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Biomedical subjects

David C Twedt

Publications and source records attributed to David C Twedt.

7 recordsLinked to original sources

Diagnostic peritoneal lavage for identification of blastomycosis in a dog with peritoneal involvement.

A 6-year-old castrated male Dalmatian was evaluated because of hematemesis. The dog had lived its entire life in South Dakota and Wyoming and had never traveled outside of these states. Results of laboratory testing were compatible with iatrogenic acute renal failure and gastrointestinal tract ulceration secondary to previous nonsteroidal anti-inflammatory drug and corticosteroid administration. Differential diagnoses for clinical signs and laboratory abnormalities that existed prior to these treatments included multisystemic infectious or inflammatory disease and neoplasia. Four-quadrant abdominocentesis did not yield any fluid, but because intra-abdominal disease was still suspected, diagnostic peritoneal lavage was performed. Fluid that was obtained was markedly cellular, and there were numerous extracellular structures with a round to oval shape; a 1-microm-thick, clear-staining capsule; a basophilic interior; and broad-based budding. Organisms were consistent with Blastomyces spp, and fungal culture yielded Blastomyces dermatitidis. Treatment with liposomal amphotericin B and itraconazole was recommended but could not be initiated because of the client's financial constraints. At necropsy, disseminated blastomycosis involving the stomach, small intestines, urinary bladder, omentum, mesentery of the small intestine, and abdominal wall musculature was seen. To our knowledge, peritoneal involvement has not been reported in dogs with blastomycosis, and gastrointestinal tract involvement has only rarely been reported. Findings in this dog suggest that diagnostic peritoneal lavage may be a useful technique in determining the cause of infectious peritonitis when the amount of abdominal fluid is below the limit of detection for abdominocentesis.

Animals↗

Canine gastritis.

Gastritis--inflammation of the stomach--is a frequently cited differential yet rarely characterized diagnosis in cases of canine anorexia and vomiting. Although the list of rule-outs for acute or chronic gastritis is extensive, a review of the veterinary literature reveals fewer than 15 articles that have focused on clinical cases of canine gastritis over the last 25 years. The dog frequently appears in the human literature as an experimentally manipulated model for the study of endoscopic techniques or the effect of medications on gastric mucosa. In the veterinary patient, cases of acute gastritis are rarely pursued with the complete diagnostic armamentarium, and cases of chronic gastritis are rarely found to occur as an entity isolated from the rest of the gastrointestinal tract. This article focuses on those findings most clinically relevant to cases of canine gastritis in veterinary medicine.

Animals↗

Laparoscopy.

Laparoscopy is a minimally invasive technique for both diagnostic biopsy and surgical procedures. After the basic technique of laparoscopy is mastered and the appropriate indications are learned, these procedures become an easy and rewarding addition to any small animal veterinary practice.

Animals↗

Transurethral resection in the management of urethral and prostatic neoplasia in 6 dogs.

OBJECTIVE: To assess cystoscopic transurethral resection (TUR) for the palliative management of dogs with neoplastic infiltration of the urethra. STUDY DESIGN: Prospective clinical trial. ANIMALS: Six client-owned dogs. METHODS: Cystoscopic examination and electrosurgical TUR were performed in dogs with urination difficulties caused by prostatic or urethral neoplasia. TUR was performed in a retrograde manner in female dogs and antegrade in male dogs via exploratory celiotomy and ventral cystotomy. Cystoscopic examination was used to determine the extent of neoplastic involvement of the urethra. TUR involved piecemeal removal of neoplastic tissue from the urethral lumen using an electrocautery cutting loop. Hemorrhage was controlled with a cystoscopic cauterized roller-ball. In 2 male dogs, intraoperative radiation therapy (IORT) was used to treat both prostatic neoplasia and the sublumbar lymph node bed. Surgical technique, complications, adjuvant treatment, and outcome were recorded. RESULTS: TUR was performed in 3 male dogs with prostatic carcinoma and 2 female dogs with urethral transitional cell carcinoma (TCC). In 1 female dog, TUR was attempted but not successful because of cystoscope diameter. Iatrogenic urethral perforation occurred during TUR in 3 dogs. In 2 dogs, prolonged exposure to lavage fluid resulted in clinical and biochemical abnormalities consistent with TUR syndrome. Dysuria resolved in 5 dogs within 10 days of TUR. Treatment-related complications included urinary tract infection and tumor seeding. Local tumor progression and metastasis occurred in all dogs. CONCLUSIONS: TUR (in combination with chemotherapy+/-IORT) resulted in rapid palliation of urination difficulties in male dogs with prostatic carcinoma. In female dogs with urethral TCC, however, electrosurgical TUR cannot be recommended because of a high intra- and postoperative complication rate with no improvement in postoperative management compared with historical reports of tube cystostomy. CLINICAL RELEVANCE: TUR is a novel alternative for the palliation of male dogs with prostatic carcinoma. In female dogs with urethral TCC, electrosurgical TUR does not provide any advantages compared with tube cystostomy.

Animals↗

Thoracoscopic lung lobectomy for treatment of lung tumors in dogs.

OBJECTIVE: To report use of thoracoscopic lung lobectomy (TLL) for treatment of lung tumors (LT) in dogs. STUDY DESIGN: Retrospective study. ANIMALS: Nine dogs. METHODS: Dogs that had TLL for tumor removal were included. Using general anesthesia and 1-lung ventilation, TLL was performed using a 30-60 mm endoscopic gastrointestinal anastomosis stapler. If the visual field was obscured, lobe resection was completed via thoracotomy. RESULTS: Metastatic and primary LT were resected by thoracoscopic lobectomy in 9 dogs (6 male, 3 female; mean (+/-SD) weight, 29+/-7 kg; mean age, 10.7+/-1.9 years). Six dogs had a solitary mass and 3 dogs had 2 masses within a single lobe. The left caudal lobe was removed in 3 dogs. In 5 dogs, TLL was used alone whereas conversion to thoracotomy was required in 4 dogs because of poor visibility. There were 7 metastatic LT and 2 primary LT. Mean duration of thoracoscopic surgery was 108.8+/-30.3 minutes compared with 150.75+/-55.4 minutes in dogs requiring conversion to thoracotomy. Mean hospitalization was 3.1+/-1.3 days. CONCLUSION: Provided the visual field is not obscured, TLL can be performed effectively in dogs. CLINICAL RELEVANCE: Dogs with metastatic or primary LTs should be considered for TLL, particularly for small masses positioned away from the hilus in the left caudal lung lobe.

Animals↗

Copper-associated liver disease in Dalmatians: a review of 10 dogs (1998-2001).

This retrospective study summarizes 10 Dalmatians suspected of having hepatic copper toxicosis. Hepatic copper toxicosis can result from either a primary metabolic defect in hepatic copper metabolism or from altered hepatic biliary excretion of copper. An inherited copper-associated hepatopathy has been documented in Bedlington Terriers, and there is evidence for familial copper-associated liver disease in West Highland White (WHW) Terriers and Skye Terriers. Nine of the 10 Dalmatians in this study presented for gastrointestinal clinical signs, including anorexia and vomiting. All animals had increased alanine aminotransferase (ALT) enzyme activity, and 9 of 10 had increased alkaline phosphatase (ALP) enzyme activity. The relative increase in ALT activity was much greater than the relative increase in ALP activity, suggesting a predominantly hepatocellular rather than cholestatic liver disease. The mean hepatic copper concentration for 9 Dalmatians was 3,197 microg/g dry weight liver (dwl) (normal, <450 microg/g). In 5 of these 9 dogs, hepatic copper concentrations exceeded 2,000 microg/g dwl. Necroinflammatory alterations associated with copper-laden parenchymal cells were the notable histopathologic finding. The inflammatory infiltrate was either primarily lymphocytic or neutrophilic. Morphologic features of cholestasis generally were not prominent except in those dogs with severe pathology. These findings lend support to the hypothesis that a primary metabolic defect in hepatic copper metabolism occurs in the Dalmatian breed. The mechanism and genetic basis of this condition require further study.

Alanine Transaminase↗