Modified lateral orbitotomy for vision-sparing excision of a zygomatic mucocele in a dog

A 1-year-old Shar Pei presented for recent-onset exophthalmos and right peri-ocular facial swelling. Physical examination revealed the facial mass was of soft-tissue consistency and nonpainful to the dog. Due to inability to retropulse the globe during ophthalmologic examination, it was suspected the mass had impinged into the orbit, resulting in rostral displacement of the globe. Anatomic location suggested the lesion was probably associated with the zygomatic salivary gland. Fine-needle aspiration and subsequent cytological evaluation of fluid extracted from the facial mass was consistent with a diagnosis of zygomatic mucocele. Computed tomography imaging confirmed a single fluid-filled mass was resulting in both the facial distention and the exophthalmos. A modified, lateral orbitotomy surgical approach was selected for excision of the lesion to provide ventral exposure to the orbit, while minimizing trauma to the globe and supporting structures. Histopathology of the excised lesion confirmed a diagnosis of zygomatic mucocele. This case demonstrates utilization of a modified lateral orbitotomy for effective surgical management of a zygomatic mucocele in a dog, with preservation of vision and absence of any significant postoperative complications.     

Orbitotomy for retrobulbar malignant fibrous histiocytoma in a dog

A retrobulbar malignant fibrous histiocytoma was diagnosed in a 12-year-old castrated male Keeshond dog. The mass was excised with a lateral orbitotomy and zygomatic arch resection. Vision was preserved in the affected eye, and no recurrence was noted up to 10 months postoperatively. Malignant fibrous histiocytoma originates from primitive mesenchymal stem cells. The malignant fibrous histiocytoma seen in our patient was most consistent with the storiform-pleomorphic variant, given the storiform arrangement of spindle cells, the presence of histiocytoid cells, and a mixed inflammatory infiltrate, without giant cells. The metastatic potential of malignant fibrous histiocytoma in general, and the storiform variant in particular, is unknown. Seventeen months later the dog was presented to the referring veterinarian with anorexia, diarrhea, weight loss and bilateral purulent nasal exudates. The dog was euthanized without necropsy.     

Clinical approach to prostatic diseases in the dog

In small animal practice, prostatic diseases are increasingly encountered. All dogs may experience prostatic disease, but particular care should be addressed to breeding dogs, in which prostatic affection may lead to decrease in semen quality and fertility. The most common prostatic disease is the benign prostatic hyperplasia (BPH) followed by prostatitis, prostatic neoplasia and prostate squamous metaplasia. These diseases do not have pathognomonic symptoms, therefore, making a correct diagnosis may not be easy. An accurate clinical examination and a correct diagnostic protocol are essential in order to begin the most appropriate treatment, and also to do a good prophylaxis where it is possible. BPH therapy is usually recommended when mild‐severe signs are present or if symptoms disturb the patient. New therapeutic approaches, both medical and surgical, allow to maintain fertility in most animals with prostatic disorders. Prostate cancer is relatively infrequent. Elective therapy is the surgical one, but it is considered palliative and can result in important post‐operative complications. The aim of this paper is to lay down the most appropriate diagnostic process describing the aetiologies of prostatic disease, their symptoms, the right investigative tools and therapy.     

Surgical management of orbital nodular granulomatous episcleritis in a dog

A 27 kg, 6‐year‐old, male castrated German shorthaired pointer presented to the University of Missouri, Veterinary Teaching Hospital with the complaint of progressive exophthalmia of 2 years duration optical density (OD). Lack of retropulsion OD was noted on physical examination. Anterior segment examination OU and fundic examination OS did not reveal any abnormalities. Examination of the fundus OD revealed focal scleral indentation of the inferior nasal globe. The indentation changed location with globe movement OD. MRI and CT scan revealed a well‐circumscribed, approximately 2 cm in diameter mass located caudal and ventral to the affected globe that appeared to communicate with the nictitating membrane with absence of any bony involvement. A modified lateral orbitotomy was recommended and performed to remove the orbital mass and nictitating membrane en‐bloc. Histopathology and immunohistochemistry of the mass confirmed a diagnosis of nodular granulomatous episcleritis (NGE). Postoperatively, the dog developed absolute keratoconjunctivitis sicca (KCS). Examples of primary episcleral inflammation in the dog include diffuse episcleritis, NGE, nodular fasciitis, fibrous histiocytoma, proliferative conjunctivitis/keratoconjunctivitis, pseudotumor, and Collie granuloma. The etiology of these episcleral inflammations is presumed to be immune mediated. To our knowledge, this is the first report of NGE affecting the orbital region of a dog. Development of absolute KCS resulting from excision of the nictitating membrane is also supported by this case.     

Lateral orbitotomy for treatment of an orbital abscess in a dog

A two‐year‐old Jack Russell terrier was diagnosed with a retrobulbar abscess and orbital cellulitis. The diagnosis was confirmed by ultrasound, magnetic resonance imaging examination and ultrasound‐guided fine‐needle aspiration. Transoral ventral drainage was attempted but was unsuccessful. The abscess was successfully treated by open drainage through a lateral orbitotomy. Despite the exposure of the orbital structures, the orbital soft tissues healed by second intention without further complications. The open drainage was well tolerated and resulted in immediate reduction of inflammation and pain, allowing a quick recovery. This report describes the diagnosis and, surgical management and the long‐term (3 years) follow‐up of an unusual case of orbital abscess associated with diffuse periorbital cellulitis successfully treated by open drainage through a lateral orbitotomy.     

Two cases of dermatophytic pseudomycetoma in the dog: an immunohistochemical study

Two cases of canine dermatophytic pseudomycetoma resulting in subcutaneous nodules resembling those previously reported in Persian cats are described. Culture performed from one nodule yielded dark yellow colonies consistent with Microsporum canis. Immunohistochemistry, using rabbit anti-M. canis, demonstrated specific binding to fungal elements in paraffin sections. The specificity of the antiserum was further tested by an agar gel immunodiffusion assay using a soluble extract from a feline isolate of M. canis as antigen. The antiserum did not cross-react with an Aspergillus fumigatus antigen. These are the first two reported cases of canine dermatophytic pseudomycetoma and immunohistochemical staining supported the diagnosis.     

Creatinine in the dog: a review

Creatinine is the analyte most frequently measured in human and veterinary clinical chemistry laboratories as an indirect measure of glomerular filtration rate (GFR). Although creatinine metabolism and the difficulties of creatinine measurement have been reviewed in human medicine, similar reviews are lacking in veterinary medicine. The aim of this review is to summarize information and data about creatinine metabolism, measurement, and diagnostic significance in the dog. Plasma creatinine originates from the degradation of creatine and creatine phosphate, which are present mainly in muscle and in food. Creatinine is cleared by glomerular filtration with negligible renal secretion and extrarenal metabolism, and its clearance is a good estimate of GFR. Plasma and urine creatinine measurements are based on the nonspecific Jaffé reaction or specific enzymatic reactions; lack of assay accuracy precludes proper interlaboratory comparison of results. Preanalytical factors such as age and breed can have an impact on plasma creatinine (P-creatinine) concentration, while many intraindividual factors of variation have little effect. Dehydration and drugs mainly affect P-creatinine concentration in dogs by decreasing GFR. P-creatinine is increased in renal failure, whatever its cause, and correlates with a decrease in GFR according to a curvilinear relationship, such that P-creatinine is insensitive for detecting moderate decreases of GFR or for monitoring progression of GFR in dogs with severely reduced kidney function. Low sensitivity can be obviated by determining endogenous or exogenous clearance rates of creatinine. A technique for determining plasma clearance following IV bolus injection of exogenous creatinine and subsequent serial measurement of P-creatinine does not require urine collection and with additional studies may become an established technique for creatinine clearance in dogs.     

Hepatic ultrasonography in the dog

Ultrasonography may be used to evaluate noninvasively a wide variety of diseases affecting the canine liver. Hepatic mass lesions, parenchymal pathology, gallbladder and biliary disease, and vascular abnormalities may be detected and characterized by ultrasonography. Ultrasonically guided percutaneous liver biopsy can improve the succes and safety of obtaining diagnostic cytologic material. The response of liver disorders to treatment may be effectively monitored by serial ultrasonographic examination. The ultrasonographic diagnosis of canine liver disease is described and illustrated with 11 case history reports.     

Anisocoria in the dog provoked by a toxic contact with an ornamental plant: Datura stramonium

We report an unusual case of anisocoria in the dog provoked by Datura stramonium, and an experimental clinical assay to reproduce the anisocoria using simple contact with part of the plant in four healthy dogs. Any part of the D. stramonium plant produced anisocoria following simple contact with the eye.     

Senile cardiac amyloidosis in the dog

Thirty-two cases of senile cardiac amyloidosis from a routine necropsy material of 594 dogs were studied. The age of the affected dogs ranged from 10 to 16 years. Amyloid was observed in the intramural arteries and arterioles, predominantly in the ventricular myocardium. The vessels were often obturated with amyloid, and myocardial necroses and fibroses were common consequences of the vascular lesions. In three cases amyloid deposits were also observed in the main subepicardial coronary arteries. In contrast to man, only slight interstitial amyloid degeneration was found in four of the dogs observed. Amyloid in the mitral valves, tricuspid valves and aortic cusps was observed in six, two and three cases respectively. It was concluded that the distribution of senile cardiac amyloidosis in the heart of the dog differs considerably from that in man.     

Creatine kinase in the dog: A review

In the dog, creatine kinase (CK) is mostly present in the skeletal muscles, myocardium, brain and intestine. The MM isoenzyme predominates in muscles and myocardium. In plasma, reference values depend on the technique used and CK-MB accounts for about 30–45% of total CK activity. Sex has no influence on plasma CK activity, which is higher in young dogs than in adults. Plasma CK is elevated after physical exercise. After its release from the cells, CK reaches the plasma mostly via the lymphatic route and then remains in the plasma compartment. It is rapidly cleared with a half-life of about 2 hours. Muscle diseases are the main source of plasma CK elevations: inherited myopathies, malignant hyperthermia, hypothyroidism, vitamin E-selenium deficiency, prolonged decubitus, intramuscular injections, surgery, etc. Plasma CK is also increased in experimental myocardial infarction, for which the dog is an interesting model, allowing quantification of the damage by measuring the total CK activity released.Abbreviations ADP adenosine diphosphate - ATP adenosine triphosphate - CK creatine kinase - DGKC Deutsche Gesellschaft für klinische Chemie - IM intramuscular - IV intravenous - K _m Michaelis constant - poly(A) polyadenylate - RNA ribonucleic acid - mRNA messenger RNA     

Imaging diagnosis: pneumothorax and focal peritonitis in a dog due to migration of an inhaled grass awn

A 1-year-old working Kelpie developed pneumothorax and focal peritonitis after inhalation of a grass awn that migrated from the lung, through the diaphragm, into the peritoneal cavity. Radiographic evidence of sternal lymph node enlargement was fundamental in the diagnosis of intraperitoneal disease and prompted abdominal ultrasound leading to definitive diagnosis.     

Uveitis and pupillary block glaucoma in an aphakic dog

Unilateral uveitis with pupillary occlusion and secondary glaucoma was treated with neodymium:YAG laser iridotomy and iridencleisis in an aphakic 2-year-old male Miniature Schnuauzer. The dog presented 4 months after bilateral phacoemulsification with a complaint of blepharospasm of the left eye. Examination revealed anterior uveitis with pupillary occlusion and iris bombé. A slit-lamp mounted Q-switched Nd:YAG laser was used to create a central iridotomy to deepen the anterior chamber and an iridencleisis was performed to recreate a pupil. The eye remained visual and normotensive over a 6-month follow-up period.     

Evaluation of serum iso-amylase in the normal dog using an improved electrophoretic technique

Six iso-amylase fractions are known to exist in human serum, three originating from the salivary glands and three from the pancreas. Although it is known that a different number and source of iso-amylase fractions occur in the dog, the routine detection of all the canine iso-amylase fractions has not been previously established. Earlier methods detected either two iso-amylase fractions or, in a proportion of cases, four fractions. A method is described which detects four iso-amylase fractions in 95% of normal canine serum samples. Trials have shown the method is reproducible and that freezing at -40°C has no effect on iso-amylase activity. The normal values for iso-amylase are recorded in 18 normal dogs.     

Successful medical treatment of an orbital osteoma in a dog

A 6‐year‐old neutered male German Shepherd‐mixed breed with a 2‐month history of bilateral conjunctival hyperemia, epiphora, and a firm, slowly progressive swelling of the medial canthal region of the left eye (OS) was examined. Ophthalmic examination OS revealed a firm and smooth mass, extending from the medial canthus toward the medial orbital wall. Indirect ophthalmoscopy revealed indentation of the nasal part OS, which corresponded to the position of the orbital mass. Orbital neoplastic diseases were the main differential considerations. Computerized tomography revealed a bony smooth orbital mass without bone destructive features. Biopsy was performed, and histologic features were suggestive of osteoma. Systemic nonsteroidal anti‐inflammatory (NSAID) drugs resulted in complete mass regression and absence of clinical signs for 5 years following initial diagnosis. This report describes the first case of canine orbital osteoma, which was responsive to NSAIDs.