Signalment and History: A 4-year-old, 25 kg (55 lb) male neutered Siberian Husky named "Kodiak" is presented for evaluation of severe and progressive polyuria and polydipsia (PU/PD) over the past six months.
The owner, a very attentive and concerned individual, provides a detailed history. The issue began subtly, with the dog needing to be let out to urinate once during the night, which was unusual for him. Over the past two months, the signs have become extreme. The owner reports filling a 2-gallon water bowl three to four times daily. The dog drinks incessantly and will seek water from any available source, including toilet bowls and puddles. The polyuria is equally dramatic; the dog produces large volumes of very clear urine and has started having accidents in the house if not let out at least every two hours, including multiple times overnight. The owner describes the urine as looking "exactly like water."
Critically, the owner reports an attempt to manage the issue last week by restricting water access for a few hours. Kodiak became extremely agitated, anxious, and frantic, digging at his empty water bowl. The owner quickly abandoned this attempt. Apart from the intense thirst and urination, the dog's appetite, energy level, and overall demeanor are reported as completely normal. He has no history of major medical issues and is current on all preventative care.
Physical Exam:
T: 101.7°F
P: 90 bpm
R: 20 bpm
MM: Tacky
CRT: < 2 sec
BCS: 5/9
Kodiak is a bright, alert, and responsive patient. He is well-muscled and in excellent body condition. The physical examination is remarkably unremarkable. No abnormalities are found on cardiac and pulmonary auscultation, abdominal palpation, or orthopedic/neurologic evaluation. The only subtle finding is that his mucous membranes are tacky, suggesting a borderline level of dehydration despite his constant water consumption. While in the exam room, he produced a very large volume of colorless urine on the floor.
Initial Diagnostic Workup: A comprehensive initial workup was performed to rule out common causes of PU/PD.
Complete Blood Count (CBC): All values within normal reference intervals.
Serum Biochemistry Profile: All values were within normal reference intervals with the exception of a mild hypernatremia (Sodium: 158 mEq/L [Ref: 142-152 mEq/L]).
Urinalysis (Free Catch):
Color: Clear/Colorless
pH: 7.0
Urine Specific Gravity (USG) by Refractometer: 1.004
Dipstick: Negative for glucose, ketones, protein, and blood.
Sediment Exam: Unremarkable.
Because of the critical importance of the USG, the measurement was repeated on two subsequent urine samples obtained over the next hour, yielding results of 1.002 and 1.006. The persistently and profoundly dilute urine (hyposthenuria) in the face of hypernatremia (which should be a powerful stimulus for the kidneys to conserve water) is a key finding.
What will be your tentative and differential diagnosis?
What further diagnostic test(s) you will perform to confirm your diagnosis?
What will be your treatment plan(s)?
Solution to Case 31 will be posted on Sept 12
No comments:
Post a Comment