use in dogs and to investigate effects of various storage conditions. The human assay was modified by using pooled canine plasma for calibration and by increasing the activation time. PC activity was measured in fresh canine plasma and in plasma stored under various conditions. PC activity of some stored samples was significantly different from that of fresh plasma; however, differences were small. No difference was detected in samples stored under similar conditions but analyzed in different laboratories using similar methodology. Results of this study indicate that the human colorimetric assay is suitable for canine samples if pooled canine plasma is used for calibration, that Clinical and Laboratory Standards Institute sample storage guidelines developed for testing in humans are appropriate for dogs, and that comparisons of results from laboratories using similar methodology are legitimate.