Clinical study evaluating the accuracy of injecting the distal tarsal joints in the horse.

BACKGROUND: Osteoarthritis (OA) of the centrodistal (CD) and tarsometatarsal (TMT) joints is a common cause of lameness in horses. Intra-articular diagnostic anaesthesia and/or therapeutic injection are relied upon to help diagnose and treat many horses with OA of these joints. OBJECTIVES: The objective of this study was to determine the accuracy of arthrocentesis of the CD and TMT joints using a sample population of equine surgeons and surgery residents. STUDY DESIGN: Randomised experimental study. METHODS: Six operators each injected four CD and four TMT joints in 12 sedated horses. The operators were randomly assigned to inject either the left CD and right TMT or the right CD and left TMT on four randomly assigned horses. The joints were injected with a 4 ml solution of contrast medium (2 ml), sterile saline (1.5 ml) and amikacin (0.5 ml). A minimum of two radiographs of each joint was obtained to evaluate the presence of contrast medium within the target joint. RESULTS: The TMT joint was successfully injected in 23/24 joints (96% accuracy). The CD joint was successfully injected in 10/24 joints (42% accuracy). Communication between the TMT and CD joints was visible in 26% of successful TMT injections. Communication between the CD and TMT joints was visible in 20% of successful CD injections. MAIN LIMITATIONS: Despite specific requests to do so, we were unable to standardise the injection technique across all operators. CONCLUSIONS: The accuracy of injecting the TMT and CD joints of sedated horses was 96 and 42%, respectively. The CD joint was frequently missed with contrast medium being placed in the periarticular tissues. These data support the clinical impression of the difficulty of injecting the CD joint and suggests that practitioners should utilise ancillary methods, such as radiographs, to ensure proper needle placement.

Current and potential renal applications of contrast-enhanced ultrasound.

The combination of microbubble technology and complementary ultrasound techniques has resulted in the development of contrast-enhanced ultrasound (CEUS) and, although initial clinical applications largely focussed on the liver, these are now becoming more diverse. With regard to the kidney, it is a safe, well-tolerated, and reproducible technique, and in selected cases, can obviate the need for computed tomography or magnetic resonance imaging. A clear advantage is the absence of nephrotoxicity. With respect to the current and potential renal applications, it is a useful technique in the evaluation of pseudotumours, acute pyelonephritis, renal tumours, cystic lesions, vascular insults, and renal transplantation. It may also be of value for monitoring the kidney following anti-angiogenic treatment or nephron-sparing interventional techniques for renal tumours. Assessment of microvascular perfusion using time-intensity curves is also likely to have further far-reaching applications in the kidney as well as other organs.

Incidence of support limb laminitis in horses treated with half limb, full limb or transfixation pin casts: a retrospective study of 113 horses (2000-2009).

REASONS FOR PERFORMING STUDY: To determine the incidence of support limb laminitis among horses treated with half limb, full limb or transfixation pin casts and determine potential risk factors. METHODS: Medical records of 113 horses treated with half limb, full limb or transfixation pin casts at an equine referral hospital from 2000 to 2009 were reviewed. Associations between potential risk factors and development of support limb laminitis were evaluated by bivariable and multivariable logistic regression analyses. RESULTS: Of the 113 horses that received casts, 14 (12%) developed confirmed support limb laminitis. The bodyweight of the horse and duration of casting in weeks were significantly associated with support limb laminitis. Horses requiring full limb casts or transfixation pin casts were more likely to develop this complication than horses requiring half limb casts. There were no significant associations between developing support limb laminitis and weightbearing capacity on presentation to the hospital, the limb affected (fore- or hind), whether there was a fracture present or breed of horse. CONCLUSIONS: Support limb laminitis is a relatively common complication among horses treated with half limb, full limb and transfixation pin casts. Greater durations of casting and higher bodyweights increase the likelihood of developing this complication. POTENTIAL RELEVANCE: Support limb laminitis may occur secondary to any painful unilateral lameness and is not necessarily more likely to develop in horses with severe orthopaedic conditions such as fractures. However, heavier horses, those requiring casts for longer periods of time and those that require a full limb or transfixation pin cast as opposed to a half limb cast should be considered to have an increased risk for developing support limb laminitis post operatively.

Concurrent or sequential development of medial meniscal and subchondral cystic lesions within the medial femorotibial joint in horses (1996-2006).

UNLABELLED: Summary Reasons for performing study: Medial meniscal injuries and subchondral cystic lesions (SCL) are known to occur independently within the medial femorotibial (MFT) joint in horses. However, there are no reports of a potential clinical relationship between these 2 types of lesions. OBJECTIVES: To: 1) document the concurrent presence or sequential development of medial meniscal and SCL of the medial femoral condyle within the MFT joint; and 2) determine the prognosis with both types of lesions. METHODS: Retrospective case series of horses with both a medial meniscal and SCL of the medial femoral condyle identified concurrently or sequentially by radiography, arthroscopy or post mortem examination. Case records and radiographs were reviewed, and a telephone survey of referring veterinarians, owners and trainers was conducted. RESULTS: Twenty-one horses (9.1% of all horses undergoing MFT joint arthroscopy) were identified to have both a medial meniscal injury and SCL of the medial femoral condyle. Thirteen horses had both abnormalities identified concurrently, 6 developed a meniscal lesion subsequent to SCL debridement, and 2 developed a SCL subsequent to a medial meniscal injury. Only 4/19 horses were classified as successful and returned to their intended use. The severity of the meniscal injury was significantly associated with the severity of lameness but not with outcome. CONCLUSIONS: A low percentage of horses may develop both a meniscal injury and SCL of the medial femoral condyle within the MFT joint and have a poor prognosis. POTENTIAL RELEVANCE: Trauma to the MFT joint may lead to both meniscal and subchondral bone damage of the medial femoral condyle that may be recognised concurrently or sequentially.

Arthroscopic injection of corticosteroids into the fibrous tissue of subchondral cystic lesions of the medial femoral condyle in horses: a retrospective study of 52 cases (2001-2006).

REASONS FOR PERFORMING STUDY: There are no published results of subchondral cystic lesions (SCLs) in the medial femoral condyle (MFC) treated with arthroscopic injection of corticosteroids into the lining of the cyst. OBJECTIVES: 1) To determine the success rate for treatment of SCLs in the MFC with arthroscopic injection of the fibrous tissue of the cyst with corticosteroids. 2) To identify any factors that may predict outcome. HYPOTHESES: Injection of the fibrous tissue of SCLs of the MFC with corticosteroids utilising arthroscopic guidance yields a similar or higher chance for intended performance than does arthroscopic debridement as previously reported; this technique will be effective for treating SCLs in older horses. METHODS: Horses with clinical and radiographic evidence of a SCL in the MFC were injected with corticosteroids under arthroscopic guidance, and case records and radiographs were reviewed retrospectively. A telephone survey of referring veterinarians, owners and trainers was conducted. RESULTS: Thirty-five of 52 (67%) cases were classified as successful involving 73 SCLs of which 56 (77%) were classified as successful. There was no significant association between age group (age3 years) and outcome, or cyst configuration and outcome. Significantly more unilateral SCLs (28/31 [90%] SCLs) were classified as successful than bilateral (28/42: 67%). There were significant differences in outcome based on the surgeon operating the case and an association between pre-existing radiographic findings of osteophytes and negative outcome. CONCLUSIONS: Injection of SCLs utilising arthroscopic guidance is an effective alternative method of surgical treatment of SCL. POTENTIAL RELEVANCE: This technique offers a similar chance of success as has been reported with debridement and may allow for a shorter period of convalescence. If unsuccessful, the option remains to debride the cyst in a second surgery.

Effects of glucosamine hydrochloride and chondroitin sulphate, alone and in combination, on normal and interleukin-1 conditioned equine articular cartilage explant metabolism.

REASONS FOR PERFORMING STUDY: Clinical trials in human and veterinary literature have documented the benefits of oral nutraceutical joint supplements containing glucosamine (GU) and chondroitin sulphate (CS) to treat mild to moderate osteoarthritis, but the effects of these components have not yet been conclusively determined. OBJECTIVES: To assess varying dosages of GU and CS on normal and interleukin-1alpha (IL-1) conditioned equine cartilage explants and rationalise the use of these products. HYPOTHESIS: Treatment would not be detrimental to cartilage metabolism and higher dosages and the combination of GU and CS would be more beneficial than lower dosages and. GU or CS alone. METHODS: Articular cartilage explants collected from the femoral trochlea and condyles were cultured in normal and IL-1 conditioned media. Treatment groups included 0, 12.5, 25,125 and 250 microg/ml concentrations of GU alone, CS alone, or GU+CS in combination. Glycosaminoglycan (GAG) synthesis and total GAG content in the explants and media were analysed. RESULTS: There were no detrimental effects of GU, CS or GU+CS on cartilage metabolism. High dosages of GU+CS reduced total GAG release into the media (degradation). CONCLUSIONS: Our results suggests that GU+CS may prevent cartilage GAG degradation. POTENTIAL RELEVANCE: The combination of GU and CS may be more effective in preventing or treating osteoarthritis in horses than either product alone.

Comparison of intra-articular drilling and diode laser treatment for arthrodesis of the distal tarsal joints in normal horses.

REASONS FOR PERFORMING STUDY: Anecdotal reports suggest that laser-facilitated arthrodesis of the distal tarsal joints improves the prognosis compared with intra-articular drilling but no objective comparisons have been performed. OBJECTIVES: To evaluate intra-articular drilling and laser-facilitated arthrodesis using in situ and in vivo techniques. METHODS: Fourteen cadaver limbs were evaluated in situ for chondrocyte viability after both surgical techniques. In vivo, one randomly selected limb was subjected to laser-facilitated arthrodesis and the other underwent intra-articular drilling in 6 normal horses. Clinical examinations were performed at 1, 3 and 5 months. Two horses were subjected to euthanasia at 1, 3 and 5 months. RESULTS: Significantly more chondrocyte death was observed with laser-facilitated arthrodesis compared to drilling, but the overall degree suggested only a focal effect. In vivo, both groups demonstrated minimal post operative morbidity. There was more evidence of arthrodesis seen at all time points with intra-articular drilling. CONCLUSIONS: This study demonstrated that changes associated with ultimate arthrodesis occur earlier after intra-articular drilling of the distal tarsal joints than laser-facilitated arthrodesis, although clinically affected horses may respond differently. POTENTIAL RELEVANCE: Intra-articular drilling may provide earlier arthrodesis of the distal tarsal joints, but not necessarily a better long-term result.

Partial nephrectomy used to treat renal cell carcinoma arising in a live donor transplant kidney.

There are few reported cases of renal cell carcinoma (RCC) arising in kidney allografts. Whether these tumours occur due to post-transplant malignant transformation or are present at the time of transplantation is unclear. The influence of immunosuppression must be considered in their development, progression and treatment. We report a case of a RCC presenting asymptomatically in a functioning live donor renal allograft 173 months after transplantation. In an attempt to avoid return to dialysis treatment, a partial nephrectomy was carried out. To optimise the procedure, and to assure cancer clearance, combined intraoperative ultrasound and frozen section analysis were used. Our patient remains disease free and dialysis independent at 22 months follow up. To our knowledge, this patient represents the only live donor organ transplant tumour reported to be treated using nephron-sparing surgery and remain dialysis independent. Partial nephrectomy should be considered as a treatment option in such cases.

Effects of dosage titration of methylprednisolone acetate and triamcinolone acetonide on interleukin-1-conditioned equine articular cartilage explants in vitro.

REASONS FOR PERFORMING STUDY: Osteoarthritis is a frequent sequela of joint disease, especially with severe injuries or if attempts at therapy are unsuccessful. Negative and positive effects of corticosteroid treatment of articular cartilage have been demonstrated by in vitro and in vivo studies. OBJECTIVES: To assess the metabolic effects of varying dosages of methylprednisolone acetate (MPA) and triamcinolone acetonide (TA) on interleukin-1alpha (IL-1) conditioned equine cartilage explants. Our hypothesis was that lower dosages of corticosteroids would be less detrimental to cartilage metabolism than higher dosages. TA would be less detrimental to cartilage metabolism than MPA. METHODS: Treatment groups included articular cartilage explants with no IL-1 (control), IL-1 alone, and IL-1 plus 10, 5, 1 and 0.5 mg/ml MPA or 1.2, 0.6, 0.12 and 0.06 mg/ml TA. Explants were labelled with 35SO4 prior to the beginning and end of the experiment to assess glycosaminoglycan (GAG) degradation and synthesis, respectively. Total GAG content in media and explants and total cartilage DNA were also analysed. RESULTS: MPA and TA reduced GAG synthesis compared to control and IL-1 alone. The highest dosage of MPA (10 mg/ml) reduced GAG synthesis less than lower dosages of MPA and all dosages of TA. Compared to IL-1 alone, all dosages of TA and lower dosages of MPA increased GAG degradation. MPA at 10 mg/ml reduced GAG degradation. Both MPA and TA increased media GAG content compared to control and IL-1 explants. Total cartilage GAGs were unchanged with MPA, but reduced with TA, compared with IL-1 alone. Total cartilage DNA was decreased with MPA and increased with TA compared to IL-1 and control explants. CONCLUSIONS: MPA and TA did not counteract the negative effects of IL-1 and did not maintain cartilage metabolism at control levels. Lower dosages of MPA and TA were not less detrimental to cartilage metabolism than higher dosages. TA did not appear to be less harmful than MPA on cartilage metabolism. The results of this study differ from the findings of comparable in vivo studies. POTENTIAL RELEVANCE: The low numbers of horses used in this study limits extrapolation of these findings to the equine population; however, this study also questions the clinical relevance of this in vitro model.

Inferior epigastric artery pseudoaneurysm: ultrasound diagnosis and treatment with percutaneous thrombin.

A case of a pseudoaneurysm arising from the inferior epigastric artery in a patient presenting with a rectus sheath haematoma is reported. The pseudoaneurysm was successfully treated by percutaneous injection of human thrombin.

Does contraction of mesh following tension free hernioplasty effect testicular or femoral vessel blood flow?

Prosthetic mesh can contract by 20-75% of its original size within ten months after implantation. We set out to determine whether this contraction has any effect on testicular or femoral vessel blood flow following open or laparoscopic hernia repair. Twenty patients who underwent mesh repair of a primary unilateral inguinal hernia repair by Open (10) or Laparoscopic (10) methods a median of 3 years previously were investigated by ultrasound to determine the haemodynamic characteristics of the testis and femoral vessels. There was no significant difference in testicular blood flow, volume or echogenicity between the different types of repair or the contralateral side. The vertical and transverse dimensions of the femoral artery and vein were similar in all groups as was blood flow. Mesh contraction following inguinal hernioplasty does not adversely affect the testis or femoral vessels and can be used safely for both anterior and preperitoneal approaches.

Ultrasound of renal transplantation.

The most effective primary treatment of chronic renal failure is renal transplantation. A significant improvement in lifestyle and family life in conjunction with it being an extremely cost-effective procedure has resulted in an intense monitoring and imaging programme to help ensure a successful outcome. Ultrasound, both grey-scale and colour-flow Doppler, are useful monitoring techniques when interpreted in the clinical context, and in the delineation of peri-transplant collections, some of which can be drained under ultrasound guidance. After the early post-operative period it can also be utilized in the diagnosis of chronic vascular complications including transplant artery stenosis and arteriovenous fistula, although it is of limited use in the diagnosis of chronic rejection. This article will discuss the role of ultrasound in all its guises and how its efficacy in both the early transplant period in the monitoring of graft dysfunction and in the detection of the more chronic conditions including transplant artery stenosis and arteriovenous fistulae. A more limited role for ultrasound also exists in the long-term follow-up of patients and to aid the detection of complications including susceptibility to malignancy.

Renal arteries in patients at risk of renal arterial stenosis: multicenter evaluation of the echo-enhancer SH U 508A at color and spectral Doppler US. Levovist Renal Artery Stenosis Study Group.

PURPOSE: To assess SH U 508A in the diagnosis of suspected renal arterial stenosis by means of ultrasonography (US) and to confirm the safety of SH U 508A in a clinical setting. MATERIALS AND METHODS: A randomized crossover study was performed in 198 patients from 14 European centers who were referred for renal arterial angiography because they were suspected of having renal arterial stenosis. All patients underwent nonenhanced and SH U 508A-enhanced Doppler US of the renal arteries. Doppler criteria included measurement of renal arterial peak systolic velocity (threshold, 1.4-2.0 m/sec) in all centers and renoaortic ratio (threshold, 3.0-3.5) in nine. RESULTS: The number of examinations with successful results increased following enhanced Doppler US examination--160 (83.8%) compared with 122 (63.9%) with nonenhanced Doppler US (P = .001), including patients with obesity or renal dysfunction. Renal arterial stenosis (> or =50%) was detected at angiography in 72 patients. Results at enhanced Doppler US were in agreement with results at angiography more often than with results at nonenhanced Doppler US in the diagnosis or exclusion of renal arterial stenosis (P = .001). For patients examined with nonenhanced and enhanced Doppler US, sensitivity (80.0% and 83.7%, respectively) and specificity (80.8% and 83.6%, respectively) remained unchanged. There were no clinically important adverse events following use of SH U 508A. CONCLUSION: In patients suspected of having renal arterial stenosis, SH U 508A increased the number of diagnostic renal arterial Doppler studies.

Extra-renal pseudoaneurysm: an uncommon complication following renal transplantation.

Vascular complications are reported in a significant proportion of patients following renal transplantation and are a contributory cause of graft dysfunction. Of these, pseudoaneurysm formation is one of the least common. We present three patients in whom extra-renal transplant artery pseduoaneurysms arising from the surgical anastomosis between the external iliac and renal transplant artery were initially diagnosed with colour Doppler ultrasound, and outline their subsequent management.

The effect of oral isoxsuprine and pentoxifylline on digital and laminar blood flow in healthy horses.

OBJECTIVE: To quantitate blood flow in the palmar digital artery and dorsal laminae of the hoof in standing, unmedicated, nonsedated horses, and in horses treated with oral isoxsuprine, oral pentoxifylline, and intravenous acetylpromazine as a positive control. STUDY DESIGN: Experimental study; treatments administered in a random cross-over design. ANIMALS: A total of 6 healthy horses selected with at least one nonpigmented forelimb hoof wall and determined to be free of laminitis. METHODS: All horses were instrumented with a flow probe placed around one palmar digital artery under general anesthesia and a laser doppler flow probe placed within a hole in the dorsal hoof wall to measure digital blood flow and laminar perfusion respectively. Baseline readings of palmar digital blood flow and laminar perfusion were recorded before and between treatments. Horses were randomly assigned to one of two groups and treated with either isoxsuprine (1.2 mg/kg, orally twice daily for 10 days) or pentoxifylline (4.4 mg/kg, orally every 8 hours for 10 days) in a random cross-over design. Digital blood flow (DBF) and laminar perfusion (LP) were measured on days 2, 5, 7, and 10 of treatment. Horses also received acetylpromazine as a positive control (0.066 mg/kg, intravenously) during the washout period, and measurements were taken every 15 minutes until measurements returned to baseline readings. Data were analyzed by using repeated measures ANOVA. RESULTS: Digital blood flow (11.2 to 97.7 mL/min) and laminar perfusion (1.0 to 11.1 Capillary Perfusion Units) differed between horses. No statistically significant increases in DBF or LP were detected over the 10 day treatment period with either isoxsuprine or pentoxifylline. Acepromazine resulted in a significant increase (P = .0007) in DBF for approximately 75 minutes beginning 15 minutes after treatment. A mild but insignificant increase in LP was identified after acetylpromazine treatment. CONCLUSION: Neither isoxsuprine nor pentoxifylline increased blood flow to the digit or dorsal laminae in healthy horses. Acepromazine caused an increased blood flow to the digit. Based on the results of this study acetylpromazine potentially would have a greater effect on improving digital blood flow than oral isoxsuprine or pentoxifylline when treating ischemic conditions of the foot in horses.

Effects of 6alpha-methylprednisolone acetate on an equine osteochondral fragment exercise model.

OBJECTIVE: To determine effects of intra-articularly administered 6alpha-methylprednisolone acetate (MPA) in exercised horses with carpal osteochondral fragmentation. ANIMALS: 18 horses: 3 groups of 6 each. PROCEDURE: An osteochondral (chip) fragment was created in 1 randomly chosen middle carpal joint of each horse. Polyionic fluid (PF) was injected into both middle carpal joints of horses in the control group. In horses of the MPA-control group, MPA was injected into the middle carpal joint without an osteochondral fragment; a similar volume of PF was injected into the contralateral middle carpal joint. In the MPA-treated group of horses, 100 mg of MPA was injected into the middle carpal joint containing the osteochondral fragment; a similar volume of PF was injected into the contralateral joint. Injections were administered on postsurgical days 14 and 28, and horses were exercised on a high-speed treadmill for 8 weeks, starting on postsurgical day 15. RESULTS: Clinical improvement in degree of lameness was not associated with MPA administration. Joints that contained an osteochondral fragment and were treated with MPA had lower prostaglandin E2 concentration in synovial fluid, and lower scores for intimal hyperplasia and vascularity in synovial membrane, compared with PF-treated joints. However, articular cartilage erosion and morphologic lesions suggested possible deleterious effect of intra-articular MPA administration. CONCLUSIONS: Some beneficial effects of MPA administration on synovial fluid and synovial membrane were identified; however, the deleterious findings contrast with those associated with triamcinolone acetonide used in a similar model, but agree with other results of MPA administration in normal and abnormal joints.

Endoscopy of the calcaneal bursa in horses.

OBJECTIVE: To describe endoscopic approaches to the calcaneal bursa and clinical findings in 2 horses with calcaneal bursitis. STUDY DESIGN: Cadaver evaluations and retrospective case reports. ANIMALS: 12 cadavers and 2 adult horses. METHODS: Cadaver specimens of the calcaneal bursa were evaluated with a rigid arthroscope and gross dissection to determine the endoscopic appearance of anatomic structures located within the bursa. The site(s) for placement of the arthroscope and instrument(s) was determined based on cadaver dissection and endoscopic examination. RESULTS: Placement of the arthroscope 1 cm dorsal to the superficial digital flexor tendon (SDFT) and 1 cm distal to the medial or lateral aspect of the SDFT retinaculum allowed consistent examination of the tuber calcis, proximal aspect of the long plantar ligament, calcaneal tendon of the gastrocnemius muscle inserting on the tuber calcis, SDFT and the proximal and distal extent of the bursa. Lesions observed and treated with use of endoscopy included local bone necrosis of the proximoplantar aspect of the tuber calcis and damage of the origin of the long plantar ligament in one horse. Mild disruption of the superficial digital flexor tendon and long plantar ligament were observed and debrided in another horse. CONCLUSIONS: Endoscopic exploration of the calcaneal bursa is clinically feasible to treat infectious and noninfectious bursitis and to help identify the cause(s) of undiagnosed bursitis or lameness associated with the calcaneus, superficial digital flexor tendon, tendon of the gastrocnemius muscle, and the long plantar ligament. CLINICAL RELEVANCE: An endoscopic approach to the calcaneal bursa is recommended whenever possible to decrease complications associated with surgery in this region and improve the diagnosis of infectious and non-infectious calcaneal bursitis.

Acute gastrointestinal disease in 27 New World camelids: clinical and surgical findings.

OBJECTIVE: To describe clinical and surgical findings from New World camelids with acute gastrointestinal disease. STUDY DESIGN: Retrospective study. ANIMAL POPULATION: 20 llamas and 7 alpacas. METHODS: Camelids were grouped based on surgical lesions. Clinical and surgical findings were compared between groups and between surviving and nonsurviving camelids. RESULTS: Twelve of 27 initial celiotomies and 3 of 4 repeat celiotomies were successful. Death occurred from euthanasia during surgery (nine camelids), peritonitis or sepsis (five), aspiration pneumonia (one), and respiratory distress (one). Survival was lowest after celiotomy for proximal obstruction (3 of 10 camelids), ruptured viscus (0 of 4), and necrotizing enteritis (0 of 2) and highest after celiotomy for distal obstruction (10 of 13) and septic peritonitis without ruptured viscus (2 of 2). Before surgery, camelids with proximal obstruction had significantly lower (P < .05) serum chloride concentrations (median, 97 mEq/L) than those with distal obstruction (median, 109 mEq/L) or ruptured viscus (median, 117 mEq/L). Serum bicarbonate concentration also was highest (median, 34.6 mEq/L) and often greater than 28 mEq/L in camelids with proximal obstruction. Camelids with distal obstruction had significantly lower (P < .05) nucleated cell counts in peritoneal fluid (median, 700 cells/microL) than those with ruptured viscus (median, 20,600 cells/microL) or septic peritonitis (median, 88,300 cells/microL). CONCLUSIONS: Camelids with proximal obstruction often had hypochloremic metabolic alkalosis. Camelids with distal obstruction had less metabolic derangement and tissue compromise and a higher survival rate. CLINICAL RELEVANCE: Awareness of the characteristics of the various types of acute gastrointestinal disease in camelids will augment veterinarians' ability to diagnose and treat these disorders.

Evaluation of digital and laminar blood flow in horses given a low dose of endotoxin.

OBJECTIVE: To measure blood flow in the palmar digital artery and laminae corium, using ultrasonic and laser Doppler flowmetry, respectively. ANIMALS: 6 healthy horses. PROCEDURE: Digital blood flow and laminar perfusion, respectively, were measured by placing a flow probe around the palmar digital artery and a laser Doppler flow probe in a hole in the dorsal aspect of the hoof wall. All horses were given saline (0.9% NaCl) solution (1 L, IV, during a 30-minute period). Seven days later, each horse was given endotoxin (0.1 microgram/kg of body weight, IV, in 1 L of saline solution, during a 30-minute period). Digital blood flow, laminar perfusion, heart and respiratory rates, body temperature, and clinical signs of endotoxemia were recorded throughout a 240-minute period. Repeated-measures ANCOVA was used to evaluate changes in outcome variables. RESULTS: Treatment with saline solution did not cause a change in measured variables. All horses had mild clinical signs of endotoxemia. Endotoxin treatment caused a significant decrease in digital blood flow and increases in heart rate and body temperature. Laminar perfusion decreased after endotoxin treatment. CONCLUSIONS: Endotoxin administration caused a profound transient decrease in digital blood flow and a less substantial decrease in laminar perfusion. CLINICAL RELEVANCE: Horses with clinical endotoxemia were likely to have decreased digital blood flow and possibly, decreased laminar perfusion, potentially predisposing them to vascular alterations within the digits.