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.
[Two rare lens abnormalities in horses]. Coloboma and ectopia of the crystalline lens are rarely encountered or diagnosed congenital defects of the equine eye. The clinical and ophthalmoscopic features of a congenital coloboma of the lens in a 3 year old Hanoverian stallion and of an ectopic lens in a 6-month old Hanoverian filly are described and depicted. In the stallion, the lens coloboma was associated with a partial coloboma of the zonules, and in the filly, the ectopic lens was small and spherical (microphakia, spherophakia) and associated with syneresis of and small floaters in the vitreous. Although it cannot be excluded that...
Arthrodesis for congenital flexural deformity of the metacarpophalangeal and metatarsophalangeal joints. A llama, a miniature horse, and a miniature donkey with severe bilateral congenital flexural deformities of the metacarpophalangeal and metatarsophalangeal joints were treated successfully by arthrodesis with dynamic compression plating or external skeletal fixation. The flexor tendons were more taut than the suspensory ligaments and were transected. In the llama, the suspensory ligament was transected, and overcorrection caused ischemic necrosis of one distal limb and subluxation of the other fetlock joint. In the horse and donkey, the suspensory ligament was preserved and wedge osteotomy was...
Inheritance of hydrocephalus in horses. From 1974 to 1979, seven stillborn foals with internal hydrocephalus were encountered from one Standardbred trotter stallion which sired 239 registered foals. An hydrocephalic foal was also aborted by a daughter of the same stallion. One affected foal from Standardbred trotters and one from a Finnish Horses were also reported. In some cases, the condition caused severe dystocia. Based on field data, possible causes of the defect could neither be proved nor specifically overruled in individual cases. Hydrocephalus was obviously not an autosomal recessive single-locus defect, nor was it X-linked...
Atresia coli in the foal: a review of six cases. Physical examination and exploratory celiotomy were performed on five neonatal foals presented with signs of acute colic. Atresia coli was confirmed in each foal during surgery. The most consistent finding on physical examination was the absence of meconium staining following repeated enemas. The large, transverse and/or small colon were involved in all foals. One eight month aborted foetus was submitted for necropsy and diagnosed as having atresia coli and congenital hydrocephalus. Atresia coli should be considered for neonatal foals with signs of acute colic.
Probable congenital esophageal stenosis in a thoroughbred foal. Esophageal stenosis was diagnosed in a 7-day-old Thoroughbred foal referred for evaluation of bilateral milky nasal discharge. Double-contrast radiography revealed concentric narrowing of the esophagus at the level of the fifth rib, overlying the base of the heart. Lateral displacement of the esophagus was not apparent. X-ray computed tomography of the cranial portion of the thorax confirmed normal cardiac and great vessel anatomy, ruling out vascular ring anomaly. A nasogastric tube was placed, extending past the stenosis and into the stomach, and the foal was fed mares' milk via this tube. O...
[Clinical case report: unilateral malformation of the eye of a thoroughbred foal]. A unilateral malformation of the eye of a thoroughbred foal is described. The specific form of the tiny lens we named, "lenticulus". It is correlated with a maximal unchangeable mydriasis. The bulb shows physiological size. A brown-black pigmented mass inhibited (internal) inspection and examination of the middle and rear part of the eye. Special emphasis is laid on the insecure behaviour of the foal. A connection with an iridocyclochoroiditis, which was treated in the mare about a year ago, and the pathological changes in the eye of the foal is not evident.
Resection of a cervical tracheal bronchus in a foal. A 3-day-old Thoroughbred foal developed a large, air-distended, midcervical swelling that was diagnosed as a congenital tracheal bronchus with associated ectopic lung tissue. Clinical signs consisted of a compressible air-filled sac that enveloped the trachea. The nature and extent of the defect were evaluated endoscopically and radiographically. Surgical resection of the bronchus and associated air-filled sac resulted in a functionally and cosmetically acceptable outcome.
Bilateral hypoplasia of the soft palate in a foal. Bilateral hypoplasia of the soft palate and aspiration pneumonia occurred in a Standardbred foal. The filly was presented with a history of illthrift, dyspnoea, coughing and bilateral nasal discharge. Abnormal sounds (crackels and wheezes) were auscultated over all lung fields and the cervical trachea. Endoscopy revealed a shortened soft palate with a uvula-like mass protruding from the free border into the nasopharynx. Mucopurulent material was present in the trachea. Samples obtained by tracheal wash were submitted for cytology, culture and sensitivity testing. Results indicated a septic inf...
Palliative repair of aortic atresia associated with tricuspid atresia and transposition of the great arteries. Successful palliative repair of aortic atresia and hypoplastic aortic arch associated with tricuspid atresia in a neonate is described. The repair consisted of reconstruction of the hypoplastic aortic arch with an equine pericardial patch, division of the patient ductus arteriosus, connection of the pulmonary artery to the aorta, implantation of the proximal part of the ascending aorta into the main pulmonary artery, and anastomosis of a polytetrafluoroethylene graft 5 mm in diameter between the right ventricular outflow tract and the central pulmonary artery, which was transferred anteriorly ...
[A case of diprosopus in a foal]. A case of diprosopus in a foal is described. This is only the second report of such a deformity in the equine species. Hereditary pathology and pathogenesis are discussed.
Atrial septal defect and atrial fibrillation in a foal. Clinical examination of a four-and-a-half-month old foal revealed evidence of progressive heart failure associated with an atrial septal defect and atrial fibrillation. Atrial septal defects are rarely reported in foals and the foal's growth, development and demeanour were normal until a sudden onset of lethargic behaviour. The value of B-mode echocardiography in identifying the congenital lesion is indicated.
Congenital atresia of the parotid salivary duct in a 7-month-old quarter horse colt. A 7-month-old Quarter Horse colt was examined because it had had a tortuous, distended vessel on the side of its head since birth. An abnormality of the parotid salivary duct was suspected on the basis of location and course of the vessel. Atresia of the duct near the parotid papilla was diagnosed by use of contrast sialography. Surgical transpositioning was attempted, but failed because of stricture formation. Chemical ablation of the salivary gland has been used to treat traumatic rupture of the duct. It proved to be an effective and practical method of resolving the problem in this case. Co...
Bilateral colobomas involving the optic discs in a quarterhorse. THIS report describes bilateral colobomas of the optic discs with associated aberrations in ocular differentiation • and unusual hypopigmentation of the uveal tissues.
Iridial hypoplasia (aniridia) accompanied by limbic dermoids and cataracts in a group of related quarterhorses. The clinical, gross and microscopic ophthalmic lesions of iridial hypoplasia, limbic dermoids and cataracts in a Quarterhorse stallion and a group of its offspring are described. It is proposed that the lesions in the stallion were the result of an independent mutation and that the defects were transmitted to its offspring by an autosomal dominant gene.
Overo lethal white foal syndrome: equine model of aganglionic megacolon (Hirschsprung disease). The lethal white foal syndrome (LWFS) is a congenital abnormality of overo spotted horses which is a model for human aganglionic megacolon or Hirschsprung disease. Foals with LWFS have an all white, or nearly all white, coat. They also present clinically with an intestinal obstruction that proves fatal within the first few days of life. The LWFS involves both melanocytes and intestinal ganglion cells, and appears to result from a genetic defect involving neural crest cells. This report describes pathologic studies of two recent cases of LWFS. Two different hypothetical models of inheritance of...
Bilateral congenital cysts in the frontal sinuses of a horse. Congenital frontal sinus cysts were found bilaterally in the frontal sinuses of a one-year-old miniature horse. Diagnosis was based on radiography of the head and cytologic examination of tissue aspirated from the frontal sinuses. The cysts were surgically removed, using a hinged bone flap technique bilaterally over the frontal sinuses.
Staphylectomy for treatment of dorsal displacement of the soft palate in two foals. Dorsal displacement of the soft palate associated with dysphagia and aspiration pneumonia was diagnosed in 2 young foals. The displacement appeared to be congenital. Clinical signs associated with the condition were resolved after staphylectomy. Dorsal displacement of the soft palate is usually recognized in adult animals as an upper respiratory tract disease, but may be a contributing factor to dysphagia and lower respiratory tract disease in young animals.
Agenesis of the corpus callosum with cerebellar vermian hypoplasia in a foal resembling the Dandy-Walker syndrome: pre-mortem diagnosis by clinical evaluation and CT scanning. DORSAL midline dysgenesis of the human brain, a complex
pattern of maldevelopment of sulcation and neuronal migration
occurring before 74 days gestation, has been recognised for over
fifty years. The association (68 per cent) of the so-called Dandy-
Walker syndrome (cystic dilatation of the fourth ventricle and
hypoplasia of the cerebellum) with other brain malformations is
common and often includes agenesis of the corpus callosum
(Hart, Malamud and Ellis 1972; Ral et a1 1980). This report
describes the first pre-mortem identification of such a structural
brain anomaly in a Thoroughbr...
Atresia of the right atrioventricular orifice with complete transposition of the great arteries in a horse. The heart of a 6-week old Arabian filly with a history of poor health and exercise intolerance revealed at postmortem examination, multiple cardiac malformations which included atresia of the right atrioventricular orifice (tricuspid atresia, with associated atrial and ventricular septal defects), complete transposition of the great arteries, anomalous drainage of the venae cavae and coronary sinus into the left atrium, coarctation of the aorta, and a small but patent ductus arteriosus. The course of blood through the heart was suggested and discussed.
Monorchidism in the horse. Six horses with monorchidism, identified at surgery for cryptorchidectomy, are reported. All six presented with a single scrotal testis. Following surgical removal of one testis, they were either hormonally, anatomically or behaviourally determined to be geldings. Three other horses reported in the literature are reviewed. Of these nine cases of monorchidism, eight were thought to be caused by testicular degeneration and one by testicular agenesis. The vaginal process was present in all of the former and absent in the latter. The left side was involved in five of these eight horses. In seven, ...