From the Guidelines
A hyaline cast is not explicitly defined in the provided evidence, however, based on general medical knowledge, hyaline casts are a type of cast that can be found in the urine, typically composed of the Tamm-Horsfall protein, which is produced by the renal tubular cells.
Types of Casts
- Hyaline casts are usually considered a normal finding, especially in individuals with concentrated urine, as they can be formed in the absence of any kidney disease.
- Other types of casts, such as granular casts, red blood cell casts, and white blood cell casts, can indicate the presence of kidney disease or other pathological conditions.
Clinical Significance
In the context of the provided evidence, cast nephropathy is mentioned as a cause of acute kidney injury (AKI) in patients with multiple myeloma and other hematological malignancies 1. However, this term refers specifically to the formation of casts composed of light chains, which can cause kidney damage, and is distinct from hyaline casts.
Diagnosis and Management
The diagnosis and management of cast nephropathy and other kidney diseases require a comprehensive approach, involving collaboration among specialists in nephrology, oncology, and other fields 1. The provided evidence highlights the importance of proper treatment and management of patients with cast nephropathy, including the use of novel agents and therapeutic plasma exchange 1.
From the Research
Definition of Hyaline Cast
- A hyaline cast is a type of cast found in urinary sediments, which is useful in the identification of kidney diseases 2.
- Hyaline casts are formed within the renal tubules and are made of Tamm-Horsfall glycoprotein (THG) 2.
- They can be found in normal subjects, in non-renal conditions, such as fever, dehydration, and acute heart failure, as well as in virtually all renal diseases 2.
Clinical Significance of Hyaline Casts
- The presence of hyaline casts in patients without renal dysfunction may suggest increased plasma brain natriuretic peptide (BNP) levels 3.
- The detection of hyaline casts in patients with normal renal function may indicate the need to check plasma BNP levels 3.
- A high number of hyaline casts (> 100 hyaline casts/whole field) may indicate decreased estimated glomerular filtration rate (eGFR) and be useful for the screening and early detection of high-risk chronic kidney disease (CKD) 4.
Ultrastructure and Composition of Hyaline Casts
- Hyaline casts are typically cylindrical in shape, with extremities often rounded, and are composed of THG fibrils that aggregate under certain physiological or pathological conditions 2.
- Ultrastructural evaluation of hyaline casts may provide useful information for establishing or suggesting a specific diagnosis, such as necrotizing glomerulopathy, IgA nephropathy, or plasma cell dyscrasia 5.