Hyperthyroidism and Thyroid Storm

1
Hyperthyroidism and Thyroid Storm

• Tintinalli Chapter 215
• 12/15/05
• Prepared by Trent W. Smith
• Lecture by Dr. Klien MD

2
Normal Thyroid State

• Synthesis and release of thyroid hormone is
  controlled by TSH relaesed form the anterior
  pituitary
• TSH is controlled by the release of thyroid
  releasing hormone (TRH) from the hypothalmus and
  a negative feedback loop to the pituitary
• Thyroid hormone production s dependent on
  adequate adequate iodine intake

3
Normal Thyroid State

• Thyroid hormone is reversible bound to various
  proteins including thyronine-binding globulin
  (TBG)
• Free unbound portions are biologically active
• T4 is the predominant circulating hormone
• T4 is deiodinated to t3
• T3 is biologically more active than T4 but has a
  shorter half-life

4
Hyperthyroidism

• Occurs in in all ages
• Uncommon under the age of 15
• 10 xs more common in women (1/10,000)
• Graves disease is the most common etiology
• 80 of cases in the U.S.
• Common in the 3rd and 4th decades
• Caused by autoimmune thyroid-stimulating
  antibodies
• Associated with diffuse goiter, opthalmopathy,
  and local dermopathy

5
Hyperthyroidism

• Toxic multinodular and toxic nodular goiters are
  the next most common etiologies
• Usually occurs in older populations
• Commonly with previous history of goiter
• Often with milder symptoms of thyrotoxicosis

6
Hyperthyroidism

• Amiodarone-induced thyrotoxicosis (AIT)
• Amiodarone is iodine rich and may cause both
  hyper and hypothyroidism
• Difficult to treat because of incomplete
  understanding of mechanism
• Two major forms exists
• Type 1 occurs with a normal thyroid
• Type 2 occurs with a abnormal thyroid
• Tx. Varies based on the the type

7
Hyperthyroidism

• Hyperthyroidism resembles a state of increased
  adrenergic activity despite a normal or low serum
  cortisol level
• Classic complaints include heat intolerance,
  palpitations, weight loss, sweating, nervousness,
  and fatigue

8
Hyperthyroidism
9
Hyperthyroidism

• Confirmed by thyroid function test
• Elevated free T4 and Low TSH
• In some cases of graves disease T4 may be normal
  and TSH decreased but the patient appears
  thyrotoxic
• T3 level should be done to rule out T3 toxicosis
• Hypothyroidism secondary to pituitary adenoma
  will have elevated TSH levels

10
Hyperthyroidism

• Treatment
• Palliative treatment of mild hyperthyroidism is
  accomplished using B-blockers
• Most commonly used is propanolol
• Treatment of Graves diseases include long-term
  use of antithyroid medications, radioactive
  iodine, or subtotal thyroidectomy
• Type I AIT is treated with methimazole and
  potassium perchlorate
• Type II AIT is treated with glucocorticoids

11
Hyperthyroidism

• Treatment cont.
• Toxic multinodular goiter and solitary adenomas
  may be treated with radioiodine therapy
• Thryoiditis is usually self limited and therapy
  is rarely needed

12
Thyroid Storm

• A life threatening hypremetabolic state due to
  hyperthyroidism
• Mortality rate is high (10-75) despite treatment
• Usually occurs as a result of previously
  unrecognized or poorly treated hyperthyroidism
• Thyroid hormone levels do not help to
  differentiate between uncomplicated
  hyperthyroidism and thyroid storm

13
Thyroid Storm

• Preciptatnts of Thyroid Storm (tabel 215-4)

14
Thyroid Storm

• Clinical features
• The most common signs are fever, tachycardia out
  of proportion to the fever, altered mental
  status, and diaphoresis
• Clues include a history of hyperthyroidism,
  exophthalmoses, widened pulse pressure and a
  palpable goiter
• Patients may present with signs of CHF

15
Thyroid Storm

• Clinical features cont.
• Common GI symptoms include diarrhea and
  hyperdefication
• Apathetic thyrotoxicosis is a distinct
  presentation seen in the elderly
• Characteristic symptoms include lethargy, slowed
  mentation, and apathetic facies
• Goiter, weight loss , and proximal muscle
  weakness also present

16
Thyroid Storm

• Diagnosis
• Thyroid storm is a clinical diagnosis based upon
  suspicion and treated empirically
• Lab work is non specific and may include
  Leukocytosis, hyperglycemia, elevated
  transaminase and elevated bilirubin

17
Thyroid Storm

• Treatment
• Initial stabilization includes airway protection,
  oxygenation, fluids and cardiac monitoring
• Treatment can then be divided into 5 areas
• General supportive care
• Inhibition of thyroid hormone synthesis
• Retardation of thyroid hormone release
• Blockade of peripheral thyroid hormone effects
• Identification and treatment of precipitating
  events

18
Thyroid Storm

• Drug Treatment of Thyroid Storm (table 216-6)
• Decrease de novo synthesis
• Porpythiouracil 600-1000mg PO initially, followed
  by 200-250 mg q 4 hrs
• Methimazole 40 mg PO initial dose, then 25 mg PO
  q6h
• Prevent relases of hormone (after synthesis
  blockade intiated)
• Iodine Iaponoric acid (Telepaque) 1 gm IV q8h for
  the first 24 h, then 500 mg bid or Potassium
  iodide (SSKI) 5 drops PO q6h or Lugol solution
  8-10 drops PO q6h
• Lithuim 800-1200 mg PO every day
• Prevent peripheral effects
• B-Blocker Propanolol (IV) titrate 1-2 mg q 5min
  prn (may need 240-480mg PO q day) or Esmolol
  (IV) 500 mcg/kg IV bolus, then 50-200 mcg/kg per
  min maintenance
• Guanethidine 30-40 mg PO q 6 h
• Reserpine 2.5-5 mg IM q4-6h
• Other consideration
• Corticosteroids Hydrocortisone 100 mg IV q 8 h or
  dexamethosone 2 mg IV q 6 hr
• Antipyretics Cooling blanket
  acteaminophen
  650 mg PO q 4-6h

19
Thyroid Storm

• Treatment cont
• Propranolol has the additional effects or
  blocking perpheral conversion of T4-T3
• Avoid Salicylates because it may displace T4
  from TBG
• If the patient continues to deteriorate despite
  appropriate therapy circulating thyroid hormone
  may be removed by plasma transfusion,
  plasmapheresis, charchoal plasmaperfusion
• Remember you must not administer iodine until the
  synthetic pathway has been blocked

20
Thyroid Storm

• Disposition
• Admit to the ICU

21
Hypothyroidism and Myxedeam Coma

• Tintinalli Chapter 215
• 12/15/05
• Prepared by Trent W. Smith
• Lecture by Dr. Klien MD

22
Hypothyroidism

• Occurs when there is insufficient hormone
  production or secretion
• Occurs more frequently in women (0.6 to 5.9 )
• The most common etiologies are
• Primary thyroid failure due to autoimmune
  diseases (Hashimoto thyroiditis is the most
  common)
• Idiopathic causes
• Ablative therapy
• Iodine deficiency
• May be transient
• Pathophysiology is unclear but may be viral in
  nature

23
Hypothyroidism

• Etiologies of Hypothyroidism
• Primary
• Autoimmune etiologies
• Hashimotos is the most common
• Idopathic
• Post ablation (surgical, radioiodine)
• Post external radiation
• Thryoiditis (subacute, silent, postpartum)
• Postpartum thyroiditis occurs within 3-6 months
  and occurs in 2- 16 of women
• Self limited etiologies, often prededed by
  hyperthroid phase
• Infiltrative disease (lymphoma, sarcoid,
  amyloidosis, Tuberculosis
• Congenital

24
Hypothyroidism

• Etiologies of Hypothyroidism
• Post Partum
• Occurs 3-6 months post partum and occurs in 2-16
  of women
• Secondary (pituitary)
• Neoplasm
• Infiltrative Dz.
• Hemorrhage
• Tertiary (hypothalamic)
• Neoplasm
• Infiltrative Dz.

25
Hypothyroidism

• Etiologies of Hypothyroidism
• Drugs
• Amiodarone
• Occurs in 1-32 of patients
• Most likely due to the large amount of iodine
  released in the metabolism of the drug which
  inhibits thyroid hormone synthesis, release, and
  conversion of T4 to T3
• Lithium
• Acts similarly to iodine and inhibit thyroid
  hormone release
• Iodine (in patients with pre-existing autoimmune
  disease)
• Antithyroid medication

26
Hypothyroidism

• Clinical Features
• The typical symptoms of hypothyroidism include
  fatigue, weakness, cold intolerance,
  constipation, weight gain, and deepening of
  voice.
• Cautaneous signs include dry, scaly, yellow skin,
  non-pitting, waxy edema of the face and
  extremities (myxedema) and thinning eyebrows

27
Hypothyroidism

• Clinical Features cont.
• Cardiac findings include bradycardia, enlarged
  heart, and low-voltage electrocardiogram
• Paresthesia, ataxia, and prolongation or DTRs
  are characteristic neurologic findings
• See table below for more complete list

28
Hypothyroidism

• Symptoms and Signs or Hypothyroidism (table
  216-2)

29
Hypothyroidism

• Treatment
• Most patient with uncomplicated symptomatic
  Hypothyroidism may be referred to the primary
  physician for further evaluation and initiation
  of treatment
• If hypothyroidism is due to a secondary etiology
  initiation of thyroid hormone therapy may
  exacerbate preexisting adrenal insufficiency

30
Myxedema

• Myxedema is a rare life threatening
  decompensation of hypothyroidism
• Usually in individuals with long-standing
  hypothyroidism
• Most often seen in the winter months
• More common in elderly women with underdiagnosed
  or undertreated hypothyroidism

31
Myxedema

• Precipitating events include
• Infection
• CHF
• Trauma
• CVA
• Exposure to cold
• Drugs
• Sedatives
• Lithium
• Amiodarone

32
Myxedema

• In addition to the clinical features of
  hypothyroidism patients may present with
• Hypothermia
• Altered metal status
• Coma, delusions, and psychosis (myxedema
  maddness)
• Hyponatremia
• Dilutional secondary to decreased free-water
  clearance
• Hypoglycemia
• Secondary to impaired gluconeogenesis
• Hypotension
• Bradycardia
• Respiratory Failure
• Secondary to decreased strength of respiratory
  muscle
• Hypercapnia and hypoxia is common

33
Myxedema

• Diagnosis
• Must have high clinical suspicion
• Commonly has Hx. Of hypothyroidism
• Delcine in function is usually insidious in onset

34
Myxedema

• Diagnosis cont
• Laboratory evaluation may reveal
• Anemia
• Hyponatremia
• Hypoglycemia
• ? Transaminases
• ? CPK
• ? LDH
• ?Po2 and ?PCo2 on ABGs

35
Myxedema

• Diagnosis cont.
• EKG may reveal
• Sinus Bradycardia
• Prolonged QT interval
• Low voltage
• Flattened or inverted T waves

36
Myxedema

• Treatment (see table 216-5 below)
• No prospective studies on optimal therapy have
  been done thus treatment recommendations are not
  uniform
• Airway stabilization with adequate oxygenation
  and ventilation or vital
• Cardiovascular status must be monitored closely
• Hypothermic patients should be gradually rewarmed
  with gentle passive external rewarming
• Hypotension from reversal of hypothermic
  vasoconstriction should be avoided

37
Myxedema

• Treatment cont.
• Hyponatremia typically responds to fluid
  restrictions. Severe cases may require hypertonic
  saline with lasixs
• Vasopressors are usually ineffective and should
  only be used in severe hypotension
• Lovothyroxine 300-500 mcg slow IVP followed by
  50-100 mcg daily

38
Myxedema

• Treatment cont.
• L-triiodothyronine 25 mcg IV or orally q 8 h is a
  alternative
• This dose should be halved in patients with
  cardiovascular disease
• Hydrocortisone 100 mg IV q 8 hours should be
  given
• Send baseline cortisol level to lab if possible
• Precipitating causes should be sought and treated

39
Myxedema

• Treatment of Myxedema Coma (table 216-5)
• Recognition
• Supportive therapy including ventilatory support
• Thyroid replacement
• Lovothyroxine 300-500 mcg slow IVP followed by
  50-100 mcg daily or
• T3 25 mcg IV or PO q 8 hrs
• Glucocorticoid
• Hydrocortisone 100 mg IV q8h
• Hypothermia
• Prevent additional loss
• Passive external rewarming
• Electrolyte correction
• Gentle fluid restriction for dilutional
  hyponatremia
• Hypertonic saline for severe hyponatremia
• Hypoglycemia
• Dextrose-containing IV fluids
• Monitoring
• Aggressive treatment of presipitating causes
• Admit patient to a monitored setting

40
Myxedema

• Disposition
• Admit to appropiately monitored bed

41
Questions

• 1. Hyperthyroidism is Characterized by which of
  the following
• A. Fatigue
• B. Palpitations
• C. Weight Loss
• D. Heat intolerance
• E. All the above

42

• 2. The most common etiology of hyperthyroidism
  is
• A. Toxic Multinodular
• B. Graves
• C. Toxic Nodular
• D. Amiodarone induces

43

• 3. Typical Feature of Hyperthyroidism include
• A. Fatigue
• B. Weakness
• C. Constipation
• E. Cold Intolerance
• F. All the above

44

• 4. T or F Hyperthyroidism is more common in women
• 5. T or F Hypothyroidism is more common in women
• 6. T or F Mild hyperthyroidism may be treated
  with B-blockers
• Answers 1. E 2. B 3. F 4.T 5.T 6.T