Kidney Disease and the GSMD
JJ was an energetic 7yo Swissy boy who loved to ride in his tractor. He had the occasional sinus infections but had routine bloodwork with no issues. When he stopped eating well and had bloodwork done, everyone was shocked to find severe kidney failure with protein in his urine. He was supported with supplements and fluids but lost his battle to kidney failure despite everything within a few weeks. Lyric was a healthy 2yo Swissy bitch who had routine bloodwork after several urinary tract infections that showed elevated kidney enzymes. She was intensively managed with supplements and special diet for 5 years until the kidney failure caused nausea, heart issues and discomfort.
Kidney disease seems to affect GSMD more than average large dogs, and this is concerning. While it is true that since the kidneys do so much work they do tend to fail before other organs in older dogs, kidney disease in younger dogs is not expected.
Kidneys function in the body to filter the blood. They keep the good things (like protein and blood cells) in and excrete the bad things or excess in the urine. The kidneys remove waste and keep the hydration status of the body at an equal level. They also keep electrolytes including calcium, phosphorous, sodium and potassium at normal levels. They are responsible for monitoring and regulation of blood pressure, protein levels and produce a hormone that causes red blood cells to be produced. In short, these two little organs do a lot of work!!
There are different types of kidney failure. Chronic kidney failure is more common and that is a slower onset process where the tubular/interstial kidney cells start to not work as well. Symptoms include inappetance, increased thirst, nausea and malaise, which worsens as the kidney function declines. Acute renal failure is a more sudden process that can be caused by toxins or other infections. This can be a much harder process to treat. Glomerulonephritis can cause acute and chronic kidney failure but the hallmark of that is the presence of protein in the urine without a urinary tract infection. Pyelonephritis or kidney infections can also lead to kidney failure.
Measurements of kidney function include the concentration or specific gravity of the urine. The kidneys need to conserve water in the bloodstream so one of the early signs of insufficient kidneys is a urine specific gravity of less than 1.020- it is important to try to get an early morning urine sample so it is not diluted by the huge amount of water our dummies like to drink sometimes.
The other blood measurements of renal function are BUN and creatinine (proteins metabolites excreted by the kidneys.) The creatinine is especially important in staging the kidney disease- values 1.4-2.8 mean mild failure, 2.9-5 moderate and >5 mg/dl severe renal failure, although this is also dependent on the individual. Unfortunately, these values do not elevate on the bloodwork until 75% of the kidney function is lost. SDMA is a newer test that can pick up disease slightly earlier as can the urine concentration. It should be noted that because of their large amount of muscle mass, some Swissies can have higher normal levels of Creatinine and BUN, so if your dog has high levels on a test, it is important to do also do SDMA, urine specific gravity and urine protein: creatinine ratio testing.
Presence or absence of protein in the urine is also a very important piece of the equation. Normal urine should not contain any protein, as the job of the glomerular cells in the kidneys is to keep the protein in the bloodstream. As the kidneys fail and toxins build up, they can start to lose protein, but the other type of kidney disease that starts with protein loss from kidney inflammation is glomerulonephritis.
Glomerulonephritis can happen even in young dogs and it can be genetic as well. It starts because of any inflammatory process in the body- often Lyme disease but also bladder infections, prostate infections, or even chronic ear or dental disease. The body creates immune complexes to fight the infection in the body and then those lodge in the glomerulus of the kidneys and cause the cells to leak protein out in to the urine. This can be found early in urinalysis tests for protein, which is part of the reason why you should always recheck a urinalysis after treatment for an infection to make sure that it has cleared and is not causing chronic issues.
There are familial or inherited forms of kidney disease in Bernese Mountain Dogs that cause glomerulonephritis. They identified this through kidney biopsies and then pedigree analysis but this does not account for all kidney disease in BMD. They are also affected with more renal disease than other dogs (especially in Europe.) Researchers also have found higher Lyme disease titers in Bernese Mountain dogs but that does not seem to account for the problems. There is a significant amount of research being done on renal disease in BMD and it will be helpful for us in the future to monitor this. There is evidence showing that the breed is predisposed to both glomerular and regular (tubulointerstital) kidney disease as young dogs (this is determined by the urine protein: creatinine ratio combined with bloodwork results)
Important information to gather if your dog is diagnosed with kidney disease includes any exposure to Lyme disease, Ehrlichia, Leptospirosis, Brucellosis or Leishmania. It is also important to determine if they have any urinary tract or prostate infections, and make sure that they do not have bladder stones. It is important to know if they actually have bacteria in the urine and what type so a culture is needed. Your vet should rule out Addison’s disease and do a urine protein: creatinine ratio as well.
There are also some toxins that can cause kidney disease that should be ruled out including NSAID anti-inflammatory medications, Vitamin D, antifreeze, grapes/raisins, and for some unknown reason, sometimes Jerky treats. Previous illnesses or issues under anesthesia could lead to issues with the kidneys later in life. If glomerulonephritis is suspected in a young dog, it is recommended to see an internal medicine specialist and consider getting a kidney biopsy- this is a major procedure but can determine if immune suppression or other treatment is needed and can certainly prolong lives.
It would benefit most Swissy owners to get routine bloodwork done. It is also important to recognize normal levels of blood enzymes for your individual dog so you can know if it changes.
Treatments for kidney disease are mostly supplements of omega 3 fatty acids, phosphate binders, low protein and salt diets, blood pressure medications if needed, and fluids. Glomerulonephritis treatment also includes identification and treatment of the primary infection, enalapril to decrease the protein loss and if indicated by a kidney biopsy, immunosuppressant treatment.
If you have a young dog (less than 7 years old) diagnosed with kidney disease, please consider collecting as much diagnostic information as possible and having their medical chart sent to me so I can collect information for the future. A CHIC DNA sample would be great to have on file also. Your vet is welcome to contact me at swallowfieldswiss@gmail.com. I would also be interested in knowing what you feed your dog and pedigree.
Sources:
Minkus G et al. Familial Nephropathy in Bernese Mountain dogs. Vet Pathol. 1994;31(4):421-8
Reusch C et al. A new familial glomerulonephropathy in Bernese mountain dogs. Vet Rec. 1994;134(16):411-5
PreyB-Jageler C, Hartmann K & Dorsch R. Changes in renal parameters and their association with sublicinical vector-borne infections in Bernese Mountain dogs. BMC Vet Res. 2020;16, 285
Littman MP. Emerging perspectives on hereditary glomerulonephropathies in canines. Adv Genom and Genet. 2015; 5:179-188
