If both kidneys measure 5 cm in length and are very echogenic, what condition should NOT be considered?

When assessing echogenicity and kidney size, it's important to understand how these characteristics correlate with various renal conditions. In the case where both kidneys measure 5 cm in length and are described as very echogenic, renal vein thrombosis is not typically associated with this combination.

Chronic glomerulonephritis and chronic pyelonephritis often result in echogenic renal parenchyma due to fibrosis and scarring; both conditions can lead to a reduction in kidney size over time, which may reflect as smaller than normal kidneys, or they can maintain similar sizes with increased echogenicity. Renal vascular disease can also result in changes in kidney size and echogenicity, particularly if there is chronic ischemia affecting renal blood flow.

However, renal vein thrombosis usually leads to an enlarged kidney due to congestion and edema, causing the kidney to appear swollen rather than smaller or echogenic. The presence of an echogenic kidney in the context given would lead clinicians to suspect other causes rather than renal vein thrombosis. Therefore, the specific combination of small size (5 cm) and high echogenicity makes renal vein thrombosis an unlikely diagnosis in this scenario.