Severe back pain goes beyond pain that is above the normal sprain and strain. Severe back pain requires in depth assessment due to the cause/s or ideology that is not easily diagnosed or apparent. This requires additional diagnostic procedures in order to determine the cause of the severity presentations. Nociceptive and neuropathic pain can be further broken down into acute and chronic pain, which differ in form and function. With acute pain, the severity of pain depends on the level of tissue damage. Individuals have a protective reflex in avoiding this kind of pain. With this type of pain there is a reflex to pull back quickly after moving or being in a certain position. Acute pain can be a sign of injured or diseased tissue. Once the problem is cured the pain is cured. Acute pain is a form of nociceptive pain. With chronic pain the nerves continue to send pain messages after the earlier tissue damage has healed. Neuropathy falls into this type.