The pain history should reveal the pain location, time of onset, intensity, character, associated symptoms, and factors aggravating and relieving the pain.

It is important to know when and how the pain started. The pain onset should be described and recorded (e.g., sudden, gradual, or rapid). If the pain started gradually, identifying an exact time of onset may be difficult. In the case of a clear inciting event, the date and circumstances of the pain onset may help determine its cause. The condition of the patient at the onset of pain should be noted if possible. In cases of injuries from motor vehicle crashes or work-related injuries, the state of the patient before and at the time of the injury should be clearly understood and documented.

The time of onset of the pain can be important. If the pain event is of short duration, as in acute pain, the treatment should
focus on the underlying cause. In chronic pain, the underlying cause has usually resolved and the treatment should focus on optimal long-term pain management.

The various methods used to measure pain intensity are described in Chapter 6. Because the complaint of pain is purely subjective, it can only be compared to the individual’s own pain over a period; it cannot be compared to another individual’s report of pain. Several scales are used for reporting the so-called level of pain. The most commonly used scale is the visual analog scale (VAS) of pain intensity. Patients using this scale are instructed to place a marker on a 100-mm continuous line between “no pain” and “worst pain imaginable.” The mark is measured using a standard ruler and recorded as a numeric value between 0 and 100. An alternative method of reporting the intensity of pain is by using a verbal numeric rating scale. The patient directly assigns a number between 0 (no pain) and 10 (the worst pain imaginable). The verbal numeric rating scale is frequently used in clinical practice. Another commonly used method is a verbal categoric scale, with intensity ranging from no pain through mild, moderate, and severe to the worst possible pain.

The patient’s description of the character of pain is quite helpful in distinguishing between the different types of pain. For example, burning or “electric shocks” often describe neuropathic pain, whereas cramping usually represents nociceptive visceral pain (e.g., spasm, stenosis, or obstruction). Pain described as throbbing or pounding suggests vascular involvement.

The pattern of pain spread from the onset should also be noted. Some types of pain change location or spread farther out from the original area of insult or injury. The direction of the spread also provides important clues to the etiology and, ultimately, the diagnosis and treatment of the condition. An example of this is the complex regional pain syndrome (CRPS), which can start in a limited area such as a distal extremity and then spread proximally and, in some instances, even to the contralateral side.

The examiner should ask about the presence of associated symptoms, including numbness, weakness, bowel and/or bladder dysfunction, edema, cold sensation, and/or loss of use of the extremity because of pain.

Aggravating factors should be elicited because they sometimes explain the pathophysiologic mechanisms of pain. Various stimuli can exacerbate pain. Exacerbating mechanical factors such as different positions or activities such as sitting, standing, walking, bending, and lifting may help differentiate one cause of pain from another. Biochemical changes (e.g., glucose and electrolyte levels and hormonal imbalance), psychological factors (e.g., depression,
stress, and other emotional problems), and environmental triggers (e.g., dietary influences and weather changes, including barometric pressure changes) may surface as important diagnostic clues. Relieving factors are also important. Certain positions will alleviate pain better than others (e.g., in most cases of neurogenic claudication, sitting is a relieving factor, whereas standing or walking worsens the pain). Pharmacologic therapies and “nerve blocks” help the clinician determine the diagnosis and select the appropriate treatment.

The patient should be asked about previous treatment attempts. Knowing the degree of pain relief, the duration of treatment, and the dosages and adverse reactions of medications helps avoid repeating procedures or using pharmacologic management that has not helped in the past. The list should include all treatment modalities, including physical therapy, occupational therapy, chiropractic manipulation, acupuncture, psychological interventions, and visits to other pain clinics.

A review of systems is an integral part of comprehensive evaluation for chronic and acute pain. Some systems could be directly or indirectly related to the patient’s presenting symptoms, whereas others are important in the management or treatment of the painful condition. Examples are the patient with a history of bleeding problems, who may not be a suitable candidate for certain injection therapies; or someone with impaired renal or hepatic function who may need adjustments in their medication dosage.

Past medical problems, including conditions that have resolved, should be reviewed. Previous trauma and any past or present psychological or behavioral issues should be recorded.

A list of operations and complications should be made, preferably in chronologic order. Because some painful chronic conditions are sequelae of surgical procedures, this information is important for diagnosis and management.

The practitioner must prescribe and intervene on the basis of medications the patient is currently taking because complications, interactions, and side effects need to be taken into account. A list should be made of medications, including pain medications. The list should include nonprescription and alternative medications (e.g., acetaminophen, aspirin, ibuprofen, and vitamins).

Allergies, both to medications and nonmedications (e.g., latex, food, and environmental factors), should be noted. The nature of
a specific allergic reaction with each medication or agent should be clearly explored and documented.