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Brighter days

  • Isabel

    Brighter days

    When hyperthyroidism and blood pressure problems caused an older cat to go blind, her care team at the VMC helped give her the gift of full sight 


Isabel was 12.5 years old when she started showing symptoms of acute blindness. Her owner took her to the Emergency and Critical Care Center at the University of Minnesota College of Veterinary Medicine’s Veterinary Medical Center (VMC).

Joseph Hediger, DVM, evaluated Isabel in the ER and referred her to Lindsay Merkel, DVM, DACVIM, a board-certified internal medicine specialist in the Veterinary Medical Center and an associate professor in the Department of Veterinary and Clinical Sciences. Merkel’s examination revealed that Isabel had detached retinas in both of her eyes and her blood pressure levels were well over 200. 

Isabel the cat in a closet
Isabel in one of her favorite spots at home, the top shelf in the front hall closet

“Detached retinas are not an uncommon finding in older cats with hypertension,” Merkel says. “Her blood pressure was so high it pushed the retinas off the backs of her eyeballs, which meant that they were floating on the inside of her eyes.” 

After a week of taking antihypertensives for her blood pressure, Isabel returned to the VMC — her blood pressure had stabilized quickly enough for her retinas to reattach.

“Cats around her age usually have hypertension from one of two causes: kidney disease or hyperthyroidism,” says Merkel. Further blood work was done to determine the cause for Isabel and pointed to hyperthyroidism, which is best treated by I-131.

I-131, also known as radioiodine therapy, is a nuclear treatment for hyperthyroidism in both humans and animals. The VMC has offered I-131 since the mid-80’s and uses it to treat more than 100 cats with hypothyroidism each year. Because I-131 is a specialty treatment, very few places in the Twin Cities area are able to offer it.

Isabel with a toy
Isabel with one of her favorite toys

During Isabel’s short stay, clinicians had to disguise her blood pressure medication in her food, rather than hand-distributing it directly to her, to avoid radioactive contamination during Isabel's I-131 treatment. Isabel’s hyperthyroidism, hypertension, and acute blindness were all successfully treated.

Without proper treatment, Isabel’s hypertension and hyperthyroidism may have led to a lethal brain bleed or stroke within months. Isabel will turn 14 this year, but due to her successful treatments, Merkel says she could live upwards of four to six more years.


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