Obesity and body-image concerns in adolescents — formative SAQs

SAQ 1 — Classification, screening and assessment (10 marks)

A 15-year-old girl is referred because her BMI plots above the 97th percentile. She has acanthosis nigricans and irregular periods. Her mother, who has type 2 diabetes, is anxious and asks whether her daughter is "obese and diabetic." In private, the girl discloses she has been skipping meals to lose weight and feels "disgusting." ^{[1] [8]}

Questions

1. Classify her weight status using the correct BMI-for-age definitions, and state the severe-obesity threshold. (3 marks) ^{[1] [7]}
2. Outline the baseline comorbidity investigations you would order and why. (4 marks) ^{[1] [2]}
3. Describe how you would assess her body-image concern and eating behaviour, including the specific screening tools and the urgency of her restrictive eating. (3 marks) ^{[10] [8]}

Model answer

Classification (3). Obesity is defined as a BMI at or above the 95th percentile for age and sex on a CDC or WHO growth reference; this girl plots above the 97th percentile, so she meets obesity. Severe obesity is defined as a BMI at least 120 percent of the 95th percentile, or an absolute BMI of at least 35. I would calculate her percentage of the 95th percentile to determine whether she has crossed into severe obesity, because that threshold triggers escalation beyond lifestyle. At 18 years the classification switches to adult cut-offs (overweight at least 25, obesity at least 30). I would use person-first, weight-neutral language with the family rather than the word "obese" directed at the patient. ^{[1] [7]}

Baseline comorbidity investigations (4). Fasting glucose or HbA1c to screen for pre-diabetes or type 2 diabetes, given her family history and acanthosis nigricans. A fasting lipid panel for dyslipidaemia. ALT to screen for non-alcoholic fatty liver disease, with the understanding that ultrasound is insensitive for early steatosis. Blood pressure with an appropriately sized cuff. Given her irregular periods and acanthosis nigricans, I would also consider the overlap with polycystic ovary syndrome and check for biochemical hyperandrogenism. An oral glucose tolerance test is added if fasting glucose is in the pre-diabetes range. ^{[1] [2]}

Body-image and eating-behaviour assessment (3). I would use the HEeadsss framework to place her weight inside her whole life. I would administer the EAT-26 (or ChEAT) and the SCOFF questionnaire to screen for disordered eating, and the PHQ-A for depression. Her disclosure of skipping meals to lose weight, alongside body-image distress, raises concern for restrictive eating that could constitute atypical anorexia if it is producing physiological instability. I would therefore assess for bradycardia, orthostatic vital-sign changes, and weight-loss tempo, and escalate to an eating-disorder pathway if there is any instability, because atypical anorexia carries the same medical danger as classic anorexia despite a higher weight. Weight-loss management is held until eating-disorder stability is established. ^{[10] [8] [15]}