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Growth, Endocrine and Metabolism 2 Flashcards

1
Q

What is precocious puberty?

A

Early puberty
Girls = <8yr
Boys = <9yr

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2
Q

Is precocious puberty concerning?

A

Usually benign in girls

Concerning in boys, rarely idiopathic

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3
Q

What are two types of precocious puberty?

A

1) Central (true) = gonadotrophin-dependent

2) Peripheral = gonadotrophin-independent

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4
Q

What is central precocious puberty?

A

Puberty beings 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

1) Congenital adrenal hyperplasia (CAH)
2) Tumours
3) McCune-Albright syndrome
4) Silver-Russell syndrome
5) Testotoxicosis
6) Exogenous oestrogen or androgen exposure (therapeutic or accidental)

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8
Q

How may precocious puberty present in females?

A

1) Isolated pubic hair (pubarche)

2) Premature breast development (thelarche)

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9
Q

How may precocious puberty present in males?

A

Bilateral enlarged tests = gonadotrophin release

Unilateral enlarged tests = suggest gonadal tumour

Premature pubarche

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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 an arachnoid cyst?

A

CSF covered by arachnoidal cells and collaged that can develop between the surface of the brain and the cranial base, or on the arachnoid membrane (middle meningeal layer)

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12
Q

What tumours may cause peripheral precocious puberty?

A

hCG-secreting tumours:
- Liver = hepatomas / hepatoblastomas

  • Choriocarcinomas of gonad, pineal gland, mediastinum
  • Adrenal tumours (rare)

Ovarian tumours may cause masculinisation or feminisation

Testicular Leydig-cell tumours can cause early virilisation in men

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13
Q

What is McCune-Albright syndrome (MAS)?

A

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

  • Thyrodoxicosis
  • Cushing’s syndrome
  • Acromegaly
  • Hyperparathyroidism etc
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14
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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15
Q

What is testotoxicosis?

A

= Familial male precocious puberty

Autosomal dominant condition characterised by progressive pubertal changes, rapid physical growth, skeletal maturation and sexually aggressive behaviour in the first 2-3yrs of life

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16
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 FESH
- Random LH useful for CPP
- Random FSH will not distinguish prepuberty from puberty

3) TFTs

4) Adrenal steroid precurorors
- If CAH suspected

5) HCG
- If hCG secreting tumour suspected

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

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

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17
Q

What is the management of precocious puberty?

A

No management required for central

Surgical resection of tumours (will not regress pubertal changes)

GnRH agonists

Testolactone

Tamixofen in MAS

Ketoconazole (eg in testotoxicosis) inhibits steroid biosynthesis

Cyproterone acetate + flutamide = anti-androgen

Medroxyprogesterone = progesterone analogo

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18
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

Used in CPPP, MAS, testotoxicosis

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19
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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20
Q

What is delayed puberty?

A

Boys:
- Absence of testicular development (or a testicular volume lower than 4ml) by 14yr

Girls:
- Absence of breast development by 13yr, or primary amenorrhoea with normal breast development by age 15yr

= Most have simple constitutional delay in growth and puberty (CDGP and do not need investigation)

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21
Q

Is CDGP more common in boys or girls?

A

Boys

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22
Q

What are some causes of central delayed puberty (relating to hypothalamo-pituitary axis)?

A

Intact axis:

1) CDPG = most common but must rule out other causes
2) Chronic illness eg Crohn’s
3) Malnutrition eg CF
5) Excessive physical exercise
5) Psychological deprivation
6) Steroid therapy
7) Hypothyroidism

Impaired axis:

8) Tumours adjacent to axis eg pituitary tumour
9) Congenital abnormalities eg congenital panhypopituitarism
10) Irradiation treatment
11) Trauma
12) IHH

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23
Q

What is IHH?

A

Idiopathic hypogonadotropic hypogonadism

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

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24
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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25
What are some causes of peripheral delayed puberty in boys?
Bilateral testicular damage eg torsion / mumps Syndromes causing cryptorchidism or gonadal dysgensis eg Prader-Wili Irradiation Drugs eg cyclophosphamide
26
What are some causes of peripheral delayed puberty in girls?
Gonadal dysgenesis eg Turner Irradiation Drugs eg cyclophosphamide or busulfan (ovarian failure) DSD eg CAH PCOS Toxic damage eg iron overload (thalassaemia) or galactosaemia
27
What investigations should be done for delayed puberty?
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: Chromosome analysis Basal FSH/LH and estradiol/testosterone TFTs GNRH and GH Pelvic USS Bone age - wrist x ray MRI/CT of pituitary ```
28
What may LH and FHSH be in CDGP and IHH? And gonadal failure?
Low in CDGP and IHH Elevated in gonadal failure
29
What is the management of CDGP?
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
30
What is given in primary testicular / ovarian failure?
Pubertal induction followed by ongoing hormone replacement
31
What is congenital hypothyroidism?
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
32
Is CH more common in boys or girls?
2x more common in girls
33
Where is CH more common?
Areas with iodine deficiency eg Bangladesh / China / Peru
34
What are some causes of CH?
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%
35
What is transient hypothyroidism usually related to?
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
36
What genetic defects have been associated with CH?
PAX8 - related to formation of kidney and thyroid gland DUOX2 - related to production of thyroid hormones
37
Why are infants with CH usually clinically normal at birth?
Presence of maternal thyroid hormones
38
What symptoms may an infant with CH present with? (4)
1) Feeding difficulties 2) Somnolence (sleepiness) 3) Low freq of crying 4) Constipation
39
What signs may an infant with CH present with? (15)
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
40
What is the appearance of a child with hypothyroidism?
``` Short stature Hypertelorism Depressed bridge of nose Narrow palpebral fissures Swollen eyes ```
41
What causes myxoedema in hypothyroidism?
Connective tissue reacts to increased TSH levels
42
How is CH diagnosed?
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
43
What is included in the UK Newborn Screening Programme?
TSH and T4 Phenylketonuria CF Sickle cell disease
44
What is the management of CH?
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
45
What monitoring is required in CH?
TFTs Growth charts Achievement of childhood milestones Mental development in all 4 areas = fine motor, gross motor, speech and language, social
46
What is the most common form of acquired childhood hypothyroidism?
Lymphocytic thyroiditis = Hashimoto's autoimmune thyroiditis
47
When does Hashimoto's autoimmune thyroiditis usually present?
Adolescence
48
In what condition are there a high incidence of Hashimoto's autoimmune thyroiditis?
Turner syndrome | Down's syndrome
49
What are the signs of Hashimoto's autoimmune thyroiditis?
Slowing of growth + other hypothyroid symptoms eg skin changes, cold intolerance Delayed puberty (younger children may have galactorrhea or precocious puberty)
50
What is a particular issue with adolescents with Hashimoto's autoimmune thyroiditis?
Poor compliance in medication
51
What are some causes of Hashimoto's autoimmune thyroiditis?
Iatrogenic eg treatment of hyperthyroidism Suppurative thyroiditis Subacute non-supperative thyroiditis = de Quervain's disease
52
What are causes of painless and painful thyroiditis?
Painful = caused by radiation/infection/trauma - Suppurative thyroiditis - De Quervain's disease Painless = AI or medication - Hashimotos
53
How common is childhood obesity?
1/10 children aged 4-5yr | 1/5 children aged 10-11yr
54
What are some contributory factors for childhood obesity? (8)
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
55
What endocrine disorders may cause obesity? (8)
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
56
What medications may aggravate weight gain?
Antidepressants - mirtazapine, paroxetine, imipramine Anticonvulsants - sodium valporate, gabapentin, vigabatrin and carbamazepine Antipsychotics - clozapine, olanzapine, pimozide Lithium Corticosteroids
57
What are good measures of obesity in children?
BMI not as useful as does not consider age, gender, puberty, race/ethnicity Gold standard = densitometry or dual-energy X-ray absorptiometry (DEXA) scanning
58
What BMI centiles are: 1) Overweight 2) Obese 3) Severely obese
1) Overweight = >91st 2) Obese = >98th 3) Severely obese = >99.6th
59
What are some complications of obesity in children?
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
60
What is phenylketonuria (PKU)?
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
61
What does high plasma concentrations of phenylalanine in PKU cause?
Formation of byproducts phenylpyruvic acid and phenylethylamine Neurotoxic above a certain threshold
62
How may PKU present?
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
63
What are the types of PKU?
Type I Type II Malignant
64
How is type I PKU inherited? Which chromosome?
Autosomal recessive Chr 12
65
What is type II PKU?
5% enzyme activity retained - less serious
66
What is malignant PKU?
Deficiency in enzymes co-factor THB = more severe
67
What investigations are done for PKU?
Heel-prick blood assayed for phenylalanine >12hrs after birth Blood levels of phenylalanine Phenylketones detected in urine
68
How is PKU managed?
Diet: - Low penylalanine - High tyrosine Avoid milk, dairy, fish, chicken, beans, eggs, nuts Regular monitoring of blood phenylalanine and its metabolites
69
What are some complications of PKU? (4)
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
70
What are the 3 main groups of short stature?
1) Primary growth disorders - condition intrinsic to growth plate 2) Secondary growth disorders - growth plate changes as a consequence of the condition 3) Idiopathic
71
What is the causes the majority of short statures?
CDGP Familial growth stature Idiopathic
72
What are some primary growth disorders? (3)
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
73
What are some secondary growth disorders? (7)
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
74
What is important to determine regarding height in a child with a short stature?
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)
75
What is important to include on examination of a child with a short stature?
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
76
How is expected final height calculated?
Mid-parental height
77
How is mid-parental height used to calculate expected height in boys?
Mid parental height = (fathers height + (mothers height + 13)) /2
78
How is mid-parental height used to calculate expected height in girls?
Mid parental height = ((fathers height - 13) + mothers height) /2
79
What investigations should be done for short stature?
Bloods - FBC, renal function, LFTs, TFTs, ESR, CRP, urinalysis Karyotyping Specific tests eg CF Bone age Dental age
80
What is bone age?
Predicts final adult height by estimating skeletal maturation from an assessment of the ossification of the epiphyseal centres
81
How is bone age measured?
Radiograph L hand and wrist using standards from standards from Greulich-Pule atlas
82
When is bone age considered delayed?
Two standard deviations below chronological age
83
What is the management of short stature?
Depends on cause Growth hormone = somatropin Can be used in: - GH deficiency - Prader-Wili - CKD - SGA with subsequent growth failure at 4yrs or later
84
What should be considered in hx of short stature?
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
85
What should be plotted in short stature?
Height Weight Head circumference = plot growth chart

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