Things worth knowing about "Hypaesthesia"
Hypaesthesia describes a reduced sensitivity to touch, pressure, or pain stimuli. It is often a sign of nerve damage or a neurological condition.
What is Hypaesthesia?
Hypaesthesia (also spelled hypesthesia or hypoesthesia) refers to a diminished sensitivity to sensory stimuli such as touch, pressure, temperature, or pain in a specific area of the body. The affected person can still perceive these stimuli, but at a noticeably reduced level compared to normal. Hypaesthesia is classified as a sensory disturbance and is a common symptom associated with a wide range of neurological and systemic disorders.
Causes
Hypaesthesia can result from conditions affecting either the peripheral or central nervous system:
- Peripheral neuropathy: Nerve damage caused by conditions such as diabetes mellitus (diabetic polyneuropathy), chronic alcohol use, or nutritional deficiencies (e.g., vitamin B12 deficiency).
- Herniated disc: Compression of spinal nerve roots can cause localised numbness or reduced sensation.
- Multiple sclerosis: Demyelination (damage to the nerve's protective sheath) frequently leads to sensory disturbances.
- Stroke: Depending on the area of the brain affected, a stroke can cause one-sided sensory loss.
- Spinal cord injury or disease: Disruption of sensory signal transmission along the spinal cord.
- Nerve entrapment syndromes: Such as carpal tunnel syndrome or other compression neuropathies.
- Medications and chemotherapy: Certain drugs can cause neuropathy as a side effect, leading to hypaesthesia.
- Circulatory disorders: Reduced blood flow to nerve tissue, for example in peripheral arterial disease.
Symptoms
As a symptom itself, hypaesthesia can manifest in various ways:
- Numbness or a feeling of limbs being “asleep”
- Reduced awareness of touch, pressure, warmth, or cold
- Accompanying tingling or pins-and-needles sensations (paraesthesia)
- Numbness in the hands, feet, face, or other body regions
- Unsteady gait or coordination difficulties in more severe cases
The pattern of hypaesthesia can vary significantly: it may be one-sided, bilateral, distributed in a stocking-and-glove pattern (typical of polyneuropathy), or follow the path of a specific nerve or spinal segment.
Diagnosis
Hypaesthesia is diagnosed by a physician through a neurological examination, which may include:
- Sensory testing: Assessment of superficial and deep sensation using standardised tools such as cotton wool, a tuning fork, and pinprick stimuli.
- Electroneurography (ENG) and electromyography (EMG): Measurement of nerve conduction velocity and muscle activity to evaluate neuropathy.
- Imaging: MRI or CT scanning to detect brain lesions, herniated discs, or spinal cord abnormalities.
- Laboratory tests: Blood count, blood glucose, vitamin B12 levels, thyroid function, and other parameters to identify underlying causes.
Treatment
Treatment of hypaesthesia always targets the underlying cause:
- Diabetes mellitus: Optimal blood glucose control to slow the progression of neuropathy.
- Nutritional deficiencies: Supplementation of vitamin B12 or other deficient nutrients.
- Nerve entrapment syndromes: Physiotherapy, splinting, or surgical decompression of the affected nerve.
- Herniated disc: Conservative management or surgery depending on severity.
- Multiple sclerosis: Immunomodulatory therapies to slow disease progression.
- Stroke: Acute treatment followed by rehabilitation including occupational therapy and physiotherapy.
- Symptomatic treatment: Physiotherapy and occupational therapy to improve compensatory ability and quality of life.
In general, the earlier the underlying cause is identified and treated, the greater the chance of recovery of normal sensation. Persistent or sudden-onset sensory disturbances should always be evaluated by a physician promptly.
References
- Mumenthaler, M. & Mattle, H. (2021). Neurology. 14th edition. Thieme Verlag.
- World Health Organization (WHO). Neurological Disorders: Public Health Challenges. Geneva: WHO Press.
- Björkman, A. et al. (2004). Neurophysiological assessment of sensory functions. Journal of Reconstructive Microsurgery, 20(3), 201–209. PubMed PMID: 15168319.