Waxy casts

Waxy casts are a type of urinary cast which are formed in the distal convoluted tubule and collecting ducts of the nephron. They are typically found in the urine and are often associated with renal diseases.

Formation

Waxy casts are formed when proteins secreted by renal tubule cells coagulate and form a mold of the tubule lumen. They are named for their waxy appearance, which is due to their high protein content and slow transit time through the renal tubules.

Clinical significance

The presence of waxy casts in the urine is often indicative of serious renal disease. They are most commonly associated with chronic kidney disease, but can also be seen in acute renal failure, nephrotic syndrome, and other conditions that cause significant proteinuria.

Diagnosis

The diagnosis of waxy casts is typically made through urinalysis. Under microscopic examination, waxy casts appear as clear, colorless, and highly refractile structures. They may be broad or narrow, and often have blunt ends. The presence of waxy casts, particularly in large numbers, is a significant finding that often prompts further investigation into the underlying cause.

Treatment

The treatment of waxy casts is primarily focused on addressing the underlying cause. This may involve management of chronic kidney disease, treatment of acute renal failure, or other interventions as appropriate.

See also

• Urinary cast
• Renal disease
• Chronic kidney disease
• Acute renal failure
• Nephrotic syndrome