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Year 4 PAEDS > Growth, Endocrine and Metabolism 2 > Flashcards

Growth, Endocrine and Metabolism 2 Flashcards

1
Q

What is precocious puberty?

A

Early puberty
Girls (breast development) = <8yr
Boys (testicular enlargement) = <9yr

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2
Q

Is precocious puberty concerning?

A

Usually benign in girls

Concerning in boys, rarely idiopathic/usually has organic cause

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3
Q

What are two types of precocious puberty?

A

1) Central (true) = gonadotrophin-dependent

2) Peripheral (false) = gonadotrophin-independent

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4
Q

What is central precocious puberty?

A

Puberty begins as a result of early activation of the hypothalamic pituitary axis

Normal pubertal development follows

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5
Q

What are some causes of central precocious puberty?

A

Idiopathic - no cause found in 80% girls and 40% boys

CNS abnormalities:

  • Tumours eg gliomas, hCG-secreting germ cell tumours
  • CNS trauma or injury eg infection, radiation, surgery
  • Hamartomas of hypothalamus
  • Congenital disorders such as hydrocephalus and arachnoid cysts
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6
Q

What is peripheral precocious puberty?

A

Puberty begins as a result of excess sex-steroids (androgens, oestrogen, progesterone) which do not involve physiological gonadotrophin secretion from the pituitary = independent of HPG axis

Gonad matures without GnRH stimulation and levels of testosterone and estradiol are elevated whilst LH and FSH are surpassed =abnormal pubertal development follows

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7
Q

What are some causes of peripheral precocious puberty?

A

Endogenous

  • Congenital adrenal hyperplasia
  • Gonadal tumours
  • Germ cell tumours
  • Adrenal tumours

Exogenous
- Environmental exogenous hormones

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8
Q

How may precocious puberty present in females?

A
  • Thelarche (breast development) < 7 years
  • Pubarche (pubic hair) < 8 years
  • Menarche < 10 years
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9
Q

How may precocious puberty present in males?

A
  • Bilateral enlargement of testes - gonadotrophin release from intracranial lesion
  • Small testes - adrenal cause (e.g. adrenal tumour or hyperplasia)
  • Unilaterally enlarged testes - gonadal tumour
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10
Q

What are hamartomas?

A

Mostly benign, focal malformation that resembles a neoplasm of its tissue of origin

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11
Q

What is McCune-Albright syndrome (MAS)?

A

A genetic condition in which there is increased risk of multiple endocrinopathies:

  • Thyrotoxicosis
  • Cushing’s syndrome
  • Acromegaly
  • Hyperparathyroidism etc
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12
Q

What are some signs of MAS?

A

Café-au-lait spots
Pathological fractures due to fibrous dysplasia of bones
Recurrent ovarian cysts

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13
Q

What investigations are done for precocious puberty?

A

1) Sex steroids
- Early morning testosterone is higher in boys in early puberty
- Estradiol levels are less reliable marker for puberty in girls as they are very variable (very high = ovarian pathology)

2) Gonadrotrophins LH and FSH
- High in central causes
- Low in peripheral causes

3) TFTs
4) Adrenal steroid precurorors (17-OH) - If CAH suspected

5) HCG
- If hCG secreting tumour suspected

6) Imaging:
- Pelvic US
- MRI of brain
- Hand and wrist x-rays for bone age

7) GnRH stimulation test
- Flat response in gonadotrophin-independent puberty

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14
Q

What is the management of precocious puberty?

A

Reduce the rate of skeletal maturation - early growth spurt might be associated with early cessation of growth leading to a short stature

Address psychosocial problems associated with early onset puberty

GnRH agonists for all patients

Peripheral PP - sex hormone inhibitors e.g. medroxyprogesterone acetate, cyproterone acetate, testolactone, ketoconazole

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15
Q

How to GnRH agonists help in precocious puberty?

A

Over-stimulate the pituitary, causing desensitisation and thus less release of LH and FSH

Continued until the time for normal puberty arrives

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16
Q

How does testolactone work?

A

= aromatase inhibitor thus inhibits steroid biosynthesis

Used most commonly for MAS but also used in testotoxicosis

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17
Q

What is delayed puberty?

A

Absent or incomplete development of secondary sex characteristics by age of:

  • 14 in boys (testicular enlargement)
  • 13 in girls (breast development)
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18
Q

What is the most common cause of delayed puberty?

A

Constitutional delay in growth and puberty (CDGP) = A temporary delay in growth and onset of puberty that is not non-pathological

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19
Q

What are the possible causes of central delayed puberty ?

A

Intact axis:

  • CDPG = most common but must rule out other causes
  • Chronic illness eg Crohn’s
  • Malnutrition eg CF
  • Excessive physical exercise
  • Psychological deprivation
  • Steroid therapy
  • Hypothyroidism

Hypogonadism (impaired axis):

Low gonatrophin secretion (hypogonadotrophic hypogonadism)

  • Hypopituitarism
  • Idiopathic hypogonadotrophic hypogonadism
  • Hypothalamic-pituitary disorders - Prader-Willi, Kallmann syndrome

High gonadtrophin secretion (hypergonatrophic hypogonadism)

  • Chromosomal abnormalities - Klinefelters, Turners
  • Steroid hormone deficiencies
  • Acquired gonadal damage
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20
Q

What is Idiopathic hypogonadotrophic hypogonadism ?

A

Low gonadotrophin and sex steroid levels in the absence of abnormalities in hypothalamic-pituitary-gonadal system

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21
Q

What features may be seen in IHH?

A 
Cryptotorchordism
Micropenis
Synkinesia (mirror movements)
Cleft lip and palate
Dental agenesis
Skeletal anomalies
Hearing loss
 \+/- Loss of smell (Kallman's syndrome)
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22
Q

What are some causes of peripheral delayed puberty in boys?

A

Bilateral testicular damage eg torsion / mumps

Syndromes causing cryptorchidism or gonadal dysgensis eg Prader-Wili, Kallmann’s

Irradiation

Drugs eg cyclophosphamide

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23
Q

What are some causes of peripheral delayed puberty in girls?

A

Gonadal dysgenesis e.g. Turner’s syndrome

Irradiation

Drugs eg cyclophosphamide or busulfan (ovarian failure)

DSD eg CAH

PCOS

Toxic damage eg iron overload (thalassaemia) or galactosaemia

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24
Q

What investigations should be done for delayed puberty?

A

Usually not required as most are CDGP

Investigations for chronic disease:
FBC
Ferritin
Renal function tests 
U&Es
Coeliac screen 
Urinalysis
Investigations for disorders of gonadal axis:
Basal FSH/LH and estradiol/testosterone
TFTs
GNRH and GH
Pelvic USS
Bone age - wrist x ray
MRI/CT of pituitary
Chromosome analysis
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25
Q

What may LH and FSH be in CDGP and IHH? And gonadal failure?

A

Low in constitutional delay in growth and puberty and idiopathic hypogonadotrophic hypogonadism

Elevated in gonadal failure

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26
Q

What is the management of CDGP?

A

Not often necessary but short courses of sex steroid can help individuals catch up with peers

Boys: testosterone PO or depot injection for 3-6 months then reassess
- Usually rapid and effective

girls: gradually increasing oestrogen treatment, with cyclical progesterone once adequate oestrogen levels

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27
Q

What is given in primary testicular / ovarian failure?

A

Pubertal induction followed by ongoing hormone replacement

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28
Q

What is congenital hypothyroidism?

A

Lack of thyroid hormones present from birth, if not detected early = irreversible neuroligcal problems and poor growth

  • some develop after birth = primary hypothyroidism rather than CH
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29
Q

Is CH more common in boys or girls? And in which areas of the world?

A

2x more common in girls

Areas with iodine deficiency eg Bangladesh / China / Peru

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30
Q

What are some causes of CH?

A

1) Thyroid gland defects = 75%
- Not inherited so low chance of sibling affected

2) Disorders of thyroid metabolism = 10%
- Eg TSH unresponsiveness / defects in thyroglobulin structure
- Usually inherited

3) Hypothalamic or pituitary dysfunction = 5%
- Pituitary hypothyroidism usually occurs with other disorders of pituitary function if GH deficiency
- Hypothalamic causes include tumours, ischaemic damage etc

4) Transient hypothyroidism = 10%

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31
Q

What is transient hypothyroidism usually related to?

A

Maternal medications eg carbimazole or maternal antibodies

In maternal thyroid disease, IgG auto-antibodies can cross the placenta and block thyroid function in utero - this improves after delivery

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32
Q

What genetic defects have been associated with CH?

A

PAX8 - related to formation of kidney and thyroid gland

DUOX2 - related to production of thyroid hormones

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33
Q

Why are infants with CH usually clinically normal at birth?

A

Presence of maternal thyroid hormones

34
Q

What symptoms may an infant with CH present with? (4)

A

1) Feeding difficulties
2) Somnolence (sleepiness)
3) Low freq of crying
4) Constipation

35
Q

What signs may an infant with CH present with? (15)

A

1) Large fontanelles
2) Myxoedema
3) Nasal obstruction
4) Macroglossia
5) Low temp (<35) with cold and mottled skin on extremities
6) Jaundice = prolongation of physiological jaundice
7) Umbilical hernia
8) Hypotonia
9) Hoarse voice
10) Cardiomegaly
11) Bradycardia
12) Pericardial effusion - usually asymptomatic
13) Failure of fusion of distal femoral epiphyses
14) Refractory anaemia
15) Goitre = more common with thyroid hormone resistance and transient hypothyroidism

36
Q

What is the appearance of a child with hypothyroidism?

A 
Short stature
Hypertelorism
Depressed bridge of nose
Narrow palpebral fissures 
Swollen eyes
37
Q

What causes myxoedema in hypothyroidism?

A

Connective tissue reacts to increased TSH levels

38
Q

How is CH diagnosed?

A

All babies are screened at birth via heel pinprick and analysed for TSH and T4 (Guthrie)
- High TSH and low T4 confirm diagnosis

Thyroglobulin levels

Thyroid USS or radionuclide scanning

39
Q

What is included in the UK Newborn Screening Programme?

A

TSH and T4
Phenylketonuria
CF
Sickle cell disease

40
Q

What is the management of CH?

A

Aim = early detection and early thyroid hormone replacement to avoid irreversible neurological disability

Lifelong thyroxine replacement with L-thyroxine given once daily and titrated to TFTs
- Levothyroxine 10-15mcg/kg/day

Regular monitoring

Transient hypothyroidism does not need to be treated unless low T4 and raised TSH last >2 weeks
- Treatment for this is usually terminated after 3-5 months

41
Q

What monitoring is required in CH?

A

TFTs
Growth charts
Achievement of childhood milestones
Mental development in all 4 areas = fine motor, gross motor, speech and language, social

42
Q

What is the most common form of acquired childhood hypothyroidism?

A

Lymphocytic thyroiditis = Hashimoto’s autoimmune thyroiditis

43
Q

When does Hashimoto’s autoimmune thyroiditis usually present?

A

Adolescence

44
Q

In what condition are there a high incidence of Hashimoto’s autoimmune thyroiditis?

A

Turner syndrome

Down’s syndrome

45
Q

What are the signs of Hashimoto’s autoimmune thyroiditis?

A

Slowing of growth
+ other hypothyroid symptoms eg skin changes, cold intolerance

Delayed puberty (younger children may have galactorrhea or precocious puberty)

46
Q

What is a particular issue with adolescents with Hashimoto’s autoimmune thyroiditis?

A

Poor compliance in medication

47
Q

What are some causes of Hashimoto’s autoimmune thyroiditis?

A

Iatrogenic eg treatment of hyperthyroidism

Suppurative thyroiditis

Subacute non-supperative thyroiditis = de Quervain’s disease

48
Q

What are causes of painless and painful thyroiditis?

A

Painful = caused by radiation/infection/trauma

  • Suppurative thyroiditis
  • De Quervain’s disease

Painless = AI or medication
- Hashimotos

49
Q

How common is childhood obesity?

A

1/10 children aged 4-5yr

1/5 children aged 10-11yr

50
Q

What are some contributory factors for childhood obesity? (8)

A

1) Poor dietary habits
2) Lack of exercise
3) Sleep deprivation
4) Genetics
5) Lower socio-economic status
6) Medication

Also:

7) High birth weight or low birth weight associated with catch-up growth
8) Intrauterine exposure to maternal gestational DM or obesity

51
Q

What endocrine disorders may cause obesity? (8)

A

1) Hypothyroidism
2) Cushing’s syndrome
3) GH deficiency
4) Muscular dystrophy and other causes of immobility
5) OCIS
6) Hypothalamic damage
7) Spina bifida
8) Genetic conditions eg Prader-Willi

52
Q

What medications may aggravate weight gain?

A

Antidepressants - mirtazapine, paroxetine, imipramine

Anticonvulsants - sodium valporate, gabapentin, vigabatrin and carbamazepine

Antipsychotics - clozapine, olanzapine, pimozide

Lithium

Corticosteroids

53
Q

What are good measures of obesity in children?

A

BMI not as useful as does not consider age, gender, puberty, race/ethnicity

Gold standard = densitometry or dual-energy X-ray absorptiometry (DEXA) scanning

54
Q

What BMI centiles are:

1) Overweight
2) Obese
3) Severely obese

A

1) Overweight = >91st
2) Obese = >98th
3) Severely obese = >99.6th

55
Q

What are some complications of obesity in children?

A

1) T2DM
2) Breathing problems eg sleep apnoea
3) Orthopaedic conditions
4) Non-alcoholic fatty liver disease
5) Psychosocial morbidity
6) PCOS
7) Metabloc syndrome
8) Vit D and iron deficiency

56
Q

What is phenylketonuria (PKU)?

A

Most common inborn error of amino acid metabolism

Absent / virtually absent phenylalanine hydroxylase (PAH) enzyme activity

This enzyme converts dietary phenylalanine to tyrosine

Products of this pathway are important in formation of catecholamines, neurotransmitters and melanin

57
Q

What does high plasma concentrations of phenylalanine in PKU cause?

A

Formation of byproducts phenylpyruvic acid and phenylethylamine

Neurotoxic above a certain threshold

58
Q

How may PKU present?

A

Usually normal at birth but picked up on newborn baby heel-prick screen

1) Very fair with blue eyes (compared to family)
2) Musty / ‘mousey’ odour
3) Developmental delay and general learning disability
4) Recurrent vomitting
5) Eczematous skin eruptions and scleroderma-like skin lesions
6) Seizures

59
Q

What are the types of PKU?

A

Type I
Type II
Malignant

60
Q

How is type I PKU inherited? Which chromosome?

A

Autosomal recessive

Chr 12

61
Q

What is type II PKU?

A

5% enzyme activity retained - less serious

62
Q

What is malignant PKU?

A

Deficiency in enzymes co-factor THB

= more severe

63
Q

What investigations are done for PKU?

A

Heel-prick blood assayed for phenylalanine >12hrs after birth

Blood levels of phenylalanine

Phenylketones detected in urine

64
Q

How is PKU managed?

A

Diet:

  • Low penylalanine
  • High tyrosine

Avoid milk, dairy, fish, chicken, beans, eggs, nuts

Regular monitoring of blood phenylalanine and its metabolites

65
Q

What are some complications of PKU? (4)

A

1) Developmental delay / intellectual disability if non-adherence to diet
2) Epilepsy
3) Severe behavioural disturbance
4) Congenital anomaly and intellectual disability in offspring of PKU mothers

66
Q

What are the 3 main groups of short stature?

A

1) Primary growth disorders - condition intrinsic to growth plate
2) Secondary growth disorders - growth plate changes as a consequence of the condition
3) Idiopathic

67
Q

What is the causes the majority of short statures?

A

CDGP
Familial growth stature
Idiopathic

68
Q

What are some primary growth disorders? (3)

A

1) Genetic syndromes:
- Down’s syndrome
- Prader-Willi etc

2) IUGR with failure to catch up:
- Prematurity
- Placental dysfunction

3) Congenital bone disorders:
- Achondroplasia
- Hydrochondroplasia
- Osteogenesis imperfecta

69
Q

What are some secondary growth disorders? (7)

A

1) Endocrine:
- Hypothyroidism
- Cushings
- GH deficiency
- Precocious puberty

2) Metabolic
- Glycogen storage disease

3) DM poorly controlled

4) Chronic disease:
- CV
- Resp eg CF
- Haemoglobinopathies
- JA

5) Malnutrition:
- IBD
- Coeliac
- Rickets

6) Psychosocial deprivation
- Hyperphagic short stature syndrome

7) Medication
- Steroid therapy

70
Q

What is important to determine regarding height in a child with a short stature?

A

Determine if there is steady growth behind centiles (more likely to be constitutional or maturational delay)

or if there is a fall-off in growth across centiles (more likely to be chronic illness or acquired hypothyroidism)

71
Q

What is important to include on examination of a child with a short stature?

A

Height and weight
- inc sitting and standing height to consider skeletal disproportion eg achondroplasia

GH deficiency

  • Look for other features of pituitary deficiency eg hypogonadism
  • Or features of pituitary tumour eg bitemporal hemaniopia

Features of Cushing’s, CKD, hypothyroidism, fetal alcohol syndrome, Turner syndrome

Skeletal causes
- Eg rickets = craniotabes, bulbous wrists and bowing of extremeties

Skin lesions

  • Café-au-lait (McCune-Albright syndrome)
  • Large hemaniomas
72
Q

How is expected final height calculated?

A

Mid-parental height

73
Q

How is mid-parental height used to calculate expected height in boys?

A

Mid parental height =

(fathers height + (mothers height + 13)) /2

74
Q

How is mid-parental height used to calculate expected height in girls?

A

Mid parental height =

((fathers height - 13) + mothers height) /2

75
Q

What investigations should be done for short stature?

A

Bloods - FBC, renal function, LFTs, TFTs, ESR, CRP, urinalysis

Karyotyping

Specific tests eg CF

Bone age

Dental age

76
Q

What is bone age?

A

Predicts final adult height by estimating skeletal maturation from an assessment of the ossification of the epiphyseal centres

77
Q

How is bone age measured?

A

Radiograph L hand and wrist using standards from standards from Greulich-Pule atlas

78
Q

When is bone age considered delayed?

A

Two standard deviations below chronological age

79
Q

What is the management of short stature?

A

Depends on cause

Growth hormone = somatropin

Can be used in:

  • GH deficiency
  • Prader-Wili
  • CKD
  • SGA with subsequent growth failure at 4yrs or later
80
Q

What should be considered in hx of short stature?

A

FH
- Parental growth rate, early/late puberty/menarche

SH
- neglect

DH
- Steroids

+ BIND !!!!!

Birth history

  • Antenatal illness/drugs
  • Gestational age

Immunisations

Neonatal

  • Birthweight
  • Illnesses

Developmental
- Goals met/ delayed

81
Q

What should be plotted in short stature?

A

Height
Weight
Head circumference

= plot growth chart

Year 4 PAEDS (23 decks)

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