Caring For Lindy: Feeling Guilty

I've been caring for a cat with chronic kidney disease (which I learned was the proper term today) for a long time. Years.

Normally, I don't feel too guilty about things with Lindy. However, I can still remember a few occasions of intense emotion and regret.

One was when she was first diagnosed. She was two years old and I was in veterinary technology school. I'd learned in school that polyuria (increased urination) and polydipsia (increased drinking, which is most often a result of the polyuria) were not normal. I'd also noticed that Lindy was significantly PU/PD (shorthand for polyuric/polydipsic) compared to Simon. I brought her into her veterinarian's office and requested blood work. The vet said I was nuts but if I wanted to waste my money running blood work on a healthy two year old cat then she'd do it.

She called the next morning to say that Lindy was azotemic and her urine was isosthenuric. In short, she had chronic kidney disease. I felt like someone had just punched me in the stomach, wishing I had caught it earlier. I put Lindy on a kidney diet and she did well for awhile...

(Note for all my veterinarian readers-- looking back at her paperwork from the rescue group, Lindy had a high creatinine when she was spayed at six months. I'll never know if her problems stemmed from congenitally deformed kidneys or from one or a number of UTIs either when she was a feral kitten or possibly silent/not clinically symptomatic UTIs while she was in my care-- ultrasound at age 2 didn't show any cysts, which was my fear then, just gross structural changes)

She continued to do fine for several years.. until I left her with my then girlfriend in the Santa Cruz mountains for a weekend, where she had her first acute on chronic episode-- I suspect because my girlfriend deprived her of water for a long time (since cats with chronic kidney disease cannot concentrate their urine they dehydrate easily which leads to the kidneys getting less blood flow which causes further damage in a vicious cycle) but I'll never be able to prove the neglect. I still feel guilty for leaving her there that weekend. She's been on fluids ever since, 175 ml LRS every night (she's a big cat).

She's also on aluminum hydroxide and pepcid. Why? Up until this week all I knew was that the aluminum hydroxide was to bind phosphate, which was high. And that pepcid was for the uremia resulting from high levels of toxins in her blood (BUN, creatinine).

Well, I learned a whole heck of a lot more this week.

Gastrin is a peptide that is normally filtered at the glomerulus, but due to the decreased glomerular filtration rate in chronic kidney disease, gastrin is filtered less and so builds up in the blood. Gastrin stimulates hydrochloric acid release by increasing histamine release from enterochromaffin-like cells and hence the drug used to block its action is a histamine receptor antagonist, pepcid.

Phosphorous is also filtered at the glomerulus, and like gastrin its levels in the blood become increased as a result of the decreased glomerular filtration rate seen with chronic kidney disease. In fact, renal failure is the most common cause of hyperphosphatemia according to my notes.
And here is the part I was totally clueless about up until Friday-- consequences of hyperphosphatemia. My notes list two:
1. Metabolic acidosis. Inorganic phosphorous is present in many acidic forms so with hyperphosphatemia there is a buildup of acids.
2. TISSUE MINERALIZATION !!! Hyperphosphatemia also promotes increased calcium complexing with phosphorous. If excessive, it can lead to precipitation of the calcium-phosphorous complexes, allowing mineralization and damage within the soft tissues.

I didn't realize that when I frequently skipped giving Lindy a phosphate binder for weeks at a stretch around the time of my neuroanatomy final that she was probably beginning to mineralize her stomach, kidney and lungs. It's so incredibly awful that it makes me feel sick just thinking about it.

It's not all my fault though. Client education, folks. You can bet that I will explain to my clients exactly WHY they are giving the phosphate binder to their pet with chronic kidney disease and what the results will be if phosphorous levels are not kept from becoming high.

I wanted to cry all Friday afternoon after my chronic kidney disease function/dysfunction rounds. Instead I studied with a bunch of classmates. But I still feel terrible about it.