THYROID%20DISORDERS - PowerPoint PPT Presentation

About This Presentation
Title:

THYROID%20DISORDERS

Description:

Title: HYPOTHYROIDISM Author: Dr. elamin Last modified by: Eugene Shubnikov Created Date: 10/3/2000 7:05:18 PM Document presentation format: 35mm Slides – PowerPoint PPT presentation

Number of Views:172
Avg rating:3.0/5.0
Slides: 40
Provided by: Dr231995
Learn more at: http://www.bibalex.org
Category:

less

Transcript and Presenter's Notes

Title: THYROID%20DISORDERS


1
THYROID DISORDERS
  • Abdelaziz Elamin. MD, PhD, FRCPCH
  • Professor of Child Health
  • Consultant Pediatric Endocrinologist
  • Sultan Qaboos University, Oman

2
HYPOTHYROIDISM-EPIDEMIOLOGY
  • Neonatal screening reveals incidence that varies
    between 1-5/1000 live births
  • The most common cause of preventable mental
    retardation in children
  • Both acquired congenital forms are linked to
    iodine deficiency
  • Diagnosis is easy early treatment is beneficial

3
ETIOLOGY
  • CONGENITAL
  • Hypoplasia mal-descent
  • Familial enzyme defects
  • Iodine deficiency (endemic cretinism)
  • Intake of goitrogens during pregnancy
  • Pituitary defects
  • Idiopathic

4
ETIOLOGY /2
  • ACQUIRED
  • Iodine deficiency
  • Auto-immune thyroiditis
  • Thyroidectomy or RAI therapy
  • TSH or TRH deficiency
  • Medications (iodide Cobalt)
  • Idiopathic

5
KILPATRIK GRADING OF GOITRE
  • Grade 0 Not visible neck extended Not
    palpable
  • Grade 1 Not visible, but palpable
  • Grade 2 Visible only when neck is
    extended on swallowing,
  • Grade 3 Visible in all positions
  • Grade 4 Large goiter

6
THYROID GLAND
  • Derived from pharyngeal endoderm at 4/40
  • Migrate from base of the tongue to cover the 23
    tracheal rings.
  • Blood supply from ext. carotid subclavian and
    blood flow is twice renal blood flow/g tissue.
  • Starts producing thyroxin at 14/40.

7
OVERVIEW (2)
  • Maternal fetal glands are independent with
    little transplacental transfer of T4.
  • TSH doesnt cross the placenta.
  • Fetal brain converts T4 to T3 efficiently.
  • Average intake of iodine is 500 mg/day. 70 of
    this is trapped by the gland against a
    concentration gradient up to 6001

8
THYROID HORMONES
  • Iodine tyrosine form both T3 T4 under TSH
    stimulation. However, 10 of T4 production is
    autonomous and is present in patients with
    central hypothyroidism.
  • When released into circulation T4 binds to
  • Globulin TBG 75
  • Prealbumin TBPA 20
  • Albumin TBA 5

9
THYROID HORMONES (2)
  • Less than 1 of T4 T3 is free in plasma.
  • T4 is deiodinated in the tissues to either T3
    (active) or reverse T3 (inactive).
  • At birth T4 level approximates maternal level but
    increases rapidly during the first week of life.
  • High TSH in the first 5 days of life can give
    false positive neonatal screening

10
TSH
  • Is a Glico-protein with Molecular Wt of 28000
  • Secreted by the anterior pituitary under
    influence of TRH
  • It stimulates iodine trapping, oxidation,
    organification, coupling and proteolysis of T4
    T3
  • It also has trophic effect on thyroid gland

11
TSH (2)
  • T4 T3 are feed-back regulators of TSH
  • TSH is stimulated by a-adrenergic agonists
  • TSH secretion is inhibited by
  • Dopamine
  • Bromocreptine
  • Somatostatin
  • Corticosteroids

12
THYROID HORMONES (3)
  • Conversion of T4 to T3 is decreased by
  • Acute chronic illnesses
  • b-adrenergic receptor blockers
  • Starvation severe PEM
  • Corticosteroids
  • Propylthiouracil
  • High iodine intake (Wolff-Chaikoff effect)

13
THYROXINE (T4)
  • Total T4 level is decreased in
  • Premature infants
  • Hypopituitarism
  • Nephrotic syndrome
  • Liver cirrhosis
  • PEM
  • Protein losing entropathy

14
THYROXINE (2)
  • Total T4 is decreased when the following drugs
    are used
  • Steroids
  • Phenytoin
  • Salicylates
  • Sulfonamides
  • Testosterone
  • Maternal TBII

15
THYROXINE (3)
  • Total T4 is increased with
  • Acute thyroiditis
  • Acute hepatitis
  • Estrogen therapy
  • Clofibrate
  • iodides
  • Pregnancy
  • Maternal TSI

16
FUNCTIONS OF THYROXINE
  • Thyroid hormones are essential for
  • Linear growth pubertal development
  • Normal brain development function
  • Energy production
  • Calcium mobilization from bone
  • Increasing sensitivity of b-adrenergic receptors
    to catecholeamines

17
CLINICAL FEATURES
  • Gestational age gt 42 weeks
  • Birth weight gt 4 kg
  • Open posterior fontanel
  • Nasal stuffiness discharge
  • Macroglossia
  • Constipation abdominal distension
  • Feeding problems vomiting

18
CLINICAL FEATURES (2)
  • Non pitting edema of lower limbs feet
  • Coarse features
  • Umbilical hernia
  • Hoarseness of voice
  • Anemia
  • Decreased physical activity
  • Prolonged (gt2/52) neonatal jaundice

19
CLINICAL FEATURES (3)
  • Dry, pale mottled skin
  • Low hair line dry, scanty hair
  • Hypothermia peripheral cyanosis
  • Hypercarotenemia
  • Growth failure
  • Retarded bone age
  • Stumpy fingers broad hands

20
CLINICAL FEATURES (5)
  • Skeletal abnormalities
  • Infantile proportions
  • Hip knee flexion
  • Exaggerated lumbar lordosis
  • Delayed teeth eruption
  • Under developed mandible
  • Delayed closure of anterior fontanel

21
OCCASIONAL FEATURES
  • Overt obesity
  • Myopathy rheumatic pains
  • Speech disorder
  • Impaired night vision
  • Sleep apnea (central obstructive)
  • Anasarca
  • Achlorhydria low intrinsic factor

22
OCCASIONAL FEATURES (2)
  • Decreased bone turnover
  • Decreased VIII, IX platelets adhesion
  • Decreased GFR hyponatremia
  • Hypertension
  • Increased levels of CK, LDH AST
  • Abnormal EEG high CSF protein
  • Psychiatric manifestations

23
ASSOCIATIONS
  • Autoimmune diseases (Diabetes Mellitus)
  • Cardiomyopathy CHD
  • Galactorrhoea
  • Muscular dystrophy pseudohypertrophy
    (Kocher-Debre-Semelaigne)

24
GOITROGENS
  • DRUGS
  • Anti-thyroid
  • Cough medicines
  • Sulfonamides
  • Lithium
  • Phenylbutazone
  • PAS
  • Oral hypoglycemic agents

25
GOITROGENS
  • FOOD
  • Soybeans
  • Millet
  • Cassava
  • Cabbage

26
CLINICAL FEATURES (4)
  • Neurological manifestations
  • Hypotonia later spasticity
  • Lethargy
  • Ataxia
  • Deafness Mutism
  • Mental retardation
  • Slow relaxation of deep tendon jerks

27
CONGENITAL HYPOTHYRODISM
  • Primary thyroid defect usually associated with
    goiter.
  • Secondary to hypothalamic or pituitary lesions
    not associated with goiter.
  • 2 distinct types of presentation
  • Neurological with MR-deafness ataxia
  • Myxodematous with dwarfism dysmorphism

28
DIAGNOSIS
  • Early detection by neonatal screening
  • High index of suspicion in all infants with
    increased risk
  • Overt clinical presentation
  • Confirm diagnosis by appropriate lab and
    radiological tests

29
LABROTARY FINDINGS
  • Low (T4, RI uptake T3 resin uptake)
  • High TSH in primary hypothyroidism
  • High serum cholesterol carotene levels
  • Anaemia (normo, micro or macrocytic)
  • High urinary creatinine/hydroxyproline ratio
  • CXR cardiomegaly
  • ECG low voltage bradycardia

30
IMAGING TESTS
  • X-ray films can show
  • Delayed bone age or epiphyseal dysgenesis
  • Anterior peaking of vertebrae
  • Coxavara coxa plana
  • Thyroid radio-isotope scan
  • Thyroid ultrasound
  • CT or MRI

31
TREATMENT (2)
  • L-Thyroxin is the drug of choice. Start with
    small dose to avoid cardiac strain.
  • Dose is 10 mg/kg/day in infancy. In older
    children start with 25 mg/day and increase by 25
    mg every 2 weeks till required dose.
  • Monitor clinical progress hormones level

32
TREATMENT
  • Life-long replacement therapy
  • 5 types of preparations are available
  • L-thyroxin (T4)
  • Triiodothyronine (T3)
  • Synthetic mixture T4/T3 in 41 ratio
  • Desiccated thyroid (38mg T4 9mg T3/grain)
  • Thyroglobulin (36mg T4 12mg T3/grain)

33
THYROID FUNCTION TESTS
  • 1. Peripheral effects
  • BMR
  • Deep Tendon Reflex
  • Cardiovascular indices (pulse, BP, LV function
    tests)
  • Serum parameters (high cholesterol, CK, AST, LDH
    carcino-embryonic antigen)

34
THYROID FUNCTION TESTS (2)
  • 2. Thyroid gland economy
  • Radio iodine uptake
  • Perchlorate discharge test (ve in Pendred
    syndrome autoimmune thyroiditis)
  • TSH level
  • TRH stimulation tests
  • Thyroid scan

35
THYROID FUNCTION TESTS (3)
  • 3. Tests for thyroid hormone
  • Total free T4 T3
  • Reverse T3 level
  • T3 Resin Uptake
  • T3RU x total T4 Thyroid Hormone Binding Index
    (formerly Free Thyroxin Index)

36
THYROID FUNCTION TESTS (4)
  • Special Tests
  • Thyroglobulin level
  • Thyroid Stimulating Immunoglobulin
  • Thyroid antibodies
  • Thyroid radio-isotope scan
  • Thyroid ultrasound
  • CT MRI
  • Thyroid biopsy

37
PROGNOSIS
  • Depends on
  • Early diagnosis
  • Proper diabetes education
  • Strict diabetic control
  • Careful monitoring
  • Compliance

38
MYXOEDMATOUS COMA
  • Impaired sensorium, hypoventilation bradycardia,
    hypotension hypothermia
  • Precipitated by
  • Infections
  • Trauma (including surgery)
  • Exposure to cold
  • Cardio-vascular problems
  • Drugs

39
PROGNOSIS
  • Is good for linear growth physical features
    even if treatment is delayed, but for mental and
    intellectual development early treatment is
    crucial.
  • Sometimes early treatment may fail to prevent
    mental subnormality due to severe intra-uterine
    deficiency of thyroid hormones
Write a Comment
User Comments (0)
About PowerShow.com