2. Case of Hypothyroidism
• History – Rafeequa 34 year old unmarried female complains of fatigue,
blurring of vision , vertigo, cold intolerance, menorrhagia , and constipation .
• Physical examination- Vital signs includes a temperature of 97 F , pulse of
64/ min and regular , BP – 90/60 mm of Hg . She is thin weighing 41.5 kg ,
small 4’7 inches speaks slowly with pale with pale , cool , dry skin . The
thyroid gland is not palpable . The deep tendon reflux is delayed .
• Laboratory studies - WBC - 5,500/ml , Hg – 11.3 g/dl ( Microcytic
Hypochromic ), Platelets-=1,14,000/ml . Serum TSH- 432 uIU/ ml , T3 -0.35
ng/ml , T4 - 5.66 ug/dl . ESR - 15 mm/ hour , serum cholesterol 201mg/dl.
3. Radiological Investigation
USG Abdomen- Liver Hypertrophied left caudate lobe with
atrophied Right lobe heterogeneous echo pattern with modular
margins. Gall bladder
showing multiple calculi (largest12mm) . Kidney Bilateral
medullary nephrocalcinosis
USG thyroid- Chronic thyroiditis with heterogeneous parenchyma
echo pattern with increased vascularity in Doppler . Left lobe
shows well encapsulated nodule 26*17*26 mm with volume 6.3 ml
with central cystic area 8*8mm . ? Follicular neoplasm ,
?Adenomatous nodule TIRADS Grade 3
5. HYPOTHYROIDISM
•2nd MC endocrine disorder after Diabetes Mellitus
•MC cause of hypothyroidism worldwide - iodine
Deficiency
•MCC in iodine sufficient areas- Hashimoto's
Thyroiditis
•99% cases- Primary Hypothyroidism
•<1% cases- Secondary Hypothyroidism
•Easy to diagnose & gratifying to treat
6. Introduction
Condition where there is a reduced production of thyroid
hormone. Categorized as primary and secondary on the basis
of its cause
Primary Hypothyroidism occurs due to improper functioning
of the thyroid gland.
May be further classified as overt and subclinical
hypothyroidism. Affects approximately 5% of individuals with
elderly women being most commonly affected.
Secondary Hypothyroidism occurs due to inadequate
stimulation of thyroid gland by thyroid stimulating hormone
(TSH). May be due to
congenital or acquired defects in the pituitary or hypothalamus.
7. Primary Hypothyroidism Etiology
Thyroid dysfunction -
Autoimmune thyroiditis (Hashimoto's thvroiditis)
Congenital absence or defect in the thyroid tissue
Thyroid removal by surgery
Radio ablation by radio active iodine or irradiation
Destruction of thyroid tissue caused by infiltrative
disorders(amyloidosis,sarcoidosis)
Impaired synthesis of thyroid hormone -
lodine deficiency---MOST COMMON CAUSE
Congenital enzymatic defects
Drug-mediated: thionamides , amiodarone , lithium, aminoglutethimide, carbemazole
8. Secondary Hypothyroidism Etiology
Reduced secretion of TRH or TSH
• Hypothalamic disorders
1. Tumor (lymphoma, germinoma , glioma)
2. Infiltrative disorders (sarcoidosis, hemochromatosis, and histiocytosis)
• Hypopituitarism
1. Mass lesions
2. Pituitary surgery
3. Pituitary irradiation
4. Hemorrhagic apoplexy (Sheehan's syndrome)
5. Lymphocytic hypophysitis
9. Clinical Manifestations Symptoms
Tiredness/weakness -
Weight gain with poor appetite
Dry skin
Cold sensation
Hair loss(diffuse alopecia)
Nail growth is retarded
Poor concentration/memory loss
Constipation
Dyspnea
Hoarseness of voice
Hearing Impairment
Carpal tunnel syndrome
Menorrhaqia(miscarriage)
Paresthesia
10. Clinical Manifestations Signs
Cold peripheral extremities
Dry, coarse and yellow skin
Puffiness of face, hands and feet
Pre tibial non pitting edema
Hair loss and brittle nails
Bradycardia/ diastolic hypertension
Slow relaxation of tendon reflex (woltmans sign)
Serous cavity effusions
Normal/enlarged/atrophied thyroid gland
Hypothyroidism in children
Delayed growth in children and delayed appearance of permanent teeth
Delayed or precocious puberty
Pseudohypertrophy of muscles
11. Maternal Hypothyroidism
One of the most common endocrine disorders in pregnancy .
Overt hypothyroidism found in 1.3 per 1000 pregnant women and
subclinical hypothyroidism in 23 per 1000 pregnant women .
Most common cause: endemic iodine deficiency .
Women with hypothyroidism carry an increased risk of infertility,
miscarriage, and obstetric complications
Foetal complications: premature birth, low-birth weight (LBW), fetal
distress in labor, fetal death, perinatal death, and congenital
hypothyroidism .
Even an untreated subclinical hypothyroidism during pregnancy can
lead to cognitive impairment in the offspring.
12. CONGENITAL HYPOTHYROIDISM
1 in 4000 newborns
2: 1 incidence in males as compared to males
Can be
• Transient - if the mother has TSH-R blocking antibodies
• Permanent- majority
Causes
• 80-85% cases - Thyroid gland dysgenesis
• 10-15% cases- Inborn errors of Thyroid hormone synthesis
• 5% cases- TSH-R antibody mediated
Gene Mutations include:
PROP-1, PIT-1, TSH-receptor, TSH beta, Thyroid Peroxidase,
Thyroglobulin, Pendrin
13. Clinical manifestations
Majority- appear normal at birth
Few cases are diagnosed on the basis of clinical features &
biochemical screening
• Clinical Features include:
Prolonged jaundice
Feeding problems
Hyotonia
Enlarged tongue, Umbilical hernia
Delayed bone maturation
• Complications:
4 times increased chances forCongenital malformations (Cardiac)
Permanent neurological damage
14. Diagnosis and Treatment
Neonatal Screening programs
Measurement of TSH or T4
Heel prick blood sample
• Treatment dose:
T3 = 10-15 ug/kg per day
Regular TSH monitoring
16. Treatment- Clinical Hypothyroidism
Dose of Levothyroxine (T4)
Ideal time of taking?
Goal of treatment?
TSH monitoring?
Symptom relief?
Risk of over-treatment?
Issues with adherence?
Do not feel any difference after missing few doses
If misses single dose?
Increased requirements?
17. Subclinical hypothyroidism
Indications of treatment
TSH > 10 mlU/L
TSH < 10 mIU/L
1. Symptoms, Goitre
2. Family history of autoimmune thyroid disease
Planning pregnancy or pregnant
3. .TPO antibody positive
4. Evidence of heart disease, dyslipidemia
5. Infertilitv
6. Psychiatic disorders
Dose
Start with low dose- 25-50 ug/day
18. Pregnancy
Thyroid function should be monitored
Before conception- therapy to target TSH in normal range
TFT
1. Every 4 weeks in first half of preghancy
2. every 6-8 weks after 20 weeks
Levothyroxine dose is increased by 45%
After delivery dose- Pre pregnancy levels
19. Elderly
Require 20% less dose than younger specially cardiac
patients
Starting dose 12.5 to 20g/day
Gradual increments in 2-3 months
20. Levothyroxine (T4) – Drug Interaction
Increase LT4 dose with
1. Drugs that reduce thyroxine production: lithium, iodine-containing drugs, and
amiodarone
2. Drugs that/reduce thyroxine absorption: sucralfate, ferrous sulfate,
cholestyramine, colestipol, aluminum-containing antacids, and calcium
supplements
3. Drugs that increase thyroxine metabolism: rifampin, phenobarbital,
carbamazepine, warfarin, and oral hypoglycemic agents
Decrease LT4 dose with
1. Drugs that displace thyroxine from binding proteins: furosemide, mefenamic
acid, salicylates, vitamin C
21. Myxedema Coma
Myxedema coma is a rare life-threatening condition.It is the
decompensated state of severe hypothyroidism in which-the
patient is hypothermic and unconscious.
The condition occurs most often among elderly women in the
winter months and appears to be precipitated by cold.
Myxedema coma, occasionally called myxedema crisis, is a rare
life- threatening clinical condition that represents severe
hypothyroidism with physiological decompensation.
The condition usually occurs in patients with long-standing,
undiagnosed hypothyroidism.
22. Why term Myxedema ?
Myxedema is also used to describe
the dermatologic changes that occur in
hypothyroidism which refers to
deposition of mucopolysaccharides in
the dermis, which results in swelling of
the affected area.
23. Factors precipitating
Infection, Exposure to cold temperatures,
Trauma
Burns
Cerebrovascular accident , Myocardial infarction
Congestive heart failure
Respiratory acidosis
Medications - sedatives, narcotics, amiodarone , rifampin, beta blockers.
Decreased drug metabolism leading to overdosing of medications particularly
sedatives, hypnotics, and anaesthetic agents; this can precipitate myxedema coma.
Metabolic disturbances - hypoglycemia, hyponatremia, acidosis and hypercapnia.
24. Myxedema Coma
20-40% mortality
Almost always - Elderly patient
Precipitating conditions- That impair respiration
1. Drugs, Pneumonia, CHF, MI
2. CVA, GI bleed
Levothyroxine
• (Initial-200-400 ug IV bolus or through Nasogastric tube f/b
• Daily oral dose 1.6 ug/kg
Liothyronine (T3)
• Since T4->T3 conversion is impaired
• 5-20 ug followed by 2.5-10 ug 8 hrly
25. Supportive therapy
1. External warming
2. Parenteral Hydrocortisone (50 mg every 6 hrly)
3. Treat precipitating factor
4. Ventilatory support, ABG
5. Hypertonic saline or IV detrose
