dromlakhani Determine when to order endocrine labs for obesity etiology
STEP 1 — Gather Information
Measure height, weight, and BMI; calculate height velocity over ≥6 months using at least two measurements; compare current height to mid-parental height percentile; assess pubertal stage (Tanner); note any dysmorphic features or symptoms suggestive of endocrine disease.
Action: Proceed to assess whether stature or height velocity is attenuated.
STEP 2 — Rule In / Rule Out
Is the patient’s height below the 3rd percentile for mid-parental height or has height velocity declined (e.g., crossing two or more major percentile curves downward)?
- Yes: Rule in for endocrine laboratory evaluation.
- No: Rule out routine endocrine labs; proceed with standard obesity comorbidity screening.
Decision: Based on binary fork, either advance to lab ordering or defer endocrine workup.
STEP 3 — Classify or Stratify
If attenuated growth is present, consider specific endocrine etiologies: growth hormone deficiency (IGF‑1), hypothyroidism (TSH, free T4), Cushing syndrome (morning cortisol, late‑night salivary cortisol), or hypothalamic obesity (clinical assessment only). Order targeted screening labs accordingly.
Action: Initiate selected endocrine laboratory tests based on suspected etiology.
STEP 4 — Decide
If any screening lab is abnormal, refer to pediatric endocrinology for definitive diagnosis and management; if all labs are normal, reassess growth in 3–6 months and consider non‑endocrine contributors to obesity.
Action: Refer for abnormal results or schedule growth re‑evaluation for normal results.
Clinical Guardrails / Mimics / Pitfalls
Do not order routine insulin, leptin, or broad endocrine panels in obese children with normal growth velocity; avoid mislabeling familial short stature as endocrine disease; remember that acquired hypothalamic obesity may preserve normal growth velocity despite weight gain.
Concrete Clinical Example
A 12‑year‑old girl with BMI at the 98th percentile has height at the 10th percentile (mid‑parental height 50th percentile); her height velocity fell from the 25th to the 5th percentile over the past year. IGF‑1 is low and TSH is elevated, prompting referral to pediatric endocrinology for growth hormone deficiency and subclinical hypothyroidism evaluation.
Source: Pediatric Obesity Assessment, Treatment, and Prevention: An Endocrine Society Clinical Practice Guideline, Dennis M. Styne et al., 2017, DOI:10.1210/jc.2016-2573
TODO: consider adding scripts/calc.py for the eso-pediatric-obesity-endocrine-lab-trigger calculator