Short Stature: Clinical Case and Viva QnA

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Clinical Case of Short Stature

A 9-year-old boy is brought to the pediatric endocrinology clinic by his parents due to concerns about his short stature. The parents report that he has always been smaller than his peers, but the difference has become more noticeable in the past two years. They state that he is the shortest in his class and often gets teased about his height.

On examination:

  • Height: 120 cm (below 3rd percentile for age)
  • Weight: 25 kg (10th percentile for age)
  • BMI: 17.4 kg/m² (50th percentile)
  • Tanner stage: 1 (prepubertal)
  • No dysmorphic features
  • Normal proportions

Family history:

  • Father's height: 168 cm
  • Mother's height: 155 cm
  • Mid-parental height: 168 cm (25th percentile)

Past medical history:

  • Full-term birth, birth weight 2.8 kg (10th percentile)
  • No chronic illnesses
  • Normal developmental milestones

Initial investigations:

  • Complete blood count: Normal
  • Thyroid function tests: Normal
  • IGF-1: Low for age
  • Bone age: Delayed by 2 years

Based on this information, further evaluation is needed to determine the underlying cause of the patient's short stature.

5 Varieties of Presentation of Short Stature
  1. Constitutional Delay of Growth and Puberty (CDGP):
    • Normal height at birth, deceleration in early childhood
    • Delayed bone age
    • Family history of late puberty
    • Normal growth velocity
    • Delayed onset of puberty
  2. Familial Short Stature:
    • Short stature consistent with parental heights
    • Normal growth velocity
    • Bone age appropriate for chronological age
    • No systemic abnormalities
  3. Growth Hormone Deficiency:
    • Decreased growth velocity
    • Delayed bone age
    • Possible midface hypoplasia, frontal bossing
    • Increased truncal adiposity
    • Low IGF-1 levels
  4. Turner Syndrome:
    • Female patient with short stature
    • Webbed neck, wide-spaced nipples
    • High arched palate, low hairline
    • Delayed puberty or primary amenorrhea
    • Karyotype showing 45,X or mosaicism
  5. Chronic Disease-Related Short Stature:
    • History of chronic illness (e.g., Crohn's disease, celiac disease)
    • Poor weight gain or weight loss
    • Delayed bone age
    • Decreased growth velocity
    • Specific symptoms related to the underlying condition
Viva Questions and Answers on Short Stature in Pediatrics
  1. Q: How do you define short stature in pediatrics?
    A: Short stature is typically defined as a height that is 2 standard deviations (SD) or more below the mean height for age and sex, or below the 3rd percentile on a standard growth chart.
  2. Q: What is the importance of mid-parental height in evaluating short stature?
    A: Mid-parental height helps determine the child's genetic growth potential. It's calculated by adding the parents' heights (in cm), adding 13 cm for boys or subtracting 13 cm for girls, and dividing by 2. A child's final height is expected to be within ±8.5 cm of the mid-parental height.
  3. Q: How do you calculate and interpret growth velocity?
    A: Growth velocity is calculated by measuring the change in height over a specific time period, usually expressed in cm/year. Normal growth velocity varies by age and pubertal status. In prepubertal children, it's typically 5-6 cm/year, while during pubertal growth spurt, it can reach 8-12 cm/year.
  4. Q: What is the role of bone age assessment in evaluating short stature?
    A: Bone age assessment helps determine skeletal maturity and predict adult height. It's particularly useful in differentiating between different causes of short stature, such as constitutional delay (delayed bone age) vs. familial short stature (normal bone age).
  5. Q: What are the key components of the initial evaluation of a child with short stature?
    A: The initial evaluation should include:
    • Detailed history (including birth, developmental, and family history)
    • Physical examination (height, weight, BMI, body proportions, pubertal staging)
    • Growth chart plotting
    • Calculation of mid-parental height and growth velocity
    • Basic laboratory tests (CBC, electrolytes, renal and liver function, thyroid function)
    • Bone age assessment
  6. Q: What are the indications for growth hormone stimulation testing?
    A: Indications include:
    • Height < -2.25 SD with low growth velocity
    • Height > 2 SD below mid-parental height
    • Bone age delay > 2 years
    • Low IGF-1 and IGFBP-3 levels
    • History suggestive of pituitary dysfunction
  7. Q: How do you differentiate between constitutional delay of growth and puberty (CDGP) and growth hormone deficiency (GHD)?
    A: Key differences include:
    • Growth velocity: Normal in CDGP, decreased in GHD
    • Bone age delay: Mild in CDGP, more significant in GHD
    • Family history: Often positive for late puberty in CDGP
    • IGF-1 levels: Normal in CDGP, low in GHD
    • Response to growth hormone stimulation test: Normal in CDGP, blunted in GHD
  8. Q: What are the criteria for diagnosing growth hormone deficiency?
    A: Criteria typically include:
    • Height < -2 SD or > 2 SD below mid-parental height
    • Growth velocity < 25th percentile for age
    • Delayed bone age
    • Low IGF-1 and IGFBP-3 levels
    • Peak GH level < 10 ng/mL on two separate GH stimulation tests
  9. Q: What are the common causes of secondary growth hormone deficiency?
    A: Common causes include:
    • Craniopharyngioma
    • Other brain tumors (e.g., germinoma, glioma)
    • Cranial irradiation
    • Traumatic brain injury
    • Infiltrative diseases (e.g., Langerhans cell histiocytosis)
    • Pituitary hypoplasia or aplasia
  10. Q: How do you approach the diagnosis of Turner syndrome in a girl with short stature?
    A: Approach includes:
    • Look for characteristic physical features (webbed neck, wide-spaced nipples, etc.)
    • Assess pubertal development and cardiac abnormalities
    • Perform karyotype analysis
    • If karyotype is normal but suspicion is high, consider FISH analysis for mosaicism
    • Evaluate for associated conditions (e.g., hypothyroidism, celiac disease)
  11. Q: What are the indications for growth hormone therapy in children without growth hormone deficiency?
    A: Approved indications vary by country but may include:
    • Turner syndrome
    • Prader-Willi syndrome
    • Chronic renal insufficiency
    • Small for gestational age with failure of catch-up growth
    • SHOX gene deficiency
    • Noonan syndrome
  12. Q: How do you monitor a child on growth hormone therapy?
    A: Monitoring includes:
    • Regular height and weight measurements (every 3-6 months)
    • Annual bone age assessment
    • IGF-1 levels (aim for upper normal range)
    • Thyroid function tests
    • Glucose metabolism (fasting glucose, HbA1c)
    • Assess for potential side effects
  13. Q: What is idiopathic short stature (ISS), and how is it managed?
    A: ISS is defined as height < -2 SD without identifiable cause. Management includes:
    • Regular monitoring of growth
    • Addressing psychosocial concerns
    • Consider GH therapy in severe cases (height < -2.25 SD), though controversial
    • Potential use of aromatase inhibitors in boys to delay epiphyseal fusion
  14. Q: How does celiac disease present as a cause of short stature, and how is it diagnosed?
    A: Celiac disease can present with:
    • Short stature with or without gastrointestinal symptoms
    • Delayed puberty
    • Anemia, fatigue
    Diagnosis involves:
    • Serological screening (TTG-IgA, total IgA)
    • Small bowel biopsy for confirmation
    • HLA-DQ2/DQ8 typing can be helpful
  15. Q: What is the approach to a child with short stature and normal growth velocity?
    A: Approach includes:
    • Assess if height is consistent with mid-parental height (familial short stature)
    • Evaluate bone age (normal in familial short stature, delayed in CDGP)
    • Monitor growth over time
    • Consider genetic causes (e.g., SHOX deficiency) if disproportionate
    • Provide reassurance if familial or CDGP
  16. Q: How does hypothyroidism contribute to short stature, and what are the key diagnostic features?
    A: Hypothyroidism contributes by:
    • Decreasing growth velocity
    • Delaying bone age
    • Interfering with GH secretion and action
    Key diagnostic features:
    • Decreased growth velocity
    • Delayed bone age
    • Other symptoms: fatigue, constipation, dry skin, cold intolerance
    • Elevated TSH, low free T4
  17. Q: What is the role of insulin-like growth factor-1 (IGF-1) in the evaluation of short stature?
    A: IGF-1 is important because:
    • It reflects GH action and nutritional status
    • Low levels suggest GH deficiency or resistance
    • Normal/high levels in a short child suggest GH insensitivity
    • It's used to monitor GH therapy
  18. Q: How do glucocorticoids affect growth, and what strategies can mitigate their growth-suppressing effects?
    A: Glucocorticoids affect growth by:
    • Directly inhibiting chondrocyte proliferation
    • Decreasing GH secretion and IGF-1 production
    • Inducing catabolism
    Strategies to mitigate effects:
    • Use lowest effective dose
    • Consider alternate-day dosing
    • Use growth-sparing alternatives when possible
    • Consider GH therapy in severe cases
  19. Q: What are the key features of Silver-Russell syndrome, and how is it diagnosed?
    A: Key features include:
    • Intrauterine growth restriction
    • Postnatal growth failure
    • Relative macrocephaly
    • Triangular face
    • Body asymmetry
    Diagnosis:
    • Clinical criteria (e.g., Netchine-Harbison Clinical Scoring System)
    • Molecular testing for 11p15 LOM and mUPD7
  20. Q: How do you approach a child with short stature and elevated BMI?
    A: The approach includes:
    • Assess for endocrine causes (e.g., hypothyroidism, Cushing's syndrome)
    • Evaluate for genetic syndromes (e.g., Prader-Willi syndrome)
    • Consider pseudotumor cerebri, which can cause growth hormone deficiency
    • Assess growth velocity and bone age
    • Screen for metabolic complications of obesity
    • Implement lifestyle interventions for weight management
    • Consider that obesity can accelerate bone age and mask underlying growth disorders
  21. Q: What is the significance of a low IGF-1 with normal growth hormone stimulation test results?
    A: This situation could indicate:
    • Growth hormone insensitivity (Laron syndrome or milder forms)
    • ALS deficiency
    • IGF1 gene defects
    • Malnutrition or chronic disease
    • Liver dysfunction (as IGF-1 is primarily produced in the liver)
    Further evaluation, including genetic testing, may be necessary to determine the underlying cause.
  22. Q: How does inflammatory bowel disease (IBD) contribute to short stature, and what are the management considerations?
    A: IBD contributes to short stature through:
    • Malnutrition and malabsorption
    • Chronic inflammation (cytokines interfering with GH-IGF-1 axis)
    • Glucocorticoid therapy
    Management considerations:
    • Optimize IBD treatment to achieve remission
    • Ensure adequate nutrition and caloric intake
    • Minimize glucocorticoid exposure
    • Monitor growth velocity and pubertal development
    • Consider growth hormone therapy in severe cases
  23. Q: What is the role of genetic testing in the evaluation of short stature?
    A: Genetic testing is important for:
    • Diagnosing specific genetic syndromes (e.g., Turner syndrome, Noonan syndrome)
    • Identifying single gene defects affecting the GH-IGF-1 axis
    • Detecting copy number variations (e.g., SHOX gene deletions)
    • Guiding treatment decisions and prognosis
    • Genetic counseling for families
    Methods may include karyotype, FISH, microarray, or next-generation sequencing panels.
  24. Q: How do you counsel parents of a child with constitutional delay of growth and puberty (CDGP)?
    A: Counseling should include:
    • Explanation of CDGP as a normal variant of growth pattern
    • Reassurance about eventual catch-up growth and normal adult height
    • Discussion of family history and genetic component
    • Addressing psychosocial concerns and strategies to cope with peer comparisons
    • Explaining the option of "watchful waiting" vs. potential interventions (e.g., short course of low-dose testosterone in boys)
    • Importance of regular follow-up to ensure appropriate progression
  25. Q: What are the potential psychological impacts of short stature, and how can they be addressed?
    A: Potential psychological impacts include:
    • Low self-esteem and poor body image
    • Social withdrawal or behavioral problems
    • Bullying or teasing from peers
    • Academic underachievement
    Addressing these issues:
    • Provide supportive counseling and normalize feelings
    • Encourage participation in activities that build self-esteem
    • Consider referral to a mental health professional if needed
    • Educate family and school about supporting the child
    • Discuss coping strategies and assertiveness skills
  26. Q: How do you approach the differential diagnosis of a child with short stature and advanced bone age?
    A: The differential diagnosis includes:
    • Precocious puberty
    • Congenital adrenal hyperplasia
    • Hyperthyroidism
    • Cushing's syndrome
    • Obesity
    • Genetic syndromes (e.g., Albright hereditary osteodystrophy)
    Approach:
    • Detailed history and physical examination, including pubertal staging
    • Endocrine evaluation (thyroid function, adrenal hormones, sex hormones)
    • Imaging studies if indicated (e.g., brain MRI for precocious puberty)
    • Genetic testing if a specific syndrome is suspected
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