A review of equine paranasal sinusitis: Medical and surgical treatments

Treatment of the different types of equine sinusitis, in particular those of chronic (>2 months' duration) sinusitis can be difficult, with many such cases not responding to more conservative measures such as rest, antibiotic therapy or sinus lavage. Such refractory cases require further clinical examinations and imaging as outlined in a companion article to achieve confirmation of the cause of the sinusitis. Many sinusitis cases will then require some form of surgical treatment that may include sinusotomy, dental extraction or intrasinus growth removal, that are increasingly being performed by less invasive techniques under standing sedation.     

Standing surgical removal of a progressive ethmoidal haematoma invading the sphenopalatine sinuses in a horse

Progressive ethmoidal haematomas (PEH) have been described as encapsulated, gradually expanding masses, which typically develop from the ethmoidal turbinates. Plain skull radiographs have been shown to be useful in determining the extent of the soft tissue mass if it invades the paranasal sinuses; however, where it is available, computed tomography (CT) offers substantial advantages in the evaluation of the full extent of a PEH. This Case Report describes a PEH invading into the sphenopalatine sinus, and the use of CT in accurately identifying the extent of the lesion.     

CASE REPORT: Anomalous nasolacrimal openings in a 2‐year‐old Morgan filly

This case report describes the clinical, diagnostic, computed tomography findings, and surgical treatment of a 2‐year‐old Morgan filly with bilateral, proximal, and distal anomalous nasolacrimal duct openings.     

Heterotopic polydontia as a cause for a cystic lesion in the paranasal sinus of a Thoroughbred filly

A 1-year-old Thoroughbred filly with left bony facial distortion was diagnosed with a multilobar expansile mass within the caudal maxillary and frontal sinuses on computed tomography (CT). Typical findings associated with a sinus cyst, including expression of amber fluid from the mass and a thick lining that could be peeled from the sinus walls, were found on surgical exploration of the sinus under general anaesthesia. Histological examination of firm structures within the fluid-filled cyst contained all components of embryologically normal dental tissue. The filly recovered well and entered training to race as a 2-year-old, as remodelling of the bony distortion and narrowing of the nasal passage was sufficient for airflow. Previous reports of paranasal cystic lesions in horses suggest developmental abnormalities as a causative factor, especially in young horses. Furthermore, heterotopic polydontia is reported as the underlying aetiology in some human paranasal sinus cysts. While polydontia has been reported in the paranasal sinuses and nasal passages of horses, this is the first case report that finds them associated with a cystic lesion within the paranasal sinus.     

Successful surgical debridement of a cerebral Streptococcus equi equi abscess by parietal bone flap craniotomy in a 2-month-old Warmblood foal

Brain abscesses and intracranial masses have been regularly described in horses. Treatment often is difficult and unrewarding and mortality rate high. This case report describes the successful treatment of a cerebral abscess in a 2-month-old female Warmblood foal with severe neurological signs of acute onset. Computed tomography (CT) revealed a 3 × 4 × 4 cm cerebral mass in the left brain hemisphere with severe cerebral oedema. Craniotomy, using a parietal bone flap technique, allowed the abscess to be sampled, drained and lavaged. Immediately, post-surgery the foal showed significant clinical improvement. Sample culture confirmed Streptococcus equi equi infection. The foal was medically treated for 6 weeks, leading to complete clinical and radiographical recovery. Intracranial surgery in equine medicine is limited. Using a parietal bone flap instead of partial craniectomy to gain access to the cerebrum is a less invasive procedure leading to a better aesthetic result and should be considered for the treatment of cerebral masses in the horse.     

Congenital unilateral facial nerve paralysis in a Warmblood filly

A 17-month-old Warmblood filly was referred to our clinic for evaluation of congenital facial nerve (FN) paralysis. Clinical examination revealed a right-sided facial paralysis with mild masticatory muscle atrophy, mild dysphagia and exposure keratitis. Apart from the FN deficits, neurological examination of the remaining cranial nerves showed no abnormalities. Magnetic resonance imaging (MRI) examination using a 3.0 Tesla scanner showed that in comparison to the left FN, the intracranial section of the right FN between the pons and internal acoustic canal was thinner, whereas it appeared indistinct and thickened within the internal acoustic canal and facial canal. Signs of meningitis or encephalitis were not present on MRI. Cerebrospinal fluid analysis showed mild pleocytosis. The owner of the filly requested euthanasia due to the guarded prognosis. At necropsy, the intracranial section of the right FN was macroscopically thinner than the left side and within the facial canal, a 5 mm tissue stump could be identified with an absent extracranial part of the right FN. Histological examination of the brain stem showed different architecture of the left and right motor nuclei of the FN: in the left nucleus, motor neurons of a normal size and well stainable Nissl bodies were present, whereas in the right nucleus, neurons with Nissl bodies were decreased in number and size. Further, a cytoplasmic rich cell population with a nucleus size compatible with normal neurons was present. These cells were suspected to be atrophic neurons. The tissue stump within the facial canal was histologically identified as connective tissue. Unilateral malformation of the FN has not previously been described in the horse. This filly showed a right-sided, intracranial hypoplasia accompanied by an extracranial aplasia of the FN causing complete, congenital facial nerve paralysis, which corresponded to a difference in the architecture of the affected motor nucleus of the FN.     

Squamous cell carcinoma of the paranasal sinuses in two horses

This case report describes the history, clinical findings, diagnostic imaging (including computed tomography), gross pathology and histopathology of 2 cases of squamous cell carcinoma in the paranasal sinuses. Radiography of the skull is a useful tool to detect a mass in the paranasal sinuses, but the position, extent and character of the lesion can be better visualised with computed tomography.     

Purulent dacryocystitis (nasolacrimal duct drainage) secondary to periapical tooth root infection in a donkey

Periapical tooth disease in the equid has been extensively described. Rostral cheek tooth abscessation usually leads to external facial swelling, and in some cases, nasal drainage. Periapical infection of the caudal cheek teeth usually results in maxillary empyema and sinusitis. This case report describes a donkey with periapical tooth root infection of the left 3rd maxillary premolar (207) diagnosed with computed tomography, which drained exclusively into the adjacent/collateral nasolacrimal duct.     

Advanced imaging of a histologically confirmed bone infarction of the distal tibia in a Warmblood mare

An 8-year-old Warmblood-cross mare presented for investigation of acute onset left hindlimb lameness. Nuclear scintigraphy identified a marked, focal, increase in radiopharmaceutical uptake in the distal aspect of the left tibia. Radiography revealed a large, oval, multi-loculated radiolucent area within the medulla of the distal metaphysis of the left tibia. The mare was treated conservatively for 6 months but showed little improvement in the lameness so the owner elected for euthanasia. Post-mortem computed tomographic imaging revealed a large, oval, hypoattenuating area within the distal tibia, surrounded by a thick, irregular, sclerotic border. The lesion occupied the majority of the medullary cavity but the cortical bone was unaffected. Gross and histopathological examination confirmed a diagnosis of a bone infarction in the medullary cavity of the distal tibia.     

The nasolacrimal duct of the mule: Anatomy and clinical considerations

This study investigated the location of the nasolacrimal orifice (NLO) and course of the nasolacrimal duct in the mule using visual examination, gross dissection and computed tomography (dacryocystography [CT‐DCG]) and concluded that the location of the NLO is distinct from that described for horses and donkeys and is easily located, by visual examination alone, within the internal cutaneous tissue of the lateral wall of the external nares. The course of the nasolacrimal duct caudal to the nasal vestibule is similar to that of the horse.     

The use of computed tomography in the diagnosis of an ectopic ureter in a Quarter Horse filly

This report describes a 4‐month‐old Quarter Horse filly with an ectopic ureter. The filly presented with signs of urinary incontinence, which had been present since birth. Computed tomography (CT) examination and cystoscopy confirmed a diagnosis of a unilateral ectopic ureter. A nephrectomy of the left kidney was performed and renal function was closely monitored post operatively. The filly was treated for abdominal chylous effusion as a post operative complication. The filly survived to discharge from the hospital, and maintained normal urinary function at 12 months post operatively.     

Supracoronary approach for keratoma removal in horses: Two cases

Two competitive horses were presented for examination of chronic lameness; one associated with a hoof‐wall deformity, the other with a firm mass over the dorsal pastern region. Radiographs revealed moderately radiopaque masses associated with both deformities. The lesions were characterised ultrasonographically as noninvasive, well‐circumscribed heterogeneous masses. Computed tomographic examination of the second case revealed a well‐defined, partially mineralised, bi‐lobed mass with associated bony resorption of the underlying middle phalanx. Both patients were anaesthetised and the keratomas surgically removed via approaches 1–2 cm proximal to the coronary bands. Both horses were stall‐sound 2 days after surgery and returned successfully to an equal level of competition by 8 months. A supracoronary approach is a viable alternative to partial or complete hoof wall resection for the removal of nonsolar keratomas from the foot of a horse.     

Epiploic foramen entrapment of the large colon in a 9-month-old Thoroughbred filly

A 9-month-old Thoroughbred filly was presented for colic of a few hours’ duration. Examination revealed tachycardia at 64 beats/min, and a colon displaced to the right with wall oedema on ultrasound. After an hour of intravenous fluid therapy, the filly became restless and exploratory laparotomy was performed. Impaction and incarceration of the large colon up to the caeco-colic fold through the epiploic foramen (EF) were diagnosed. After evacuating the colonic contents through a pelvic flexure enterotomy, the EF entrapment (EFE) was reduced. The large colon appeared congested with a fragile serosa, serosal tear at its antimesenteric aspect, and amotile for the remainder of the surgery. Colon motility resumed as evidenced by ultrasonographic examination on the second day post-surgery, and despite pasty diarrhoea, the filly made a complete and uneventful recovery and was alive at 6 months’ follow-up. Epiploic foramen entrapment of the large colon is very rare but should be included as a differential diagnosis of colon displacements, even in young horses, requiring prompt surgical resolution.     

An atypical case of recurrent cellulitis/lymphangitis in a Dutch Warmblood horse treated by surgical intervention

The case reported here describes an atypical presentation of cellulitis/lymphangitis in an 8‐year‐old Dutch Warmblood mare. The horse was presented with a history of recurrent episodes of cellulitis/lymphangitis and the presence of fluctuating cyst‐like lesions on the left hindlimb. These lesions appeared to be interconnected lymphangiectasias. Surgical debridement followed by primary wound closure and local drainage was performed under general anaesthesia. Twelve months post surgery, no recurrence of cellulitis/lymphangitis had occurred and the mare had returned to her former use as a dressage horse.     

Calcified tumours of the paranasal sinuses in three horses

Three horses, a 10-year-old Thoroughbred mare, a 9-year-old Thoroughbred gelding and a 6-year-old Arab gelding, with calcified tumours of the paranasal sinuses, are described. All horses presented with purulent nasal discharges and facial distortion. Exophthalmos, blepharospasm and ocular discharge were also a feature in individual horses. A presumptive diagnosis of a calcified tumour was made on the basis of clinical signs and radiographic and endoscopic findings. The tumours ranged from 15 to 25 cm in diameter. A large frontonasal bone flap was used to expose the tumours, which were cleaved into several pieces with an osteotome and removed. Histological examination of the masses identified cementomas in two cases and an osteoma in the third. Long term follow up from 18 months to 5 years after surgery indicated that there was no recurrence. This case series demonstrates that, although calcified tumours of the paranasal sinuses are rare in horses, they should be considered in the differential diagnosis of purulent nasal discharge, facial swelling and ocular distortion, and are amenable to surgical treatment.     

Equine paranasal sinus disease: a long-term study of 200 cases (1997-2009): treatments and long-term results of treatments

Reasons for performing study: There is limited objective information available on the treatment and the long‐term response to treatment of the different types of equine sinus disease. Objectives: To document the treatments and long‐term response to these treatments in 200 cases of equine sinus disease (1997–2009). Methods: The treatments of horses affected with subacute primary sinusitis (n = 52); chronic primary sinusitis (n = 37); dental sinusitis (n = 40); sinus cyst (n = 26); traumatic (n = 13); dental‐related oromaxillary fistula (n = 8); sinus neoplasia (n = 10); mycotic sinus disease (n = 7); and intrasinus progressive ethmoid haematoma (n = 7) and the long‐term response to these treatments were retrospectively reviewed. Results: Treatments evolved throughout the study and latterly were as conservative as possible, including sinoscopic lavage and standing sinusotomy, with a maxillary sinusotomy approach preferred for the mainly mature horses treated in this study. Removal of intrasinus inspissated pus, including transendoscopically (by sinusotomy and via existing sinonasal fistulae), was the main treatment for chronic primary sinusitis and sinonasal fistulation was seldom performed latterly. Attempted oral extraction of infected cheek teeth, even if unsuccessful, facilitated subsequent dental repulsion, resulting in few post operative problems. Sinus cyst removal carried an excellent prognosis. Except for cases of sinus neoplasia (only 22% cured), an excellent long‐term response to treatment (91% fully cured, 7% partially cured) was obtained for all other types of sinus disease following a median of one treatment. Conclusions: More conservative treatments, including removal of intrasinus inspissated pus by sinoscopy, pre‐existing sinonasal fistula or sinusotomy, are effective for chronic primary sinus disease. Standing sinusotomy, mainly using a small maxillary site, was suitable for most cases of sinus disease in mature horses.