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SDMA case study: Molly

Background information

Name: Molly
Age: 7 months
Breed: Shih tzu
Gender: Intact female

Presenting reason
Molly presented for a routine ovariohysterectomy (OVH).

History
Molly was purchased healthy from a breeder at 2 months of age. Molly’s diet consisted of puppy food and she reportedly had a good appetite. While Molly had occasional household accidents, Molly’s owners thought nothing of it, as they felt it might have been part of house training or her excitable nature, and that it would improve with time.

Physical examination
Molly was bright, alert, and responsive (BAR). She was well-hydrated and had a normal temperature, pulse, and respiratory rate. Her body condition score (BCS) was excellent, and her weight was stable.

Diagnostic plan

Complete blood count (CBC), chemistry panel including the Catalyst SDMA Test and electrolytes, the SNAP 4Dx Plus Test, and a complete urinalysis as a presurgical screen were recommended.

Laboratory findings

Molly’s presurgical diagnostic results showed a negative SNAP 4Dx Plus Test, a normal CBC, and the chemistry findings shown here.

Diagnostic review

  • Increased SDMA* result guides us to investigate further: The increased SDMA result indicated an issue with kidney function. Finding low total protein as a result of low globulins is common in puppies and was not concerning in this young dog.
  • Next step considerations: A complete urinalysis should accompany an increase in SDMA. Additional diagnostics could include imaging of the kidneys as well.
  • Status of OVH appointment: Further investigation of the laboratory results was recommended to rule out any conditions that could complicate Molly’s surgery.
     

Diagnostic review following SDMA result signals to investigate further

  • Molly’s complete urinalysis showed a urine specific gravity of 1.022, with white blood cells and rod-shaped bacteria on sediment evaluation. The urine was submitted to the reference laboratory for a urine culture and MIC (minimum inhibitory concentration) susceptibility.
  • Diagnostic imaging can hold value for identifying and localizing disease: Molly’s ultrasound showed both kidneys slightly decreased in size and mild bilateral renal pelvic dilation. 

Patient reports

Chemistry

IDEXX SDMA report screenshot for Molly case study

Urinalysis

Urinalysis reports screenshot for Molly case study

Discussion

Molly’s single SDMA result led to the investigation and ultimate diagnosis of acute kidney injury (AKI), specifically pyelonephritis with concurrent renal dysplasia. Antibiotic therapy based on the urine culture and MIC susceptibility findings proved valuable in getting the infection under control, and Molly’s urinalysis was normal at her 1-month follow-up appointment. Additionally, her SDMA returned to within normal limits at that recheck following treatment.

SDMA is more sensitive than creatinine as a biomarker of kidney health,1–5 and increases above the reference interval should be investigated further for the underlying cause. For cases like Molly, it can identify a health situation that is treatable and discovered early so that you can establish a longer-term monitoring plan for blood work and urinalyses to quickly recognize infections the patient can be predisposed to.

*Symmetric dimethylarginine.

References

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.