IDEXX SDMA
SDMA Case Study: Mary Jane
SDMA helps to rule out kidney disease in a highly muscled dog with increased creatinine
Background information
Name: Mary Jane
Age: 3 years
Breed: Leavitt bulldog
Gender: Female
Presenting reason
Mary Jane had just moved into the area and had come in for a checkup and to see how her kidney disease was doing.
History
Mary Jane was diagnosed with kidney disease by her former veterinarian when she presented for an ovariohysterectomy at 1 year of age. At the time, Mary Jane’s owners were informed that she would likely not live very long, as she was being diagnosed so early in her life. The owners reported that Mary Jane appeared to be a happy and healthy dog aside from her diagnosis of kidney disease and noted normal thirst and urination, without urinary accidents or the need to go out at night time.
Her owners heard about a new test for kidney disease in dogs and cats that they thought may give them more information to potentially help Mary Jane. They considered Mary Jane a valued member of their family, and they were saddened by the possibility that her time with them is going to be short because of her condition.
Physical examination
Mary Jane was bright, alert and responsive (BAR). She had a normal temperature, pulse and respiration rate. She was well-hydrated and appeared well-muscled. The pet owner brought along copies of Mary Jane’s laboratory results from her former veterinarian so they could be compared to current laboratory results.
Diagnostic plan
A chemistry panel, including the IDEXX SDMA Test; complete urinalysis; the SNAP 4Dx Plus Test; and a fecal ova and parasites test were recommended.
Mary Jane’s CBC came back within normal limits, and her SNAP 4Dx Plus Test results were all negative.
Diagnostic review
The implications of an incomplete patient workup given today’s diagnostic capabilities:
- Better information yields better patient outcomes and appropriate pet owner conversations – innovations in diagnostics afford us the opportunity to more specifically identify disease conditions, investigate underlying causes and complications, and plan treatment and follow-up supportive care.
- While SDMA* and creatinine are inversely proportional to glomerular filtration rate (GFR), they vary in reliability for assessing kidney function – SDMA has not been shown to be influenced by medications, advanced age, or muscle mass like creatinine can be.1,2
Diagnosis
Mary Jane’s kidney function was normal. Creatinine is not specific for kidney function, and it was likely increased because of Mary Jane’s muscle mass.
Patient reports
Previous laboratory results
IDEXX VetConnect laboratory results
Discussion
Creatinine is a breakdown product of muscle and, as such, blood creatinine concentration is highly influenced by muscle condition of patients.
“SDMA is a more reliable indicator of kidney function than creatinine”1,5
Mary Jane’s case is an example of how a healthy pet can have a creatinine that is increased above the reference interval while other commonly evaluated kidney disease parameters (e.g. SDMA, urine specific gravity) are within normal limits. SDMA should always be assessed first alongside creatinine to more reliably determine kidney health and response to treatment.
*Symmetric dimethylarginine.
References
- Hall JA, Yerramilli M, Obare E, Yerramilli M, Yu S, Jewell DE. Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in healthy geriatric cats fed reduced-protein foods enriched with fish oil, L-carnitine and medium-chain triglycerides. Vet J. 2014;202(3):588-596.
- Hall JA, Yerramilli M, Obare E, Yerramilli M, Melendez LD, Jewell DE. Relationship between lean body mass and serum renal biomarkers in healthy dogs. J Vet Intern Med. 2015;29(3):808-814.
- Nabity MB, Lees GE, Boggess M, et al. Symmetric dimethylarginine assay validation, stability and evaluation as a marker for early detection of chronic kidney disease in dogs. J Vet Intern Med. 2015;29(4):1036-1044.
- Hall JA, Yerramilli M, Obare E, Yerramilli M, Jewell DE. Comparison of serum concentrations of symmetric dimethylarginine and creatinine as kidney function biomarkers in cats with chronic kidney disease. J Vet Intern Med. 2014;28(6):1676-1683.
- Hall JA, Yerramilli M, Obare E, Yerramilli M, Almes K, Jewell DE. Serum concentrations of symmetric dimethylarginine and creatinine in dogs with naturally occurring chronic kidney disease. J Vet Intern Med. 2016;30(3):794-802.