Has a blood test been done? It does sound like Kidney disease to me. Diabetes Insipidus is what I call 'jumping to conclusions' at this stage.
Yes, here is a copy of his dismissal from the ultrasound. Blood work was done at this time.
Logan, a 9 month old neutered male Labrador Retriever, presented to MSU VTH today for a history of frequent urination and a negative urine culture. Logan has had to go outside to urinate every 15-30 minutes since he was adopted in September 2011. In November 2011, he was neutered without any change in his urination habits. He was placed on Cephalexin in mid-January and started dribbling urine in the house before he went outside. He was switched to Clavamox and his owners feel it has helped. He does not urinate in his sleep and his urine is clear with no odor. No stones have been found on radiographs or previous ultrasounds. He has not been straining to urinate. No increase in drinking water has been noted.
He was adopted from a breeder and no other problems have been noted with his littermates. He is being treated with Panacur for whipworms and roundworms. He is up to date on vaccines.
PHYSICAL FINDINGS:
T: 102.0 P: 100 beats/minute R: 36 breaths/min Weight: 19.7 kgs (43.4 lbs)
Logan was bright, alert, and responsive upon physical examination. His heart and lungs auscultated normally. No pain was elicited upon abdominal palpation. His bladder was small on initial presentation but rapidly increased in size upon additional palpations. When he went outside to urinate, he produced a normal stream of urine, after which his bladder was empty.
DIAGNOSTIC TESTS:
Urine analysis
UA Collection UA Vol Sub UA Vol Spun UA Color UA Appear UA Spec Grav UA pH UA Protein UA Glucose UA Ketones UA Heme UA Bili UA WBC UA RBC
Voided
50 mL
5 mL Yellow
Clear 1.009 7.2 Negative Negative Negative Negative Negative
mg/dL mg/dL
None Seen /hpf None Seen /hpf
OwnerName: PatientName: MSURecord#: Signalment: Phone #:
p1ngputts LOGAN
423862 LabradorRetriever,N,0
Copy Sent On ____________ Copy Sent By ______
DATE OF DISCHARGE: 02/16/2012
Page 1 of 3
MSU VTH LOGAN (#423862), owned by p1ngputts 02/16/2012
UA Epi Cells See Below
UA Squamous Epi1 - 10 (Few) /lpf
UA Casts UA Bacteria UA Sperm UA Crystals UA Fat Droplets
None Seen /lpf None Seen /hpf None Seen /hpf None Seen /lpf
Moderate /hpf
Urinary system ultrasound:
Results from a board-certified radiologist are pending. Initial review shows an unremarkable urinary tract.
Venous blood gas:
pH at 37 PCO2 at 37 PO2 at 37 SO2%
pH Temp Corr PCO2 Temp Corr PO2 Temp Corr A BG Calc HCO3 Calc
7.43 H[7.34-7.42]
BEecf BG Calc -4.8 BE-B Calc -2.8 P50 BG Calc 23.6 SBC BG Calc 21.7 Sodium BG 147
Potassium BG 3.8 Chloride BG 116 I Calcium BG 4.5 I Magnesium BG 0.95
Glucose BG 80 Lactate BG 0.4 BUN BG 13 Creatinine BG 0.8
[-6.1-0.7]
[145-152] [3.0-4.8] [113-124] [3.6-5.4]
[66-115] [0.3-3.4] [11-31] [0.7-1.8]
mmol/L mmHg mmol/L mmol/L mmol/L mmol/L mg/dL mg/dL mg/dL mmol/L mg/dL mg/dL
29.3 42.8 79.5 7.40 31.8 48.9 110.6 19.7
[24.4-39.3] mmHg [30.6-57.4] mmHg [50.4-89.2] %
mmHg mmHg mmHg
[16.0-24.0]mmol/L mmol/L
TCO2 Calc
An Gap BG Calc 11.3[10.6-21.3] mmol/L
Ca/Mg BG Calc 2.9
n Calcium Calc 4.5 [3.6-5.4] mg/dL
n Magnesium Calc1.00 mg/dL Osmol BG Calc 291 [290-300] mOsm/kg
BUN/Cre BG Calc16.2
TREATMENT/PROCEDURES PERFORMED: None performed today
DISMISSAL INFORMATION:
The reason that Logan continually needs to urinate outside is that his urine is always very dilute. His kidneys are not doing their job to reabsorb water that he drinks to concentrate his urine appropriately. There are several possible causes for dilute urine. This can occur with primary disease of the kidneys, such as some congenital diseases in which the kidneys do not form correctly (renal dysplasia), or this can occur with a defect or deficiency of the hormone vasopressin, which is responsible for telling the kidneys to reabsorb water. Today, we performed a urinalysis and ultrasound of Logan's urinary system. Ultrasound of his urinary tract is normal at this time. His urine analysis is unremarkable, with the exception of a low specific gravity. Low urine specific gravity indicates his urine is very dilute. There was no evidence of a urinary tract infection or inflammation within the urine. We also ran a venous blood gas to check his BUN and creatinine values (markers of kidney function). These values were within normal limits.
20.6
[17.1-24.7]mmol/L
Page 2 of 3
MSU VTH LOGAN (#423862), owned by p1ngputts 02/16/2012
At this time, bloodwork, radiographs and ultrasound have not shown any abnormalities in Logan's urinary tract. Further
diagnostic testing is recommended as we are concerned about the filtration rate of Logan's kidneys.
Iohexol Clearance Test
The next diagnostic stop for Logan would be an iohexol clearance test. This test will measure the rate in which Logan's kidneys are filtering his blood (glomerular filtration rate or GFR). Iohexol is a contrast agent that contains iodine. By measuring disappearance of iodine in serum following a single IV dose of iohexol, GFR can be estimated. As with any procedure where radiographic contrast material is being administered IV, potential rare adverse reactions to iohexol can occur and include anaphylaxis, arrhythmias, hypotension, acute renal failure, nausea and vomiting.
To perform this test, Logan will need to be fasted 12 hours prior to testing. He must have access to water to ensure he is adequately hydrated. You can drop Logan off in the morning and pick him up in the afternoon, if all goes well with the testing. Test results will take 4-6 business days. The approximate cost for this test is $350-$400.
This test is recommended as the next step to determine if there is a disease in Logan's kidneys causing the kidneys not to
function appropriately. Although the kidneys look normal on ultrasound, there may be microscopic disease within the kidneys causing them not to filter blood like they should. This can cause dilute urine without necessarily causing abnormalities in the kidney blood markers (BUN and creatinine).
DDAVP Trial
If Logan's iohexol clearance test comes back normal. the next diagnostic step would be a trial run of DDAVP (desmopressin acetate) to treat diabetes insipidus. Diabetes insipidus has two possible causes - a lack of production of vasopressin (hormone that resorbs water from urine) or a lack of kidney response to vasopressin. A positive response (less frequent urination) to DDAVP would indicate a diagnosis of central diabetes insipidus (lack of production of vasopressin). A negative response to DDAVP would indicate a diagnosis of nephrogenic diabetes insipidus (lack of response to vasopressin). There is no treatment for nephrogenic diabetes insipidus but we can modify Logan's diet and prescribe medication to help decrease the frequency of his urination.
It may helpful also to measure the specific gravity of his urine several times over the course of the day to determine how
dilute it becomes, starting with the first urination of the morning. If you can catch samples from multiple outings over
the course of a day, starting with the first urination, and bring the individual samples to MSU, we can check them for you
at no charge. We can also provide you with urine specimen cups if you need them.
