*2.2.1 Neuropathic pain*

This type of pain is characterized by the damage or improper function/misfiring of the neurons. The IASP defines neuropathic pain "pain initiated or caused by a primary lesion or dysfunction in the peripheral or central nervous system. A study by Martin, L. A., & Hagen, N. A. (1997) broadly classified them into peripheral and central neuropathic pain. Peripheral neuropathic pain has many sub iterations depending on the nerves involved. In a case study done by them, it was stated that out of 72 patients, six of whom had benign tumors, suffered central neuropathic pain [13]. This study concludes that the nerves that get damaged will start firing erratically with or without any nociceptive signal. Patients suffering from such chronic pain have reported that they experience pain constantly and are shooting in nature [13]. The pain can be triggered by a small number of stimuli or even without any stimuli. Multiple reports and studies suggest that hyperactivity of damaged neurons and further release of neurotransmitters, inducers, modulators, increase the effect [2, 10, 14]. Also, it is noted that the person's immune response to the pain releases cytokines which also elevate the neuropathic pain. Diseases such as diabetes, chronic back pain, alcohol consumption, cancer stroke are some reasons for this type of pain. The sympathetic nervous system can lead to the increased sensitivity

of the nerves. The release of hormones during flight/fight response increases awareness and due to this the nerves also get more sensitized leading to such pain suggested by Gierthmühlen, J. and R. Baron in 2016 [10].
