The presence of which protein in urine is suggestive of the diagnosis multiple myeloma?

Chitranjjan National Cancer Institute Kolkata - 2021

Medical Surgical Nursing

Easy

Appeared in: Chitranjjan National Cancer Institute Kolkata - 2021

Explanation

Bence-Jones proteins are monoclonal immunoglobulin light chains (either kappa or lambda) produced by neoplastic plasma cells.
In multiple myeloma, these light chains are produced in excess, overwhelming the reabsorptive capacity of the renal tubules and spilling into the urine, a phenomenon known as overflow proteinuria.
Their presence in urine is a hallmark finding used in the diagnosis of multiple myeloma.
These proteins have a unique property of precipitating when heated to 45–60°C and redissolving upon boiling, which was the basis for a historical diagnostic test.

Option A: Fibronectin is an adhesive glycoprotein involved in cell adhesion and wound healing. It is part of the extracellular matrix and is not a product of malignant plasma cells, nor is it a specific urinary marker for multiple myeloma.
Option B: Elastin is a structural protein found in connective tissues, providing elasticity to organs and tissues like the skin, lungs, and blood vessels. It has no role in the pathophysiology of multiple myeloma.
Option D: Collagen is the most abundant structural protein in the body, forming the framework of skin, bones, and connective tissues. It is not produced by plasma cells and its presence in urine is not a marker for multiple myeloma.

Clinical Relevance

Nursing practice connection: Use the key finding related to Urinary protein markers in multiple myeloma to guide bedside assessment, documentation, and the next nursing action.
Detection of Bence-Jones proteinuria is crucial for diagnosing multiple myeloma and assessing the risk of renal complications, known as 'myeloma kidney' or cast nephropathy.
Nurses must be aware that a standard urine dipstick test may be negative for protein because it primarily detects albumin, not immunoglobulin light chains. This can give a false sense of security.
Patient education should include the importance of maintaining adequate hydration to help prevent the precipitation of Bence-Jones proteins in the renal tubules, which reduces the risk of kidney damage.

How to Approach the Question

First, identify the core of the question, which asks for a specific urinary protein marker for multiple myeloma.
Access your knowledge of hematologic malignancies. Recall that multiple myeloma is a cancer of plasma cells.
Remember the primary function of plasma cells is to produce immunoglobulins (antibodies). In myeloma, this process becomes malignant and monoclonal.
Connect this pathophysiology to the overproduction of immunoglobulin components, specifically the light chains, which are small enough to be filtered by the kidneys.
Identify 'Bence-Jones proteins' as the specific name for these monoclonal light chains found in the urine.
Evaluate the other options (Fibronectin, Elastin, Collagen) and recognize them as common structural proteins, making them unlikely candidates for a specific cancer marker of this type.

Concept Tested & Keywords

QwkVV4qF-0WOF_nMYKBE6q

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 55-57

E6 Pathology- ROBBINS & COTRAN PATHOLOGIC BASIS OF DISEASE 10TH Ed p. 612-614

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart B (pp 240-463 of 478) p. 94-96