14.1 Endocrine and Reproductive Effects

CPHON Test Content Outline (TCO) IV.A.8–9 tests endocrine and reproductive acute, chronic, and late effects of cranial radiation, hypothalamic-pituitary tumors, corticosteroids, neck radiation, hematopoietic stem cell transplantation (HSCT), alkylators, and gonadal radiation. This is not the emergency chapter for diabetes insipidus (DI), the syndrome of inappropriate antidiuretic hormone, or adrenal-crisis titration. Those algorithms live later. Here the nurse names the exposure, plots height velocity and Tanner stage, checks glucose when asparaginase meets dexamethasone, and starts fertility counseling before the gonadotoxic dose—not after azoospermia is already documented.

A 6-year-old whose height percentile is falling two years after cranial radiation for medulloblastoma, a 5-year-old on acute lymphoblastic leukemia (ALL) induction with a moon face and a glucose of 280 mg/dL, and a 16-year-old who will receive cyclophosphamide tomorrow without a private sperm-banking conversation are all endocrine-reproductive patients.

Cranial radiation, hypothalamic-pituitary tumors, and the hormone map

The hypothalamus is more radiosensitive than the pituitary. After cranial radiation (historical ALL cranial fields, medulloblastoma or other brain-tumor beams, total body irradiation (TBI)) or after a craniopharyngioma, germinoma, or other hypothalamic-pituitary tumor—and after the surgery that follows—the CPHON watch is a hormone map, not a single random cortisol.

Growth hormone (GH) deficiency is the most common endocrinopathy after cranial radiation, especially in children treated at a young age. The clue is falling height velocity, not a one-time short-stature note. Plot height at every visit. A child who grew 6 cm last year and 2 cm this year needs endocrinology, not a reassurance that chemotherapy stunts everyone. GH replacement is an oncology–endocrine shared decision; do not start or stop GH from a website, and do not invent a gray-dose cutoff as ONCC fact.

Puberty can run too early or too late. Lower hypothalamic-pituitary injury may disinhibit gonadotropins and produce precocious puberty (classically recognized more often in girls): early Tanner staging, a growth spurt, then early epiphyseal closure and short adult height if untreated. Higher-dose injury produces delayed or absent puberty from gonadotropin deficiency. Both are CPHON problems. Tanner staging—breast and pubic hair in girls, genital development and pubic hair in boys—is the nursing assessment, compared with last visit. Tanner 2 (breast bud or testicular enlargement) is the biologic start of puberty; document it rather than guessing from a parent’s memory of a growth spurt.

Adrenocorticotropic hormone (ACTH) deficiency blunts the stress cortisol response: fatigue, nausea, hypoglycemia, and, under infection or surgery, shock. Thyroid-stimulating hormone (TSH) deficiency produces central hypothyroidism—low or inappropriately normal TSH with a low free T4—unlike the high-TSH picture of primary thyroid injury after neck radiation. Check free T4 as well as TSH; do not skip free T4 because TSH looks normal.

Antidiuretic hormone (ADH) deficiency is central DI: polyuria, polydipsia, and rising sodium after hypothalamic-pituitary tumor or surgery. Track intake and output and urine specific gravity, then signpost the sodium and desmopressin pathway to the metabolic-emergency chapter. Do not treat overnight urine output of several liters as ordinary hospital intravenous fluid without a sodium.

Steroids, adrenal suppression, Cushingoid change, and hyperglycemia

Dexamethasone and prednisone on ALL and lymphoma pathways, and steroids used for nausea, spinal edema, or graft-versus-host disease (GVHD), cause Cushingoid change: moon face, truncal weight gain, striae, and buffalo-hump fat. Families need to hear that the face will look different and that this is the medicine, not a parenting failure.

The same drugs suppress the hypothalamic-pituitary-adrenal axis. After weeks of pharmacologic steroids, the child’s own ACTH-cortisol axis may not mount a fever or surgical stress response. Do not stop corticosteroids abruptly. Taper as the protocol orders. Teach stress-dose rules only as the team writes them. Adrenal crisis is an emergency-chapter problem; missed tapers are how children arrive there.

Hyperglycemia is expected on high-dose dexamethasone and is worse when asparaginase (including pegylated asparaginase) is combined with steroids during ALL induction. Older age and obesity add risk. Fingerstick or serum glucose monitoring is nursing, not optional. Insulin is given as ordered. Polyuria in a Cushingoid child on asparaginase is glucose until proven otherwise—not automatically DI, and not a reason to hold asparaginase without the team. Pancreatitis from asparaginase is a gastrointestinal emergency and is signposted, not restated.

Thyroid after neck radiation and HSCT

Primary hypothyroidism follows neck radiation (Hodgkin lymphoma neck fields, nasopharyngeal fields) and TBI before HSCT. Compensated disease is a high TSH with a still-normal free T4; overt disease adds a low free T4, fatigue, weight gain, cold intolerance, and slipping school performance. Screen on the survivorship calendar. Thyroid nodules and secondary thyroid cancer are late radiation effects—palpate the neck and obtain ultrasound as the team orders; do not invent a screening interval as ONCC fact.

Central hypothyroidism (cranial radiation) and primary hypothyroidism (neck radiation or TBI) can coexist after craniospinal radiation plus a neck field. That is why both TSH and free T4 matter.

Gonadal toxicity, fertility counseling, Tanner stage, and pregnancy precautions

Alkylators—especially cyclophosphamide, ifosfamide, and busulfan—and radiation to the pelvis or testes injure germ cells. Testicular radiation (including a leukemia testicular boost or scatter from pelvic fields) and pelvic radiation for rhabdomyosarcoma, Ewing sarcoma, or Hodgkin nodes are classic exposures. Leydig cells are relatively more radioresistant than germ cells: a young man may have Tanner-appropriate testosterone and erectile function and still be azoospermic. Ovarian oocytes are sensitive: risk includes acute ovarian failure and premature menopause. Do not quote invented live-birth percentages for sperm banking, oocyte cryopreservation, or ovarian-tissue cryopreservation.

Counsel before the gonadotoxic cycle when the clinical situation allows. Sperm banking (cryopreservation) is the established option for pubertal and post-pubertal males; have the conversation privately, not in a hallway with siblings present. Oocyte cryopreservation requires time and ovarian stimulation that many new leukemia diagnoses cannot spare. Ovarian-tissue cryopreservation is an option for some children, including selected prepubertal girls; availability varies by center and is not a guaranteed fertility plan. Testicular-tissue cryopreservation for prepubertal boys is similarly center-dependent. Refer to fertility specialists; do not promise a baby.

Sexual function is not fertility. Body image after Cushingoid change or pelvic surgery, vaginal dryness from hypoestrogenism, and libido changes are real nursing topics. A preserved erection does not mean preserved sperm. Irregular menses do not prove infertility—and they do not prove fertility either. Keep plotting Tanner stage during alkylator and cranial-radiation follow-up so delayed or precocious puberty is not missed in the same visit as the fertility talk.

Pregnancy precautions during chemotherapy exist because cytotoxic drugs are teratogenic and because patients may still conceive. Do not assume alkylator exposure has already sterilized the teen. Teach contraception during therapy for patients who can become pregnant, and teach that chemotherapy appears in body fluids. Obtain a pregnancy test before pelvic radiation and before teratogenic cycles as protocol requires. Breastfeeding during chemotherapy is generally not compatible; follow the protocol and pharmacy, not a blog.

The CPHON product is a height chart that was actually plotted, a Tanner stage that was actually recorded, a steroid taper that was not improvised at home, a glucose that was checked during asparaginase-plus-dexamethasone induction, and a fertility conversation that happened before cyclophosphamide—without a fabricated percentage on the consent form.