Transcript Thyroid Emergencies

Thyroid Emergencies
Heidi Chamberlain Shea, MD
Endocrine Associates of Dallas
Thyroid Trivia
• Largest endocrine gland
– 20 grams in adult
– Each lobe
• 2-2.5cm in width and
thickness
• 4cm in height
– Isthmus
• 0.5cm thick
• 2cm height and width
• Named for the
relationship to the
laryngeal thyroid cartilage
– Resembles a Greek shield
Thyroid Hormone Synthesis
• Iodide trapping
• Oxidation of iodide and
iodination of
thyroglobulin
• Coupling of iodotyrosine
molecules within
thyroglobulin
(formation of T3 and T4)
• Proteolysis of
thyroglobulin
• Deiodination of
iodotyrosines
• Intrathyroidal
deiodination of T4 to T3
Thyroid Hormones
T4
T3
 T4 ( Tetraiodothyronine )
 T3 ( Triiodothyronine ) , Reverse T3
Goals of Discussion
• Hypothryoidism
– Clinical symptoms
– Myxedema Coma
• Definition
• Treatment
• Hyperthryoidism
– Clinical symptoms
– Thyroid Storm
• Definition
• Treatment
Hypothyroidism
Symptoms
• Nervous system
– Forgetfulness and
mental slowing
– Paresthesias
– Carpal tunnel
– Ataxia and decreased
hearing
– Tendon jerk slowed
with prolonged
relaxation phase
• Cardiovascular
– Bradycardia
– Decreased cardiac
output
– Pericardial effusion
– Reduced voltage on
EKG and flat T waves
– Dependent edema
Hypothyroidism
Symptoms
• Gastrointestinal
– Constipation
– Achlorhydria with
pernicious anemia
– Ascitic fluid with high
protein
• Renal
– Reduced excretion of water
load
• Hyponatremia
– Decreased renal blood flow
and glomerular filtration
• Pulmonary
– Responses to hypoxia and
hypercapnia are decreased
– Pleural effusions high
protein
• Musculoskeletal
–
–
–
–
Arthralgia
Joint effusions
Muscle cramps
CK can be elevated
• Anemia
– Normochromic normocytic
– Megaloblastic
• Pernicious anemia
Hypothyroidism
Symptoms
• Skin and hair
– Loss of lateral eye brows
– Dry, cool skin
– Facial features
• Coarse and puffy
– Orange skin
• Carotene
• Reproductive system
– Menorrhagia from
anovulatory cycles
– Hyperprolactinemia
• No inhibition of thyroid
hormone
• Metabolism
– Hypothermia
– Intolerance to cold
– Increased cholesterol and
triglyceride
• Decreased lipoprotein
receptors
– Weight gain
Myxedema Coma
Diagnosis
• Altered mental status
– Decreased orientation
– Increased lethargy
– Confusion/psychosis
– May be secondary to
•
•
•
•
Stroke
Medication effect
Sepsis
CO2 narcosis
Myxedema Coma
Diagnosis
• Defective
thermoregulation
– Normal body temperature
with sepsis
• Age
– Most are elderly
• Decreased ability to
compensate
• Precipitating illness or
event
– Exclude pulmonary or
urinary tract source
– Trauma
– Stroke
– Hypoglycemia
– Hypothermia
– CO2 narcosis
– Diuretics
– Sedatives
– Tranquilizers
– Drug overdose
Myxedema Coma
Management
• When in doubt, treat
– Mortality 30-40%
• ICU setting
• Lab tests
– TSH, T4, T3-uptake, Cortisol, CBC with diff and
routine chemistries
– Blood, sputum and urine cultures
– WBC may not be elevated
• Bands present of other concerning finding, empiric treatment
is appropriate
Myxedema Coma
Management
• Body temperature support
– Poikilothermic
– No aggressive warming
• Vasodilatation= vascular collapse
– Passive warming
• Respiratory support
– Intubation may be needed
– If HCT <30%, transfuse
• Provide adequate perfusion and oxygen carrying capacity
Myxedema Coma
Management
• Cardiovascular support
– Fall in blood pressure is ominous
• Look for GI bleed, MI, over diuresis or iatrogenic
vasodilatation
• Endocrine support
– Hydrocortisone 100 mg Q8 hrs
• Treat possible coexisting primary or secondary
adrenal insufficiency
• Stop once cortisol level is confirmed to be normal
Myxedema Coma
Management
• Thyroid hormone therapy
– 300-500 ug IV Levothyroxine x1
– 50-100 ug IV Qday
• Lower doses for smaller people or older at risk for
cardiac events
• IV to bypass poor absorption in the bowel
– Alternately give T4 and T3 due to decreased
T3 conversion
• 200-300 ug T4 then 50 ug/day
• 5-20 ug T3 then 2.5-10 ug Q8 hrs
Myxedema Coma
Management
• Addition of
Levothyroxine causes
– Increase in cardiac index
1-2 days
– TSH falls 32% in 24 hrs
– Serum T3 levels increased
on 3rd day
– Reversal of blunted
ventilatory responses 7
days
Myxedema Coma
Management
• Obtain Free T4- 3 days after initiation of
therapy to make sure it is increasing
– Adjust to normalize value
• Once tolerating PO can change to oral
therapy
– Increase IV dose by 40% for oral dosing
• ie: IV 100 mcg then 140 mcg PO
Hyperthyroidism
Hyperthyroidism
Symptoms
•
•
•
•
•
Nervousness/Anxiety
Weight loss
Increased hunger
Heat intolerance
Cardiac
– Atrial fibrillation
– Palpitations
• Increased stool frequency
• Decreased concentration
•
•
•
•
•
Weakness
Fatigue
Decreased sleep
Irritablity
Change in menstrual
patterns
• Infiltrative orbitopathy
– Exopthalmos
• Goiter
– 20% elderly no goiter
– 3% normal size
Hyperthyroidism
• Cardiac
– Sinus tachycardia
– 15% atrial fibrillation
– Increased cardiac
output 2-3 times
normal
• Nervous system
– Diaphoresis
– Tremor
Hyperthyroidism
• Increased metabolic rate
– Increased blood flow to tissues by
vasodilatation
• T3 affects smooth muscle tone
– Systemic vascular resistance is decreased by
50%
• Decreased diastolic blood pressure
• Increased rate and force of cardiac contraction
– Increased erythropoietin = increased blood
volume
Hyperthyroidism
Lab Tests
• TSH
• Free T4
– If done by RIA can be
falsely elevated
– Gold standard equilibrium
dialysis
• T4 and T3 uptake
• T3
• Thyroid stimulating
immunoglobulin (TSI AB)
• TSH suppressed with
increase in T3 and T4
Thyroid Storm
Diagnosis
• Decompensation of function due to symptoms
– Hyperthermia
– CNS effects
• Delirium, psychosis, coma, seizure
– Cardiac
• Tachycardia
• Heart failure
• Abnormal rhythm
– GI/Liver dysfunction
• Jaundice
• Diarrhea, nausea, vomiting and abdominal pain
Hyperthyroidism
Treatment
• B-adrenergic blockade
– Use cautiously in
asthmatics and diabetics
– Improves
•
•
•
•
•
Tachycardia
Widens pulse pressure
Decreases palpitations
Anxiety
Sweating
– Propranolol
• Some decrease in T4 to
T3 conversion
• 20-40 mg Q4-6hrs
– Atenolol or Metoprolol
• Longer acting
Hyperthyroidism
Treatment
• Thionamide medications
– Block the thyroid hormone synthesis by
blocking organification of iodine
• Propylthiouracil (PTU)
– Blocks peripheral conversion of T4 to T3 in liver and
kidney
– 300-600 mg Q8 hrs
• Methimazole (Tapazole)
– 30-60 mg Q8hrs, BID or QD
Thyroid Storm
Management
•
•
•
•
ICU setting
Mortality of 20-30%
Obtain thyroid function tests
Load PTU oral 1000 mg x1
then 200-250 Q4 hrs.
– Rectal administration
• Use Tapazole 30 mg Q6hrs
– Rectal administration
• Side Effects
– Rash, arthralgia, serum
sickness, abnormal liver
function tests and
agranulocytosis
• Sodium ipodate and
iopanoic acid
– Radiographic contrast
agents
– Potent inhibitors of T4 to T3
conversion
– Structurally similar to
thyroxine
– 1 gram daily
• Decrease T3 in 24-48
hours
• Continue for 7-14 days
Thyroid Storm
Management
• Inorganic iodine
– Blocks thyroid hormone release
– Lugol’s solution (8 drops) or saturated solution of
potassium iodide (SSKI) (6 drops) Q6 hrs.
• Can dilute and give as a retention enema
– Give iodine one hour after thionamides
• Lithium
–
–
–
–
Patient’s with iodine allergy
300 mg Q6 hrs
Titrate to level of 1 mEq/L
Renal and neurological toxicity impair lithium’s
usefulness
Thyroid Storm
Management
• Corticosteroids
– Decrease secretion of
thyroid hormone and
decrease T4 to T3
conversion
– Hydrocortisone 100
mg Q8 hrs
– Dexamethasone 2 mg
Q6 hrs
– Use for 2 weeks
Thyroid Storm
Management
• B-adrenergic blockade
– Need higher doses
– Propranolol 0.5 to 1.0 mg initially with
monitoring up to 2-3 mg in 1 minutes
• 60-80 mg oral every 4 hours
– Esmolol loading 250-500 μg/kg
• 50-100 μg/kg/minute
– Can use diltiazem and guanethidine
• Asthma and heart failure
• With tachyarrhythmia can use loading propranolol
Thyroid Storm
Management
• Hyperthermia
– Cooling blankets
– Acetaminophen
– Avoid aspirin
• Can displace thyroid hormones
from binding proteins
– Fluids 3-5 liters per day
• Include glucose and thiamine
– Depletion of liver glycogen and
thiamine deficiency
– Congestive heart failure
• Diuretics
• Digoxin
– Requires higher doses in thyroid
storm
Thyroid Storm
Management
• Look for precipitating event
– All febrile patients should be cultured
– Unless source found, no empiric treatment
needed
• Once stable and T4 levels are decreasing
can decrease dosing of thionamides
Hyperthyroidism
• Limit activity
– In patients with heart disease
• Increased risk of heart failure
– Young patients
• High output failure
– Increased circulating volume
– During exercise not able to increase LVEF
• Not able to further decrease SVR
Conclusion
• Myxedema coma
– Critical samples
– Passive warming
– Load Synthroid
• Daily IV
– Start Hydrocortisone
– Look for inciting event
• Thyroid storm
– Critical samples
– Control heart rate
• B-blockade
• Calcium channel
blockade
– Thionamide therapy
– Look for inciting event