Exploring the relationship between calcitonin, ionized calcium, and bone turnover in cats with and without naturally occurring hypercalcemia.

Objectives: This case-control study aimed to evaluate calcitonin response in naturally occurring hypercalcemia in cats and assess the relationships between calcitonin and ionized calcium (iCa) and examine relationships between calcitonin, iCa and bone turnover. Methods: Hypercalcemic cats (persistently increased iCa concentration [>1.40 mmol/l]) were identified retrospectively via a medical database search; additional hypercalcemic and normocalcemic cats were recruited prospectively. Data regarding routine biochemical and urine testing, diagnostic imaging and additional blood testing were obtained. Serum alkaline phosphatase (ALP) activity was used as a marker of bone turnover. Serum calcitonin concentration was analyzed using a previously validated immunoradiometric assay. Hypercalcemic cats with an increased calcitonin concentration (>0.9 ng/L) were termed responders. Group comparisons were performed using a Mann-Whitney test for continuous variables and a χ2 test for categorical variables. Spearman's correlation coefficient was used to examine the relationships between calcitonin, iCa and ALP. Results: Twenty-six hypercalcemic and 25 normocalcemic cats were recruited. Only 5/26 (19.2%) of the hypercalcemic cats were identified as responders, and all were diagnosed with idiopathic hypercalcemia. There was no significant correlation between the concentrations of calcitonin and iCa (p = 0.929), calcitonin and ALP (p = 0.917) or iCa and ALP (p = 0.678) in hypercalcemic cats, however, a significant negative correlation was observed between calcitonin and ALP (p = 0.037) when normocalcemic and hypercalcemic cats with an elevated calcitonin concentration were analyzed together. Discussion: The expected increase in calcitonin concentration was present in only a small subset of hypercalcemic cats; no correlation was found between iCa and calcitonin concentration. The inverse relationship between calcitonin and ALP in cats with increased calcitonin concentrations suggests that the ability of calcitonin to correct hypercalcemia may be related to the degree of bone turnover.

CTSK variant implicated in suspected pyknodysostosis in a domestic cat.

Case summary: A 9-month-old entire male domestic longhair cat presented with a history of pathological fractures, chronic musculoskeletal pain and poor growth. Multiple facial and skeletal abnormalities were identified on physical examination and advanced imaging (CT and radiographs). A variant in CTSK was identified in the affected cat following whole-exome sequencing (WES). The cat was managed symptomatically with diet, environmental modifications and analgesia. Relevance and novel information: This is the first report of a cat with a similar clinical presentation and genetic variant to the hereditary human genetic disorder pyknodysostosis. In this case, WES was performed, which often facilitates the diagnosis of various hereditary disorders (ie, a conceptual framework for practicing feline genomic medicine). Despite the severe skeletal and appendicular abnormalities described, the cat was alive more than 2 years after its initial presentation.

Evaluation of the Attitudes and Confidence of Veterinary Undergraduates toward Working with Cats in the Veterinary Hospital Environment.

An understanding of feline behavior is required to successfully handle cats in the hospital environment and avoid triggering escalation to fear-aggression due to heightened anxiety. Some veterinary students appear to misinterpret feline behavioral cues, resulting in frustration and poor success when performing basic handling. This article investigates the following in regard to veterinary students and feline handling: (a) attitudes toward working with feline patients in the hospital environment; (b) experience of working with feline patients; (c) satisfaction in acquisition of feline handling and examination skills; and, (d) confidence in feline handling skills; and to explore influencing factors. An electronic questionnaire was circulated to fourth and final year veterinary students (May 2012) and final year students (June 2013) for anonymous voluntary completion. One hundred and seventy-three of 293 students completed the questionnaire. Of final year respondents, 87/115 (75.7%) indicated that they enjoy interacting with cats in veterinary hospitals; 95/115 (82.6%) indicated that they were satisfied with their cat handling skills; 105/115 (91.3%) felt confident handling quiet and wriggly cats; significantly fewer 63/115 (54.8%) felt confident handling unpredictable cats (p < .05). Factors significantly affecting confidence in handling unpredictable cats included: frequency of examination practice during extra-mural studies (p < .05), enjoyment of interacting with cats in veterinary hospitals (p < .05), self-perceived understanding of feline behavior (p < .05), self-perceived ability to interpret cats' behavioral expressions (p < .05), satisfaction with cat handling skills (p < .05), and perception of feline versus canine handling ability (p < .05).

Incidence of microcytosis in hyperthyroid cats referred for radioiodine treatment.

OBJECTIVES: The study aimed to document the incidence of erythrocyte microcytosis in a population of hyperthyroid cats referred for radioiodine (RAI) treatment. Microcytosis has been observed but not described in feline hyperthyroid patients and is associated with hyperthyroidism in humans. METHODS: Retrospective clinicopathological data were collected for cats undergoing RAI between January and December 2017. Microcytosis was defined as mean cell volume (MCV) <41.3 fl using the ADVIA 2120 haematology analyser (Siemens) and identified on blood smear examination by a haematology laboratory scientist or board-certified specialist in veterinary clinical pathology. Hyperthyroidism was classified as mild (total thyroxine [TT4] 60-124.9 nmol/l), moderate (TT4 125-250 nmol/l) or severe (TT4 ⩾251 nmol/l) immediately before RAI. Data were analysed descriptively and using a Pearson correlation coefficient to test the relationship between TT4 and microcytosis, and time elapsed between first diagnosis and MCV. RESULTS: There were 41 female and 37 male cats with an age range of 7.2-20.8 years. Most cats were non-pedigree (98.7%). Microcytosis (median MCV 39.8 fl, interquartile range 32.3-41.2) was present in 29.5% (23/78) of the cats. Of the 23 microcytic samples, 86.9% (20/23) were confirmed as such on smear examination. Of mildly, moderately and severely hyperthyroid cats, 23% (6/26), 28.1% (9/32) and 40% (8/20) were microcytic, respectively. Two microcytic cats had low red blood cell counts (<6 × 1012/l) and low haemoglobin concentration (<8.2 g/dl). There was no correlation between TT4 or time elapsed from first diagnosis and MCV. Microcytosis resolved in 77.7% (7/9) of cases with follow-up. One microcytic cat had significant comorbidities (portosystemic shunt). CONCLUSIONS AND RELEVANCE: Microcytosis was present in a significant proportion of hyperthyroid cats, most without clinically significant comorbidities, and resolved in some following RAI.

Concurrent thoracic pathology identified with radiology in hyperthyroid cats referred for radioiodine therapy.

OBJECTIVES: Radioiodine (RAI) treatment for hyperthyroidism is becoming increasingly available in the UK. Pretreatment assessment is commonly performed, as patient handling is limited once RAI has been administered. The aims of this study were to determine the prevalence of thoracic pathology using thoracic radiography in hyperthyroid cats referred for RAI treatment and to determine the value of this technique pretreatment. METHODS: The hospital databases were searched for hyperthyroid cats referred for RAI treatment at the Feline Centre, Langford Vets, between January 2012 and July 2016. Radiographs were reviewed by Diplomates of the European College of Veterinary Diagnostic Imaging at the time of treatment and each set of radiographs was subsequently reviewed by one radiologist for the study. Cardiorespiratory signs were recorded, if present, and any change in treatment plan or suitability for RAI treatment was documented. RESULTS: Two hundred and fifty-two cats were included in the study. Thoracic pathology was identified in 77% (n = 194/252) of the cats, of which 59% (n = 115/194) had pulmonary abnormalities with bronchial and bronchointerstitial patterns most frequently; 57% (n = 111/194) had skeletal abnormalities and 43% (n = 84/194) had cardiac abnormalities, with mild-to-moderate cardiomegaly most prevalent. Other abnormalities included sternal lymphadenomegaly (7%; n = 13/194), mediastinal pathology (3%; n = 5/194), oesophageal pathology (2%; n = 4/194) and pleural space disease (0.5%; n = 1/194).Twelve cases (6%) had a change in their treatment plan as a result of thoracic radiographic abnormalities, of which five subsequently underwent RAI treatment. CONCLUSIONS AND RELEVANCE: A low prevalence of significant thoracic pathology was identified on radiographs in hyperthyroid cats referred for RAI treatment. Incidental thoracic abnormalities were found much more commonly; hence, results of thoracic radiology need to be combined with the clinical picture, to decide whether further investigations or alterations to the treatment plan are required pre-RAI.

A UK-based survey of cat owners' perceptions and experiences of antibiotic usage.

OBJECTIVES: The aim of this study was to explore owners' knowledge of antibiotics, experience of antibiotic use in their cats and involvement in decision-making regarding antibiotic prescriptions. METHODS: Cat owners were recruited via social media and veterinary practices to complete a survey designed to evaluate general knowledge of antibiotics, attitudes to antibiotic stewardship and experiences of antibiotic use in their own cat between November 2017 and March 2018. Data were analysed descriptively. RESULTS: A total of 1436 surveys were completed; 247 respondents (17.2%) had a veterinary background. The majority of the remaining respondents correctly identified that antibiotics treat bacterial infections (84.0%; n = 999) but do not treat viral infections (72.8%; n = 865). A minority (n = 338; 28.4%) agreed that antibiotic resistance was a problem in cats in the UK; 92.3% (n = 1097) identified that resistance was a problem in human medicine. Seventy percent (n = 832) of the respondents' cats had received antibiotics; 29.6% (n = 246) received a long-acting injectable antibiotic (14 days' duration). Diagnostic tests were performed before antibiotic prescription in 38.7% (n = 322) of cats; 1.4% (n = 7) of respondents reported declining suggested tests and 65.8% (n = 778) indicated that they would be happy to pay for diagnostic tests to allow selection of the most appropriate antibiotic. Most respondents (95.8%; n = 792) indicated that they were happy to follow their veterinarian's advice and recommendations; however, 49.2% (n = 405) had expected antibiotics to be prescribed. CONCLUSIONS AND RELEVANCE: Cat owners demonstrated good knowledge of antibiotic action; however, greater owner education regarding the potential for veterinary antibiotic resistance, requirement for diagnostic testing and training in the administration of oral medication with first-line antibiotics, as well as the use of veterinary antibiotic guidelines, will improve antibiotic stewardship. Good communication between veterinarians and owners is necessary for rational antibiotic use.

Hyperplastic and fibrosing gastropathy resembling Ménétrier disease in a cat.

CASE SUMMARY: A 3.5-year-old domestic shorthair cat presented with a 6 month history of weight loss and polyphagia. Clinical examination revealed a markedly reduced body condition score (2/9) and a quiet demeanour. Laboratory abnormalities comprised a mild non-regenerative anaemia, stress leukogram, hypoproteinaemia due to hypoalbuminaemia, azotaemia, hypokalaemia, total hypocalcaemia and sub-maximally concentrated urine (specific gravity 1.020). Abdominal ultrasonography revealed marked thickening of the gastric mucosa within the fundus, body and pylorus; the most dorsal portion of the fundus was spared. The thickened mucosa contained multiple small, anechoic cyst-like structures. The gastric submucosa, muscularis and serosa appeared normal. Histopathology, performed on a full-thickness gastric biopsy, revealed mucosal hypertrophy and markedly dilated gastric glands in areas; not all gastric glands were affected, with some appearing normal or atrophic. Focal interstitial fibrosis was present in some areas. The findings of hypoproteinaemia, gastric ultrasonographic changes and histopathology results share several similarities to those reported with Ménétrier disease. RELEVANCE AND NOVEL INFORMATION: Ménétrier disease is a rare condition of the stomach in humans. A similar condition, giant hypertrophic gastritis (or Ménétrier-like disease), has also been described rarely in dogs. To our knowledge, Ménétrier-like disease has not been previously described cats. This case shares features of Ménétrier-like disease, raising the suspicion of a similar aetiopathogenesis.

Clinicopathological features and comorbidities of cats with mild, moderate or severe hyperthyroidism: a radioiodine referral population.

OBJECTIVES: This study sought to explore the clinicopathological features and comorbidities of cats with mild, moderate and severe hyperthyroidism in a radioiodine referral population. METHODS: Medical records were reviewed, along with results of serum biochemistry, urinalysis, systolic blood pressure and diagnostic imaging performed at the time of radioiodine referral. Cats were grouped by total thyroxine (TT4) levels as mildly (TT4 60.1-124.9 nmol/l), moderately (TT4 125-250 nmol/l) or severely (TT4 >250 nmol/l) hyperthyroid at the time of diagnosis and referral. RESULTS: Thirty percent (42/140) of the cats were <10 years old at diagnosis. In 24.3% (34/140), hyperthyroidism was diagnosed incidentally. The time between diagnosis and referral for radioiodine was significantly longer in cats with severe hyperthyroidism at the time of referral ( P = 0.004). An increase in severity group between the time of diagnosis and referral occurred in 38.6% (54/140) of cats. At referral, 54.3% (25/46) of cats with mild, 66.7% (42/63) with moderate and 80.6% (25/31) with severe hyperthyroidism were unstable despite ongoing medical or dietary management. The prevalence of cardiac abnormalities was significantly increased in cats with severe hyperthyroidism ( P = 0.014) compared with those with mild or moderate hyperthyroidism. There was no significant difference in the likelihood of renal disease ( P = 0.708) or hypertension ( P = 0.328) between the groups. CONCLUSIONS AND RELEVANCE: Incidental diagnosis of hyperthyroidism occurs commonly, potentially owing to increased disease screening. Cats with severe hyperthyroidism at referral were more likely to be chronically hyperthyroid with a history of poor stabilisation. This subset of patients was significantly more likely to have cardiac abnormalities. Thyrotoxic cardiomyopathy may ultimately affect patient suitability for curative treatments (radioiodine or thyroidectomy) owing to higher anaesthetic risks and potential for decompensation into congestive heart failure with the stress of travel and hospitalisation. Curative therapy should be considered before the development of severe hyperthyroidism.

Vitamin D toxicity of dietary origin in cats fed a natural complementary kitten food.

CASE SERIES SUMMARY: This case series describes two young sibling cats and an additional unrelated cat, from two separate households, that developed hypercalcaemia associated with hypervitaminosis D. Excessive vitamin D concentrations were identified in a natural complementary tinned kitten food that was fed to all three cats as part of their diet. In one of the cases, there was clinical evidence of soft tissue mineralisation. The hypercalcaemia and soft tissue mineralisation resolved following withdrawal of the affected food and medical management of the hypercalcaemia. RELEVANCE AND NOVEL INFORMATION: This case series demonstrates the importance of obtaining a thorough dietary history in patients presenting with hypercalcaemia and the measurement of vitamin D metabolites when investigating such cases. Complementary foods may have the potential to induce nutritional toxicity even when fed with complete, nutritionally balanced diets.

Management and monitoring of hyperthyroid cats: a survey of Australian veterinarians.

Objectives This study sought to evaluate how Australian veterinarians approach management and monitoring of feline hyperthyroidism and compare these results with a similar survey recently performed in the UK. Methods An invitation to complete an online survey was sent to veterinarians in all states and territories of Australia. The survey comprised questions relating to management of hyperthyroidism, use of antithyroid drugs vs radioiodine treatment vs surgical thyroidectomy, in addition to demographic information for respondents. Results A total of 546 clinicians completed the survey. The most commonly preferred treatments for long-term management of feline hyperthyroidism were antithyroid medications (305/546; 56%) and radioiodine (210/546; 38%), with substantially more respondents selecting radioiodine when cost was removed as a consideration (425/546; 78%). However, most respondents had treated or referred few cases for radioiodine (median 2). Most veterinarians (500/546; 92%) used antithyroid medications either long term or prior to definitive treatment of hyperthyroidism. For medical management, 45% (244/546) of veterinarians used twice-daily carbimazole. Half of respondents (274/546) aimed to maintain the total thyroxine concentration anywhere within the laboratory reference interval in hyperthyroid cats without chronic kidney disease. Blood pressure monitoring was uncommon. Surgical thyroidectomy was rarely performed. Conclusions and relevance Radioiodine was more frequently preferred by Australian veterinarians compared with those in the UK, likely associated with greater availability, reduced cost and shorter hospitalisation times in this jurisdiction, although antithyroid medications were the most frequently used treatment modality. Barriers remain to its utilisation, however, including perceived cost, misconceptions with regard to expected success rate and accessibility. Recent changes to recommendations on the management and monitoring of hyperthyroid cats do not appear to have been widely adopted by veterinarians at this time.

Use of cefovecin in a UK population of cats attending first-opinion practices as recorded in electronic health records.

Objectives The objective was to use electronic health records to describe the use of cefovecin (Convenia; Zoetis UK), a third-generation long-acting injectable antimicrobial, in a UK population of cats attending first-opinion practices, and to compare the use of Convenia with the licensed uses described on the UK Convenia datasheet. Methods Data were obtained as an Excel database from the Small Animal Veterinary Surveillance Network for all feline consultations containing the word Convenia and/or cefovecin from 1 September 2012 to 23 September 2013 inclusive. Entries were classified according to body system treated, confirmation or suspicion of an abscess, evidence of microbiological evaluation being performed, any concurrent therapies given and whether any reason was given for use of Convenia over alternative antimicrobials. Data were exported to IBM SPSS Statistics and descriptive analysis performed. Results In total, 1148 entries were analysed. The most common body system treated was skin in 553 (48.2%) entries, then urinary (n = 157; 13.7%) and respiratory (n = 112; 9.8%). Microbiological evaluation was recorded in 193 (16.8%) entries, with visible purulent material most commonly cited (in 147 [12.8%] entries). A reason for prescribing Convenia over alternative antimicrobials was given in 138 (12.0%) entries; the most cited was an inability to orally medicate the cat in 77 (55.8%) of these entries. Excluding 131 entries where no body system or multiple body systems were described, the use of Convenia complied with a licensed use in the UK datasheet in 710 (69.8%) of 1017 entries. Conclusions and relevance Most administrations were licensed uses; however, most entries did not describe any microbiological evaluation, or a reason for prescribing Convenia over alternative antimicrobials. Further education of the public and the veterinary profession is needed to promote antimicrobial stewardship in the UK. Health records provide a valuable tool with which to monitor, both locally and at scale, the use of important therapeutics like antimicrobials. Information relevant to decision-making should be recorded in individual animal health records.

A survey of owners' perceptions and experiences of radioiodine treatment of feline hyperthyroidism in the UK.

The efficacy of radioiodine treatment of feline hyperthyroidism is well established; however, limited information is known about owners' perceptions or experiences of radioiodine. This study aimed to examine factors that influence owner treatment choices and their opinions following radioiodine. Surveys were sent to owners of cats referred for radioiodine treatment between 2002 and 2011 (radioiodine group; 264 cats) and owners of non-radioiodine-treated hyperthyroid cats seen at first-opinion practices (control group; 199 cats). The response rate was 67.0% (310 returned: 175 radioiodine, 135 control). Of 135 controls, 72 (53.3%) were unaware of radioiodine as a treatment option. Owners of cats ⩾15 years old and uninsured cats were less likely to pursue radioiodine. Cost of treatment, travel distance, potential human or animal health risks and waiting periods for radioiodine had a low impact on owners' treatment choice. Owners reported a moderate level of concern about treatment hospitalisation length, which included (158 respondents) the possibility of the cat being unhappy 130 (82.3%), owner missing the cat 102 (64.6%), inappetence 50 (31.6%), other pets missing the cat 32 (20.3%), development of co-morbid disease 28 (17.7%) and side effects 25 (15.8%). Owners assessed their cat's quality of life on a scale of 1 (very poor) to 10 (excellent), as 4 (4) (median [interquartile range]) pre-radioiodine (134 respondents) and 9 (2) post-radioiodine (131 respondents). Of 132 respondents, 121 (91.7%) were happy with their decision to choose radioiodine. The results of this questionnaire may assist veterinarians in addressing common owner concerns when discussing radioiodine as a treatment option for hyperthyroidism.

Medical management and monitoring of the hyperthyroid cat: a survey of UK general practitioners.

Feline hyperthyroidism is commonly diagnosed in general practice. This study assessed the opinions and experiences of UK general practitioners (GPs) regarding the management of feline hyperthyroidism. This included an evaluation of preferred treatment modalities and the monitoring of medically treated cats in relation to thyroxine (T4) level, co-morbid disease and adverse drug reactions. Six hundred and three GPs completed an online questionnaire comprising 34 questions. Oral medication was the most commonly preferred treatment option (65.7% of respondents), followed by thyroidectomy (27.5%) and then radioiodine (5.5%). When cost of treatment was eliminated as a consideration factor, significantly more respondents selected radioiodine (40.5%, P <0.001). Concerning target total T4 levels during medical management, 48.4% aimed for the lower half of the reference interval (RI), 32.3% anywhere within RI, 13.1% within the top half of RI and 0.5% above the RI; 3.4% evaluated efficacy by physical assessment only. In the presence of chronic kidney disease (CKD) respondents were significantly more likely to target total T4 levels within the upper half of the RI (40.3%) or above it (9.8%) when compared with targets for routine cases (P <0.001). Assessment for unmasking of CKD after initiating treatment or for hypertension was not consistently performed. Variability in monitoring strategies may result in CKD and hypertension remaining undetected, inadequate suppression of T4 levels in cats with concurrent CKD and delayed recognition of potentially significant haematological abnormalities.

The flat cat: 1. a logical and practical approach to management of this challenging presentation.

AIM: Detailed information regarding the causes and treatment of acute collapse in the cat can be difficult to locate in a single published source. This two-part review aims to provide a logical approach to the clinical assessment and stabilisation of the critically ill collapsed cat. PRACTICAL RELEVANCE: Cats are particularly challenging when presented as emergency patients, often in the later stages of an illness or with a vague history and non-specific signs. The nuances of the critically ill cat are considered, especially for shock and its management. CLINICAL CHALLENGES: Shocked cats do not present in the classic stages typically seen in dogs, and the signs are more subtle. Therefore, the clinician must consider whether physical parameters are appropriate for the state and environment of the patient; for example, a normal heart rate in a shocked cat would be considered inappropriate. AUDIENCE: This review is directed at any veterinarian working with feline patients, and particularly those dealing with emergencies on a regular basis. EVIDENCE BASE: There is an extensive body of published literature, both original studies and textbook chapters, pertaining to the causes and treatment of collapse in the cat. In this article the authors draw on information from original publications, reviews and their clinical experience to provide practical guidance to assist in the emergency setting.

The flat cat: 2. the emergency database and management of common metabolic abnormalities.

AIM: Detailed information regarding the causes and treatment of acute collapse in the cat can be difficult to locate in a single published source. This two-part review aims to provide a logical approach to the clinical assessment and stabilisation of the critically ill collapsed cat. PRACTICAL RELEVANCE: Laboratory evaluation, in the form of an emergency database, is an important part of the initial assessment of a collapsed patient and should be considered in conjunction with physical abnormalities. CLINICAL CHALLENGES: Rapid identification and correction of life-threatening metabolic abnormalities, including hypoglycaemia, hypocalcaemia and hyperkalaemia, is essential in stabilising this group of patients. Clinicians often lack confidence if they are not dealing with these problems regularly. AUDIENCE: The information provided in this article will be of use to any veterinarian working with feline patients and particularly those dealing with emergencies on a regular basis. EVIDENCE BASE: There is an extensive body of published literature, both original studies and textbook chapters, pertaining to the causes and treatment of the important metabolic abnormalities covered in this article. The authors draw on information from original articles, reviews and their clinical experience to provide simple but detailed practical information to guide interpretation of the emergency database and its application to therapy in the emergency setting.

Serum cobalamin concentrations in cats with gastrointestinal signs: correlation with histopathological findings and duration of clinical signs.

The aims of this study were to investigate the prevalence of hypocobalaminaemia in UK cats presented for referral investigation of gastrointestinal signs and to ascertain whether the duration of clinical signs or severity of disease (based on WSAVA Gastrointestinal Standardization histopathological grading) related to cobalamin concentration. The study population comprised 39 cats, of which 11 (28.2%) had hypocobalaminaemia. Eight of these cats were diagnosed with a single cause of gastrointestinal signs: intestinal inflammation (five); alimentary lymphoma (two); and cholangitis (one). Two or more concurrent diseases were diagnosed in the three remaining cases. Alimentary lymphoma and the most severe grade of histological intestinal inflammation were associated most commonly with concurrent hypocobalaminaemia, but there was no statistically significant correlation between serum cobalamin concentrations and histopathological score or duration of clinical signs.

Scintigraphic findings in 120 hyperthyroid cats.

The aim of this study was to characterise the scintigraphic findings in a large population of hyperthyroid cats in order to determine the location of thyroid pathology in newly diagnosed hyperthyroid cats and those that had previously undergone thyroidectomy. A specific aim was to identify the proportion of cats with ectopic hyperfunctional thyroid tissue and characterise the scintigraphic and clinical features of this subset of cats. Nearly one in five hyperthyroid cats was identified to have multiple areas of hyperfunctional thyroid tissue and/or intrathoracic hyperfunctional thyroid tissue where surgical thyroidectomy would not be curative. In addition, this study demonstrated that scintigraphy cannot reliably distinguish between thyroid carcinoma and adenoma. Owners should always be warned about the possibility of ectopic thyroid tissue before thyroidectomy is performed. In this study, intrathoracic hyperfunctional thyroid tissue and multiple areas of increased radionuclide uptake (IRU) were a common feature of benign thyroid disease and responded well to treatment with low dose radioiodine.

Feline thyroid carcinoma: diagnosis and response to high-dose radioactive iodine treatment.

This study reports the scintigraphy, histopathology, sole treatment with high-dose radioactive iodine and outcome of eight cases of feline thyroid carcinoma. Scintigraphic findings were variable and in 7/8 cases scintigraphic features could not reliably distinguish whether the thyroid tissue was malignant. Histopathology revealed typical criteria of malignancy in all cases, with mitotic activity described most frequently (7/8 cases), followed by infiltration of local tissues (4/8 cases). Cellular pleomorphism was infrequently observed. Single high-dose (1100MBq I(131)) radioiodine therapy was successful in 6/8 cases, with complete resolution of hyperthyroidism, and was associated with prolonged survival times (181-2381 days). Sole treatment with high-dose radioiodine is a safe and effective treatment for functional thyroid carcinoma. The prognosis for feline thyroid carcinoma successfully treated with radioiodine is good, with extended survival times commonly achieved.