Transcript Hypothyroidism

Hypothyroidism
Dr. Januchowski
2012
Objectives
• List the different causes for hypothyroidism
• Know the clinical presentations of hypothyroidism
• Explain the work up done when suspecting
hypothyroidism to include knowledge of differential
diagnoses
• List the treatment options for hypothyroidism
• List the complications from untreated hypothyroidism
Overview
• Deficiency of thyroid hormone
• Subclinical
– mild hypothyroidism
– slightly high TSH with normal T4
• Primary
– thyroid doesn’t produce T3/T4
• Secondary
– TSH not produced (pituitary)
• Tertiary
– TRH not produced (hypothalamus)
Etiology for Primary Hypothyroidism
• Localized thyroid destruction is the most common cause
– Autoimmune destruction
• Hashimoto’s thyroiditis is most common cause in the US
• Reidel’s thyroiditis
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Postpartum thyroiditis
Subacute granulomatous thyroiditis (deQuervain’s) – viral
Surgery
Radioactive Iodine therapy / exposure
Radiation therapy
Infiltrative diseases (sarcoidosis)
Medications (lithium, amiodarone)
Iodine deficiency (most common in developing world)
Congenital hypothyroidism (Cretinism)
Etiology for Secondary/Tertiary
• Mass lesions are the most common cause
– Pituitary adenomas
• Infiltrative disorders
– infectious (TB, syphilis, toxoplasmosis)
– non-infectious (sarcoidosis, hemochromatosis)
• Head trauma
• Brain irradiation
• Postpartum pituitary necrosis (Sheehan’s Syndrome)
– Low blood flow causes necrosis
• Genetic disorders
Risk factors
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Female
Middle Age
Family history
Autoimmune
disorders
• Down’s Syndrome
• Multiple Sclerosis
• Type 1 DM
• Textile workers
– polychlorinated and
polybrominated
biphenyls / resorcinol
History
• Slowing of mental
and physical activity
– Fatigue
– Weight gain
– Cold intolerance
– Dry skin
– Hair loss
– Depression
– Constipation
– Menstrual
irregularities
– Neck pain
– Sore throat
Physical
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Hypothermia
• Goiter
– caused by
Slowed speech
overstimulation of the
Dry skin
thyroid gland from any
Periorbital puffiness
factor (TSH, iodine for
example)
Bradycardia
– not very common as an
Macroglossia
initial presentation of
Coarse facial features
hypothyroidism
Melmed: Williams Textbook of Endocrinology, 12th ed.
Evaluating the Patient – Labs
• TSH
– Best and easiest lab to get
– TSH is high (primary)
• peaks in the evening, lowest in the afternoon
• T4 / T3
– Highly protein bound
• Antimicrosomal antibodies
• Antithyroid peroxidase (anti-TPO)
• Antithyroglobulin antibodies
Evaluating the Patient – Imaging
• Ultrasound
– Hashimoto thyroiditis = heterogeneous
ultrasonographic image
• Radioactive Iodine uptake (not useful in
hypothyroidism)
– All types just have a low to normal uptake
Hypothyroid Common Differentials
• Hashimoto’s thyroiditis (autoimmune)
• Subacute thyroiditis (most are painful, no autoimmune Ab)
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DeQuervain’s thyroiditis (granulomatous)
Postpartum thyroiditis
Drug induced
Subacute lymphocytic thyroiditis (painless)
• Euthyroid sick syndrome
– Have some acute illness causing this (cardiac issues, etc…)
• Nontoxic goiter
• Reidel’s thyroiditis
– Replacement of the normal thyroid gland with fibrotic tissue
– “woody, rock hard thyroid”
Treatment – Primary
• Replacement of thyroid hormone
– Levothyroxine (LT4)
• Most common tx we use
– Thyroxine + triiodothyronine (T4 + T3)
– Liothyronine (T3) – rare use
• Used in Myxedema coma
• No surgery for goiters unless compromising
tracheoesophageal function
– Can do surgery if aesthetic issues
– If you treat the thyroid, it usually treats this
Treatment – Subclinical
• Pt will have TSH slightly high, free T4 normal
• Observe and follow
• Or Treat as in Primary hypothyroidism
• Consider ultrasound to look for chronic findings
(diffuse hypoechogenicity  think hashimoto)
• Check for antibodies – treat with medication if
positive (autoAb think hashimoto)
• Follow these pts closely, because need to stop tx
eventually if this is just a subclinical state
Complications
• Myxedema Coma
– Most serious complication
– Happens when hypothyroidism is left untreated (See next slide)
• Cholesterol changes
– accumulation of LDL and triglycerides
• Obstructive sleep apnea
• Anemias
– response to the diminished oxygen requirements
• Hypertension
– rate of turnover of aldosterone is decreased, but the plasma level is normal
– Plasma renin activity is decreased
– sensitivity to angiotensin II is increased
Myxedema Coma
• Severe, untreated hypothyroidism
• High mortality rate
• Usually seen in older patients during the
winter months
Myxedema Coma – Symptoms
• Mental status changes • Bradycardia
• Hypothermia
• Seizures
• Myxedema
• Delayed relaxation in
DTR’s
– Can be everywhere on
the body
• CO2 retention
• Hypotension
• Hyponatremia
• Cardiac arrhythmias
• Pericardial effusion
Pericardial effusion
Myxedema
Myxedema Coma – Treatment
• Diagnosis is Key (T4 level – very low)
• Thyroid Hormone replacement (IV)
– 500-800 μg bolus, then 100 μg daily
• Hydrocortisone for relative adrenocortical insufficiency
• Fluids
– Normal saline (dehydration)
– hypertonic saline (if Na+ is extremely low)
• Cardiopulmonary support as needed
– Intubation, pacing, etc…
Case presentation #1
• 35 year old female patient presents with sore
throat, neck pain and fatigue noted over the past
month.
• Her history is significant for a viral illness about 3
months ago – she went to the ER for neck pain,
sore throat. Meningitis work up done at that
time was normal. She felt bad (sweating, jumpy,
high heart rate) for a few weeks after this
Case presentation #1 (cont.)
• Physical exam showed localized tenderness
over the left lobe of the thyroid. There was
some mild swelling noted.
• Labs:
– TSH = 18.4 (nl 0.3-3.0)
– T4 = slightly low
Thyroid
biopsy
/
scan
Granulomatous aggregations
with large histiocytes and
damaged follicles
Radioactive
Iodine Uptake
negative
Diagnosis and Treatment
• What differentials?
– Some kind of hypothyroidism
• Subacute granulomatous thyroiditis (deQuervain’s) – viral
• Hashimoto’s thyroiditis
• What treatment would you provide for the most likely
diagnosis?
– Subacute granulomatous thyroiditis (deQuervain’s)
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Granulomatous aggregations
Radioactive Iodine Uptake negative
viral illness preceding
Pain
Case #2
• 45 year old female presents with a non-painful
swelling in her neck which seems to be
causing some trouble swallowing and
breathing
• Physical exam
– Vital stable
– hard, fixed, painless goiter noted ***
Labs
• TSH elevated
• T4 low
• What is in your differential at this time?
– Reidel’s (hard, fixed, painless goiter)
– Cancer
Open Thyroid Biopsy done:
Shows heavy inflammatory infiltrate and
dense fibrosis replacing normal thyroid
tissue. No anaplastic cells noted
Case #2 conclusion
• What is the most likely diagnosis?
– Reidel’s
• What would be your treatment plan?
– Treat thyroid
– Radiotherapy and surgery
• Need to stop fibrotic infiltration
Case #3
• A 50-year-old woman was presented to the emergency department with
chest pain and dyspnea. She was previously healthy except for some
ongoing fatigue
• On the day of admission she collapsed and was unresponsive for a short
while.
• Physical examination
– Well nourished woman with a blood pressure of 80/60 mmHg and a pulse rate
of 50-100 beats per minute. Temperature was 95.2 F
– She had a puffy face and examination of the neck revealed no bruits. The
jugular venous pressure was normal. Cardiac auscultation was normal and the
lungs were clear. Peripheral pulses of radial, femoral and dorsalis pedis were
present.
Labs
• CBC, Metabolic panel normal except for sodium of 130
• No other labs done at this time
• Differential?
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Myxedema coma
CVA
Stroke
PE
• What labs or imaging would you want?
– TSH, T4
– Cardiac enzymes
– CXR, US chest
Treatment
• What are the major considerations in this case
for treatment?
– TH replacement, hydrocortisone, cardiopulm
support
• What is the patient’s prognosis?
– Let pt and family know they are seriously ill