Pakistan Society Of Chemical Pathologists Distance Learning Programme In Chemical Pathology (DLP-2) Lesson No 15 Disorders of Growth By Brig Aamir Ijaz MCPS, FCPS, FRCP (Edin) Professor of Pathology / Consultant Chemical Pathologist AFIP Rawalpindi

Part I MCQs (One Best Type)

Slides courtesy of Dr Sabiha Waseem (Canada) Short Stature Slides courtesy of Dr Sabiha Waseem (Canada)

Definition Short stature is defined as height that is 2 standard deviations (SD) or more below the mean height for children of that sex and chronological age in a given population. This translates to a height that is below the 2.3rd percentile

Differential Diagnosis (ABCDEFG) Alone ( neglected child) Bone dysplasias (rickets, scoliosis) Chromosomal (Turner’s, Down’s) Delayed growth Endocrine(GH deficiency, Hypothyroid, Cushing’s) Familial GI malabsorption (celiac, Crohn)

Questions to be answered for evaluation for short stature Was there IUGR? Is the growth proportionate? Is the growth velocity normal? Is bone age delayed?

Q.1: A 5 y girl has presented in a Rural Dispensary of Pakistan with height and weight <2nd percentile and 3rd percentile, respectively. Which of the following conditions is the most likely cause of short stature in this girl: a. Familial short stature b. Growth Hormone (GH) Deficiency c. Hypothyroidism d. Malnutrition e. Turner syndrome d. Malnutrition 9/20/2018

c. Height velocity < 5 cm/y in a 4 y child Q.2: The term ‘Growth Failure’ will be used for which of the following conditions: a. Bone age < 20% of chronological age b. Height < 2.3rd percentile for the age c. Height velocity < 5 cm/y in a 4 y child d. Projected height < 5 cm of mid-parental height e. Weight < 3rd percentile for the age c. Height velocity < 5 cm/y in a 4 y child 9/20/2018

Growth Failure The height-for-age curve has deviated downwards across two major height percentile curves (e.g. from above the 25th percentile to below the 10th percentile).   Or, if the child is growing slower than the following rates:   Age two to four years: Height Velocity (HV) less than 5.5 cm/year (<2.2 inches/year) Age four to six years: HV less than 5 cm/year (<2 inches/year) Age six years to puberty: HV less than 4 cm/year for boys (<1.6 inches/year) HV less than 4.5 cm/year for girls (<1.8 inches/year) Ref: UpToDate 2014

Height Velocity (HV) The hallmark of Pathological Short Stature is HV If HV is normal in a short stature child, it is usually due to a non-pathological cause e.g. Familial Short Stature (FSS) or Constitutional delay of growth and puberty (CDGP) If HV is grossly low all pathological causes should be excluded before starting GH investigations.

Q.3: On a routine working day 5 children (age 8-12 y) reported in a Growth Clinic. Their preliminary clinical examination and laboratory tests where done for selection of GH testing. Which of the following children is an ideal candidate for GH testing: a. Height 4th percentile, Hb: 9.4g/dl; TSH : 2.4 mIU/ml; Anti-gliadin antibodies: negative b. Height 5th percentile, Hb: 9.2 g/dl; TSH : 2.4 mIU/ml; Anti-gliadin antibodies: positive c. Height 11th percentile, Hb: 13.4g/dl; TSH : 2.4 mIU/ml; Anti-gliadin antibodies: negative d. Height 2.5th percentile, Hb: 14.2g/dl; TSH : 2.4 mIU/ml; Anti-gliadin antibodies: negative e. Height 7th percentile, Hb: 11.4g/dl; TSH : 10.2 mIU/ml; Anti-gliadin antibodies: negative d. Height 2.5th percentile, Hb: 14.2g/dl; TSH : 2.4 mIU/ml; Anti-gliadin antibodies: negative 9/20/2018

a. Bone age 10% less than chronological age Q 4: In a Growth Clinic various growth abnormalities are found in children. Which of the following growth abnormalities is the LEAST indicator of GH deficiency: a. Bone age 10% less than chronological age b. Height < 0.5th percentile for the age c. Height velocity < 10th percentile for age and gender d. Height velocity < 4 cm/y in an 8 y boy e. Projected height < 160 cm in a male a. Bone age 10% less than chronological age 9/20/2018

Delayed or Advanced Bone Age Delayed or advanced bone age is defined as 2 SD or more below or above the mean, respectively. This is approximately 20 percent below or above the chronological age. This translates to a difference between bone age and chronological age of approximately 12 months between 2 and 4 years of chronological age, 18 months between 4 and 12 years, and 24 months after age 12 . If the bone age is delayed or advanced near or beyond these parameters, then the projected height should be recalculated based on the bone age rather than the chronologic age. The most important point to differential between FSS and CDGP is bone age. In CDGP bone age is delayed while it is according to chronological age in FSS Ref: UpToDate 2014

Calculation of Predicted (Target) Height from Mid-Parental Height Boy= (father height in cm + mother height in cm + 13 cm)/2 Girl= (father height in cm + mother height in cm - 13 cm)/2

d. Serum Insulin like Growth Factor 1 (IGF-1) Q 5 : A 34 y female suspected of Acromegaly has been referred to you to rule out the disease. Which of the following is the single most important first test to rule out acromegaly in this patient: a. CT scan b. MRI c. Serum GH level basal d. Serum Insulin like Growth Factor 1 (IGF-1) e. Serum IGF-1-binding protein-3 (IGFBP-3) d. Serum Insulin like Growth Factor 1 (IGF-1) 9/20/2018

Slides courtesy of Dr Amina Tariq (AFIP Rwp) Acromegaly Slides courtesy of Dr Amina Tariq (AFIP Rwp)

Clinical Features Acromegaly occurs due to persistently increased GH production, usually as a result of a pituitary adenoma. Excess GH stimulates hepatic secretion of IGF-I, which causes most of the clinical manifestations of acromegaly including: Acral and soft tissue overgrowth Joint pains Diabetes mellitus, hypertension Cardiac failure Respiratory failure 9/20/2018

Diagnosis The clinical diagnosis is often delayed because of the slow progression of disease. Biochemically, elevated GH and IGF-1 levels are required for the diagnosis. The ideal screening test of acromegaly is serum IGF-I as: Unlike growth hormone, serum IGF-I concentrations do not fluctuate but instead reflect integrated GH secretion during the preceding day or longer. IGF-1 has much longer half life (18-20 h) than GH (15-20 min) Serum IGF-I concentrations are elevated in virtually all patients with acromegaly and provide excellent discrimination from normal individuals 9/20/2018

Diagnosis (Contd) The most specific dynamic test for establishing the diagnosis of acromegaly is OGTT with 75 g glucose; with subsequent GH measurement up to 120 min. GH cannot be suppressed in the presence of liver failure, kidney failure, poorly controlled diabetes, malnutrition, anorexia, pregnancy, estrogen therapy, or in late adolescence. Radioimmunoassays were initially developed for GH measurement which have largely been replaced by more sensitive techniques like IRMA and immunochemiluminescence. Cut off limits for diagnosis are variable depending on type of measurement technique. 9/20/2018

Diagnosis Contd.. 9/20/2018

Q 6 : A 42 y male has undergone Glucose Suppression Test for the diagnosis / exclusion of acromegaly with 75 g glucose. He is not a known case of Diabetes Mellitus or liver disease. The results of his investigations showed following results: GH basal : 2.2 ng/ml GH level at 1 h : 0.6 ng/ml GH level at 2 h : 0.4 ng/ml What is the most probable diagnosis? a. Active acromegaly b. Equivocal results c. Extra-pancreatic islet cell tumour d. Extra-Pituitary Acromegaly e. Normal study e. Normal study 9/20/2018

Glucose Suppression Test Criteria for Normal Result (Teitz) Suppression to < 1ng/ml (or imicrogram/l) Criteria for Acromegaly (Teitz) Failure of Suppression (> 2 ng/ml (or 2 microgram/l) Criteria for Normal Result (UpToDate) Suppression to < 0.3 ng/ml (or 0.3 microgram/l) Criteria for Acromegaly (UpToDate) Failure of Suppression (> 0.3 ng/ml (or 0.3 microgram/l)

Part II Match the answers (Extended Matching Questions)

Disorders of Growth Options  Achondroplasia Acromegaly Constitutional delay of growth and puberty Constitutional tall stature Familial short stature Gigantism Precocious puberty Growth Hormone Deficiency Growth hormone insensitivity Idiopathic short stature Noonan syndrome Osteogenesis imperfecta Prader-Willi syndrome  Primordial Dwarfism Small for gestational age with catch-up growth Systemic disorders with secondary effects on growth  9/20/2018

(8) Growth Hormone Deficiency Q 7 : A 5 y girl is brought in a Growth Clinic for short stature (height <2nd percentile). The growth velocity of the girl is 3.5 cm/y. Her father is 170 cm and mother is 165 cm. All systemic and endocrine (other than GH related) investigations were normal. Her GH related investigations were as following • IGF-1: Low for the age and gender • IGF BP3: Low for the age and gender • GH levels after Insulin Tolerance Test: Sub-normal response • Bone age: 3 y What is the most probable diagnosis? (8) Growth Hormone Deficiency 9/20/2018

Growth Hormone Deficiency (GHD) Slides courtesy of Dr Uzma Ansari (AFIP Rwp)

Causes Of GHD Congenital causes: Mutation of genes e.g. GH1 and GHRH genes GHRH receptor defect Congenital absence of pituitary Midline defect syndrome e.g. Septo-optic dysplasia, or de Morsier syndrome.

Diagnosis of GHD Auxological examination: Biochemical testing should be done only in short stature children with low height velocity and low bone age. Exclusion of other causes of short stature by clinical or biochemical means IGF-1 and IGF-BP3: If levels are > 50th percentile: GHD is extremely unlikely and stimulation tests are not warranted. GH stimulation tests: e.g. Insulin hypoglycaemia test or glucagon stimulation test.

(10) Idiopathic short stature Q 8 : An 8 y boy is brought in a Growth Clinic for short stature (2nd percentile). The growth velocity of the boy is 3.0 cm/y. His father is 165 cm and mother is 163 cm. All systemic and endocrine (other than GH related) investigations were normal. His GH related investigations were as following • IGF-1: Within reference range for the age and gender • IGF BP3: Within reference range for the age and gender • GH levels after Insulin Tolerance Test: normal response • Bone age: 6 y What is the most probable diagnosis? (10) Idiopathic short stature 9/20/2018

Idiopathic short stature(ISS) Slides courtesy of Dr Qurrat-Ul-Ain, AFIP Rwp

Definition Heterogeneous group of children with height more than 2 SD score (SDS) below the corresponding mean height for a given age, sex, and population group without evidence of systemic, endocrine, nutritional, or chromosomal abnormalities 60-80% of all short statured are labeled ISS Diagnosis of exclusion

Characteristic Findings Clinical Normal birth weight Phenotypically normal ( no dysmorphic features or skeletal dysplasia) Normal growth velocity (often near or at the lower limit) Laboratory No biochemical or genetic evidence for a specific growth-retarding condition Normal growth hormone (GH) responses to pharmacologic agents that lead to growth hormone release Some children may have reduced activity of GH-IGF-1 axis

Subcategorization of ISS The term ISS is generally reserved for children at the more severe end of the spectrum in each of these categories, but the distinction between normal and abnormal growth patterns is not clear. Though patients labeled as ISS may have variant of normal growth, monitoring is required for the possibility of unrecognized underlying disease. In children shorter than 2.25 SDS (1.2 percentile) or male with projected height < 63 inches (160 cm) and female with projected height less than 59 inches (150 cm) FDA recommends GH treatment.

(3) Constitutional delay of growth and puberty Q 9 : A 16 y boy was followed-up at a Growth Clinic for 10 years. At presentation his height and weight were 3rd percentile and 39th percentile, respectively. His growth velocity remained from 4.5 cm to 5.5 cm/y during first three years of life. His bone age was 8 years at chronological age of 11 years. His puberty was also delayed but now his height is absolutely normal (68th percentile). His parents are of normal height. What is the most probable diagnosis? (3) Constitutional delay of growth and puberty 9/20/2018

(15) Small for gestational age with catch-up growth Q 10 : An 18 month baby has been brought in your Growth Clinic for short stature (< 2nd percentile). His mother gave history of his short length since birth. His father and mother are of normal height. All systemic and endocrine (other than GH related) investigations were normal. No GH related tests were done. The treating physician just reassured and advised follow-up. After 1 y the height of the child was at 15th percentile. What is the most probable diagnosis? (15) Small for gestational age with catch-up growth 9/20/2018

(5) Familial short stature Q 11 : A 10 y boy is < 3rd percentile for height and 22nd percentile for weight. His father is 138 cm and mother is 144 cm. His growth velocity monitored at a Growth Clinic was found to be 5.0 cm to 6.0 cm/y. All systemic and endocrine (other than GH related) investigation were normal. His GH related investigations were as following: • IGF-1: Within reference range for the age and gender • IGF BP3: Within reference range for the age and gender • GH levels after Insulin Tolerance Test: normal response • Bone age: 10 y What is the most probable diagnosis? (5) Familial short stature 9/20/2018

Q 12 : An 11 year boy has been brought by his parents with complaint of short stature. His height is 10th percentile. His parents narrate that his height was more than his peers until 9 years of age when suddenly he stopped growing and started developing facial and pubic hair. Now he has fully developed male sexual characteristics. His father is 162 cm and mother is 160 cm. His growth velocity was not monitored. His GH related investigations were as following: • IGF-1: Within reference range for the age and gender • IGF BP3: Within reference range for the age and gender • GH levels after Insulin Tolerance Test: normal response • Bone age: 15 y What is the most probable diagnosis? (7) Precocious puberty 9/20/2018

(9) Growth hormone insensitivity Q 13 : An 8 y child is being investigated for short stature (<3rd percentile). His father is 171 cm and mother is 164 cm. His growth profile shows: • IGF-1: Low for the age and gender • IGF BP3: Low for the age and gender • GH levels after Insulin Tolerance Test: normal response • Bone age: 6 y What is the most probable diagnosis? (9) Growth hormone insensitivity 9/20/2018

Part III Short Answer Questions:

Q. 14: Short stature can be a presenting feature of an underlying sinister disease or a condition which can be treated or taken care of very easily. Please write TEN most important causes of Short Stature in children and adolescents other than GH related conditions. Please write ONE line about the possible mechanism of short stature for each of these causes   9/20/2018

Non-GH related Causes of Short Stature 1. Malnutrition: It may be due to a lack of proper food, primarily due to lack of protein and other basic nutrient ions the diet or other conditions like gastrointestinal problems. 2. Glucocorticoid therapy: Glucocorticoids exert multiple growth-suppressing effects, interfering with endogenous growth hormone secretion and action, bone formation, nitrogen retention, and collagen formation. 3. Renal disease: Growth failure in children with renal disease is multifactorial. Implicated factors include metabolic acidosis, uremia, poor nutrition secondary to dietary restrictions, anorexia of chronic illness, anemia, calcium and phosphorus imbalance, renal osteodystrophy and potential adverse effects on the serum concentrations of insulin-like growth factors and their binding proteins. 4. Cancer: Children with cancer may grow poorly before diagnosis because of poor food intake, nausea, vomiting, and increased caloric utilization. 9/20/2018

Non-GH related Causes of Short Stature (Cont) 5. Pulmonary disease: Severe asthma alone probably results in slow growth, but it is slowed more by treatment, especially with glucocorticoids. 6. Cystic fibrosis is both a pulmonary and gastrointestinal disease. Growth failure is multifactorial in this disorder as poor food intake, increased fecal caloric losses because of maldigestion or malabsorption, chronic infection, and increased energy requirements (work of breathing) can all contribute. 7. Cardiac disease: Growth failure is common in children with severe heart disease of any cause. The major pathogenetic factors are thought to be anorexia and increased basal energy requirements. 8. Gastrointestinal disease: Celiac disease is a prime example of a remediable cause of short stature, especially in younger children. Older children with inflammatory bowel disease, especially Crohn disease, may present with growth failure before the onset of gastrointestinal symptoms. 9. Immunologic disease: Growth failure also can occur with other immunological deficiencies such as the severe combined immunodeficiency syndrome. As with HIV infection, multiple factors are probably involved. 9/20/2018

Non-GH related Causes of Short Stature (Cont) 10. Metabolic and endocrine diseases: inborn disorders of metabolism. Type 1 diabetes mellitus. Vitamin D deficiency or decreased vitamin D action. Hypothyroidism, Hypopituitarism Hypercortisolism (Cushing's syndrome, exogenous and endogenous). 9/20/2018

Q. 15: A variety of GH stimulation tests have been described for the diagnosis of GH deficiency with wide variation in specificity and specificity. Please answer following questions regarding these tests (0.5 mark each): a. Name THREE most specific GH stimulation tests. • Glucagon Stimulation Test • Arginine Stimulation Test • Insulin-induced hypoglycemia (Insulin Tolerance Test)   9/20/2018

Q. 15: b. Which one of these tests (or combination) you will like to carry out in your Growth Clinic for the diagnosis of GH deficiency in children and why?   I will prefer Glucagon Stimulation Test test in children. In this test administration of glucagon causes transient hyperglycemia, which in turn stimulates endogenous insulin secretion followed by controlled hypoglycemia, and consequent GH secretion. Reason: It is less risky than insulin-induced hypoglycemia, and is a good choice for infants and young children. 9/20/2018

Q. 16: IGF1 and IGF-BP3 are the new tests now widely used for the diagnosis of GH Deficiency in children. Please answer following questions related to these two tests (0.5 mark each): a. As per latest guidelines, what is role of these two tests in a child selected for GH investigations, whether they should be carried out before the GH stimulation tests or as a part of these stimulation tests? IGF-1 and IGF-BP3 are used for screening, diagnosis and treatment monitoring of cases with GHD. They should be carried out before GH stimulation tests. Abnormal results of IGF-1 &/or IGFBP-3 necessitate confirmation by GH stimulation test. In patients with IGF-1 and IGF-BP3 > 50th percentile, no need to carry out GH stimulation tests.   9/20/2018

Q. 16: b. Why both these tests are recommended and why either of them is not sufficient? There are certain limitations for IGF-1 and IGFBP-3 so use of both these tests is recommended. • IGF-1 is more sensitive for GHD as IGF-1 is also low in malnutrition, hypothyroidism, GHI, DM while IGFBP-3 level is more specific for GHD. But levels of IGFBP-3, though less dependent on nutrition and relatively stable, are also affected by sex steroids and thyroid hormones. • IGF-1 level is quite low early in life and normal range overlaps with that of GHD. • IGFBP-3 level is more discriminatory and better screening test for GHD in younger children. However as IGFBP-3 is also affected by sex steroids, IGF-1 is more useful in pubertal age. • Both IGF-1 and IGFBP-3 levels must be interpreted against age and gender specific reference intervals.   9/20/2018

Thank You and Best Of Luck