This Case Report describes a 5-year-old Standardbred gelding that was referred to the Equine Hospital of ONIRIS Veterinary School of Nantes, France for a surgical procedure under general anaesthesia. Anaesthesia was induced and maintained intravenously and the horse was placed in left lateral recumbency with a padded halter. On post operative Day 1, a post anaesthetic distal facial nerve branch paresis was diagnosed based on clinical signs. The horse was discharged on post operative Day 2 with medical treatment based on anti-inflammatory drug administration locally and systemically. The horse was re-examined 2 weeks after the surgery; the left partial facial paralysis was still present and associated with amyotrophy of the muscles supplied by the buccal branches of the facial nerve. In accordance with the owner, the horse was hospitalised to start an electrostimulation treatment. The horse was treated every day for the first 4 days, then every 2 or 3 days during the following 3 weeks, for a total of 11 sessions. At the end of the second week of treatment, the horse was able to normally prehend the food and atrophy seemed reduced. The horse was discharged from hospitalisation at the end of the third week of treatment with specific recommendations. One month after discharge from the hospital just a slight asymmetry could be noticed at rest. Six months later, the training season began and the horse was able to perform. Facial paralysis due to nerve compression is a well-known complication of anaesthesia. Gradual recovery of function over the weeks of treatment suggests that electroacupuncture may promote recovery and may hasten time of recovery.

A 7-year-old Paint mare presented for evaluation of a swollen right hindlimb of approximately 6 weeks' duration. Ultrasonography and radiography suggested a severe osteomyelitis and abscessation of the right tibia. Previous treatment included systemic antimicrobial therapy using procaine penicillin G (22,000 u/kg bwt, q. 12 h, i.m.) and gentamicin sulfate (6.6 mg/kg bwt, q. 24 h, i.v.) initially followed by oral doxycycline (10 mg/kg bwt, q. 12 h, per os) and rifampin (5 mg/kg bwt, q. 12 h, per os). Based on the poor prognosis the mare was subjected to euthanasia. Necropsy results subsequently revealed a severe, chronic, focal, necrotising osteomyelitis with localised cellulitis and abscessation. Rhodococcus equi was isolated from the tibia, subcutaneous abscess and from a pectoral abscess found at necropsy. Immunological testing of blood samples obtained ante mortem revealed normal blood lymphocyte phenotyping, but markedly increased IgG and IgM concentrations, indicating an active humoural response. While there have been reports of Rhodococcus equi infection in mature horses this is an area previously unreported in the literature.

Lactate concentrations can now be measured rapidly and inexpensively in equine hospitals or in the field with a degree of accuracy that is acceptable when compared to laboratory analysers. Arterial or venous blood samples can be used. Short-term storage of samples for up to 4 h at room temperature does not appear to affect the result. Taking a sample in the field and returning to the practice to analyse it is therefore feasible.

Lactate measurement is useful in horses with colic to aid in the diagnosis of an ischaemic lesion and to determine the probability of a successful outcome if surgery is undertaken. Lactate concentrations are also useful as an indicator of hypoxia and/or circulatory disturbances associated with intra-, or post partum abnormalities including dystocia, prematurity, dysmaturity, neonatal encephalopathy, sepsis, systemic inflammatory response syndrome or enteritis. Measuring lactate concentrations may assist in determining the severity of these conditions and the need for intensive care. Initial lactate concentration and increases or decreases in blood lactate concentration following a period of treatment can provide useful prognostic information. Lactate may also be measured during training to monitor fitness and performance.

Polyodontia is defined as the presence of teeth in excess of the normal dental formula. In equids, supernumerary teeth are uncommon but, when present, are usually located mainly in the caudal aspects of the cheek teeth rows (distomolars), also being found adjacent to normal cheek teeth or even in an ectopic location. It is believed that this disorder is a result of an inappropriate differentiation of dental germinal tissue during gestational development, with external trauma also acting as an initiating factor, when teeth germs are affected. The presence of these abnormal teeth can lead to axial displacement, dental overgrowths, dental-related soft tissue damage, diastemata formation, periodontal disease and development of secondary sinusitis. A large prospective, cross-sectional study was performed in 800 donkeys, with the aim to investigate the prevalence and aetiopathogenesis of clinically diagnosed oral and dental disorders. Polyodontia was recorded in 2.25% of the donkeys, presenting 36 supernumerary teeth, with 2.80% being incisors and 97.20% cheek teeth, with prevalence increasing with age. The caudal aspects of the maxillary cheek teeth rows were the most common locations for supernumerary teeth development (distomolars). The mandible was far less commonly affected than the maxilla. Although polyodontia is uncommon in donkeys, it should be considered in the differential diagnosis of dental disease. A methodical oral examination and a complete radiographic survey of the entire dental arcades are crucial for a correct early diagnosis and treatment plan implementation. The increasing prevalence of fully erupted supernumerary teeth recorded in older groups suggested a late onset eruption process, and therefore, in donkeys undergoing regular dental prophylaxis, the presence of previously unnoticed supernumerary teeth should always be sought.

A 12-year-old Belgian Warmblood gelding was examined for haematuria and dysuria of 24 h duration. Cystoscopy revealed an intraluminal multinodular soft tissue mass originating from the dorsal bladder neck. Histopathological examination of biopsies identified transitional cell carcinoma. The bladder mass was surgically debulked via a temporary perineal urethrotomy. The horse commenced treatment with oral piroxicam. Follow-up examination 18 months post operatively revealed no evidence of tumour recurrence. Neoplasia of the equine bladder is uncommon and this case describes the successful short-term outcome of treatment of a transitional cell carcinoma by surgical debulking and oral piroxicam.

Roundworms and flatworms that affect donkeys can cause disease. All common helminth parasites that affect horses also infect donkeys, so animals that co-graze can act as a source of infection for either species. Of the gastrointestinal nematodes, those belonging to the cyathostomin (small strongyle) group are the most problematic in UK donkeys. Most grazing animals are exposed to these parasites and some animals will be infected all of their lives. Control is threatened by anthelmintic resistance: resistance to all 3 available anthelmintic classes has now been recorded in UK donkeys. The lungworm, Dictyocaulus arnfieldi, is also problematical, particularly when donkeys co-graze with horses. Mature horses are not permissive hosts to the full life cycle of this parasite, but develop clinical signs on infection. In contrast, donkeys are permissive hosts without displaying overt clinical signs and act as a source of infection to co-grazing horses. Donkeys are also susceptible to the fluke, Fasciola hepatica. This flatworm can be transmitted, via snails and the environment, from ruminants. As with cyathostomins, anthelmintic resistance is increasing in fluke populations in the UK. A number of the anthelmintic products available for horses do not have a licence for use in donkeys, and this complicates the design of parasite control programmes. As no new equine anthelmintic classes appear to be near market, it is important that the efficacy of currently effective drugs is maintained. It is important that strategies are used that attempt to preserve anthelmintic efficacy. These strategies should be based on the concept that the proportion of worms in a population not exposed to anthelmintic at each treatment act as a source of ‘refugia’. The latter is an important factor in the rate at which resistance develops. Thus, it is imperative that parasite control programmes take into account the need to balance therapy to control helminth-associated disease with the requirement to preserve anthelmintic effectiveness.

Penetrating injuries to the foot are potentially serious injuries in the horse. Diagnosis is usually straightforward and a combination of radiography (including positive contrast studies) and synoviocentesis usually is necessary to determine which structures within the foot are involved. Superficial punctures usually carry a good prognosis but involvement of deep structures such as the distal phalanx or deep digital flexor tendon and navicular bursa adversely influence this. Knowledge of wound healing in the foot and a rational approach to antimicrobial selection and surgical intervention are all necessary for successful case management.

This report describes the use of low-field standing magnetic resonance imaging (MRI) in the diagnosis and clinical decision making process in a 14-year-old Dutch Warmblood mare with a comminuted central tarsal bone fracture. Magnetic resonance imaging in the standing horse was preferred over computed tomography examination under general anaesthesia because the animal had sustained the injury during a poor recovery from a previous general anaesthetic episode. Magnetic resonance imaging examination identified a comminuted central tarsal bone fracture with a configuration that was not identifiable with radiography. Due to extensive comminution of this fracture, conservative management was pursued. Standing low-field MRI examination enabled safe examination of this animal and provided useful diagnostic information whilst facilitating the clinical decision making process.

Multi-systemic eosinophilic epitheliotropic disease (MEED) is a relatively uncommon disease characterised by eosinophilic infiltration of more than one organ system, with the skin and gastrointestinal tract most commonly affected. This case report describes a gelding that presented for weight loss, increased respiratory rate and effort and chronic intermittent epistaxis. During post mortem examination diffuse eosinophilic granulomatous lesions were identified in the lung and liver, leading to a diagnosis of MEED. Veno-occlusive pulmonary remodelling was also discovered, believed to be the cause of the chronic epistaxis and a result of the pulmonary fibrosis and eosinophilic granulomas.

Platelet transfusions might be indicated in horses with thrombocytopenia. The need for a transfusion cannot be determined by platelet numbers alone, as primary or co-existing disease processes, platelet function and age of the recipient also need to be considered. In patients with no co-morbidities, relevant bleeding is uncommonly observed with platelet counts >10 x 10⁹/l and a therapeutic approach with initiation of treatment when signs of bleeding are observed might be justified.

Progressive haematomata (PH) are a rare cause of equine paranasal sinusitis and are thought to result from recurrent haemorrhage within the respiratory submucosa of the ethmoidal labyrinth. Clinical signs of PH are variable but mostly attributable to rupture of the mass with haemorrhage, occlusion of nasomaxillary drainage and secondary infection. Almost all affected horses have unilateral or bilateral, intermittent, serosanguinous nasal discharge. Radiographic examination is useful in identifying large PH, but small masses can be overlooked because of superimposition. Computed tomography (CT) has the benefit of producing cross-sectional images of the sinuses, overcoming the limitations of radiography. The cases in this report suffered from bilateral PH not associated with the ethmoidal labyrinth. They highlight the benefit of CT in the diagnosis, surgical planning and evaluation of the architecture of the sinuses. Preoperative treatment with formalin to desiccate the mass prior to removal can be performed more safely when guided by CT.

A 12-year-old donkey and a 6-year-old Connemara pony, both sexually intact males, were admitted for surgical removal of urinary calculi. Both underwent a laparoscopic-assisted cystotomy technique to exteriorise the bladder and remove uroliths via the inguinal canal after hemi-castration. Both surgeries were successful and no complications occurred. This modified technique, which is minimally invasive, may be a safe and efficient way to remove bladder stones from adult stallions.

An 8-year-old grey Quarter Horse gelding was referred for evaluation of a rapidly growing mass associated with the third eyelid of the left eye. A pigmented mass of approximately 2 cm in diameter was palpated and visualised associated with the conjunctival lining of the nictitans. It was not possible to palpate normal nictitans deep to the base of the mass. A full dermatological examination revealed no other melanomas in common sites. Based on the size and rapid growth of the mass, surgical excision and one application of local chemotherapy was performed under general anaesthesia. Histopathology confirmed the diagnosis of malignant melanoma and the presence of clean surgical margins. There was no recurrence at 5 weeks post surgery. To our knowledge, this is the first report of a primary malignant melanoma of the third eyelid in a horse.

Bacterial meningitis in the mature horse is a rare and typically fatal condition. This report describes a 7-year-old Quarter Horse gelding that initially presented following suspected trauma to the left eye but subsequently developed bacterial meningitis, and a nasal and palpebral abscess, all of which cultured the same isolate of Escherichia coli. The entry site of infection in bacterial meningitis is often related to a breach in the calvarium and extension of bacteria residing in the paranasal sinuses. This case is unique as there were multiple pathways through which bacteria may have entered the central nervous system including haematogenous spread from a nasal abscess, local extension of periocular infection or an undetected skull fracture. Aside from persistent blindness in the left eye, the horse made a full recovery.

The multiple congenital ocular anomalies (MCOA) syndrome has been associated with the Silver phenotype only in a few equine breeds. This report describes the phenotypic and genotypic characteristics of MCOA in a family of Silver-coated Shetland ponies including a 20-year-old stallion, 17-year-old mare and their 1.5-year-old female offspring. Another 7-year-old Silver female Deutsches Classic Pony descending from the same dam but from a different sire, was also examined. Each pony underwent a complete ophthalmic examination, tonometry, ocular ultrasonography and genotyping for the silver coat colour. The stallion had a thickened iris, temporal retinal atrophy and bilateral iridociliary and peripheral retinal cysts. All females presented more severe anomalies: cornea globosa, iridocorneal adhesions, miosis, hypoplastic granula iridica and poorly responsive pupils to light and to pharmacological mydriasis. Iris hypoplasia, anterior cortical cataracts and temporal retinal atrophy were detected in 2 mares. One female presented bilateral lens subluxation. Supero-temporal cystic structures were confirmed ultrasonographically in all ponies. The stallion was heterozygous for the Silver mutation, whereas all females were homozygous. This is the first report of the MCOA syndrome in a family of Shetland ponies and a Deutsches Classic Pony in association with the Silver phenotype, in Europe.

Analgesia usually occurs within 5 min after administration of local anaesthetic solution into joints or around nerves in the distal portion of the limb. Gait should be assessed within 10 min after diagnostic regional analgesia of the distal portion of the limb because rapid diffusion of anaesthetic solution can result in anaesthesia of other nerve branches, thus confusing results of the examination. A palmar digital nerve block (PDNB) anaesthetises most of the foot, including the distal interphalangeal (DIP) joint (coffin joint), rather than just the palmar half of the foot, as was once commonly believed. To avoid partially anaesthetising the proximal interphalangeal joint (pastern joint), the palmar digital nerves should be anaesthetised near or distal to the proximal margin of the collateral cartilages. Clinicians should be aware that an abaxial sesamoid nerve block (ASNB) may ameliorate or abolish pain within the metacarpo/metatarso-phalangeal joint (fetlock joint). Mepivacaine administered into the DIP joint desensitises the DIP joint and probably the palmar digital nerves to also cause anaesthesia of the navicular bursa, the navicular bone, the toe region of the sole, the digital portion of the deep digital flexor tendon (DDFT) and the distal portions of the collateral ligaments of the DIP joint. When a large volume of mepivacaine HCl (e.g. 10 ml) is administered, the heel region of the sole may also be desensitised. Only a small percentage of horses with disease of the collateral ligament(s) of the DIP joint show a significant improvement in lameness after intra-articular analgesia of the DIP joint, and no horse is likely to improve after intrabursal analgesia of the navicular bursa. A PDNB, however, improves lameness substantially in most horses that are lame because of disease of the collateral ligament(s) of the DIP joint, and all affected horses are likely to become sound after an abaxial sesamoid nerve block. The degree of improvement in lameness associated with injury to one or both collateral ligaments of the DIP joint after PDNB is determined by the extent of the injury and the level at which the palmar digital nerves are anaesthetised. The further proximal the level of the injury within the collateral ligament, the less likely that lameness is ameliorated by analgesia of the DIP joint or a PDNB. Verschooten's technique appears to be the most accurate technique for centesis of the navicular bursa. Even though analgesia of the DIP joint results in analgesia of the navicular bursa, analgesia of the navicular bursa does not result in analgesia of the DIP joint. Pain arising from the DIP joint can probably be excluded as a cause of lameness when lameness is attenuated by analgesia of the navicular bursa. Analgesia of the digital flexor tendon sheath (DFTS) is likely to desensitise only structures that are contained within or border on the sheath itself (i.e. the superficial and deep digital flexor tendons, the straight and oblique distal sesamoidean ligaments, the annular ligaments of the fetlock and pastern, and the portion of the DDFT that lies within the foot). Because lameness caused by disease of the DDFT within the foot may fail to improve appreciably after analgesia of the palmar digital nerves, the DIP joint, or the navicular bursa, a portion of the DDFT within the foot and distal to the DFTS probably receives its sensory supply from more proximal deep branches of the medial and lateral palmar digital nerves that enter the DFTS. Performing intrathecal analgesia of the DFTS on horses with lameness that is unchanged after anaesthesia of the palmar digital nerves but resolves after an ASNB, may be useful in localising lameness to that portion of the DDFT that lies within the foot. Resolution of lameness after intrathecal analgesia of the DFTS justifies suspicion of a lesion within the digital portion of the DDFT or within structures contained within the DFTS. The belief that concurrent or sequential intra-articular administration of medication substantially increases the risk of joint infection or that inflammation caused by the local anaesthetic solution may dampen the therapeutic response to intra-articular medication appears to be unfounded.

A 7-year-old Quarter Horse gelding was referred for magnetic resonance (MR) imaging due to chronic left hindlimb lameness localised to the foot. On presentation, a previously undiagnosed draining tract was identified at the plantar aspect of the pastern. Radiographs revealed severe osteolysis of the navicular bone. Positive contrast MR fistulography was performed using a gadolinium based contrast agent following conventional MR imaging of the left hind foot. Fistulography allowed characterisation of a fistulous tract, which was closely associated with the deep digital flexor tendon, navicular bursa and osteomyelitis of the navicular bone.

Two foals were admitted for neurological signs after trauma. Clinical and diagnostic investigations were performed that were suggestive of closed head trauma characterised by right parietal bone deviation (ping-pong fracture), cerebral contusion, haematoma and cerebellar contusion. The histopathological findings were consistent with areas of abnormal signal found on magnetic resonance investigations.

A 22-year-old Quarter Horse mare exhibited neurological signs consisting of head pressing, central blindness, minimal ataxia and dysphagia. Despite treatment, the mare collapsed and died shortly after onset of signs. On necropsy, there were approximately 15 l of free blood in the abdominal cavity. A 12 × 4 cm diameter, irregularly-shaped, nodular, firm, tan/yellow mass was found adhered to the outer surface of the right lateral aspect of the caudal abdominal aorta. A similar mass also affected the caudal aspect of the right kidney. Histopathology of the aortic and renal masses revealed multiple coalescing granulomas containing intralesional nematodes compatible with Halicephalobus gingivalis. Inflammatory cells disrupted the aortic tunica adventitia as well as the outer tunica media. Similar exudate also affected the cerebrum, cerebellum and brainstem. Polymerase chain reaction amplification and sequencing of a portion of the large subunit ribosomal ribonucleic acid gene were performed using previously published primers for H. gingivalis to confirm the identity of the nematode. Although rupture of a blood vessel could not be demonstrated grossly, the histological findings suggest that inflammation may have breached a small calibre artery and caused the haemoabdomen.

A 20-month-old Warmblood filly was evaluated for acute onset of a nonweightbearing lameness and swelling of the left hindlimb. Clinical and lameness evaluation and diagnostic intrasynovial anaesthesia isolated the lameness to the left hind metatarsophalangeal region. Radiography and ultrasonography revealed a subchondral cystic lesion of the apical portion of the lateral proximal sesamoid bone associated with oedema and synovial effusion of the metatarsophalangeal joint. Arthroscopic surgical debridement of the subchondral cystic lesion resulted in immediate post operative improvement in the lameness score. Rest and controlled exercise achieved complete resolution of the lameness with the filly being able to start training without apparent lameness. Subchondral cystic lesions of the proximal sesamoid bones can be a cause of nonweightbearing lameness. Surgical debridement resulted in complete resolution of the lameness with a favourable outcome in this case.

A 5-year-old, 520 kg Standardbred mare was admitted for an osteosarcoma of the right premaxilla. Two horizontal incisions of the labial mucosa and lingual surface were made 1 cm around the ulceration from the canine tooth to the premaxillary symphysis. The premaxilla and rostral portion of the maxilla were transected 1 cm caudal to the canine tooth with an oscillating saw. The maxillary symphysis was transected using an oscillating saw and a hammer. The wound was closed by primary intention and healed without complication. The cosmetic appearance of the mare was good. The mare was able to prehend hay and grain and grazed without difficulty and the tongue did not protrude. The neoplasm had not recurred 18 months after the surgery. A premaxilla and rostral portion of the adjacent maxilla can be resected to treat horses for a unilateral lesion of the premaxilla but care must be taken to avoid the palatine and incisive arteries which lie within the interincisive canal.

Adverse drug reactions to potentiated sulfonamide antimicrobial drug combinations have been reported in many species, including horses. This report describes the occurrence of pancytopenia in 2 horses, one subsequent to an immune mediated reaction and the other bone marrow aplasia following the administration of trimethoprim and sulfadimidine. These cases highlight the importance of judicious use of antimicrobial agents and describe adverse drug reactions in horses receiving potentiated sulfonamide antimicrobials.

This case report describes the endoscopic findings and outcome in 6 horses diagnosed with dynamic epiglottic retroversion (ER) during exercise. Horses included 2 showjumpers, one eventer, one pleasure riding horse and 2 Thoroughbred racehorses. All were adults (age range: 4–10 years). Dorsal angulation of the epiglottis was identified at rest in one horse. However, resting endoscopy was unremarkable in the remaining 5 horses. Exercising endoscopy was performed during high-speed treadmill exercise in 3 horses and during ridden exercise in the other 3. Intermittent ER occurred during inspiration in all horses and the frequency increased with increasing speed. In 2 horses the epiglottis retroverted beyond the rima glottidis. All horses made an abnormal respiratory noise described as a ‘grunt’ when retroversion of the epiglottis occurred. Poll flexion was found to be an exacerbating factor in the nonracehorses. Two horses continued in work but abnormal inspiratory noise persisted. Surgical treatment, in the form of subepiglottic resection, was attempted in one horse. However, it never raced again after the procedure. Of the remaining horses, 2 were retired and the third was subjected to euthanasia.

This report describes a multilobular ameloblastoma that invaded the left mandible of a 31-year-old pony. The pony presented initially with a palpable mass that protruded from the left mandibular region. Ante mortem radiographs of the mass revealed an invasive, multilobular, bony mass with significant loss of dentition. One month following initial diagnostic work-up, the pony was subjected to euthanasia due to unrelated clinical signs of colic, secondary to a strangulating lipoma. Magnetic resonance imaging (MRI) of the head was performed post mortem to further characterise the mass and determine the extent of its invasion. The macroscopic and histopathological morphology and immunohistochemical properties of the neoplastic cells strongly supported a diagnosis of a multi-cystic ameloblastoma. To the authors' knowledge, this is the first report of an MRI of an ameloblastoma in the horse.

Tumours arising from the dorsal surface of the tongue occurred in 3 horses from 14 to 23 years of age. Tumours were surgically excised at a referral hospital (1 case) and on the farm (2 cases) and submitted for histopathology. All tumours were multilobular and composed of vaguely nested, bland, oval to slightly elongated cells with an infiltrative growth pattern. Mitotic activity was not detected. Immunohistochemical studies found that tumour cells were often positive for S-100 and cytokeratin and occasionally positive for vimentin. Tumour cells were negative for glial fibrillary acidic protein, neuron specific enolase, synaptophysin, muscle actin and chromogranin A. Follow-up obtained from 7 months to 2 years following tumour removal indicated no evidence of regrowth or metastasis. The origin of these distinctive tumours is not clear but the immunohistochemical profile suggests the possibility of origin from lingual taste buds. These cases and review of the literature indicate that successful surgical excision of tongue tumours can be performed by practitioners in private practice as well as by surgeons at referral hospitals.

Complications following castration are a potential problem in equine practice. Intestinal evisceration is a life-threatening condition requiring immediate correction. The following case report describes a rare condition associated with post castration evisceration in a 3-year-old Thoroughbred. Shortly after the eviscerated small intestine was repositioned in the abdomen, the horse showed signs of colic and at the second surgery a 4.5 m jejunal loop was found incarcerated in the femoral canal. After resection and anastomosis, the femoral canal was obliterated using large moistened gauze sponges. The horse made a complete recovery and returned to race training. The occurrence of femoral hernia, a condition fairly common in man, has been described but no clinical cases have been reported in horses. This is a severe, although rare, complication after castration.

Squamous cell carcinoma (SCC) accounts for approximately 20% of all equine mucocutaneous (MC) tumours and continues to present a therapeutic challenge to practitioners. Most MC-SCC are locally invasive and slow to metastasise, but metastasis to local lymph nodes is not uncommon. The most common location for MC-SCC is the periorbital region, with the eyelid most commonly affected. Although only 13% of MC-SCC involves the external genitalia, MC-SCC is the most common neoplasm of male genitalia. Equine caballus papillomavirus-2 has recently been linked to MC-SCC and may prove to be necessary for tumour development. Risk factors may include chronic exposure to ultraviolet light and chronic skin irritation. Horses developing genital MC-SCC tend to be older compared to those with periorbital MC-SCC. Histopathology is required for definitive diagnosis of MC-SCC, although horse phenotype and lesion location may suggest MC-SCC. Several treatment modalities have been successful in eliminating or managing MC-SCC, with surgical excision and intratumoural chemotherapy yielding the best results. Other treatment options including cryotherapy, hyperthermia, radiotherapy and photodynamic therapy are often used as adjunctive therapies. Early recognition of tumours and prompt intervention are associated with a positive outcome.

This case report describes an unusual diagnosis of central nervous system botryomycosis in a horse. A 16-year-old Welsh Section D gelding was evaluated for acute onset of hypermetric ataxia, leaning to the left and head tilt to the right. Based on the neurological signs, a cerebellar lesion with accompanying vestibular disease was suspected and supportive therapy consisting of antimicrobial and glucocorticosteroid drugs and hypertonic saline was instituted. This resulted in marked clinical improvement over a 48 h period. Computed tomography performed in the standing, sedated horse following initial stabilisation identified extensive sclerosis and lysis of the right temporal and occipital bones, consistent with an infectious or neoplastic process. Based on the grave prognosis for survival despite the clinical improvement, euthanasia was undertaken. Post mortem magnetic resonance imaging identified a mass lesion impinging on the right cerebellar hemisphere, sclerosis of the temporal and occipital bones lateral and ventral to the mass, as well as destruction of the temporal bone between the inner ear and the cerebellum. These changes corresponded to the presence of a mass within the right dorsal temporal bone, extending into the right lateral temporal bone. The mass extended to compress and adhere to the right lateral hemisphere of the cerebellum. A histopathological diagnosis of botryomycosis was made, affecting the temporal and occipital bones and compressing the cerebellum.

Identification of regional and/or distant metastasis following treatment and local resolution of primary ocular squamous cell carcinoma (SCC) was observed in 5 horses. In all cases, identification of metastasis occurred at least 18 months following treatment of the primary ocular lesions. In 3 cases, invasion of blood or lymphatic vessels by neoplastic cells was identified in the excisional biopsies of the primary tumour. Two horses developed SCC at 2 or more separate sites. At the time metastases were identified, there was no evidence of local recurrence of the ocular tumour in any of the horses. These cases confirm the importance of long-term monitoring of horses for metastatic disease following treatment of ocular SCC even in the absence of local recurrence.

An 18-year-old Warmblood stallion was presented for an acute onset nonweightbearing right hindlimb lameness following a mild lameness of 2 weeks' duration. Severe swelling was present in the right femoral area. Despite extensive diagnostic procedures, no definitive diagnosis could be made. Packed red cell volume was persistently low. The horse improved with supportive treatment and was discharged at the owner's request. The horse presented 4 days later for bleeding from a previously made incision on the lateral femoral area. Due to deterioration of his condition, the stallion was subjected to euthanasia. Diagnosis of disseminated haemangiosarcoma, affecting primarily the hindlimb musculature and leading to pathological fracture of the femur was made at necropsy and subsequent histopathology.

In this report, we describe the diagnostic findings and outcome of a uterine B cell lymphoma in a mare. A well circumscribed uterine mass with significant peripheral vascularisation was identified by transrectal ultrasonography during the reproductive examination of an 8-year-old Thoroughbred mare. Subsequent hysteroscopy revealed that the uterine mass was located intramurally and contained a protruding polyp-like structure. A diagnosis of uterine B cell lymphoma was established by histopathological examination of a hysteroscopically-obtained tissue sample. Additional diagnostics demonstrated that the uterus was a site of metastasis. Due to her deteriorating condition, extensiveness of the tumour and poor prognosis, the owner decided that the mare should be subjected to euthanasia.

A 3-year-old pregnant Standardbred mare was treated at the University of Helsinki Equine Teaching Hospital for severe idiopathic immune-mediated thrombocytopenia and haemolytic anaemia (Evan's syndrome). Despite initial improvement with supportive care and immunosuppressive doses of corticosteroids and azathioprine, the mare died from a fatal cerebral haemorrhage on Day 21 of treatment.

Verminous myeloencephalitis is a rare, but predominately fatal, cause of neurological disease in horses. A 6-year-old mare was admitted to the Royal Veterinary College Equine Referral Hospital following acute onset of depression, central unilateral blindness and compromised vision in the opposite eye. Based on pronounced eosinophilic inflammation detected in the cerebrospinal fluid (CSF) and diagnostic imaging findings indicating a space-occupying lesion within the brain, a presumptive diagnosis of aberrant parasitic migration causing parasitic encephalitis was made. Treatment consisted of anti-inflammatories and high doses of an anthelmintic. The horse's condition improved, the neurological deficits and observed space-occupying lesion within the brain resolved completely and the mare returned to full work. To the authors’ knowledge, this is the first report describing complete recovery from suspected aberrant parasite migration in the CNS and will hopefully encourage treatment of suspected cases in the future.

Temporohyoid osteoarthropathy (THO) is a progressive bilateral disease of unknown aetiology that most commonly affects adult horses. Irrespective of aetiology, THO frequently results in pain or fracture of the petrous temporal bone during normal movement of the tongue and larynx. In an effort to decrease pain and reduce the likelihood of petrous temporal bone fracture, partial stylohyoidectomy and ceratohyoidectomy have been developed. Serious complications have been reported following stylohyoidectomy and therefore the current recommendation is to perform unilateral ceratohyoidectomy. Benefits of ceratohyoidectomy include a lower risk of vascular and nerve damage and a reduced risk of clinical signs recurrence when compared with stylohyoidectomy. This report describes a case of THO in which clinical signs recurred approximately 2 years after unilateral ceratohyoidectomy was performed. Due to this complication, resection of the contralateral ceratohyoid bone was performed, which resulted in complete resolution of clinical signs. Although the clinical signs are frequently unilateral, the disease is most commonly a progressive bilateral condition and some horses may not have complete resolution of clinical signs when unilateral ceratohyoidectomy is performed. Therefore, if clinical signs persist after unilateral ceratohyoidectomy, a therapeutic consideration should include bilateral ceratohyoidectomy. This report suggests a favourable short-term prognosis for a horse treated with bilateral ceratohyoidectomy.

Equine multinodular pulmonary fibrosis (EMPF) is a progressive fibrosing interstitial lung disease, which has been associated with γ-herpesviruses. This report describes a 22-year-old Warmblood stallion diagnosed with EMPF on the basis of clinical examination, laboratory results, lung radiographs and ultrasound, lung biopsy and inclusion bodies found in macrophages of broncho-alveolar lavage fluid (BALF) as well as an identification of EHV-5 DNA by polymerase chain reaction (PCR). The horse recovered after one week of treatment with valacyclovir (40 mg/kg bwt per os q. 8 h) and is clinically healthy 2 years later. To our knowledge this is the first report describing treatment of EMPF with valacyclovir.

This report describes the use of a parainguinal approach to the abdomen to remove an obstruction in the small colon that could not be removed using an initial ventral midline approach. The use of a parainguinal approach should be considered for removal of an obstruction in the distal portion of the small colon.

This case report describes a geriatric gelding with a 2 month history of fast-growing masses within the parotid and submandibular regions. The horse was dyspnoeic on presentation and upper airway endoscopy revealed partial airway obstruction at the level of the pharynx, secondary to a space-occupying mass. Cytological evaluation of multiple fine-needle aspirates obtained from the masses were suggestive of salivary gland neoplasia, therefore the horse was subjected to humane euthanasia. A computed tomographical scan was obtained post mortem and revealed a large multi-lobulated mass involving both guttural pouches, resulting in 80% occlusion of the naso- and oropharynx. Histopathology confirmed a parotid salivary gland carcinoma (papillary-cystic type). Salivary gland tumours are extremely rare in horses, with only a few cases reported in the literature. Treatment of these malignancies proves to be challenging, requiring complete parotidectomy or surgical debulkment, in combination with adjunctive therapy.

A mature Thoroughbred gelding that was used as a high level jumper presented for evaluation of a nonweightbearing forelimb lameness following a fall. Radiographs revealed a complete, noncomminuted, minimally displaced sagittal fracture of the greater tubercle. Supporting limb laminitis was a major concern in the short term based on the severe lameness at presentation. Open reduction with internal fixation was chosen over stall rest in an attempt to more rapidly return the weightbearing function to the limb. The procedure was performed standing and 3 bone screws were placed standing in an attempt to avoid implant or catastrophic bone failure that can accompany recovery from general anaesthesia. The day following surgery the lameness was significantly improved as the horse was able to bear some weight on the heel. The gelding was discharged 5 days following surgery and was fully weightbearing at the walk. Six months following surgery the horse was free of lameness and resumed training. This report describes our experience and rationale in placing bone screws in a standing horse for treatment of a greater tubercle fracture.

A horse with unilateral forelimb lameness and pain localised to the palmar aspect of the foot was evaluated using radiography and low field magnetic resonance (MR) imaging. A distal border fragment of the navicular bone, an osseous cyst-like lesion (OCLL) in the distal third of the navicular bone and focal distal sesamoidean impar desmitis were identified as the most likely causes of pain and lameness. No other lesions likely to contribute to pain and lameness were identified on MR images or gross post mortem examination. The OCLL was characterised histologically by enlarged bone lacunae containing proliferative fibrovascular tissue. Focal lesions of the distal aspect of the navicular bone are rarely found in isolation but can be causes of pain and lameness in horses.

A 9-week-old Standardbred colt was presented for investigation of dull demeanour, exercise intolerance and heart murmurs. Cardiac auscultation revealed a grade 5/6 holosystolic murmur and a grade 5/6 pansystolic murmur over the left and right cardiac apex respectively, and an irregularly irregular cardiac rhythm. Electrocardiographic examination findings were consistent with atrial fibrillation and tachycardia. Echocardiographic examination identified marked atrioventricular regurgitation and atrial dilation bilaterally, thickening of the mitral and tricuspid valves and dilation of the pulmonary artery consistent with pulmonary hypertension. No ventricular or atrial septal defect was present. Cardiomegaly and diffuse pulmonary oedema were evident on examination of lateral thoracic radiographs. Dysplasia of the mitral and tricuspid valves, eccentric cardiomegaly and pulmonary oedema were confirmed by post mortem examination. Dysplasia of the atrioventricular valves represents a rare cause of biventricular failure in the horse.

An 18-year-old Warmblood gelding was presented with a recent, abrupt onset of ataxia. Transcranial magnetic stimulation (TMS) was performed and revealed a delayed response in both thoracic and pelvic limbs. Radiographic examination of the cervical region demonstrated osteolytic lesions in the vertebral body and arch of the third cervical vertebra (C3). A cervical myelogram revealed spinal cord swelling in this region on the lateral projection. Computed tomographic (CT) myelography was performed, which showed osteolytic lesions and circumferential thinning of the contrast column due to extra-dural compression at the cranial cervical region. These findings were compatible with an aggressive bone lesion compressing the spinal cord. Primary or secondary neoplasia and osteomyelitis were considered in the differential diagnosis. Because of the severity of the findings and poor prognosis, the horse underwent euthanasia. Post mortem histopathological diagnosis was a haemangiosarcoma involving the cranial cervical vertebrae and epidural space. This report demonstrates the additional value of CT myelography on the extent and exact location of cervical vertebral compressive lesions in the horse. This information can be useful for prognosis, biopsy and/or planned surgery of these lesions.

A 3-week-old Pony of the Americas foal presented with a history of respiratory distress presumed to result from Actinobacillus equuli pleuropneumonia and septic arthritis. Failure of transfer of passive colostral immunity was suspected, but not confirmed, based on a history of the foal being separated from its dam shortly after parturition. Transient improvement was noted following thoracocentesis and removal of approximately 600 ml of pleural fluid but progressive clinical signs of congestive heart failure developed. Fibrinous pericarditis with evidence of cardiac tamponade was subsequently diagnosed via thoracic ultrasonography. Early clinical signs of cardiogenic shock were identified and fibrinopurulent exudate removed through a catheter placed with ultrasound guidance into the pericardium. The foal experienced cardiorespiratory arrest during the procedure and died despite resuscitative efforts. Post mortem examination identified extensive hypertrophy of the pericardium, septic arthritis, mild pleural effusion and focal bronchopneumonia. This report details the clinical evaluation, haematology, treatment and post mortem pathology of a foal with Actinobacillus equuli associated fibrinous pericarditis, as well as a brief review of cardiac tamponade.

A 17-year-old gelding was presented with mild to moderate signs of colic. Exploratory laparotomy revealed an intussusception of ileum and jejunum into the caecum. The starting point of the intussusception was an intramural mass in the jejunum. Half a metre of jejunum was resected and the horse recovered without complications. Histopathology and immunohistochemistry revealed a myxoma with no myogenic or neurogenic origin.

Paralysis of a nostril is uncommon in horses and is reported to occur secondary to trauma to the facial nerve. This report of a mare who presented with bilateral nostril paralysis includes descriptions of the clinical presentation, surgical and post operative results and discusses the features unique to this case. The technique involves surgically elevating and stabilising the lateral alae dorsally to enlarge the nostril opening.

Eyelid squamous cell carcinoma in equine patients often presents a therapeutic challenge to practitioners due to the generally large area affected upon presentation. Surgical excision can be curative if wide enough margins are achieved, but this is not often attainable without enucleation. Other alternatives have been examined including cryotherapy, radiotherapy, brachytherapy, intralesional chemotherapy and photodynamic therapy. Intralesional chemotherapy using cisplatin, mitomycin-C and bleomycin have been shown to be successful in treating eyelid squamous cell carcinomas but may be prohibitive to some owners due to the cost of therapy. To the authors' knowledge, this is the first case series to illustrate the effectiveness of intralesional 5-fluoruracil in treating large equine eyelid squamous cell carcinomas. Macroscopic reduction in the size of the affected areas was noted in each case together with regression of clinical signs associated with the mass. This, coupled with the relative inexpensive nature of the procedure, makes this technique an attractive therapy for either primary treatment of eyelid squamous cell carcinoma or as a cytoreductive technique prior to surgical excision.

Fourth branchial arch defects (4-BAD) is a syndrome that consists of aplasia, or varying degrees of hypoplasia, of one or more of the cartilaginous or muscular structures derived from the fourth branchial arch, unilaterally or bilaterally. This case report describes the cases of 2 directly related siblings admitted with a complaint of abnormal respiratory noise at rest and complete exercise intolerance. Laryngeal palpation, resting upper airway (UA) endoscopy, lateral radiography of the larynx and cervical trachea, and laryngeal ultrasonography revealed multiple laryngeal and pharyngeal abnormalities. The clinical findings were compatible with the diagnosis of fourth branchial arch defects. A left partial arytenoidectomy and a unilateral ventriculocordectomy were performed in both cases. The follow-up endoscopies revealed a functional airway aperture. The surgery enabled the horses to be used for riding. Considering the direct family relationship between the horses, these cases would support a genetic component of 4-BAD.

Idiopathic muscular hypertrophy of the oesophagus (IMHO) is reported in equids as an incidental post mortem finding, infrequently associated with clinical signs of oesophageal dysfunction or additional oesophageal abnormalities. Clinicopathological and post mortem findings are presented from a 15-year-old gelding that developed a spontaneous perforation of the distal, intrathoracic oesophagus, in association with IMHO. The majority of oesophageal perforations documented in the equine literature have been related to external or iatrogenic trauma resulting in rupture of the cervical portion of the oesophagus. In this case, the early presenting features included pyrexia and inappetance, and progressed over a 4 day period to include signs of tachypnoea, tachycardia and endotoxaemia due to the development of a fatal septic pleuritis and pleural effusion. Oesophageal obstruction was not a presenting feature. Diagnostic investigation in cases of unexplained septic pleural effusion should include oesophageal endoscopic evaluation to rule out perforation of the intrathoracic oesophagus. IMHO may represent a clinically significant, primary disease entity with the potential to lead to oesophageal perforation.

This report describes the clinical course and the surgical findings in a 7-day-old foal referred for signs of abdominal pain. The foal underwent abdominal celiotomy due to the degree of pain unresponsive to medical treatment and, upon exploration, an ovarian pedicle was found to be wrapped around the small colon. The lesion was corrected, the foal recovered well from anaesthesia, and a 4 month follow-up revealed no other signs of abdominal pain or complications.

A Thoroughbred gelding had chronic episodic intra-abdominal haemorrhage following standing castration, presumed to originate from a testicular artery. No coagulopathy could be detected and resolution of haemorrhage was achieved by laparoscopic electrocoagulation of both testicular arteries 6 weeks after castration. Blood drained from the abdomen during surgery was filtered then auto-transfused. Post operative complications included pigmenturia, incisional pain and large colon impaction.

A unique complication to castration is published in the preceding Case Report in this issue, whereby a 2-year-old Thoroughbred racehorse gelding suffered chronic haemoperitoneum weeks after standing castration. The causes and treatment of post castration haemorrhage are reviewed along with haemoperitoneum and the use of laparoscopy. Supplementary explanations are discussed.

This article reports the results of a faecal egg count reduction test on 4 farms in France, as an integrated part of the routine deworming strategy against horse cyathostomins and Parascaris equorum. Treatment with fenbendazole (FBZ) or ivermectin (IVM) was evaluated in yearlings on Farms 1 and 2 and treatment with pyrantel embonate (PYR) was tested on Farms 3 and 4. Calculation of the arithmetic mean faecal egg count reduction and the 95% confidence intervals (95% CI) around the mean was performed using bootstrap analysis. For equine cyathostomins, resistance to FBZ was found with an arithmetic mean reduction of 48.8% (95% CI: 1.9–69.3%). On Farms 1 and 2, horses with reduced efficacy were identified. PYR was found to be effective against cyathostomins, with an arithmetic mean reduction of 95.3% (95% CI: 84.6–99.8%), as well as IVM (100%). For P. equorum, both FBZ and PYR were effective (100% reduction). The efficacy of IVM, however, was low (45.5%; 95% CI: 0–96.3%). These results confirm that FBZ resistance in equine cyathostomins is present in France and that anthelmintic resistance to IVM is present in P. equorum. This study underlines the necessity to evaluate the efficacy of horse deworming strategies on a regular basis under field conditions.

Atypical myopathy is highly fatal, but about a quarter of affected horses survive. This highlights the need for provision of supportive treatment for these patients. This review is a practical guideline for equine practitioners and includes suggestions for close monitoring of involved organ systems and discusses options of supportive treatment based on current knowledge of the condition. Part 2 covers the muscular, urinary, respiratory and hepatic systems, and the general inflammatory/infectious status of the case.

The last 30 years have seen many changes in the understanding of the pathogenesis and treatment of equine corneal stromal abscesses (SAs). Stromal abscesses were previously considered an eye problem related to corneal bacterial infection, equine recurrent uveitis, corneal microtrauma and corneal foreign bodies in horses. They were more commonly diagnosed in horses living in subtropical climatic areas of the world. Therapeutic recommendations to treat equine SAs were historically nearly always a medical approach directed at bacteria and the often associated severe iridocyclitis. Today the pathogenesis of most equine SAs appears to be more often related to fungal inoculation of the anterior corneal stroma followed by posterior migration of the fungi deeper into the corneal stroma. There is also now an increased incidence of diagnosis of corneal SAs in horses living in more temperate climates. Medical and surgical treatments are now directed towards elimination of fungal and bacterial infections, reduction and replacement of diseased corneal stroma, and suppression of iridocyclitis. If the abscess and anterior uveitis do not respond satisfactorily to medical therapy, full thickness or split thickness lamellar keratectomy to remove the fungal hyphae and diseased stroma, followed by transplantation of healthy corneal allografts has a high rate of success in speeding healing and preserving sight. This paradigm shift in the ability to diagnose and institute therapy for corneal SAs in horses has evolved over the last 30 years, and is the focus of this paper.