Palmar Digital Neurectomy in Horses 57 Cases (1984–1990)

The medical records of 57 horses that had palmar digital neurectomy performed between 1984 and 1990 were reviewed. Neurectomies were performed either by transection and elec-trocoagulation (47 horses) or by the guillotine technique (10 horses). Middle-aged geldings, Quarter Horses, and Thoroughbreds were significantly over-represented when compared with the hospital population. Horses used as hunter/jumpers also appeared to be over-represented. Complications occurred in 17 (34%) of the 50 horses for which follow-up information was obtained. Recurrence of heel pain was the most common complication (14 horses). Palpable painful neuromas were detected in three horses. One year after neurectomy, 74% of the horses were sound; this decreased to 63% after 2 years.     

The Effect of Occlusive and Semi-Occlusive Dressings on the Healing of Acute Full-Thickness Skin Wounds on the Forelimbs of Dogs

This project compared the effects of hydrocolloid (HC) and hydrogel (HG) occlusive dressings and a polyethylene (PE) semi-occlusive dressing on the healing of acute full-thickness skin wounds on the forelimbs of 10 dogs. All treatments resulted in a similar degree of healing at postoperative days 4 and 7. No significant differences existed in the number of wounds that were more than 90% healed at postoperative day 28 between the group treated with the HG dressing and the group treated with the PE dressing. There were significantly fewer wounds more than 90% healed at postoperative day 28 in the group treated with the HC dressing. Wounds under the HG dressing had the largest mean percentage of contraction at postoperative days 21 and 28. Wounds under the HG dressing also had the largest contraction/re-epithelialization ratio (postoperative days 21 and 28) compared with wounds under the PE and HC dressings. Wounds under the PE dressing had a significantly higher mean percentage of re-epithelialization than wounds under both occlusive dressings on postoperative days 14, 21, and 28. Wounds under the two occlusive dressings had exuberant granulation tissue present more often than wounds under the PE dressing. The two occlusive dressings had significantly higher bacterial counts on wounds compared with wounds under the PE dressing; analysis of variance (ANOVA), P = .0008. Wounds under the HC dressing showed the poorest healing in all parameters.     

Thrombolytic Therapy in Dogs and Cats

Objective: To review the thrombolytic agents most commonly used in humans, their mechanisms of action, potential uses, adverse effects, and reports of their use in dogs and cats.
Human data synthesis: Thrombolytic agents avaliable in human medicine include streptokinase, urokinase, tissueplasminogen activator (t-PA), single-chain urokinase plasma activator (scu-PA) and anisoylated plasminogen-strep-tokinase activator complex (APSAC). These agents were originally used for the management of proximal deep vein thrombosis and severe pulmonary embolism but more recently, use of these drugs has been extended to include the treatment of acute peripheral arterial disease, cerebrovascular disease (stroke) and acute coronary thrombosis. The most predictable side effect associated with the use of thrombolytic therapy is hemorrhage.
Veterinary data synthesis: Clinical experience with thrombolytic agents in small animals is limited to streptokinase and t-PA. It is possible, that as in humans, canine and feline patients with PTE and right ventricular dysfunction may benefit from thrombolytic therapy but there are no veterinary studies to support this theory to date. Successful use of streptokinase has been documented in a small number of canine patients with systemic thromboembolism. ⁶³ Thrombolytic therapy is relatively efficacious in cats with aortic thromboemboli but is associated with a high mortality rate. ^59,60,64 With regard to use of t-PA in veterinary medicine, the small number of animals treated with varying protocols makes it impossible to provide safe and effective dose recommendations at this time.
Conclusions: Future goals for thrombolytic therapy in veterinary medicine include determination of more specific clinical indications, as well as design of effective protocols that minimize mortality and morbidity.     

Evaluation of auditory evoked potentials to predict depth of anaesthesia during fentanyl/fluanisone−midazolam anaesthesia in rats

Objectives To assess a method for monitoring depth of anaesthesia using components of middle latency auditory evoked potential (AEP) waveforms during anaesthesia with fentanyl/fluanisone and midazolam. Study design Prospective observational study. Animals Five female Wistar rats weighing between 210 and 250 g. Methods Implanted electrodes were used to record AEPs in animals receiving five doses of anaesthetic. Recordings were made at 5 minutes post‐injection (deep anaesthesia; no pedal withdrawal response, PWR) and then at 25 minutes (light anaesthesia; strong PWR). Responses showed five characteristic peaks occurring at 11, 14, 23, 42 and 68 ms that were measured for latency of occurrence and peak amplitude. Results Auditory evoked potential peaks P14, N23 and P42 were increased significantly in latency with successive anaesthetic injections [avg. F(1,4) = 12.53, p < 0.001; avg. F(1,4) = 10.6, p < 0.001; avg. F(1,4) = 3.9, p = 0.02, respectively]. Peak N23 showed a significant reduction in latency during the 20 minute recovery period following both the first and second anaesthetic injections (t(3) = 7.52, p = 0.005; t(4) = 5.17, p = 0.007, respectively). Peak P42 occurred significantly earlier 20 minutes following the second anaesthetic injection (t(4) = 4.75, p = 0.009). The mean overall depth of anaesthesia assessed using PWR scores was significantly correlated with the mean latency of peak N23, such that as the strength of PWR increased, N23 occurred significantly earlier (r = ?0.99, p = 0.01). The amplitude difference between peaks N23 and P42 increased after the second and third drug administrations [avg. F(1,4) = 10.65, p = 0.031 and avg. F(1,4) = 11.24, p = 0.028, respectively]. Conclusion The characteristics of these peaks, and in particular latency of peak N23, may provide a useful tool for assessing depth of anaesthesia produced by this, and possibly other anaesthetic agents.     

Diagnosis of systemic cryptococcosis by fecal cytology in a dog

A 3-year-old Boxer was presented with progressive diarrhea, vomiting, and lethargy of 5-months duration. The dog had watery black feces, a mature neutrophilia, and microcytic anemia. Cytologic evaluation of a direct fecal smear stained with Wright's-Giemsa revealed numerous encapsulated, narrow-based, budding organisms consistent with Cryptococcus sp. Pyogranulomatous inflammation and Cryptococcus organisms also were observed in ultrasound-guided fine-needle aspirates of the small intestine and mesenteric lymph nodes, and in histologic sections of colonic biopsies obtained by endoscopy. Multifocal chorioretinitis by fundic examination was consistent with systemic mycosis, and the reciprocal antigen titer (1600) on a cryptococcal antigen latex agglutination test for Cryptococcus neoformans was markedly increased. Using immunohistochemistry, the organism was identified further as C neoformans var. grubii (C neoformans var. neoformans serotype A). After 3 weeks of antifungal treatment, ultrasound examination revealed urinary bladder wall thickening, and Cryptococcus organisms were found in a urine sediment preparation. After 4 months of treatment, the dog was clinically normal and had no abnormal findings on CBC, serum biochemistry, urinalysis, or fecal cytology; however, the antigen titer remained unchanged, mesenteric lymphadenomegaly and jejunal wall thickening were still evident, and cytologic evaluation of fine-needles aspirates of the jejunal wall revealed budding Cryptococcus organisms. Intestinal involvement in dogs with cryptococcosis is rare, and diagnosis by fecal cytology has not been documented previously.     

Hepatocellular carcinoma with secondary abscessation in a cat

A 16-year-old castrated male domestic shorthair cat was presented for investigation of weight loss, lethargy, inappetence and polydypsia. On serum biochemical analysis there was evidence of severe hepatocellular damage and cholestasis. Abdominal ultrasonographic examination revealed an irregular lesion of mixed echogenicity in a left hepatic lobe. It was compromised of a hypoechoic periphery surrounding an anechoic central area containing highly echogenic densities with distal acoustic shadowing suggestive of gas formation. On necropsy, the only gross abnormality was a solitary 5 cm x 3 cm x 3 cm multilobulated mass in the left lateral hepatic lobe, containing foul-smelling purulent fluid within a thick fibrous wall. Cytological examination of the fluid revealed numerous degenerate neutrophils and large numbers of Gram-positive spore-forming rods. The histopathological diagnosis was hepatocellular carcinoma with secondary abscessation. The bacterial morphology was consistent with Clostridia sp. Both hepatocellular carcinoma and focal hepatic abscessation are rare in cats. Hepatic abscesses should be included in the differential diagnosis of cats with non-specific signs, even in the absence of biochemical evidence of a hepatopathy.     

Concurrent Fusarium chlamydosporum and Microsphaeropsis arundinis infections in a cat

A 7-year-old cat was presented initially with multiple draining sinuses on the metatarsal region of its right hindlimb. Another lesion had appeared at the same time on the fifth proximal interphalangeal joint of the left forelimb. Histopathological examination of a biopsy from the right hindlimb lesion revealed chronic pyogranulomatous inflammation associated with yeast-like bodies and septate mycelia; a fungus was cultured on conventional media but not identified further. Culture of a swab collected from the left forelimb lesion demonstrated a pigmented fungus, also not characterised further. Although there was initially a favourable response to ketoconazole (Nizoral, Janssen-Cilag Pty. Ltd) and beta-lactam therapy, the infection in the hind limb relapsed subsequently, and Fusarium chlamydosporum was cultured from deep biopsy specimens. Clinical improvement followed debridement and itraconazole (Sporanox, Janssen-Cilag Pty. Ltd; 100 mg orally once daily), however amputation of the limb represented the best chance for a cure. The cat made an uncomplicated recovery following surgery and remained well for five months until the lesion on the left forelimb recurred. Amputation of the distal fourth digit was then performed, and the resected tissue submitted for culture. The dematiaceous fungus Microsphaeropsis arundinis was subsequently cultured. The cat remained well for several months, until a further F. chlamydosporum infection developed on the body wall. This was excised 7 months ago, and no lesions have recurred in this area. Importantly, this is the first reported case of M. arundinis infection in a mammalian host.     

Nocardia infections in cats: a retrospective multi-institutional study of 17 cases

OBJECTIVE: To record 17 cases of nocardiosis in cats from eastern Australia and to compare this series with cases previously reported. DESIGN: Retrospective/prospective study. RESULTS: Nocardia spp infections were diagnosed in 17 cats over 14 years from the three eastern states of Australia. There were no isolates from dogs during this period, but one isolate from a koala and two from dairy cows. The majority of cats presented with spreading lesions of the subcutis and skin associated with draining sinus tract(s). Early cutaneous lesions consisted of circumscribed abscesses. Infections spread at a variable rate, generally by extension to adjacent tissues. Lesions were generally located in regions subjected to cat bite or scratch injuries, including limbs, body wall, inguinal panniculus and nasal bridge. In some other cases, lesions were situated on distal extremities. The clinical course was variable, from chronic, indolent, initially localised infections to acute fulminating disease. Of the 17 cats, 14 were domestic crossbreds and three were purebreds. There was a preponderance of male cats (12 castrated, 1 entire young adult, 1 entire kitten). Nine of 17 cats were 10 years or older. Interestingly, the majority of infections were attributable to N nova. Immediate and/or predisposing causes could be identified in all cases, and included: renal transplantation [one cat]; chronic corticosteroid administration [three cats]; catabolic state following chylothorax surgery [one cat]; fight injuries [seven cats]; FIV infections [three of seven cats tested]. Of the 17 cats, three were apparently cured. Four were thought to be cured, but infection recurred after several months. Three cats responded partially but were euthanased, while another was improving when it died of unrelated complications. Two died despite treatment and two were euthanased without an attempt at therapy. For two cats there were either insufficient records or the patient was lost to follow up. CONCLUSION: Nocardiosis is a rare, serious disease. Currently it is more common in cats than dogs. Nocardial panniculitis may be clinically indistinguishable from the syndrome caused by rapidly growing mycobacteria. Although the prognosis is guarded, patients with localised infections caused by N nova often respond to appropriate therapy. If definitive treatment is delayed because of misdiagnosis, the disease tends to become chronic, extensive and refractory. Insufficient duration of therapy leads to disease recurrence.     

Plasma concentrations of chloramphenicol after subcutaneous administration to koalas (Phascolarctos cinereus) with chlamydiosis

Nine mature koalas with chlamydiosis, typically keratoconjunctivitis and/or urogenital tract infection, were treated with daily subcutaneous injections of chloramphenicol at 60 mg/kg for 45 days (five koalas), or for a shorter duration (four koalas). All koalas were initially positive for Chlamydia pecorum as determined by real-time polymerase chain reaction (qPCR). Plasma chloramphenicol concentrations were determined at t = 0, 1, 2, 4, 8, and 24 h after the day 1 injection (nine koalas) and after the day 15 injection (seven koalas). Chloramphenicol reached a median (and range) maximum plasma concentration of 3.03 (1.32-5.03 μg/mL) at 4 (1-8 h) after the day 1 injection and 4.82 (1.97-27.55 μg/mL) at 1 (1-2 h) after day 15. The median (and range) of AUC(0-24) on day 1 and day 15 were 48.14 (22.37-81.14 μg·h/mL) and 50.83 (28.43-123.99 μg·h/mL), respectively. The area under the moment curve (AUMC)(0-24) median (and range) for day 1 and day 15 were 530.03 (233.05-798.97 h) and 458.15 (291.72-1093.58 h), respectively. Swabs were positive for chlamydial DNA pretreatment, and all koalas except one, produced swabs negative for chlamydial DNA during treatment and which remained so, for 2-63 days after treatment, however whether chloramphenicol treatment prevented long-term recrudescence of infection was not established. At this dose and dosing frequency, chloramphenicol appeared to control mild chlamydial infection and prevent shedding, but severe urogenital disease did not appear to respond to chloramphenicol at this dosage regime. For koalas affected by severe chlamydiosis, antibiotics alone are not sufficient to effect a cure, possibly because of structural or metabolic changes associated with chronic disease and inflammation.