2016 AAFP Guidelines for the Management of Feline Hyperthyroidism

Today, primary clinicians manage hyperthyroidism cases on a regular basis. To better equip practitioners, the Journal of Feline Medicine and Surgery published the updated American Association of Feline Practitioners’ guidelines on management of feline hyperthyroidism (FHT).

• Provide recommendations on best diagnostic testing protocols to help avoid misdiagnosis. 
• Separate FHT diagnosis into 6 categories. 
• Underscore the importance of treating all hyperthyroidism cases (regardless of comorbidities). 
• Outline current treatment methods. 
• Detail monitoring methods. 
• Give a communication script for veterinary teams to use with these patients and their owners. 

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• Serum T4 assay should be included with routine screening panels for geriatric cats. 
• All hyperthyroid cats should be treated and comorbidities concurrently managed.
• Signalment, history, physical examination, and a minimum database (CBC, serum chemistry profile, urinalysis, T4 assay) should be used to identify suspected FHT cases. 
• Suspected cases should be placed into one of the following categories for diagnosis and optimum management:
• Classic clinical disease
• Possible FHT with possible nonthyroidal disease
• Enlarged thyroid without clinical FHT
• Subclinical FHT 
• Clinical FHT with confirmed nonthyroidal disease
• Clinically normal

• Diagnostic testing for nonthyroidal disease should include: thoracic radiography, echocardiography, abdominal imaging.
• Identification of hypertension in suspected or confirmed FHT cases is essential.
• Blood pressure should be monitored at every visit.
• Patients should be routinely assessed for hypertensive retinopathy via fundic examination.
• If hypertension does not resolve with control of FHT, further diagnostics are warranted.
• Hypothyroidism secondary to FHT treatment should be avoided in cats with concurrent chronic kidney disease (CKD). 
• Full staging of CKD is indicated as FHT treatment recommendations vary with IRIS stage.
• Careful, frequent monitoring of T4 and TSH is essential.
• Cats with concurrent cardiac disease should first have FHT corrected, and then have heart disease assessed.
• Exception: Congestive heart failure (CHF) should be treated simultaneously with FHT.
• Four main treatment options include radioactive iodine, oral/transdermal medication, surgical thyroidectomy, and dietary therapy.
• All treatments have advantages and disadvantages that should be considered.
• Total cost of treatment is similar among all options for uncomplicated FHT cases.

• Routine monitoring of FHT cases is important to determine response to therapy, iatrogenic hypothyroidism, and comorbidities unmasked by treatment of FHT.
• Physical examination, T4 assay, CBC, renal values, +/- TSH and other diagnostics for comorbidities. 
• Median survival for hyperthyroid cats without CKD is up to 5.3 years.

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Practice Changers is a new column intended to brief readers on the release of new best practices; readers are encouraged to view the guidelines or statements in full at their respective publisher’s sources. 

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The updated FHT guidelines can be accessed at http://jfm.sagepub.com/content/18/5/400.full.pdf+html