Weight Gain and Obesity (Case 40)

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Weight Gain and Obesity (Case 40)

Elizabeth Briggs MD

Case: The patient is a 38-year-old woman who is referred to you for evaluation of a 40-pound weight gain over 2 years. She tells you that she had weighed about 110 pounds from age 18 until age 24 years, when she gained 25 pounds over the course of a successful pregnancy. By 6 months after this pregnancy, she had lost 15 lb and had been stable at about 120 lb until the past 2 years. She says that she has tried to decrease her intake of calories and increase her exercise, but these measures haven’t been effective in slowing her weight gain. In addition, she has been noticing facial hair, as well as hair on her chest and abdomen, which is new for her. She is clearly distressed over the changes she sees physically. Her menstrual cycle, usually regular since menarche, has been less so, with eight to nine menses per year and occasional months with 5 to 8 days of menstrual bleeding, which is longer than what she was used to until 3 years ago. On further questioning, she complains of easy bruising, acne, emotional lability, and difficulty walking up stairs due to leg weakness.

On physical examination, her blood pressure is 150/102 mm Hg, weight 164 pounds, height 62 in., and BMI 30. She has an obese trunk with relatively thin extremities. She has a rounded face with ruddy cheeks and excess supraclavicular and dorsocervical fat. She has hair on her chin, upper lip, chest, abdomen, back, and upper thighs, as well as acneiform lesions on her face, chest, and upper back. She has purple-red striae, 1 cm in diameter, on her abdomen, proximal thighs, and axillae, and ecchymoses on her upper and lower extremities. She has proximal weakness in her upper and lower extremities.

Differential Diagnosis

Exogenous obesity

Cushing syndrome

Hypothyroidism

Polycystic ovarian syndrome (PCOS)

 

Speaking Intelligently

Weight gain is a common problem encountered in clinical practice. When I evaluate a patient for weight gain I consider what could be its cause, as well as the potential consequences of the weight gain. Weight gain and obesity are very common; about one third of American adults are classified as overweight and about one third as obese. Obesity increases the risk for several disorders, including type 2 diabetes, hypertension, obstructive sleep apnea, dyslipidemia, atherosclerosis, osteoarthritis, and several cancers. Patients are often distressed by weight gain because of societal pressures to attain thinness. Interventions for weight loss include dietary modification, exercise, medications, and weight loss surgery. As clinicians, our responsibility is to identify factors contributing to weight gain and remove them if possible, attenuate risks associated with obesity, and facilitate safe and sustainable weight loss.

PATIENT CARE

Clinical Thinking

• When I evaluate a patient for weight gain, I first consider what has been the change in body composition. In most cases, patients have an increase in fat mass, but they should be examined for other causes, such as fluid retention, as might be seen with congestive heart failure.

• Weight gain caused by increase in fat mass, simplistically, reflects relatively more energy intake than expenditure.

• Most patients who gain weight have increased caloric intake, decreased energy expenditure, or both, perhaps in the context of a genetic predisposition to obesity.

• Occasionally, weight gain may be a sign of another underlying disorder.

• Patients should be evaluated with history and examination for possible causes of weight gain, and clues to possible diagnoses should be followed up with appropriate testing.

History

• In evaluation of weight gain, history should include lifetime weight history and time line and quantity of weight gain, such as was obtained for our patient.

• The pace and amount of weight gain vary with different etiologies and should be considered in the context of life and health events, such as pregnancy, change in environment, and new life stressors.

• Ask about symptoms of possible contributing disorders, such as glucocorticoid excess, psychiatric disease, androgen deficiency in males, growth hormone deficiency, and hypothyroidism.

• Additionally important is medication history, as multiple medications, including antihyperglycemic agents, glucocorticoids, and antipsychotic medications, are known to be associated with weight gain.

• In reviewing the dietary history, ask patients to recall intake and, if possible, to keep a food diary. These tools often will reveal that a patient is taking in more calories than he or she recognizes and will identify components in the diet that can be eliminated or substituted.

• Ask the patient to describe exercise history, including frequency, type, intensity, duration, and limiting injuries.

Physical Examination

• Physical exam should focus on the degree of obesity, signs of potential causative disorders, and signs of conditions caused or exacerbated by excess weight.

• Calculate the BMI for the patient (body weight in kilograms/(height in meters)2) to classify underweight (<18.5), normal weight (18.5–24.9), overweight (25–29.9), and obesity (>30).

• Track the pace of weight gain, if possible, with an objective record.

• Assess the patient’s body habitus. Truncal obesity (apple-shaped) might reflect glucocorticoid excess, and this pattern of obesity is more commonly associated with metabolic syndrome than is gluteal-femoral obesity (pear-shaped).

• Look for potential signs of glucocorticoid excess (truncal obesity, rounded face, increase in supraclavicular and dorsocervical fat, hirsutism, red-purple wide striae, ecchymoses), hypothyroidism (puffy face; yellowish hue; delayed relaxation phase of reflexes; dry, cool skin; rough elbows), and male hypogonadism (fine wrinkles at corners of eyes, gynecomastia, soft or small testes).

• Examine for edema, which could reflect another cause for weight gain than increase in fat mass (congestive heart failure, cirrhosis, nephrotic syndrome).

• With respect to conditions exacerbated by obesity, look for signs of insulin resistance (acanthosis nigricans, skin tags), hypertension, PCOS (hirsutism), and type 2 diabetes (signs of insulin resistance, complications of diabetes–peripheral neuropathy, infections, carpal tunnel syndrome).

Tests for Consideration

• Testing should generally be guided by clinical suspicion generated by clues on history and physical examination.

• Obesity is common, and Cushing syndrome is rare. Screening for Cushing syndrome is thus associated with false positive and false negative test results. Specific features of Cushing syndrome, as noted in our patient case, should be identified in order to proceed with screening, which consists of three potential tests:

Midnight salivary cortisol: In normal subjects, midnight cortisol is very low as a consequence of diurnal variation, which is lost in syndromes of endogenous hypercortisolism.

$23

24-hour urine free cortisol

$24

1 mg overnight dexamethasone suppression test

$23

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