Endo Fha Rpth Delayed Fracture Low Bmd

Consider short-term recombinant parathyroid hormone 1-34 for delayed fracture healing and very low BMD

STEP 1 — Gather Information

Confirm FHA diagnosis (amenorrhea ≥3 months after excluding pregnancy, thyroid disease, hyperprolactinemia, anatomic outflow tract obstruction). Document fracture type, duration, immobilization status, and lack of radiographic healing. Obtain lumbar spine or hip BMD by DXA (Z‑score). Screen for rPTH contraindications: history of bone malignancy, Paget’s disease, pediatric/open epiphyses, unexplained elevated alkaline phosphatase, prior skeletal radiation, hypercalcemia. Ensure energy imbalance is being addressed (nutrition, psychological support, exercise modification). If all data collected and no contraindications, proceed to Step 2.

STEP 2 — Rule In / Rule Out

Is there delayed fracture healing (no radiographic callus after expected healing period for fracture type) AND BMD Z‑score ≤ -2.5?

• Yes → Proceed to Step 3.
• No → Continue standard FHA management; avoid bisphosphonates per guideline; consider other osteoporosis agents only after multidisciplinary review.

STEP 3 — Classify or Stratify

Stratify BMD severity:

• Moderate low: Z‑score -2.5 to -3.0
• Very low: Z‑score < -3.0
  Also note fracture location (weight‑bearing vs non‑weight‑bearing). If BMD is very low (Z‑score < -3.0) and fracture healing is delayed, proceed to Step 4; otherwise, optimize energy balance and repeat DXA in 3‑6 months.

STEP 4 — Decide

For very low BMD with delayed fracture healing, discuss a trial of subcutaneous teriparatide (recombinant PTH 1‑34) 20 µg daily for up to 6 months. Review limited evidence in FHA, osteosarcoma black‑box warning, and need for concurrent multidisciplinary FHA treatment. Obtain informed consent. Initiate therapy while maintaining nutritional rehabilitation, CBT, and exercise modification. Arrange follow‑up: serum calcium at 1 month, clinical/radiographic fracture healing assessment at 3 months, and BMD DXA at 6 months.

Clinical Guardrails / Mimics / Pitfalls

Teriparatide carries a black‑box warning for osteosarcoma in rats; human data in FHA are limited to small studies. Do not use in patients with history of bone malignancies, Paget’s disease, unexplained elevated alkaline phosphatase, pediatric/open epiphyses, prior skeletal radiation, or hypercalcemia. Avoid as first‑line therapy; correcting energy imbalance remains cornerstone. Monitor serum calcium periodically (e.g., q3mo). Not recommended in pregnancy or lactation. Do not confuse delayed healing due to infection or inadequate immobilization with low BMD‑related poor healing.

Concrete Clinical Example

A 26‑year‑old woman with 9 months of amenorrhea from low BMI and intensive running presents with a navicular stress fracture unhealed after 4 months of casting. DXA lumbar spine Z‑score is -3.1. Infection ruled out, nutritional rehab underway. She opts for a 6‑month course of teriparatide 20 µg daily alongside continued CBT and weight‑gain goal. At 3‑month follow‑up, repeat radiographs show early callus formation and serum calcium remains normal.

Source: Functional Hypothalamic Amenorrhea: An Endocrine Society Clinical Practice Guideline, Endocrine Society, 2017, DOI:10.1210/jc.2017-00131