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OG23.1-3,OG24.1,OG25.1 | Puberty and Menstrual Disorders — PBL Case

CLINICAL SETTING

Priya is a 7-year-old girl brought to the paediatric gynaecology outpatient clinic by her mother, Mrs Krishnamurthy, a schoolteacher. Mrs Krishnamurthy is visibly anxious. She explains that over the last 8 months she has noticed her daughter developing breasts, and in the last 2 months, pubic hair has appeared. Priya has also grown 7 cm in height over the past year, which is well above the 5–6 cm expected for her age. She has no headaches, no vision problems, and her school performance is normal. There is no relevant family history — her older sister started her periods at age 13, and the mother at age 12. Priya has no chronic illnesses, takes no medications, and has had no significant previous illnesses. She is not exposed to any exogenous hormonal products at home. On examination: Priya appears healthy and well-nourished. Height is at the 90th percentile for her age, weight at the 75th percentile. Tanner staging: breast B3, pubic hair PH2. The external genitalia appear oestrogenised (labial minora more prominent, vaginal mucosa moist and pink). There is no clitoromegaly. No axillary hair. No thyroid enlargement. No abdominal mass. No café-au-lait spots or skin pigmentation. Neurological examination is normal.

Trigger 1: Initial Presentation — What Is Happening to Priya?

The registrar reviewing Priya's case notes that she is 7 years and 4 months old and has Tanner B3 breast development and PH2 pubic hair — well before the lower normal age limit for puberty in girls (8 years). Her growth velocity is above normal. The mother is asking: 'Will she be short forever? Is this dangerous? Could it be something she ate?'

DISCUSSION POINTS

  • Define precocious puberty precisely — what is the age cut-off, and why is there a different cut-off for boys and girls?
  • What is the fundamental difference between CENTRAL (GnRH-dependent) and PERIPHERAL (GnRH-independent) precocious puberty? Draw the HPO axis and show where each type goes wrong.
  • The mother asks whether Priya will be short when she grows up. Based on the physiology of growth spurt timing in relation to puberty in girls, how would you counsel her?
  • Generate a differential diagnosis list for this presentation, organised by central vs peripheral aetiology.
Click to reveal Trigger 2: Investigation Results — Classifying the Type (discuss previous trigger first!)

Trigger 2: Investigation Results — Classifying the Type

Initial investigations are returned: Bone age X-ray (left wrist): skeletal age is 10 years (advanced by ~2.5 years relative to chronological age of 7.5 years). Serum oestradiol: 62 pmol/L (early pubertal range). Basal LH: 3.8 IU/L, FSH: 4.2 IU/L. GnRH stimulation test: GnRH 100 µg IV administered; 30-minute LH 18.2 IU/L, FSH 8.1 IU/L. Pelvic ultrasound: uterine length 4.2 cm (pubertal), ovarian volume 3.2 mL bilaterally with multiple small follicles. Serum DHEAS and 17-hydroxyprogesterone: normal for age.

DISCUSSION POINTS

  • Interpret the GnRH stimulation test result. What LH:FSH ratio pattern and absolute LH value confirm central precocious puberty? What would you expect in peripheral PP?
  • The bone age is 2.5 years advanced. What are the clinical implications for adult height? Explain the mechanism linking oestrogen excess and early epiphyseal fusion.
  • The DHEAS and 17-OHP are normal. What diagnoses have you effectively excluded and why?
  • What diagnosis has been confirmed, and what critical investigation must now be performed URGENTLY before any treatment decision?
Click to reveal Trigger 3: Brain MRI Result and the Treatment Decision (discuss previous trigger first!)

Trigger 3: Brain MRI Result and the Treatment Decision

Brain MRI is performed with contrast. Report: 'A 1.2 cm well-defined non-enhancing lesion is identified in the region of the hypothalamus, consistent with a hypothalamic hamartoma. No other intracranial lesions. Normal pituitary gland.' The paediatric endocrinologist reviews the case and advises that GnRH analogue therapy is indicated.

DISCUSSION POINTS

  • What is a hypothalamic hamartoma and how does it cause central precocious puberty? Why does it NOT require neurosurgical intervention?
  • Explain the pharmacological mechanism of GnRH analogue (e.g. leuprolide depot) therapy in treating central precocious puberty. Why does a continuous (non-pulsatile) GnRH stimulus SUPPRESS rather than stimulate the pituitary?
  • What are the monitoring parameters during GnRH analogue treatment? How do you judge whether treatment is working?
  • The mother asks whether Priya will ever have normal puberty after stopping treatment. How would you counsel her?
Click to reveal Trigger 4: An Unexpected Finding — The Sister Is Also Referred (discuss previous trigger first!)

Trigger 4: An Unexpected Finding — The Sister Is Also Referred

Priya's 16-year-old sister, Deepa, is also seen at the clinic on the same day, referred from a different outpatient department. Deepa has had no menarche and no breast development. She is 148 cm tall (short for her family), has a broad neck, widely spaced nipples, and low posterior hairline. FSH is 52 IU/L, LH 38 IU/L. The two sisters now sit in the waiting room together — one with precocious puberty, one with delayed puberty.

DISCUSSION POINTS

  • Using the FSH/LH result alone, classify Deepa's delayed puberty as hypogonadotrophic or hypergonadotrophic. What does this localise in the HPO axis?
  • The clinical features (short stature, broad/webbed neck, widely spaced nipples, low hairline) are characteristic. What is the most likely diagnosis and what investigation confirms it?
  • Why must a cardiac MRI be ordered in addition to echocardiography for this diagnosis? What specific cardiac anomalies must be excluded?
  • Compare and contrast the management of Priya (central PP, HPO activated prematurely) with that of Deepa (likely Turner syndrome, HPO never activated). What are the treatment goals and hormonal strategies for each?
Click to reveal Trigger 5: Synthesis and Counselling (discuss previous trigger first!)

Trigger 5: Synthesis and Counselling

Both girls have been diagnosed and have their management plans. The parents of both patients are now together and ask: 'Why did this happen? Is it genetic? Will they be able to have children?' The treating team must counsel both families together, address the psychological impact of these diagnoses on the girls at their respective ages, and arrange a multidisciplinary follow-up plan.

DISCUSSION POINTS

  • How would you explain the cause of each condition in lay terms to the families, being careful to address the genetic component (if any) accurately and sensitively?
  • What are the fertility implications for each girl? How do current assisted reproductive technologies and oocyte/embryo preservation apply here?
  • What psychological support does each girl need, given the significant difference in their age and developmental stage at diagnosis?
  • Design a multidisciplinary follow-up plan for each patient — which specialties need to be involved and what are the key monitoring milestones?

Group Task Assignments

  • Construct a side-by-side comparison table of central vs peripheral precocious puberty: definition, mechanism, HPO axis state, LH/FSH on GnRH stimulation, clinical features, imaging, and management.
  • Draw the compartment-based HPO axis diagram and annotate where each condition (hypothalamic hamartoma, Turner syndrome, CDGP, functional hypothalamic suppression) disrupts the axis.
  • Role-play the counselling consultation between the treating doctor and Priya's mother at the point of MRI result disclosure — one student is the doctor, one is the mother. Focus on breaking the news, explaining the treatment plan, and addressing the mother's fear about short stature.

Learning Issues

Research these questions and bring your findings to the discussion.

  1. [OG23.3] What is the complete differential diagnosis of precocious puberty in girls, classified by central and peripheral causes? What distinguishes benign variants (premature thelarche, premature adrenarche) from true precocious puberty?
  2. [OG23.2] What is the FSH/LH pattern that distinguishes hypogonadotrophic from hypergonadotrophic hypogonadism, and what does each pattern localise in the HPO axis?
  3. [OG23.1] What is the physiological basis of the growth spurt in girls, and why does precocious puberty (or any cause of early oestrogen exposure) result in short adult stature despite an initial growth acceleration?
  4. [OG23.2] What are the structural cardiac anomalies associated with Turner syndrome, and why is cardiac MRI required in addition to echocardiography?
  5. [OG23.1] What is the mechanism by which GnRH analogues (leuprolide, triptorelin) suppress the HPO axis when given continuously, and what are the monitoring parameters during treatment?