Patients across all ages, genders, races, and behaviors experience pain. Pain perception is influenced by the neurological system. Pain sensations are created when the nervous system processes and receives stimuli. There are three kinds of pain: acute, chronic and referred. The most common type of pain is acute. It can be sudden and vanishes in a matter of minutes. Chronic pain refers to persistent or recurring discomfort that persists over six months. Referred pain refers to pain that is different from the source of the pain. This paper describes the pathophysiology and treatment of chronic, acute and referred painful conditions. It also discusses the impact of patient factors such as genetics, gender and ethnicity on the diagnosis and treatment of chronic, acute and referred symptoms.
Pathophysiology for Acute, Chronic and Referred Pain
Acute pain refers to a sensation of sudden discomfort that results from tissue injury or inflammation. A-delta fibers that are myelinated have a high conduction speed and transmit acute pain. A-delta fibres can be activated by noxious stimulations and send pain signals to thymus. Second-order neurons are found in the dorsal Horn and they receive the pain signals sent by the A-delta fibres. They also transmit these messages to the thalamus. The thalamus acts as a relay station for pain signals and transmits them to the somatosensory cortex, where they are processed and perceived as pain sensations (Huether & McCance, 2017).
Chronic pain refers to persistent or recurrent pain over a period of six months. You can have chronic pain that is nociceptive or neuropathic. While nociceptive pain can be caused by tissue injury and inflammation, neuropathy is due to dysfunction or damage of the nervous system. C-fibers transmit chronic pain. They are slow in conduction velocity, unmyelinated. These C-fibers can be activated with mechanical, thermal, and chemical stimuli. They transmit pain signals into the dorsal portion of the spinal cord. Dorsal horn is home to second-order neuron that transmit pain signals from C-fibers to the brainstem. Chronic pain also activates the descending pain pathway, which modulates pain perception by releasing endogenous opioids, serotonin, and norepinephrine (Huether & McCance, 2017).
Referred pain happens when pain’s source is not at the same place. The convergence of sensory nerves in different parts of the spine can cause referred pain. One example is that pain from the heart can be referred towards the arm or shoulder while pain from gallbladder might go to the back and shoulders. Referred pain is caused by the overlap of dermatomes. These are areas of skin that are innervated only one spinal nerve. The brain misinterprets the pain signals and perceives them as originating from the referred site (Huether & McCance, 2017).
Patients’ factors have an impact on pathophysiology, pain diagnosis and treatment
Patients can be affected by their genetics, gender, age and ethnicity. The expression of genes that encode for neurotransmitters, pain receptors and ion channel genes can be affected by genetics. Individuals with SCN9A mutations, which code for the Nav1.7 sodium channel (Nav1.7), may feel congenital pain perception (CIP) and erythromelalgia. This is characterised by burning sensations in the hands and feet.