Bilateral Carpal Tunnel Syndrome in a 71-Year-Old: Exploring Possible Underlying Causes

QUESTION

Over a period of 2 months, a 71-year-old man has developed bilateral carpal tunnel syndrome (CTS). Which of the following abnormal laboratory values would be expected to be noted in this patient to cause the syndrome? 1. Serum thyroid stimulating hormone level 0.4 to 5.0 mU/L 2. Normal serum IGF concentration 3. Serum anti-citrullinated peptide antibody (< 20 EU) 4. Fasting plasma glucose 162 mg/dL

ANSWER

Bilateral Carpal Tunnel Syndrome in a 71-Year-Old: Exploring Possible Underlying Causes

Introduction

Bilateral carpal tunnel syndrome (CTS) can be a debilitating condition characterized by pain, numbness, and weakness in the hands due to compression of the median nerve as it passes through the carpal tunnel. While the most common cause of CTS is idiopathic or related to repetitive hand use, there are underlying medical conditions that can contribute to its development. In this essay, we will discuss potential laboratory abnormalities that may be associated with bilateral CTS in a 71-year-old man.

Understanding Bilateral Carpal Tunnel Syndrome

Bilateral CTS involves the compression of the median nerve in both wrists, leading to symptoms in both hands.
Common symptoms include pain, numbness, tingling, and weakness in the affected hands, which can impact daily activities.

Potential Laboratory Abnormalities

While CTS is often related to mechanical factors and repetitive hand use, there are certain medical conditions that can contribute to its development. Let’s explore the laboratory abnormalities mentioned in the options:

1. Serum Thyroid Stimulating Hormone Level

An abnormal thyroid stimulating hormone (TSH) level may be associated with thyroid dysfunction, particularly hypothyroidism.
Hypothyroidism is a medical condition where the thyroid gland does not produce enough thyroid hormones. It has been linked to CTS as it can lead to the accumulation of mucopolysaccharides within the carpal tunnel, contributing to nerve compression.

2. Normal Serum IGF Concentration

Normal serum insulin-like growth factor (IGF) concentration suggests that there is no indication of an overproduction of growth hormone, which is associated with acromegaly.
Acromegaly, characterized by excessive growth hormone, can lead to soft tissue swelling and, in some cases, contribute to CTS. However, a normal IGF level would not be considered an abnormality.

3. Serum Anti-Citrullinated Peptide Antibody

Serum anti-citrullinated peptide antibody is primarily associated with rheumatoid arthritis (RA).
RA is a systemic autoimmune disease that can affect multiple joints, including the wrists. It can lead to tenosynovitis and synovial inflammation, contributing to CTS-like symptoms.

4. Fasting Plasma Glucose

Elevated fasting plasma glucose levels, such as 162 mg/dL, may indicate poorly controlled diabetes mellitus.
Diabetes is a known risk factor for CTS. High blood sugar levels can lead to the accumulation of sorbitol within the median nerve, contributing to nerve compression and CTS symptoms.

Conclusion

While bilateral CTS is often associated with repetitive hand use, there are underlying medical conditions, such as hypothyroidism, acromegaly, rheumatoid arthritis, and diabetes mellitus, that can contribute to its development.
In the case of the 71-year-old man with bilateral CTS, further evaluation and laboratory testing may be necessary to identify any underlying medical conditions that could be contributing to his symptoms.
A comprehensive medical assessment, including a physical examination, imaging studies, and laboratory tests, can help determine the precise cause of bilateral CTS in this patient and guide appropriate management.