Chapter 14: Pain Management in the Obese Population

PAIN MANAGEMENT

Chronic pain, like other medical comorbidities such as cardiovascular disease and diabetes, is more prevalent in obese patients than in the overall population. One recent study showed close to 40% of obese people suffer from chronic pain, with an increased incidence as body mass index (BMI) increases.¹ A survey of more than 1 million people showed that overweight individuals had approximately 20% more pain compared to normal weight individuals, increasing to 254% more pain in individuals with BMIs greater than 40.²

Acute and chronic pain that develops during pregnancy as well as chronic pain related to gynecologic disorders or within pelvic structures can be challenging to manage in the obese population. As is the case with many other comorbid conditions related to obesity, weight reduction first and foremost can at least help correct some of the metabolic and physical derangements that contribute to pain, if not provide relief of pain symptoms in and of itself.³

PREGNANCY

Given the high prevalence of chronic pain disorders in obese patients plus the overall increased incidence of new musculoskeletal pain in pregnancy, addressing acute or chronic pain during pregnancy can be challenging in the obese woman. Although there are numerous texts and publications discussing pain and pain management during pregnancy, the focus here is on specific aspects as they relate to the obese pregnant patient.

The interplay between increased mechanical loading, increased inflammation, and a negative psychological state mediates some of the relationships between pain and obesity.⁴ Adipose tissue itself as well as high loading pressures on bones, joints, and muscles, can cause an increase in inflammatory markers that results in pain. Depression can also cause increases in systemic inflammation as well as unhealthy lifestyle choices that can lead to further weight gain. Obesity is associated not only with depression and anxiety but also with pain catastrophizing that can amplify the pain experience and hinder the physical activity required for weight loss due to a fear of causing more pain. As these factors are already an issue in the obese patient, the extent to which they affect the obese pregnant patient, for whom further weight gain, systemic inflammation and labile psychological states are generally inevitable, can be more extreme.

Medication Considerations

In general, it is always better to exhaust all nonpharmacologic means of treatment before prescribing any new medication to the pregnant patient. As polypharmacy may already be an issue given the comorbidities associated with obesity (e.g., hypertension, diabetes, and depression), avoiding additional medications that may have adverse side effect profiles for the mother or that may cross the placenta is always best if possible.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are relatively contraindicated during the third trimester of pregnancy due to their association with decreased fetal urine production, resulting in low amniotic fluid levels and constriction ...