Sensory Loss and Paresthesia

Definition and Clinical Presentation

The American Academy of Neurology defines sensory loss as a reduction or absence of the ability to detect sensory stimuli, which can manifest as numbness, reduced sensation, or complete loss of perception, and is typically documented as "sensory loss" and graded according to severity (mild, moderate, severe) 1, 2, 3
The American College of Physicians notes that paresthesia is a positive, abnormal, and subjective sensation that patients experience spontaneously, described as tingling, pins and needles, burning, or electric sensations, resulting from ectopic activity in cutaneous afferent nerve fibers or their central projections 1, 3

The National Institute of Neurological Disorders and Stroke states that sensory loss is caused by interruption or damage to sensory pathways, which can originate from axonal injury, demyelination, or damage to central nervous system structures 1, 4
The European Federation of Neurological Societies notes that paresthesia is generated by ectopic discharges in healthy or damaged axons due to changes in membrane excitability, and can be induced in normal nerves by hyperventilation, ischemia, or post-ischemic release 1, 5

The American Academy of Neurology recommends that sensory loss requires objective documentation through tests of tactile, thermal, painful, and vibratory sensitivity, while paresthesias are subjective symptoms reported by the patient but may not have a correlate on physical examination 1, 5
The International Association for the Study of Pain notes that neurophysiological studies, such as electromyography and nerve conduction velocity, help differentiate patterns of nerve damage, and that intraepidermal nerve fiber density can detect small fiber neuropathy when the examination is normal 1, 5

The American College of Physicians warns that paresthesias of acute onset, rapidly progressive, asymmetric, proximal, or multifocal require urgent evaluation to rule out Guillain-Barré syndrome or vasculitis, and that paresthesias with predominant motor weakness or severe dysautonomia are warning signs 2, 5
The National Comprehensive Cancer Network notes that permanent sensory loss affects quality of life negatively in 25% of patients post-ablative procedures, and that severe paresthesias (grade 3) interfering with function have a greater impact on quality of life than mild sensory loss 2, 3

The European Federation of Neurological Societies states that in peripheral neuropathy, symptoms include sensory loss, paresthesias, numbness, cramps, burning feet, and tingling, and that both can coexist: parestesias distally with objective sensory loss in a distal symmetric distribution 1
The American Society of Clinical Oncology notes that in surgical procedures, permanent sensory loss occurs in 15% with radiation therapy <90 Gy versus 54% with 90 Gy, and that mild parestesias (16%) are more frequent than severe (12%) post-radiosurgery 2, 7
The National Cancer Institute warns that chemotherapy-induced neuropathy can cause severe objective sensory loss or parestesias interfering with function (grade 3), and that symptoms include pain, tingling, numbness, sensation of pins and needles, or inability to feel thermal or painful sensations 3