Localised Mycobacterium ulcerans infection in four dogs

Localised infection caused by Mycobacterium ulcerans is described in two Kelpies, a Whippet and a Koolie domiciled on the Bellarine Peninsula, Victoria, Australia. The diagnosis was confirmed using real-time polymerase chain reaction (PCR) targeting the M. ulcerans-specific insertion sequence (IS2404) in DNA extracted from swabs of ulcerated lesions in all cases. Where available, molecular typing confirmed that three of the dogs were infected with a strain of M. ulcerans that was indistinguishable from a disease-causing strain in people and other animals in Victoria. One dog was still undergoing treatment at the time of writing, but the remaining three dogs were successfully treated with a combination of surgical debridement and medical therapy in one case, and medical therapy alone in the other two. Investigation of the home environs of three of the dogs using real-time PCR revealed low amounts of M. ulcerans DNA in various environmental samples. Mycobacterium ulcerans infection should be included in the differential diagnoses of any ulcerated skin lesions in dogs that live in or visit endemic areas of Victoria and Queensland.     

Brown spider envenomation

The venom from spiders of the genus Loxosceles, the most famous being Loxosceles recluse (the most brown recluse spider) can cause serious poisoning. These spiders inhabit the south and south central states from Georgia through Texas and north to southern Wisconsin. They are commonly called violin spiders because of the violin-shaped marking on the dorsum of the cephalothorax. Many dermonecrotic lesions are incorrectly diagnosed as Brown recluse bites, as up to 50% of the diagnoses are in geographic regions of the country which do not have Loxosceles spiders. Sphingomyelinase D is the primary venom dermonecrotic factor. The toxin depletes serum hemolytic complement, prolongs the activated partial thromboplastin time and depletes clotting factors VIII, IX, XI, and XII. The venom induces rapid coagulation and occlusion of small capillaries, causing subsequent tissue necrosis. A classic "bulls eye" lesion develops, an erythematous area inside of which is a pale ischemic region that develops a dark necrotic center as the lesion matures. Healing is slow, and these ulcers may persist for months leaving a deep scar. Systemic signs occur less commonly but can be life threatening. The most prevalent sign is a hemolytic anemia with significant hemoglobinuria. There is no specific antidote. Dapsone a leukocyte inhibitor has been shown to be effective in treating dermal lesions in animal models. Conservative therapy includes several cleanings daily with Burrow's solution and hydrogen peroxide. Systemic signs of Loxosceles envenomation are potentially fatal and should be aggressively addressed. Hospitalization and intravenous fluid therapy may be needed to maintain adequate hydration and to protect renal function.     

Mycobacterium ulcerans infections in two horses in south-eastern Australia

Two horses were diagnosed as having Mycobacterium ulcerans infections. The first was a 21-year-old Quarterhorse-cross mare living in Mallacoota (a coastal town near the border of New South Wales and Victoria, Australia) that presented with lichenification, hair-loss and oedema on a fetlock, which subsequently ulcerated, as well as a non-healing ulcer on the wither. The second horse was a 32 year-old Standardbred gelding from Nicholson, near Bairnsdale, Victoria, that had an ulcerated lesion on its caudal thigh. Histologically, there were characteristic changes seen with M. ulcerans infections in other species, including extensive necrosis without associated granulomatous inflammation. The organisms were seen in Ziehl-Neelsen-stained smears or sections of the lesions from both horses and were isolated in culture from the first horse. A definitive diagnosis was provided by real-time polymerase chain reaction targeting the M. ulcerans-specific insertion sequence, IS2404. Delayed identification of the infectious agent in the first case led to the use of suboptimal antimicrobial therapy, resulting in failure to control the infection and the horse was subsequently euthanased. The second horse was successfully treated following surgical debulking of the centre of the lesion and one session of aggressive cryosurgery. Mycobacterium ulcerans should be considered in the differential diagnosis of unexplained lichenification with oedematous and ulcerated skin lesions in horses living in regions where this organism is endemic.     

The Effect of Tramadol and Indomethacin Coadministration on Gastric Barrier Function in Dogs

Background

Tramadol is a centrally acting analgesic that is often used in conjunction with nonsteroidal anti‐inflammatory drugs (NSAIDs). The effect of coadministration of tramadol and indomethacin on gastric barrier function in dogs is unknown.

Hypothesis/Objectives

That coadministration of a nonselective NSAID (indomethacin) and tramadol would decrease recovery of barrier function as compared with acid‐injured, indomethacin‐treated, and tramadol‐treated mucosa.

Animals

Gastric mucosa of 10 humanely euthanized shelter dogs.

Methods

Ex vivo study. Mounted gastric mucosa was treated with indomethacin, tramadol, or both. Gastric barrier function, prostanoid production, and cyclooxygenase expression were quantified.

Results

Indomethacin decreased recovery of transepithelial electrical resistance after injury, although neither tramadol nor the coadministration of the two had an additional effect. Indomethacin inhibited production of gastroprotective prostanoids prostaglandin E₂ (acid‐injured PGE ₂: 509.3 ± 158.3 pg/mL, indomethacin + acid injury PGE ₂: 182.9 ± 93.8 pg/mL, P < .001) and thromboxane B₂ (acid‐injured TXB ₂: 233.2 ± 90.7 pg/mL, indomethacin + acid injury TXB ₂: 37.9 ± 16.8 pg/mL, P < .001), whereas tramadol had no significant effect (PGE ₂ P = .713, TXB ₂ P = .194). Neither drug had an effect on cyclooxygenase expression (COX‐1 P = .743, COX‐2 P = .705). Acid injury induced moderate to marked epithelial cell sloughing, which was unchanged by drug administration.

Conclusions and Clinical Importance

There was no apparent interaction of tramadol and a nonselective cyclooxygenase in this ex vivo model. These results suggest that if there is an adverse interaction of the 2 drugs in vivo, it is unlikely to be via prostanoid inhibition.     

Primary malignant melanoma in the oesophagus of a foal

A 2‐month‐old filly was evaluated for severe colic. Ultrasound, abdominocentesis and physical examination findings prompted an abdominal exploratory surgery. Perforation of the stomach was discovered during the surgery. The filly was humanely subjected to euthanasia under anaesthesia and post mortem examination was performed. In addition to gastric and duodenal ulceration, a thickened, black area of the proximal oesophagus was discovered. Histopathology of the lesion revealed primary malignant melanoma. Although rare, primary melanoma can occur in noncutaneous locations.     

Courses for horses: Rethinking the use of proton pump inhibitors in the treatment of equine gastric ulcer syndrome

Oral omeprazole has been the cornerstone of equine gastric ulcer syndrome (EGUS) treatment for nearly 20 years. However, approximately 15–30% of equine squamous gastric disease (ESGD) cases and 75% of equine glandular gastric disease (EGGD) cases fail to heal within current treatment guidelines. Recently, a number of factors that may affect the efficacy of oral omeprazole have been highlighted and the pharmacodynamics of a number of novel proton pump inhibitors (PPIs) have been described in the horse. The purpose of this article is to review the factors that affect oral omeprazole efficacy, with the goal of maximising therapeutic response, and the novel PPIs recently described.     

Comparative endoscopic evaluation of normal and ulcerated gastric mucosae in Thoroughbred foals

To contribute to early diagnosis and treatment of gastric ulcer of foals, we examined the gastric mucosa of healthy and affected foals using an endoscope. In healthy foals, the characteristic changes in the development of the squamous mucosa were seen mainly in the squamous mucosa, and maturation of the squamous mucosa in the greater curvature (GC-S) occurred more slowly than that of the squamous mucosa in the lesser curvature (LC-S). Epithelial desquamation in the LC-S and GC-S was observed between 6 and 90 days but was not observed in the LC-S at about 60 days, whereas it was observed in the GC-S until 90 days old. These findings suggest that there is a difference in the development of the gastric mucosa by region and that desquamation continues over a term longer than studies have reported in the past. In the affected foals, the minimum age at which gastric ulcer was observed was 4 days old. Gastric ulcers formed predominantly in the squamous mucosa (LC-S and GC-S) of foals with an immature mucosa before the weaning period, and the peak incidence occurred between 61 and 90 days old. The differences in the ulceration sites were considered to depend on the difference in the development (maturation) stage of the squamous mucosa. The grading score of the gastric ulcer increased with the growth of the affected foals. The gastric ulcer might be enhanced greatly by stress in the weaning period.     

一例奶牛皱胃溃疡伴低血钾综合征的临床治疗

2005年12月郑州牧业工程高等专科学校附属兽医院接诊了1例皱胃溃疡伴低血钾综合征的奶牛，该牛同时患有低血钙、酮病等。病情发展中患牛在血钾含量为2.28 mmol/L时四肢无力，卧地不起，通过补钾及综合治疗血钾升至3.45 mmol/L时又能自主站立，对皱胃溃疡采取消炎、抑制胃酸分泌、收敛止血等方法进行治疗。     

Review of Pododermatitis circumscripta (ulceration of the sole) in dairy cows

Sole ulcers are among the most frequent causes of lameness in dairy cattle. They are found most commonly in the hind lateral claw, are frequently bilateral, and have a high rate of reoccurrence. The pathogenesis of sole ulceration is primarily based on mechanical injury by the 3rd phalanx to the corium, basement membrane, and basal layers of the sole epidermis as a result of failure of the suspensory apparatus in the claw. The main pathways in the failure of the suspensory system include inflammatory (dermal vascular changes followed by disruption of keratinocyte proliferation and differentiation caused by local and systemic mediators) and noninflammatory (hormonal and biochemical changes in the peripartum period resulting in alterations of connective tissue in the suspensory system) pathways. Sole ulcers tend to occur in specific locations; the most reported site is the junction of the axial heel and sole. Other locations include the apex of the toe and the heel. Varying degrees of lameness may result, and the most severe are seen with complicated cases in which ascending infection affects the deeper structures of the claw. Pathologic changes at the ulcer site include dyskeratosis and dilated horn tubules with microcracks. Vascular changes include dilatation and thrombosis of capillaries with "neocapillary formation." Areas of dyskeratosis may remain for as long as 50 days at the ulcer site. Treatment includes corrective trimming and relief of weight bearing. Complicated cases may require surgical intervention.     

Placement of an indwelling percutaneous gastrotomy (PEG) tube for the measurement of intra‐gastric pH in two horses

Intra‐gastric pH monitoring is an important tool in the validation of acid suppressive drugs. To date, several methods of monitoring intra‐gastric pH in the horse have been described. However significant limitations are present in the existing models. This article describes the placement of a percutaneous gastrotomy (PEG) tube secured with a button gastropexy in the standing horse through which the pH of the ventral stomach can readily be measured under both fed and fasted conditions.     

The Effects of Peptide-Precipitating Lignosulphonic Acids on the Proteolytic Activity of Pepsin in Vitro and on the Response of Pigs to an Ulcer Inducing Diet

The inhibitory effect of peptide-precipitating lignosulphonic acids on the proteolytic activity of pepsin in vitro has been studied. When an unfractionated lignosulphonic acid preparation was used, total inhibition of the activity of 5 µg crystalline pepsin was obtained by addition of about 15 mg of lignosulphonic acids.The greatest inhibitory effect was seen with the high-molecular weight lignosulphonic acids, but an effect was also seen with middle-and low-molecular weight lignosulphonic acids.A reduction in the inhibitory effect was seen when the experiments were performed in the presence of arginine. The inhibition mechanism is discussed in relation to the peptide-precipitating ability of the lignosulphonic acids.No obvious protection against the appearance of stomach ulcers in four pigs receiving an ulcerogenic diet was seen.     

Distichiasis causing recurrent corneal ulceration in two Friesian horses

Two cases of distichiasis with subsequent recurrent superficial corneal ulceration are described in Friesian horses. Case 1 was a 9‐year‐old Friesian stallion with distichiae on the superior and inferior eyelids of both eyes corresponding to areas of recurrent superficial corneal ulceration. Case 2 was a 5‐year‐old Friesian gelding with a single distichia on the inferior lid associated with recurrent superficial corneal ulceration in the right eye. Case 1 underwent cryotherapy and epilation twice under standing sedation without resolution of distichiasis. A partial tarsal plate excision was then performed on the inferior left lid, which was the most severely affected. Cryotherapy was repeated one and 4 months post operatively due to recurrence. Cryotherapy was associated with skin depigmentation and repigmentation several months following the procedure. No recurrence has been reported up to 3 years following the fourth cryotherapy procedure. Case 2 was treated with epilation. Distichiasis should be included as a differential diagnosis when presented with a horse experiencing recurrent superficial corneal ulcerations. There has been no established breed association for Friesian horses and distichiasis but, due to the inherited nature of this condition in some human patients and dogs, this possibility should be investigated.