dromlakhani Assess need for formal GHD testing with multiple deficits
STEP 1 — Gather Information
Confirm childhood cancer survivor status and history of hypothalamic–pituitary axis radiation or tumor/surgery affecting the region. Document baseline anterior pituitary hormone levels: TSH (or free T4), ACTH (or cortisol stimulation), LH/FSH (or sex steroids), and prolactin if available. Verify that at least three of these axes are biochemically deficient according to age‑appropriate cutoffs (e.g., low TSH with low/normal free T4, subnormal cortisol response to ACTH stimulation, low LH/FSH with low sex steroids). Exclude transient deficiencies due to acute illness or medication.
STEP 2 — Rule In / Rule Out
If the patient has three or more confirmed anterior pituitary hormone deficiencies (excluding GH) → proceed to Step 3 (consider foregoing formal GHD testing).
If fewer than three deficiencies are confirmed → proceed to formal GHD testing (e.g., insulin tolerance test or glucagon stimulation test) per standard provocative testing.
STEP 3 — Classify or Stratify
When three or more deficits are present, classify as “multiple pituitary deficits” and note that formal GHD testing is unlikely to alter management per guideline 2.6.
When fewer than three deficits, stratify by clinical suspicion (e.g., growth deceleration, increased fat mass, low IGF‑I) and proceed to testing.
STEP 4 — Decide
For multiple pituitary deficits: do not order formal GHD testing; manage based on clinical assessment and consider GH therapy only if clear clinical GHD phenotype emerges despite other deficits.
For fewer than three deficits: order formal GHD testing and, if confirmed, initiate GH replacement per guideline 2.8.
Clinical Guardrails / Mimics / Pitfalls
Do not assume that GH deficiency is absent simply because other axes are deficient; symptomatic patients may still benefit from GH therapy. Ensure deficiencies are truly confirmed (not borderline or transient) before foregoing testing. Avoid misattributing fatigue or increased adiposity solely to other hormone deficits without considering GHD. Remember that spinal radiation may disproportionately affect growth; assess sitting height to differentiate spinal vs. GH‑related growth impairment.
Concrete Clinical Example
A 15‑year‑old survivor of medulloblastoma treated with 35 Gy craniospinal irradiation presents with persistent fatigue and mild central adiposity. Baseline labs show low TSH with low‑normal free T4, subnormal cortisol response to ACTH stimulation, and low LH/FSH with low estradiol/testosterone. Three anterior pituitary axes are deficient. According to the guideline, formal GHD testing is not required; the clinician monitors growth and symptoms and considers GH therapy only if clear GHD features develop.
Source: Endocrine Society Clinical Practice Guideline: Hypothalamic Pituitary and Growth Disorders in Survivors of Childhood Cancer, Section 2.6, Sklar et al., 2018, DOI: 10.1210/jc.2018-01175
TODO: consider adding scripts/calc.py for the es-ghd-formal-testing-need calculator