A variety of disorders may cause polydipsia or polyuria and an ordered, rational diagnostic approach to the problem is important. Identify the Problem. The initial. as a part of the routine workup for polyuria Figure 2. Proposed algorithm for the diagnostic approach to polyuria. *Observed in cases of obstructive uropathy or unspecified acute kidney injury and chronic kidney disease (CKD). Abbreviations: DI, diabetes insipidus; Uosm, urine osmolality. This article provides a structured, logical approach for investigating polyuria, highlights the importance and relevance of various tests, and.
|Author:||Miss Mathias Wolf|
|Published:||23 September 2016|
|PDF File Size:||47.83 Mb|
|ePub File Size:||27.71 Mb|
|Uploader:||Miss Mathias Wolf|
How to assess these possibilities and to determine the specific cause of the diuresis is discussed in detail. Polyuria approach representative case examples are provided.
Diagnostic approach to polydipsia and polyuria.
Full Text Abstract Polyuria is an important symptom polyuria approach sign because of its potential severity, diverse causes, and interesting pathophysiology. Whereas polyuria approach induced by water diuresis is reasonably well understood and easily recognized by clinicians, that produced by solute diuresis is more likely to cause confusion.
Therefore, a period of gradual water deprivation to restore renal medullary hypertonicity is sometimes recommended before these tests are conducted.
polyuria approach For example, a dog with HAC may be polyphagic and lethargic. Polyuric animals may have an increased frequency of urination but produce a large volume of urine with no signs of pain or straining.
They may show nocturia or may urinate polyuria approach in the house. A previously continent pet may develop urinary incontinence.
The Polyuria of Solute Diuresis
Markedly polyuria approach diets can impair renal concentrating ability by depleting renal medullary urea concentrations. Examples include coat and skin changes, a potbellied appearance, and hepatomegaly in patients with HAC.
polyuria approach Enlarged lymph nodes may polyuria approach the presence of neoplasia, which can lead to hypercalcemia.
It should include pH, USG, sediment examination, and tests for the presence of hemoglobin, protein, glucose, ketones, and bilirubin.
Polyuria: A Pathophysiologic Approach
However, subtle changes or values that are technically within the polyuria approach ranges may also provide polyuria approach clues that suggest a direction for further investigation. Clinicians should ensure that serum chemistry profiles are complete and include electrolytes because valuable diagnostic clues can be missed when only partial or abbreviated panels are evaluated.
When chemistry or CBC values are borderline or unexpected, the tests should be repeated so that the findings can be verified. For polyuria approach, a serum total calcium value that is slightly above the normal reference range should never be ignored.
If pyelonephritis is suspected but an initial urine culture has negative results, further tests are indicated, including repeated urine cultures, abdominal ultrasonography, ultrasound-guided aspiration of the renal pelvis, and excretory urography, as well as possibly a trial course of antibiotics.
The total thyroxine T4 level should be obtained initially. If this value is normal and hyperthyroidism is still suspected, repeated total T4 testing, free T4 testing by equilibrium dialysis, or nuclear scintigraphy is indicated.
Hyperthyroidism in dogs is uncommon and is usually associated with a palpable thyroid mass. Polyuria approach patients with these disorders have other appropriate historical or clinical findings or clues on a serum chemistry panel a low BUN, albumin, or cholesterol levelbut this is not true in all cases.
Thoracic and abdominal radiography and abdominal ultrasonography can be used to screen for neoplasia. Contrast studies or ultrasonography may be indicated in the pursuit of specific diagnostic differentials, such as excretory urography for pyelonephritis, ultrasonography to rule out stump pyometra, and adrenal ultrasonography for suspected HAC or pheochromocytoma.
An In-Depth Look: Normal and Abnormal Water Balance: Polyuria and Polydipsia
Brain imaging may be indicated if CDI is suspected or diagnosed in an older dog. These cases are, therefore, not polyuria approach diagnostic challenge, and a GFR study is usually not indicated. Thus a GFR measurement should be considered in a dog that repeatedly and consistently has isosthenuria or minimally concentrated polyuria approach for which no other explanation is found.
GFR may be assessed by iohexol clearance, exogenous creatinine clearance, or nuclear scintigraphy. Therefore, the details of the test are polyuria approach presented here, and interested readers should consult one of the many excellent available references.
If the patient does not produce concentrated urine, the final part of the WDT involves assessing the response to the administration of exogenous ADH. Although the WDT is simple in principle, in practice, there are several challenges involved in conducting this test correctly, and the results are often difficult to interpret.
This test polyuria approach also be dangerous to the patient if polyuria approach incorrectly or if patient selection is inappropriate.
Polyuria approach to the Water Deprivation Test In some patients, primary polydipsia can be diagnosed by obtaining several serial USGs and demonstrating the production of concentrated urine on at least some occasions.