Topic:Congenital Disorders
Congenital disorders in horses encompass a range of structural, functional, or metabolic anomalies present at birth. These disorders may arise from genetic mutations, environmental factors, or a combination of both, affecting various systems in the equine body. Common congenital disorders in horses include cleft palate, umbilical hernias, and limb deformities. The diagnosis and management of these conditions require a multidisciplinary approach involving veterinary genetics, surgery, and rehabilitation. This page compiles peer-reviewed research studies and scholarly articles that explore the etiology, diagnosis, and management strategies for congenital disorders in equine medicine.
Bilateral colobomas in a horse. Bilateral true colobomas with retrobulbar cysts located over the optic nerves are described in an 8-year-old Quarterhorse mare with a history of progressive blindness. Colobomas result from the failure of an embryonic fissure to close and retrobulbar cysts result from eversion of the neuroectoderm through the colobomas. It could not be determined whether the small optic nerves and the scars, rosettes and disorganization of the cell layers in the retina were the result of concurrent dysplasia or were secondary to degeneration.
Congenital malignant melanoma in two foals. Two cases of congenital malignant melanomas in horses are described in this report. In each case, wide surgical excision of the mass was performed; no recurrence or metastasis was detected after a minimum of 15 months' follow-up. Melanomas are among the most common neoplasms of horses, but they typically develop in gray horses greater than 6 years old.
Occipitoatlantoaxial malformation with duplication of the atlas and axis in a half Arabian foal. An unusual occipitoatlantoaxial malformation is described in a 2-week-old male part Arabian foal that was unable to stand at birth and showed signs of spastic tetraparesis due to a cervical spinal cord compression. There were 2 atlases present. One was fused to the occipital bones. The other articulated with the first atlas and an axis which had a long dens that projected into the vertebral canal. Examination of the ossification centers of the axis indicated partial duplication of that bone.
Surgical management of congenital and perinatal abnormalities of the urogenital tract. Surgical management of various congenital and perinatal abnormalities of the urogenital tract are discussed, including ruptured bladder, ruptured urachus, ureteral defect, patent urachus and umbilical remnant infection, ureteral ectopia, congenital inguinal hernia, and atresia ani and rectourethral or rectovaginal fistula.
Congenital inguinal hernias associated with a rent in the common vaginal tunic in five foals. Five foals were admitted because of colic that developed within 24 hours after birth. Physical examination revealed swelling from the inguinal region to the cranial aspect of the prepuce. Through the skin overlying the swelling, distended loops of bowel could be palpated. The hernias could be reduced with the foals restrained in dorsal recumbency. Surgical exploration showed the swelling to be an inguinal hernia with small bowel herniation through a rent in the common vaginal tunic. Concurrent rupture of the vaginal tunic should be suspected when a congenital inguinal hernia is associated with...
Chylothorax associated with a congenital diaphragmatic defect in a foal. PLEURAL effusions (the presence of excessive quantities of pleural fluid) have been associated with a variety of disease processes affecting the equine thorax. The majority of reported cases have involved exudative effusions associated with pneumonia, lung abscesses or neoplasia (Raphel and Beech 1982 Mair 1987). Transudative effusions have been less com• monly described, being associated with such conditions as hypoproteinaemia. cardiac failure and diaphragmatic rupture. Chylothorax, the accumulation of chylous fluid in the mediastinum and/or pleural cavity, is a relatively uncommon conditi...
Incomplete subaortic stenotic rings in domestic animals–a newly described congenital anomaly. A newly described congenital heart anomaly, the incomplete subaortic stenotic ring was detected at necropsy in four dogs, one cat, one cow, one horse, one sheep and one pig. These structures were grossly and histologically similar to complete subaortic stenotic rings, being composed of variably dense interlacing bands and sheets of fibrous connective tissue. In all nine cases, their presence at necropsy was considered an incidental finding.
Heterotopic polyodontia in horses: nine cases (1969-1986). Nine horses with heterotopic polyodontia, examined at Purdue University since 1969, were treated surgically and had a favorable outcome. Six of the horses had received prior medical or surgical treatment, but without success. An understanding of the congenital nature of the problem contributed to an accurate diagnosis in each case. General anesthesia, aseptic technique, removal of all aberrant tissue, and wound suture for primary healing appeared to be essential for preserving ear function and obtaining an effective treatment.
Aortic valve insufficiency in a one-year-old colt. Aortic insufficiency was suspected in a thin 1-year-old colt with a grade IV/V decrescendo holodiastolic murmur and a bounding arterial pulse. Echocardiographic findings (diastolic fluttering of the septal leaflet of the mitral valve, left ventricular volume overload, and incomplete aortic valve closure) were diagnostic for aortic valve insufficiency. Moderately thick fibrotic aortic valve leaflets were found at necropsy. Fenestrations were found in the aortic and pulmonic valve cusps. Congenital valvular disease may have led to aortic valvular insufficiency in this horse.
Echocardiographic detection of tricuspid atresia in two foals. M-mode, 2-dimensional, and contrast echocardiographic studies were used to detect tricuspid atresia in 2 foals. M-mode echocardiographic findings included a small right ventricle, large left ventricle, large mitral valve excursion, large left atrium (foal 2), dropout of the cranial aspect of the aortic root, and a thick band of echoes in the tricuspid valve region. These findings were confirmed by 2-dimensional echocardiography. In addition, a large right atrium, persistent foramen ovale, ventricular septal defect, and large mitral valve apparatus were imaged. One foal also had a thick right a...
Unilateral phalangeal dysgenesis and navicular bone agenesis in a foal. This research journal article documents a rare case of a five-day-old foal suffering from a congenitally malformed hoof and the associated lameness. The disorders studied were unilateral navicular bone agenesis […]
Congenital vascular tumours in the skin of horses. Congenital vascular tumours in the skin of the legs of two horses showed histological features at biopsy which were consistent with capillary haemangioma but, at necropsy, one tumour had invaded the superficial digital flexor tendon and was therefore classified as a haemangiosarcoma.
Congenital sinus cyst in a foal. Radiography and endoscopy of a 17-day-old Standardbred foal that had right-sided facial swelling and dyspnea since birth revealed a soft tissue mass in the right nasal passage and right maxillary and frontal sinuses. A bone flap was used to expose the mass, and a fluid-filled structure was removed surgically. After surgery, the dyspnea was alleviated. The facial deformity resolved by the time the foal was 6 months old. The upper airway obstruction was absent clinically and endoscopically by the time the foal was 17 months old.
Right atrioventricular atresia and ventricular septal defect in a foal. Right atrioventricular atresia with a ventricular septal defect, a rare congenital cardiac anomaly of either animals or man, was diagnosed in a one week old Arabian foal. The foal had been weak and cyanotic since birth, sometimes becoming dyspneic when stressed. Necropsy revealed a dilated and hypertrophied left ventricle with the right ventricle being small. The right atrioventricular valve was absent. The right and left ventricles communicated via a septal defect which was located immediately adjacent to the aortic valve.
Investigation into the heredity of congenital lateral patellar (sub)luxation in the Shetland pony. A breeding experiment was carried out in a group of Shetland ponies in order to investigate the heredity of congenital lateral patellar (sub)luxation. A breeding herd was established and consisted of stallions and mares acquired at different times. Some were free from, and others were affected by lateral patellar (sub)luxation in either one or both femoropatellar joints. Over a period of 20 years, 49 foals were born from different mating combinations. Some offspring were free from the defect and others showed the abnormality. Though the number of foals bred during the experiment is rather smal...
The pathogenesis of dystocia and fetal malformation in the horse. From a total of 601 severe dystocias in mares, 408 (68%) of the fetuses were in anterior, 95 (16%) in posterior and 98 (16%) in transverse presentation, compared with 99%, 1% and 0.1% respectively for spontaneous parturitions. From the cases with anterior presentation, 151 (37%) showed reflected heads and necks. From the cases with posterior presentation, 47 (50%) presented hip flexions, 25% had hock flexions, and 25% had stretched hind legs, 45 (47%) of the fetuses were in lateral or ventral position, and 28 (30%) of the fetuses were malformed (mainly torticollis and head scoliosis). All 98 c...
Bilateral renal hypoplasia in four young horses. Three horses less than or equal to 3 years old were evaluated because of stunted growth, weight loss, anorexia, depression, and lethargy of at least 1 month's duration. A neonatal foal was examined after its death. In each case, gross and microscopic renal lesions were compatible with bilateral renal hypoplasia (ie, cortical hypoplasia with severe medullary hypoplasia). In young horses with renal failure, bilateral renal hypoplasia should be considered in the differential diagnosis, and may represent a congenital lesion.
Familial congenital occipitoatlantoaxial malformation (OAAM) in the Arabian horse. Familial occipitalization of the atlas with atlantalization of the axis was defined as a single congenital disease in Arabian horses following a clinical, radiologic, and morphologic study of 16 horses with congenital malformations of the occiput, atlas, and axis, and from a study of three reported cases. The constant morphologic features were interpreted as congenital atlantooccipital fusion, hypoplasia of the atlas and dens, malformation of the axis, and modification of the atlantoaxial joint. Atlantoaxial subluxation was also a frequent finding. The clinical syndromes shown by these horses ...
Congenital malformation of the large colon causing colic in a horse. An abnormal mesocolic attachment which resulted in a stellate malformation of the left colon adjacent to the pelvic flexure was suspected to be the cause of intermittent episodes of colic in a horse. Resection and side-to-side anastomosis of the large colon at the level of the sternal and diaphragmatic flexures was performed and the horse made an uneventful recovery from surgery. Only minor serum biochemical changes were observed in the initial postoperative period. The abnormal mesocolic attachment was probably a congenital anomaly.
Pulmonary lobar hypertrophy in a foal. Pulmonary lobar hypertrophy was diagnosed in a 4-hour-old Quarter Horse full-term foal that had respiratory arrest shortly after birth. The gross and microscopic appearances were consistent with polyalveolar lobe, a congenital anomaly of human infants.
Bilateral atavistic polydactyly in a colt and its dam. POLYDACTYLY is perhaps the most frequently reported congenital phalangeal anomaly in horses and, with reference to the stallion Boukephalos ridden by Alexander the Great, it has commanded attention since antiquity (Leipold and MacDonald 1971). Polydactylism is defined as the occurrence of a larger number of digits than typical for a certain species. It has been described in horse, cattle, swine, dog, cat, pigeon, poultry and guinea pig as well as in man (Wiesner and Willer 1974). In horses, the supernumerary digit is found in the forelimb in about 80 per cent of cases, and mainly on the medial...