Evaluation of Pain Characteristics & Intensity

Acute vs. Persistent Pain

The distinction between acute and persistent pain is particularly relevant. Acute pain characteristically is of recent onset and is anticipated to have a relatively short duration of no more than days or weeks. Pain is usually considered persistent if it continues more than 3 to 6 months or if it meets one of the following criteria: 1) persisting for at least one month beyond the usual course of an acute illness or the time required for an injury to heal, 2) associated with a chronic pathologic process, or 3) recurring at relatively short intervals (days, weeks, or several months). (Table: Differences Between Acute and Persistent Pain )

Recurrent acute pain is highly prevalent and is the hallmark of some diseases, such as sick cell disease, hemophilia, some inflammatory arthropathies, and some subsets of headache. Nearly all patients with progressive diseases, such as cancer and AIDS, also experience repeated episodes of acute pain which may be related to the disease, therapeutic interventions, or unrelated processes.

Patients with persistent pain commonly experience intermittent episodes of acute pain, which may occur spontaneously or in association with a particular activity. When acute severe pains occur in the setting of persistent “background” pain that is otherwise well controlled with an opioid regimen, they are called “breakthrough pains.” Almost two-thirds of cancer patients with persistent pain report breakthrough pain. Given their frequency, breakthrough pain and other types of acute pain should be specifically assessed during the evaluation of persistent pain. A daily pattern of varying pain intensity may exist and diurnal variations are found in some painful conditions such as rheumatoid arthritis (i.e., pain worse in the morning).

The terms acute, persistent, and recurrent pain can be used to depict a wide variety of pain syndromes. Acute monophasic pain is usually of brief duration and is expected to resolve as the underlying cause resolves over hours, days, weeks, or months. This type of pain follows surgery and trauma. When the acute pain is recurrent at relatively brief intervals, the impact can mirror persistent pain. Recurrent pains of this type may be reported by patients with headaches, dysmenorrhea, sickle cell anemia, inflammatory bowel disease, arthritis or musculoskeletal disorders. Pain that is present most of the time, typically fluctuating but seldom absent, comprises a broad clinical group, including persistent pain associated with cancer, many noncancer progressive diseases (e.g., AIDS, some patients with sickle cell anemia, some patients with autoimmune diseases, some patients with neurological syndromes, such as small fiber neuropathies), nonprogressive or slowly progressive diseases (e.g., severe osteoporosis, many types of neuropathic pain, such as postherpetic neuralgia and painful polyneuropathy), and idiopathic syndromes (e.g., fibromyalgia, atypical facial pain, chronic pelvic pain of unknown etiology).