From the Guidelines
A patient with paresthesias can still have intact sensory function, as paresthesias are abnormal sensations that do not necessarily indicate complete sensory loss. Paresthesias are characterized by tingling, burning, prickling, or numbness without an obvious physical cause, but they don't always result in complete sensory loss. Many patients experience these unusual sensations while still retaining their ability to detect touch, temperature, vibration, and position sense. This occurs because paresthesias often result from minor irritation or compression of sensory nerves that alters normal signal transmission without completely blocking it. For instance, vitamin B12 deficiency can cause demyelination in the central and peripheral nervous systems, leading to neuromuscular symptoms such as paresthesia and numbness, but the extent of sensory dysfunction can vary 1. Clinicians should perform a complete sensory examination, including light touch, pinprick, temperature, vibration, and proprioception testing, to determine the extent of any sensory dysfunction in patients reporting paresthesias. Key points to consider include:
- Paresthesias can result from various conditions, including vitamin B12 deficiency, which can cause demyelination and axonal degeneration in the nervous system 1
- The presence of paresthesias does not necessarily confirm sensory deficit, and a thorough sensory examination is necessary to assess the extent of any sensory dysfunction
- Patients with paresthesias may still respond to sensory stimuli, such as touch, temperature, and vibration, despite experiencing abnormal sensations
- A complete sensory examination should include testing for light touch, pinprick, temperature, vibration, and proprioception to determine the extent of any sensory dysfunction.
From the Research
Paresthesias and Sensory Function
- Paresthesias can be caused by central or peripheral nervous system abnormalities, and may not necessarily indicate a loss of sensory function 2.
- Peripheral neuropathy, which can cause paresthesias, may result in abnormal sensations, but the extent of sensory impairment can vary 3.
- A patient with paresthesias may still have intact sensory function, as paresthesias can be caused by a variety of factors, including metabolic disturbances, trauma, or nutritional deficiencies, which may not necessarily lead to a complete loss of sensory function 2, 3.
Diagnostic Approach
- A concise history and physical examination are essential in diagnosing the cause of paresthesias and determining the extent of sensory impairment 2, 3.
- Laboratory and radiologic studies, as well as nerve conduction studies, may be necessary to confirm the diagnosis and establish an etiology 2, 3.
- Even with a diagnosis of peripheral neuropathy, defining the underlying cause may remain elusive in a significant proportion of cases, despite involvement of consultants 3.
Treatment and Management
- Treatment is based on the relevant diagnosis and mechanism to address the cause, and may include better glycaemic control for diabetes, lifestyle modifications, or medication changes 3.
- Interventions to relieve symptoms of neuropathic pain may be required if initial treatments fail to alleviate symptoms 3.
- Vitamin B12 deficiency has been associated with peripheral neuropathy, and treatment with B-vitamins may improve symptoms of neuropathy 4.