**2.1 Nociceptive pain**

It is also known as momentary pain. It is a form of acute pain caused by the triggering of nociceptive nerve receptors. This triggering occurs as a result of damaging chemicals or inflammation in the region [8]. A great example will be hitting your head on the table or stubbing your toe. Generally, nociceptive pain location is local. This type of pain gets notified by the nociceptors present throughout the skin and the internal organs. They can detect any chemical or physical damage send through the nervous system for immediate action [9]. There are two types of nociceptors as suggested by F. Cervero in 1985; one of them works for the fast transmission of pain called A-delta fibers whereas another one that slowly transmits pain is C–fibers [8]. The unmyelinated structure of C-fibres detects sudden pain while A-delta fibers detect pain arising due to noxious elements

**169**

*Assessment and Management of Pain in Palliative Care DOI: http://dx.doi.org/10.5772/intechopen.96676*

• Somatic

• Visceral

*2.1.1 Somatic pain*

*2.1.2 Visceral pain*

nausea vomiting etc. [12].

**2.2 Non-nociceptive pain**

*2.2.1 Neuropathic pain*

Nociceptive pain is divided into two components:

harder to pinpoint as it diffuses easily and tends to radiate.

or mechanical stress [8]. Increased abnormal sensitivity to the pain or chemical stimulus is named hyperalgesia caused by inflammation in the area [8–10].

This type of pain arises from the stimulation of the nerve cells in the tissue such as skin, bones muscles, etc. due to damage [11]. Based on the site of cause the person can have superficial or surface-level deep somatic pain in bone or tendons and this type of pain comes in a flash as the injury is sustained [9, 11]. Due to the two varied nature of this pain person suffering from superficial pain will have an easier go at finding and pinpointing the pain rather than the deep somatic pain which is much

Visceral pain occurs in cases when the person suffers from damage to the internal organs such as the intestine etc. The sensation of pain can be caused by damage to the tissue by external force or extensive pressure caused due to oncological reasons or infection in the abdominal organs [4, 8, 12]. This pain is not easy to pinpoint as the patient feels dull and as if squeezing most of the time due to the scarcity of the nociceptors [4]. Feeling in the area of damage detected by the nociceptors present in the abdominal cavity and on the organs it doesn't have a sharp onset visceral pain [8]. This effect is also termed as viscero-somatic convergence where the pain signal transported by afferent nerves converge with the nerves that are transferring pain from the say skin area can cause side effects such as

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

#### *Assessment and Management of Pain in Palliative Care DOI: http://dx.doi.org/10.5772/intechopen.96676*

or mechanical stress [8]. Increased abnormal sensitivity to the pain or chemical stimulus is named hyperalgesia caused by inflammation in the area [8–10].

Nociceptive pain is divided into two components:

• Somatic

*Suggestions for Addressing Clinical and Non-Clinical Issues in Palliative Care*

as it gets resolved within a short duration whereas pain that cannot be resolved within six months is considered chronic pain. Chronic pain is further of three types: non-cancer, cancer and episodic. The intensity of pain ranges from mild to severe. Pathophysiology is mostly done by the utilization and knowledge of the damage caused to the tissue (nociceptive) and nerve (neuropathic) or could be unlocalized (visceral) or break-through that was given by the International Association for the Study of Pain (IASP) [2, 3]. It is noteworthy that pain can be physical as well as emotional. European Association for Palliative Care (EAPC) conducted an extensive review on the management of the use of pain assessment tools in palliative care research [3–5]. The newly revised version of cancer pain prognostics has included emotional/psychological distress, cognitive impairment caused by pain in the Edmonton staging system for cancer pain [4]. This improvement in pain prognostics has been able to be predictive than the previous methods used by IASP [3]. There are methods for the staging and progression of cancer like TNM Classification of Malignant Tumors (TNM). Unfortunately, there is no consensus on a single standardized tool for pain assessment [6]. The reason behind this is the varied nature of cancer and its malignancy and different perceptive and tolerance of pain in patients [6, 7]. Also, to blame is less predictability of the nature of tools available, as sometimes the mechanisms are not well known. To work on this problem, an extensive literature study on the physical, medical, psychological background and education on self-awareness/acceptance of pain should be deemed

It is also known as momentary pain. It is a form of acute pain caused by the triggering of nociceptive nerve receptors. This triggering occurs as a result of damaging chemicals or inflammation in the region [8]. A great example will be hitting your head on the table or stubbing your toe. Generally, nociceptive pain location is local. This type of pain gets notified by the nociceptors present throughout the skin and the internal organs. They can detect any chemical or physical damage send through the nervous system for immediate action [9]. There are two types of nociceptors as suggested by F. Cervero in 1985; one of them works for the fast transmission of pain called A-delta fibers whereas another one that slowly transmits pain is C–fibers [8]. The unmyelinated structure of C-fibres detects sudden pain while A-delta fibers detect pain arising due to noxious elements

**168**

feasible.

**Figure 1.**

*Classification of pain.*

**2. Cause of pain**

**2.1 Nociceptive pain**

• Visceral
