Another aspect in the evaluation of the patient in pain is the psychological component. Chronic pain has been associated with depression and a desire for a "hastened death." 59 It is important to consider the patient's mood and affect, screening for signs of depression and suicidality as warranted. These emotional consequences of pain are also a reminder of the broad benefits to the patient when his pain is effectively controlled.
A focused physical exam includes vital signs, especially pulse, respiratory rate, and blood pressure. Stressing the importance of pain assessment, the American Pain Society has coined the phrase, "Pain: the 5th vital sign." Studies have shown a correlation between pain and changes in vital signs, but even in acute pain the vital signs are not necessarily abnormal. Tousignant-Laflamme et al demonstrated an increase in resting heart rate with acutely painful stimuli. 60 However, it is important to note that the upper limit of the 95% confidence intervals for patient's heart rates even at the height of acute pain in this study were still less than 100 bpm (beats per minute). While there is typically a rise in heart rate with pain, the values need not be abnormal. Selfreport should therefore be considered more indicative of the presence of pain. However, observation of a patient's response to pain (i.e., facial expression, guarding) may be all you have to go on in a pre-verbal or cognitively impaired patient.
The extent of the physical exam depends on the type of pain; pain in an extremity directly related to an injury requires a limited exam while a patient with a nonspecific complaint of pain may require a comprehensive, systematic exam. Patients with a complaint of headache require a meticulous exam of cranial nerves II, III, IV, and VI; consideration should also be given to examining the temporal artery and assessing for vertebral or carotid dissection. A complaint of chest pain requires a careful assessment of the pulses, heart, and lungs specifically looking for evidence of pneumothorax, pulmonary embolus, pneumonia, pericarditis, and aortic dissection; a careful skin exam should be done looking for evidence of herpes zoster. The differential diagnosis of abdominal pain is extensive and the clinician must carefully perform a comprehensive evaluation in order not to miss diagnostic findings. A complaint of back pain requires a full neurologic evaluation with a focus on bowel and bladder function, motor, sensory, and reflexes.