Download Thyroid Diseases

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Common Thyroid Disorders in
Children
Dr Sarar Mohamed
FRCPCH (UK), MRCP (UK), CCST (Ire), CPT (Ire),
DCH (Ire), MD
Consultant Paediatric Endocrinologist & Metabolic Physician
Associate Professor of Pediatrics
King Saud University
Agenda
• Thyroid Function Test
• Congenital Hypothyroidism
coommon in peds.
• Newborn screening for congenital
hypothyroidism
• Acquired hypothyroidism e.g.
hashimoto thyroditis.
• Hyperthyroidism
• Causes of goiter
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Thyroid Function: blood tests
TSH
mU/L
Free T4 (thyroxine)
pM
Free T3 (triiodothyronine)
0.4 –5.0
9.1 – 23.8
2.23-5.3 pM
The main tests to be done is TSH and free T4
Dysfunction Thyroid Gland
1. Too little thyroxin – hypothyroidism
a. short stature (acquired), developmental delay
(congenital)
2. Too much thyroxin – hyperthyroidism
a. Agitation, irritability, & weight loss
Goiter is common in children with hypo/hyperthyroidsim due to
both congenital and acquired diseases.
Hypothyroidism
• Decreased thyroid hormone levels
• Low T4
• Possibly Low T3 too.
• Raised TSH (unless pituitary problem!)
Causes of hypothyroidism
1. Congenital
2. Autoimmune (Hashimoto)
1st two are the main causes.
1. Iodine deficiency
2. Subacute thyroiditis usually viral infection.
3. Drugs (amiodarone)
4. Irradiation
5. Thyroid surgery
6. Central hypothyroidism (radiotherapy, surgery, tumor)
secondary to any pituitary disease.
7. Any disease of the pituitary can lead to hypothyroidism.
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Clinical features of Acquired hypothyroidism
1. Weight gain
2. Goitre
3. Short stature: any child with short stature should be
worked up for hypothyrodism because it responds
dramatically to thyroxin)
4. Fatigue
5. Constipation
6. Dry skin
7. Cold Intolerance
8. Hoarseness
9. Sinus Bradycardia
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Hypothyroidism with short stature
Diagnosis
• High TSH, low T4
• Thyroid antibodies
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Hashimoto’s Disease
• Most common cause of acquired hypothyroidism
• Autoimmune lymphocytic thyroiditis
• Antithyroid antibodies:
• Thyroglobulin Ab
• Microsomal Ab
• TSH-R Ab (block)
• Females > Males
• Runs in Families!
Subacute (de Quervain’s) Thyroiditis
•
•
•
•
Preceding viral infection
Infiltration of the gland with granulomas
Painful goitre
Hyperthyroid phase  Hypothyroid phase
Treatment of Hypothyroidism
•
•
•
•
Replacement of thyroid hormone medication: Thyroxine
Daily thyroxine with follow up with thyroid function test.
If congenital, treatment is needed for life.
In acquired, you may stop the treatment when thyroid function
test is back to normal but 50% will require treatment for life.
Congenital Hypothyroid
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Incidence 1:3000 – 4000 (more than PKU).
Female:Male is 2:1.
Almost all affected newborns have no S/S at birth
because maternal thyroxine crosses the placenta;
therefore, signs and symptoms will only appear if the
mother has hypothyroid too.
Because of that, we do not rely on clinical assessment
and need to do biochemical testing.
.
Facts
Mother
supplies T4
to fetus via
placenta
Normal Newborn
Mother
Fetus
Immature
Hypothalamic
Pituitary
Thyroid Axis
T4
Mid-Gestation
T4
Euthyroid
Mother
Mature
Hypothalamic
Pituitary
Thyroid Axis
Pregnancy
Congenital Hypothyroidism: Causes
1. Agenesis or dysgenesis of thyroid gland
2. Dyshormonogenesis (structurally normal, but function is
affected)
3. Ectopic gland
4. Maternal hypothyroidism
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Clinical Features of Congenital Hypothyroidism
non-specific signs and symptoms
Finding
%
Lethargy
96%
Constipation
92%
Feeding problems
83%
Respiratory problems
76%
Dry skin
76%
Thick tongue
67%
Hoarse cry
67%
Umbilical hernia
67%
Prolonged jaundice
12%
Goiter
8%
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Newborn Screening
Course facial feature and big tongue are
classical for hypothyrodism
Any newborn with jaundice must rule
out hypothyrodism by checking TFT
In neonates the most common cause is
congenital but in later ages hoshimoto is
more common.
Babies present early with non-specific
signs and symptoms.
Congenital Hypothyroidism
suspect
X
Clinical
Biochemical (screening)
Optional
Confirm
Lab ( TSH & FT4 )
T scan
B age
Rx & FU
Thyroxine
Growth & D
TSH & FT4
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Newborn Screening
Definitions
Every new born baby has hypothyroidism until proven otherwise,
which is tested by umbilical cord sampling (showing high TSH and
low T4). The treatment is usually thyroxine for life.
Screening: search for a disease in a large unselected
population
PKU
Congenital hypothyroidism
Method: If umbilical cord blood TSH is high then you should do
thyroid function test and other imaging studies if necessary
Principal of newborn screening
• Aim is to identify affected infants before
development of clinical signs
• Objective : Eradication of MR (mental
retardation) secondary to CH (congenital
hypothyroidism).
• The earlier dx the better IQ
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Screening Technique
• cord blood TSH at birth
•
blood spot in a filter paper obtained by heel prick
for TSH /T4 at 3- 5 days (because thyroxine
reaches a rise in these days) to check peripheral
blood. The test is called “Guthrie” test.
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Newborn Screening
Clinical Outcome (the outcome is worse if the
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mother has hypothyroidism).
• Pre-screening data:
– Mean IQ = 76
• Post-screening data:
– Children screened & treated by age 25 days
• Mean IQ = 104
Age of Diagnosis
% with IQ > 85
3 months
78%
6 months
19%
> 7 months
0%
Newborn Screening
> screening
< screening
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Congenital Hypothyroidism
Newborn Screening
• In the congenital cause of hypothyroidism,
some babies do not have the symptoms
because they get the thyroxine from the
mother in the first and half of the second
trimester and so there is no diseases
manifestation.
• If the child presents with symptoms, this
means that the mother is hypothyroid and
that is difficult to treat.
Newborn Screening
• Follow-up (TSH) should be done every 2 months for the first
year because it takes 2 months to reflect the change in TSH,
then every 6 months with growth assessment every 3-6 months.
• If TSH is elevated increase the dose of thyroxine.
Hyperthyroidism
• Increased thyroid hormone levels
• High T4 +/- High T3
• Low (suppressed) TSH
Causes of hyperthyroidism
• Graves Disease most common where they present
very similarly to adults.
• Overtreatment with thyroxin; therefore, close
monitoring of dosage in hypothyroidism.
• Thyroid adenoma (rare)
• Transient neonatal thyrotoxicosis: when the mother
has graves disease her antibodies might cross the
placenta and stimulate the thyroid function but at the
age of 4-6 months it disappears alone without
treatment.
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Graves’ Disease
• Most common cause of hyperthyroidism
• TSH-R antibody (stimulating)
• Main presentation: Goitre, proptosis
Hyperthyroidism S&S
•
•
•
•
•
•
•
•
•
•
•
Heat intolerance
Hyperactivity, irritability
Weight loss (normal to increased appetite)
diarrhea
Tremor, Palpitations
Diaphoresis (sweating)
Lid retraction & Lid Lag (thyroid stare)
Proptosis
Menstrual irregularity
Goitre
Tachcardia
Neonatal hyperthyroidism born to mother
with Graves’ disease
A Color Atlas of Endocrinology p51
Grave’s ophthalmopathy
Hyperthyroid Eye Disease
Investigations
• TSH, free T3&T4
• Thyroid antibodies (TSH receptors antibodies)
• Radionucleotide thyroid scan (incease uptake)
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Hyperthyroidism
• Treatment
– Beta-blockers
– Carbimazole is the most commonly used drug in
children
– PTU (propylthiouracil) is avoided because it
causes liver failure (commonest cause) and
requires LFT follow up. Usually used in
adolescents. If medical treatment fails we start
radioactive iodine if it fails surgery is last line.
– Radioactive iodine (in adults); enough to keep the
person on thyroxine for life.
– Surgery (rare)
Radioactive therapy and surgery are usually avoided
in children and only used in case medical therapy
Quiz
•
What is the obvious
abnormality of this 14 years old
girl?
•
What are the most likely
causes?
• How do you investigate? You
1. TSH T3 T4 if results are
abnormal you do 2.nuclear
scan you can also measure
immunoglobulin
3. Routine ultrasound or U/S
radioisotope to check gland
function
• How do you treat?depends on
the cause if hypothyroid give
thyroxin if hyperthyroid give
antithyroid.
Causes of goiter
• Physiological (puberty) is the commonest in adolescents its an
euthyroid state, you don’t treat it and it resolves by itself.
• Secondary to Iodine deficiency (fourth commonest cause)
• Hashimoto thyroiditis (hypothyroidism is the second commonest
cause)
• Graves disease (3rd commonest cause)
• Tumor (very rare)
• Congenital (maternal antithyroid drugs, maternal
hyperthyroidism, dyshormonogenesis)
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Quiz


16 year 7 month
Growth failure x 1 1/2 years
Labs:
TSH:
T4:
1008 µIU/ ml
<1.0 µg/dl
(0.3-5.0)
(4-12)
Antithyro Ab.
A-perox Ab.
232 U/ml
592 IU/ml
(0-1)
(<0.3)
Prolactin:
29 ng/ml
(2-18)
patient asked about prognosis what you tell?
41
In hashimoto 50 % will respond to thyroxin
treatment and normalize by 5-10 years and
50% will relapse.
Newborn Screening