Brighter days

April 10, 2020

Isabel the cat
Isabel (Photo by Steve Woit)

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, 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. 

“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 reattached.

“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.

Isabel headshot
Isabel (Photo by Steve Woit)

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 have the knowledge and licensing to offer it.

During Isabel’s short stay, clinicians had to disguise her blood pressure medication in her food to avoid radioactive contamination during the 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.