Thyroid Disorders:4Hypothyroidism

Prof. Tariq WaseemDr. Hina Latif

Prof. Tariq Waseem

Progress

A” Wireless” pole alongside an abandoned British Era

railway track Pind Dadan Khan

Salt Range Punjab Pakistan

Prof. Tariq Waseem

A 32 year old female executive in a multinational organization started having low mood, lethargy and lack of initiative and drive. She had been receiving excellent performance awards for three consecutive years but was not even considered for regular annual promotion this year. She got frustrated over this neglect and started using anti-depressants on advice of her GP. She was repeatedly found somnolent in her office and the pile of files in need of her comments swelled up on her desk. Her boss arranged a psychiatrist consultation.laboratory screening was ordered and a medical consultation was advised.

Case Scenario: 1

Prof. Tariq Waseem

A lady with depressed mood who is slow to respond to questions reports being lethargic, somnolent and feels that winters are becoming increasingly cold over past three years. Her appetite has reduced, she feels constipated and her periods have been unusually heavy for past 9 months. Her hemoglobin was low so she started taking iron supplements on advice of her GP. She also c/o pain and numbness in lateral half of her hands particularly when she rise up from her desk placing them on table for support.

History

Prof. Tariq Waseem

A lady with cold, rough and coarse skin. She has a slightly hoarse and croaky voice. A mild diffuse goitre was noted. Pulse: 56 beats/minBP 150/95Non pitting edema feetHypoaesthesia over lateral 3 fingers of both hands and delayed relaxation of ankle jerks was noted.

Examination

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Hb 11.5 g/dl , MCV 104 CPK 550 ng/l Serum Cholestrol 230mg/dl ALT 55 iu/L TSH > 100 ng/L

Laboratory Reports

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ECG

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Chest X-Ray

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What’s the Diagnosis?

Prof. Tariq Waseem

The most common endocrine diseaseYet Grossly under diagnosed

Females > Males – 8 : 1

90 % patients have Primary Hypothyroidism

Menstrual irregularities, miscarriages, growth retard. Vague pains, anemia, constipation, lethargy, cold intolerance, gain in weight, carpel tunnel syndrome are frequent complaints.

Hypothyroidism

Prof. Tariq Waseem

How Common is Hypothyroidism?

1. 5% of the general population are Sub-clinically Hypothyroid

2. 15 % of all women > 65 yrs are hypothyroid

3. Detecting sub-clinical hypothyroidism in pregnancy is highly essential – order for

TSH and FT4 routinely in all pregnant

women at the beginning of each trimester4. All persons aged above 60 years – Order

for TSH

Prof. Tariq Waseem

Hypothyroidism is common in people of every age.

It is most frequent in elderly Most common in females 1 in every 10 people have a thyroid disorder 1 in every 5000 infant has hypothyroid

disorder

Who has Hypothyroidism?

Prof. Tariq Waseem

IODINE DEFICENCY is the most common cause of hypothyroidism worldwide.

In Iodine sufficient areas, Autoimmune disease (HASHIMOTO’S THYROIDITIS) is most common.

HYPOTHYROIDISM

Prof. Tariq Waseem

With GoiterHashimoto’s Thyroiditis

I2 deficiency goiter

Drug induced goiter

(Li, Amiodarone, PAS, ethionamide, Rifampicin)

Due to goitrogens

Riedel’s thyroiditis

Without Goiter Hashimoto’s Thyroiditis

Post ablative(radioactive I 2)

After thyroidectomy

Congenital hypothyroidism

Secondary hypothyroidism

(Sheehan syndrome)

HypothyroidismCauses

Prof. Tariq Waseem

Autoimmune hypothyroidism (Hashimoto’s, atrophic thyroiditis)

Iatrogenic (I123treatment, thyroidectomy, external irradiation of the neck)

Drugs: iodine excess, lithium, antithyroid drugs, etc

Iodine deficiency Infiltrative disorders

of the thyroid: amyloidosis, sarcoidosis,haemochromatosis, scleroderma

Causes of Hypothyroidism

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Primary◦ Thyroid dysfunction…

Secondary◦ Hypopituitarism

Tertiary◦ Hypothalamic dysfunction

Others Post partum Drugs

Types of Hypothyroidism:

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Fatigue Weight Gain Depression Dry skin Bradycardia Constipation Intolerant to cold

Hypothyroidism-Symptoms

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Hypothyroidism Signs Dry skin, cool extremities Puffy face, hands and feet Delayed tendon reflex

relaxation Carpal tunnel syndrome Bradycardia Diffuse alopecia Serous cavity effusions

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Symptoms

Dry & coarse skin- 76%Cold intolerance – 64%Puffiness of face- 60%Sweating- 54%Wt gain-54%Paresthesia - 52 %Constipation- 50%Aches & pains non specific

SignsAnkle reflex delayed

relaxation- 77%Bradycardia - 58%SomnolenceDiastolic hypertensionDepressionAnemiaMenorrhagia Infertility

HYPOTHYROIDISM Common presentation

Prof. Tariq Waseem

Hoarseness of voiceDeafnessAscitesPericardial & pleural effusionCarpel tunnel syndromeImpotenceGalactorrhoea & AmenorrhoeaCardiac failurePsychosis

HYPOTHYROIDISM Uncommon Presentations.

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HYPOTHYRODISM

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Prof. Tariq Waseem

Depression Dementia Parkinsonism Proximal Myopathies

Differential Diagnosis

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Hypercholesterolemia Infertility – Menstrual

Irregularities Diabetes mellitus

Co-morbidity

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Primary Test

TSHAdditional Test

Free T4

Initial tests for diagnosis of Thyroid Dysfunction

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Hypothyroidism: Initial Diagnosis

TSH raised (>3.5-5.5 according to the lab)

Free T4 decreased

Total T4 decreased

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TSH , free T4 , free T3 ,

Ultrasound of thyroid – little value

Thyroid scintigraphy – little value

Anti thyroid antibodies – anti-TPO

Lab Investigations of Hypothyroidism

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CPK , AST LDH Cholestrol , Triglycerides Anemia: Normochromic normocytic/macrocytic /

microcytic Increased serum prolactin Hyponatremia

Other investigations:

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Sinus Bradycardia

  Low voltage 

  Prolongation of the PR interval

  Bundle branch blocks

  Flattening or inversion of the T wave 

  Ventricular premature contractions (VPS) 

  Sustained or non-sustained attacks of ventricular tachycardia (VT) 

  Prolongation of the QT interval

ECG findings in Hypothyroidism

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Primary hypothyroidism Transient Recovery from NTIS Pituitary adenoma Primary adrenal insufficiency T4 resistance TSH resistance at receptor level

Differential Diagnosis of elevated TSH

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Central hypothyroidism Imaging indicated to distinguish

hypothalamic from pituitary disease Evaluate for 2dary adrenal insufficiency

Free T4 low, TSH low

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Improvement of symptoms Normalization of TSH Reduction of goiter Avoid over supplementation : risk of A-fib in elderly risk of bone loss

Treatment goals:

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Algorithm for Hypothyroidism

Measure TSH

Elevated TSH Normal TSH

Measure FT4 Considering Pituitary

Normal Low No Yes

Sub-clinical hypo

TPO + TPO -

T4 repl Annual FU

Primary hypothyroid

TPO + TPO -

No tests Measure FT4

Low Normal

No testsEvaluate PituitarySick EuthyroidDrugs effect

Hashimoto

Others

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Adverse Effects◦ Angina in patients having occult IHD◦ Osteopenia

Contraindicated◦ Acute MI◦ Treatment of obesity◦ Uncontrolled HTN

Hypothyroidism-Treatment

Prof. Tariq Waseem

Goal : Normalize TSH level regardless of cause of hypothyroidism

Treatment : Once daily dosing with Levothyroxine sodium (1.6µg/kg/day-1.8ug/kg/day)

Monitor TSH levels at 6 to 8 weeks, after initiation of therapy or dosage change

Treatment:

Prof. Tariq Waseem

Dose of Levothyroxine depends on the degree of Hypothyroidism, Age & General health condition of the patient

Usually daily replacement dose is 1.6µgm/Kg body weight

Start with Low Dose

Treatment Of Hypothyroidism

Prof. Tariq Waseem

Levothyroxine ◦If no residual thyroid function 1.5

μg/kg/day◦Patients under age 60, without cardiac

disease can be started on 50 – 100 μg/day. Dose adjusted according to TSH levels

◦In elderly especially those with CAD the starting dose should be much less (12.5 – 25 μg/day)

Treatment of Hypothyroidism

Prof. Tariq Waseem

Age (in elderly start with half dose) Severity and duration of hypothyroidism (↑

dose) Weight (0.5µg/kg/day ↑ upto 3.0µg/kg/day) Malabsorption (requires ↑ dose) Concomitant drug therapy (only on empty

stomach) Pregnancy ( 25% -50%↑ in dose), safe in

lactating mother Presence of cardiac disease (start alt. day

Rx)

Dosage Adjustments

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How the patient improves

Feels better in 2 – 3 weeks

Reduction in weight is the first improvement

Facial puffiness then starts coming down

Skin changes, hair changes take long time to regress

TSH starts showing decrements from the high values

TSH returns to normal eventually

Decrease in cholesterol level

Prof. Tariq Waseem

Serum TSH levels should be measured

after 6-8 weeks of therapy and dosages

should be adjusted accordingly

Target TSH levels should be between 1-2

mU/l

Once a stable TSH is achieved, it should be

estimated every year

Follow up

Prof. Tariq Waseem

Obtain baseline FT4, TSH, LFT, CBCs before initiation of therapy

Repeat FT4 and TSH after 4-6 weeks on therapy and 4-6 weeks after adjustments

Once euthyroid state obtain thyroid function test after 3-6 months

Monitoring :

Prof. Tariq Waseem

During pregnancy requirement of thyroxin

increases by 25-50µg/d during pregnancy

Even on mild Thyroxin hormone deficiency

there are chances of low IQ and

developmental delay of the child

Hypothyroid And pregnancy

Prof. Tariq Waseem

Thyroid Hormone exists in two forms :

Free (Active) & Bound (with thyroxine binding globuline).

In Pregnancy increased Estrogen, increases TBG which in turn increases Total T4 & T3 level

However Free T4, Free T4 REMAINS NORMAL.

SO Free T4 should be used in the treatment and follow up during pregnancy & not total T4

Hypothyroid And pregnancy

Prof. Tariq Waseem

Same for the non-pregnant pt Goal is to normalize TSH Adjust dose at 4 week intervals Should check TSH levels every trimester in

pts with hypothyroidism

Levothyroxine in Pregnancy

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Myxedema

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Myxedema

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Occurs in previously: undiagnosed hypothyroidism inadequately treated hypothyroidism elderly patients more susceptible

MEDICAL EMERGENCY

Myxedema Coma:

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Infection/sepsis Drugs…(sedatives, antidepressants, anesthetic

drugs) Cardiac failure/ MI Respiratory failure/ pneumonia CVA GI bleed Hypoglycemia Dilutional hyponatremia Hypoxia/ hypercapnia

Precipitating factors:

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Myxedema Coma

Signs and Symptoms : Hypothermia Coma Seizures Other features of hypothyroidism Usually older age Bradycardia, ↓ Na,↓ glucose, ↑ CO2, ↓ WBC,

↓ Hct, ↑ CPK ↓ EKG voltage

Prof. Tariq Waseem

Treatment

ICU transfer,

IV levothyroxine 500 µg bolus followed by 50-100µg/d (same dose can be given through NG tube),

antibiotics, ventilation, hydrocortisone IV, passive warming, careful volume management,

correction of hypoglycemia and hyponatremia

Myxedema Coma

Prof. Tariq Waseem

When being crazy is not in your head BUT IN THYROID

Delirium With Auditory Hallucinations & Paranoid Delusions

Takes The Form Of Psychotic Depression Or Pure Psychosis.

No Cognitive Impairment

Treatment- Thyroxine

Myxedema Madness.

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Sick Euthyroid Syndrome

Total T3 reduced FT3 reducedTotal T4 reducedFT4 NormalTSH NormalClinically Euthyroid

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Women > 60 women with a family history of thyroid

disease, prior thyroid dysfunction, symptoms suggestive of hyperthyroidism or

hypothyroidism, abnormal thyroid gland on examination,

type 1 diabetes personal history of autoimmune disorder

Screening:

Prof. Tariq Waseem

Abandoned British Era Railway Track

Pind Dadan Khan Salt Range Punjab Pakistan

Mudat se koyi ayaa naa gayaWiran paree hai Ghar Ki Fiza