Paediatrics - Growth, puberty, endocrine (2) Flashcards
1
Q
What is the definition of short stature?
A
Height below the second centile (ie. two standard deviations below the mean)
2
Q
Height velocity is a sensitive indicator of what?
A
Growth failure
3
Q
How is height velocity calculated?
A
2 measurements at least 6 months but preferably a year apart = cm/year
4
Q
A height velocity of consistently below what centile is abnormal?
A
25th
5
Q
How is a child’s genetic target centile for height calculated?
A
Mean of father and mothers height + 7cm for boy and -7cm for girl.
The 9th-91st centile range of this estimate is given by +- 10cm for boys and +-8.5cm for girls
6
Q
What percentage of children born with severe IUGR remain short?
A
33%
7
Q
Give 6 causes of short stature in children
A
- Familial short stature or constitutional delay of growth and puberty
- IUGR
- Endocrine
- Nutritional/ chronic illness
- Psychosocial deprivation
- Chromosomal disorder/syndromes
8
Q
Give 3 endocrine causes of short stature in children
A
- Hypothyroidism (autoimmune thyroiditis during childhood)
- Growth hormone deficiency (can be secondary to hypopituitarism)
- Corticosteroid excess (Cushing’s syndrome)
9
Q
Where is IGF-1 produced?
A
Growth plate and in the liver
10
Q
Give two causes of growth hormone deficiency
A
- Craniopharyngioma
2. Laron syndrome
11
Q
How does a craniopharyngioma often present?
A
Bitemporal hemianopia
12
Q
What is Laron syndrome?
A
Defective growth hormone receptors = high levels of growth hormone and low levels of IGF-1.
13
Q
Give 3 examples of chronic illnesses that may result in short stature?
A
- Coeliac disease
- Crohn’s disease
- Chronic renal failure
14
Q
Give 4 examples of syndromes in which short-stature is seen.
A
- Down’s syndrome
- Turner’s syndrome
- Noonan syndrome
- Russell-Silver syndrome
15
Q
Deficiency of which gene on the X chromosome is thought to be linked to short stature and skeletal abnormality
A
SHOX
16
Q
How is growth hormone deficiency treated?
A
Biosynthetic growth hormone, given by subcutaneous injection daily
17
Q
Give two examples of syndromes or scenarios in which administering daily growth hormone is a treatment.
A
- Prader-Willi syndrome - improves muscle strength and body composition
- Turner’s syndrome -
- Chronic renal failure
- SHOX deficiency
- IUGR
18
Q
How do you calculate the ideal weight of children based upon their age?
A
(age+4) x 2 = weight (kg)
19
Q
Give the type of fluid that is typically prescribed to older children
A
0.9%NaCl + 5% glucose +-KCl
20
Q
Give the fluid requirements per kg for the first four days of life (per day)
A
Day 1 = 60ml/kg/day
Day 2 = 90ml/kg/day
Day 3 = 120ml/kg/day
Day 4 = 150ml/kg/day
21
Q
Give the electrolyte requirements per day of sodium, potassium and calcium in neonates
A
Na = 3mmol/kg/day K = 2mmol/kg/day Ca = 1mmol/kg/day
22
Q
Give maintenance fluids per day
A
First 10 kg = 100ml/kg/day
Second 10 kg = 50ml/kg/day
Over 20kg = 20ml/kg/day
23
Q
Give hourly maintenance fluids
A
First 10kg = 4ml/kg/hour
Second 10kg = 2ml/kg/hour
Over 20kg = 1ml/kg/hour
24
Q
Give 5 signs of a dehydrated infant
A
- Depressed fontanelle
- Cap refill 2-3 s
- Alert/tired
- Reduced urine output
- Dry lips/mucous membranes
25
How much extra fluid would you give on top of maintenance in a child that was clinically dehydrated? and over how long would you give it?
50ml/kg over 4 hours
26
How much extra fluid would you give on top of maintenance in a child that was shocked?
100ml/kg + BOLUS
27
What is the fluid bolus you'd give to a shocked child?
20ml/kg 0.9% NaCl
28
In what two cases would you not give a 20ml/kg 0.9%NaCl bolus to a shocked child and what would you give instead?
1. Trauma
2. Diabetic ketoacidosis
Instead give 10
29
What are the sodium requirements of an older child?
First 10kg - 2-4mmol/kg/day
Second 10kg 1-2mmol/kg/day
Every kg after 20 0.5-1mmol/kg/day
30
What are the potassium requirements of an older child?
First 10kg 1.5-2.5
Second 10kg 0.5-1.5
Every kg after that 0.2-0.7
31
Why is a 20ml/kg bolus in a child with diabetic ketoacidosis avoided?
Causes cerebral oedema
32
Preterm infants may have very low levels of what for the first few weeks of life?
T4 (thyroxine)
33
What endocrine problem is one of the few preventable causes of severe learning difficulties ?
Congenital hypothyroidism
34
Give four causes of congenital hypothyroidism
1. Maldescent of the thyroid and athyrosis
2. Dyshormonogenesis
3. Iodine deficiency
4. Hypothyroidism due to TSH deficiency
35
What is the commonest cause of sporadic congenital hypothyroidism?
Maldescent of the thyroid and athyrosis
36
Where does the thyroid migrate from in fetal life?
The base on the tongue (sublingual)
37
What cause of congenital hypothyroidism is the most common in ethnic groups with consanguineous marriage?
Dyshormonogenesis (an inborn error of thyroid hormone synthesis)
38
What is the commonest cause of congenital hypothyroidism worldwide? (But rare in UK?)
Iodine deficiency
39
How is congenital hypothyroidism caused by iodine deficiency prevented?
By iodination of salt in the diet
40
Give 5 clinical features of congenital hypothyroidism
1. FTT
2. Feeding probs
3. Prolonged jaundice
4. Constipation
5. Pale, cold, mottled dry skin
6. Large tongue
7. Goitre
8. Umbilical hernia
9. Delayed development
(LARGELY ASYMPTOMATIC AND PICKED UP ON SCREENING)
41
Give 5 clinical features of acquired hypothyroidism
1. Short stature or growth failure
2. Cold intolerance (cold peripheries)
3. Dry skin
4. Bradycardia
5. Thin, dry hair
6. Goitre
7. Constipation
8. Delayed puberty
9. Obesity
10. SUFE
11. Deterioration in school work/learning difficulties
42
Why is hypothyroidism due to TSH deficiency rare?
Usually associated with panhypopituitarism which usually manifests with growth hormone, gonadotrophine and ACTH deficiency leading to hypoglycaemia/ micropenis/ undescended testes before the hypothyroidism becomes a problem
43
What is the term used for the test which detects congenital hypothyroidism?
Guthrie test (routine neonatal screening), detects increased TSH in the blood
44
How is congenital hypothyroidism managed?
Treatment with thyroxine is started at 2-3 weeks of age and extends lifelong
45
What kind of congenital hypothyroidism will not be picked up by routine screening (Guthrie test)?
Thyroid disfunction secondary to pituitary abnormality because they will have a low TSH
46
What is the cause of juvenile hypothyroidism?
Autoimmune thyroiditis
47
What children are at an increased risk of juvenile hypothyroidism?
Children with Down's or Turner's
48
Give examples of other autoimmune illnesses seen in children with juvenile hypothyroidism
1. Vitiligo
2. RA
3. Diabetes mellitus
4. Addisons disease
49
Which gender is juvenile hypothyroidism more common in ?
Females
50
How is juvenile hypothyroidism treated?
Thyroxine
51
What is the most common cause of hyperthyroidism in children?
Graves disease (autoimmune thyroiditis) secondary to the production of thyroid stimulating immunoglobulins (TSI)
52
Give some clinical features of hyperthyroidism in children?
1. Increased appetite
2. Sweating
3. Diarrhoea
4. Weight loss
5. Rapid growth
6. Advanced bone marturity
7. Tachycardia, tremor, warm vasodilated peripheries
8. Learning difficulties/behaviour problems
9. Psychosis
53
What symptoms of hyperthyroidism commonly seen in adults are not generally seen in children?
Eye symptoms e.g. exopthalmos, opthalmoplegia, lid retraction, lid lag
54
What type of patient is hyperthyroidism commonly seen in?
Teenage girls
55
What markers are elevated or reduced in hyperthyroidism?
T3 and T4 elevated
TSH low
Antithyroid perioxisomal antibodies can be present but may cause hashitoxicosis (hypothyroidism)
56
What is the first line treatment of hyperthyroidism?
Carbimazole for 2 years
| B-blockers for symptomatic relief of tremor and anxiety and tachycardia
57
What is the risk with anti-thyroid medication?
Neutropenia
58
What advice should be given to parents of children starting anti-thyroid medication?
Seek help if sore throat and high fever occur starting treatment
59
What is the treatment of relapsed hyperthyroidism?
Subtotal thyroidectomy (or radioiodine treatment) and thyroxine replacement
60
What is the function of PTH?
Promotes bone formation via osteoblasts
When calcium low:
1. Promotes bone resorption via osteoclasts
2. Increases renal uptake of calcium
3. Activates metabolism of vit D to promote gut absorption of calcium
61
What are the electrolyte balances in hypoparathyroidism?
Low serum calcium
Raised serum phosphate
Normal alk phos
PTH low
62
Give a cause of hypocalcaemia in children
Hypoparathyroidism
63
What are the clinical features of severe hypocalcaemia?
1. Muscle spasm
2. Fits
3. Stridor
4. Diarrhoea
64
What is the main serious long term sequalae of hypocalcaemia in children?
Rickets
65
What is the main cause of hypoparathyroidism in an infant and in an older child?
Infant = DiGeorge syndrome (congenital deficiency)
| Older child = Autoimmune
66
Other than hypoparathyroidism give three clinical features of a child with DiGeorge syndrome?
1. Thymic aplasia --> defective immunity
2. Cardiac defects
3. Facial abnormalities
67
Hypoparathyroidism in older children can often be associated with which other autoimmune disease?
Addisons
68
A child presents with short stature, obesity, subcut nodules, short fourth metacarpals and learning difficulties.
Serum calcium and phosphate are abnormal but PTH levels are normal. What is the diagnosis?
Pseudohypoparathyroidism
69
What is the treatment for acute hypocalcaemia?
IV calcium gluconate (10%)
70
What is the treatment of chronic hypocalcaemia
Oral calcium and high doses of vit D analogues (promotes gut absorption of calcium)
!! Monitor hypercalcuria as it can cause nephrocalcinosis
71
What are the symptoms of hyperparathyroidism?
1. High calcium
2. Constipation
3. Anorexia
4. Lethargy
5. Behavioural effects
6. Polyuria
7. Polydipsia
8. Bony erosions of the phalanges can be seen on radiograph
72
Causes of hyperparathyroidism?
1. Neonates = rare genetic abnormalities
| 2. Older children = secondary to adenomas occurring spontaneously
73
Treatment of hypercalcaemia?
1. Rehydration
2. Diuretics
3. Bisphosphonates
74
What is the most common non-iatrogenic cause of insufficient cortisol and mineralocorticoid secretion?
Congenital adrenal hyperplasia (CAH)
75
What is the main cause of congenital adrenal hyperplasia and what enzyme is involved?
Autosomal recessive disorders of steroid production in adrenal gland (cortisol). 70-80% also cannot synthesise aldosterone.
21-hydroxylase deficiency (required for cortisol synthesis)
76
What are the zones of the adrenal gland and what do they secrete?
Zona glomerulosa - mineralocorticoids e.g. aldosterone
Zona fasciculata - glucorticoids e.g. cortisol
Zona reticularis - androgens e.g. testosterone and oestrogen
77
Aldosterone does what?
Reabsorbs sodium in the collecting duct and excretes potassium.
78
In CAH aldosterone is not produced. What is the effect on serum sodium and potassium?
Low sodium and high potassium and hypotension
79
What are the implications of CAH on the fetus (give implications for both males and females)
Males - enlarged penis and pigmented scrotum
| Females - clitoral hypertrophy and fusion of labia
80
Why does virilisation of external female genitalia and an enlarged penis in males occur in CAH?
Cortisol deficiency causes pituitary to secrete ACTH which causes overproduction of adrenal androgens.
81
What raised marker is often looked for in children suspected of having CAH?
17-a hydroxyprogesterone
82
What is the management of CAH?
Hydrocortisone (cortisol replacement) and fludrocortisone (aldosterone replacement)
Monitoring of bone age, growth and biochemistry. Genital surgery required
83
An adrenal crisis is often seen in males with Congenital Adrenal Hyperplasia between weeks 1-3 after birth. What are the presenting features?
1. Weight loss
2. Hypotonia
3. Circulatory collapse (hypotension)
4. Vomiting
Hypoglycaemia, hyponatraemia, hyperkalaemia
84
What are the biochemical abnormalities seen in a salt losing adrenal crisis?
Hypoglycaemia
Hyponatraemia
Hyperkalaemia
Metabolic acidosis
85
Management of a salt losing adrenal crisis?
IV:
1. Sodium chloride (saline)
2. Glucose
3. Hydrocortisone
86
What is the most common presenting factor in males and females with CAH?
1. Males - salt losing crisis
| 2. Females - virilisation of external genitalia
87
What is Addisons disease?
An autoimmune condition which causes primary adrenal insufficiency
88
What is the most common cause of Addisons disease?
Autoimmune. Can be associated with diabetes mellitus, hypothyroidism, hypoparathyroidism
89
Give a secondary cause of adrenal insufficiency
1. Pituitary dysfunction
| 2. Hypothalamic-pituitary-adrenal suppression following long term steroid therapy
90
Give 3 primary causes of adrenal insufficiency
1. Autoimmune
2. Haemorrhage/infarction
3. X-linked adrenoleucodystrophy
4. TB
91
How do infants with Addison's present?
Acutely with a salt losing adrenal crisis.
92
How do older children with Addisons present?
More chronically, with fatigue, pigmentation and postural hypotension.
93
Give 3 acute and 3 chronic features of adrenal insufficiency
Acute:
1. Hyponatraemia, hyperkalaemia, hypoglycaemia
2. Dehydration
3. Circulatory collapse (hypotension)
4. Growth failure
Chronic:
1. Vomiting
2. Lethargy
3. Brown pigmentation of gums, scars, skin creases
94
What is the test used to detect adrenal insufficiency (Addisons)?
Synacthen
95
How many times does the dose of hydrocortisone need to be increased by in times of illness or presurgery in children with Addisons
3
96
What are the three main causes of adrenal insufficiency
1. Withdrawal from long term steroids
2. CAH
3. Addisons
97
What is the main cause of glucorticoid excess in children?
Side-effect of a long term glucocorticoid treatment (IV or oral) for conditions such as nephrotic syndrome or asthma
98
What are the two main side effects of prolonged use of corticosteroids in high dosage?
1. Reduced adult height
| 2. Osteopenia
99
How are the unwanted side effects of corticosteroids reduced?
Take them in the morning on alternate days
100
Give 3 causes of glucocorticoid excess
1. Long term glucocorticoid treatment
2. Pituitary adenoma producing ACTH (CUSHINGS)
3. Ectopic ACTH producing tumour
101
Clinical features of a child with Cushing's syndrome?
1. Overweight (truncal obesity)
2. Short stature
3. Striae on abdo
4. Rounded face
5. Hypertension
6. DM
7. Osteoporosis and vertebral fractures
8. Skin thinning
8. Proximal myopathy
9. Facial plethora
10. Frequent infections
102
What is the treatment for Cushing's?
1. Transsphenoidal resection of pituitary adenoma
103
What is the test used to detect Cushing syndrome and what does the test show?
UFC (Urinary Free Cortisol)
High
Late night salivary cortisol (high)
Dexamethosone suppression tests - failure to show normal suppression
104
What is the most common cause of a disorder of sexual development? (DSD)
Congenital Adrenal Hyperplasia
105
What is another name for Trisomy 21
Down's syndrome
106
What is the most common autosomal trisomy?
Down's syndrome (21)
107
What is the incidence of Trisomy 21
1 in 650
108
Give 5 clinical features of a baby with Down's syndrome
1. Hypotonia
2. Flat occiput
3. Single palmar crease
4. Sandal gap
5. Incurved fifth finger
6. Small mouth and protruding tongue
7. Small ears
8. Third fontanelle
9. Flat nasal bridge
10. Upslanted palpebral fissures
11. Epicanthic folds
109
What is the major cause of early mortality in patients with Down's syndrome?
Congenital heart disease
110
What is the prevalence of CHD in Trisomy 21?
40%
111
Give three complications of Down's in the neonatal period that must be considered
1. CHD
2. Duodenal atresia
3. Hirschprung's disease (<1%)
112
Children with Trisomy 21 should be screened periodically for what 5 things?
1. Impairment of vision
2. Impairment of hearing
3. Coeliac disease
4. Hypothyroidism
5. Atlantoaxial instability
113
What is the cause of Trisomy 21?
Meiotic nondisjunction. One gamete has two chromosome 21's as they fail to separate at meiosis. When fertilised zygote has 3 chromosome 21s
114
All pregnant women are offered a screening test for Down's syndrome. What does the screening test look at?
1. Biochemical markers in blood samples
| 2. Nuchal thickening on ultrasound
115
If a fetus is thought to be at increased risk of Down's syndrome due to increased nuchal thickening, what test can then be done to assess the fetal karyotype?
Amniocentesis
116
What is the risk of recurrence of Down's syndrome in mothers who have previously had a down's syndrome child?
1 in 200 (if under 35)
117
Give 5 later potential co-morbidities in children with Downs
1. Delayed milestones
2. Learning difficulties
3. Short stature
4. Increased susceptibility to infection
5. Hearing impairment (caused by secretory otitis media) 75%
6. Visual impairments - myopia 50%, cataracts 15%
7. OSA (50-75%)
8. Hypothyroidism (15%)
9. Coeliac disease
10. Epilepsy
11. Early onset Alzheimers
118
What are the three cytogenetic causes of Downs?
1. Meiotic nondisjunction
2. Translocation
3. Mosaicism
119
Patau's syndrome is trisomy of what chromosome?
13
120
Edward's syndrome is trisomy of what chromosome?
18
121
What are the clinical features of a baby with Edwards syndrome?
1. Overlapping fingers
2. Prominent occiput
3. Rockerbottom feet
4. Low birthweight
5. Small mouth and chin
6. Cardiac and renal malformations
122
What are the clinical features of a baby with Patau syndrome?
1. Cleft lip and palate
2. Structural defect of brain
3. Scalp defects
4. Small eyes
5. Polydactyly
6. Cardiac and renal malformations
123
How are Edwards and Patau syndromes detected?
By ultrasound scan during second trimester
| Confirmed antenatally by amniocentesis and chromosome analysis
124
What is the karyotype of an individual with Turner's syndrome
45 X
125
What percentage of embryos with Turner's syndrome result in early miscarriages?
95%
126
What is the incidence of Turners?
1 in 2500 females
127
Give 5 clinical features of a patient with Turner's syndrome
1. Lymphoedema of hands and feet
2. Short stature
3. Webbed neck
4. Widely spaced nipples
5. Delayed puberty
6. Ovarian dysgenesis = infertility
7. Hypothyroidism
8. Renal anomalies
9. Recurrent otitis media
10. Congenital heart defects
11. Normal intellectual function
128
What is the congenital heart defect seen in Turner's syndrome?
Coarctation of the aorta
129
What is commonly the only abnormality seen in children with Turner's syndrome?
Short stature
130
What is the treatment of Turner's syndrome
1. Growth hormone therapy
| 2. Oestrogen replacement for development of secondary characteristics
131
What is the karyotype for Kleinefelter's syndrome
47 XXY
132
What is the incidence of Kleinefelter's syndrome
1-2/1000 males
133
Give an example of a syndrome that arises from a deletion of part of a chromosome.
Monosomy 5p - Cri-du-chat
or DiGeorge syndrome, Williams syndrome, velocardiofacial syndrome
134
Give an example of a disease arising from a duplication of a chromosome
Charcot-Marie-Tooth - partial trisomy of 17p
135
What is the technique used to detect deletions or duplications in genetic material?
FISH (Fluorescence in situ hybridisation)
136
Give the clinical features (5) of a child with Kleinefelter syndrome
1. Tall stature
2. Infertility
3. Hypogonadism with small testes
4. Gynaecomastia
5. Pubertal development normal
6. Normal intelligence
137
Give three reasons for a de novo mutation in an AD disease, which does not appear to affect either parent
1. New single point mutation in gamete e..g achondroplasia
2. Parental mosaicism - a parent can harbour a mutation in only some of their cells e.g. gonads
3. Non paternity
138
Give five examples of autosomal dominant disorders
1. Achondroplasia
2. Ehlers-Danlos
3. Huntington
4. Marfan
5. Neurofibromatosis
6. Osteogenesis imperfecta
7. Familial cholesterolaemia
8. Myotonic dystrophy
9. Noonan syndrome
10. Otosclerosis
11. Polyposis coli
12. Tuberous sclerosis
139
Give five examples of autosomal recessive disorders
1. CAH
2. Cystic fibrosis
3. Friedreich ataxia
4. Galactosaemia
5. Sickle cell
6. Thalassemia
7. Phenylketonuria
140
In X-linked recessive inheritance how are males and females affected?
Males affected
| Females carriers and are usually healthy
141
What chance does a son of a female carrier have of being affected by an X-linked recessive disease
1 in 2
142
What percentage of daughters from affected males with X linked recessive disorders will be carriers?
100%
143
Give 5 examples of X-linked recessive disorders
1. Colour blindness
2. Duchenne and Becker
3. Fragile X
4. Glucose-6-phosphate dehydrogenase deficiency
5. Haemophilia A and B
6. Hunter syndrome
144
Give 3 examples of diseases affected by trinucleotide repeat mutations.
1. Fragile X
2. Myotonic dystrophy
3. Huntingtons
145
How are inherited diseases affected by trinucleotide repeat mutations different to other inherited disorders?
The triplet repeat mutation is unstable and can expand between subsequent generations, meaning the conditions can become more severe in successive generations
146
Fragile X is a trinucleotide repeat X-linked inherited condition. Are males or females affected by the learning difficulties associated with the disease?
Males affected, 40-50% of females also affected (only in learning aspect)
147
What are the two most common genetic causes of severe learning disability?
1. Down's
| 2. Fragile X
148
Give the clinical features of males with fragile X syndrome
| 5
1. Moderate - severe learning disability
2. Macrocephaly
3. Macroorchidism
4. Characteristic facies
5. Mitral valve prolapse
6. Joint laxity
7. Scoliosis
8. Autism
9. Hyperactivity
149
What are the characteristic facies of a child with Fragile X
1. Long face
2. Large everted ears
3. Prominent mandible
4. Broad forehead
150
Clinical features of Prader-Willi syndrome?
1. Hypotonia
2. Developmental delay
3. Hyperphagia
4. Obesity
5. Neonatal feeding difficulty
6. Faltering growth in infancy
7. Hypogonadism
151
Which chromosome is affected in Prader-Willi syndrome?
15 q11-13
152
Which syndrome is affected by the same chromosomal region as Prader-Willi syndrome, if there is failure to insert a functioning maternal copy (therefore paternal imprinting) of this chromosomal region as opposed to a paternal copy?
Angelman syndrome
153
Clinical features of Angelman syndrome?
1. Severe cognitive impairment
2. Characteristic facial appearance
3. Ataxia
4. Epilepsy
154
Clinical features of Noonan syndrome?
1. Characteristic facies
2. Short webbed neck with trident hair line
3. Pectus excavatum
4. Short stature
5. Congenital heart disease (pulmonary stenosis, atrial septal defect)
6. Occasional mild learning difficulties
155
Inheritance of Noonan syndrome?
AD
156
Clinical features of Williams syndrome?
1. Short stature
2. Neonatal hypercalcaemia (transient)
3. CHD
4. Learning difficulty
157
Symptoms of congenital adrenal hyperplasia
Females
1. Enlargement of clitoris
2. Acne
3. Hirsuitism
4. Early onset of puberty and axillary hair
5. Ambiguous genitalia
Males
1. Ambiguous genitalia
2. Enlarged penis and pigmented scrotum
