Hypoesthesia (also spelled as hypesthesia) is a common side effect of various medical conditions which manifests as a reduced sense of touch or sensation, or a partial loss of sensitivity to sensory stimuli. In everyday speech this is generally referred to as numbness.
Hypoesthesia primarily results from damage to nerves, and from blockages in blood vessels, resulting in ischemic damage to tissues supplied by the blocked blood vessels. This damage is detectable through the use of various imaging studies. Damage in this way is caused by a variety of different illnesses and diseases. A few examples of the most common illnesses and diseases that can cause hypoesthesia as a side effect are as follows:
Intradrual extramedullary tuberculoma of the spinal cord
Cutaneous sensory disorder
Treatment of hypoethesia are aimed at targeting the more broad disease or illnesses that has caused the side effect of sensation loss.
This is an example of a brain MRI, shown as a sagittal cross section.
A patient experiencing symptoms of hypoesthesia are often asked a series of questions to pinpoint the location and severity of the sensory disruption i.e. does it last all day or does it come and go? A physical examination may follow where a doctor may tap lightly on the skin to determine how much feeling is present. Depending upon the location of the symptoms occurring, a doctor may recommend some tests to determine the overlying cause of the hypoesthesia. These tests include imaging computerized axial tomography and magnetic resonance imaging scans (CT and MRI scans respectively), nerve conduction studies to measure electrical impulses passing through the nerves in search of damage to the nerves, and various reflex tests. An example of a reflex test would be the patellar reflex test.