Hypothyroidism and Hyperthyroidism

1. Hypothyroidism and
Hyperthyroidism in the Elderly
Chien Yung-Chang , MD .

3. Free T4
•Reference range 0.7-1.8 ng/Dl .
•Converted to triiodothyronine (T3) .
•The thyroid gland is the sole source of T4 .
•Free T4 measures the nonprotein-bound
circulating T4 .

4. Total T4
•Normal range 50-120 ng/mL , 5-12
mcg/dL .
•Measurement of total T4 is not particularly
helpful .
•Only 0.03% of T4 circulates in the unbound
state .
•There is no clinical indication for
performing total thyroid hormone
measurement .

5. TSH
•Normal 0.4-5.5 mIU/L .
•Serum TSH will be decreased to<0.1 mIU/L
in most hyperthyroid patients .
•The findings of a low serum T4 and low
TSH mandate a search for pituitary disease .

6. T3
•T3 is more biologically active .
• Binding proteins : thyroid-binding
globulin , transthyretin and albumin .
•T3 thyrotoxicoisis : approximately 5% of
clinically hyperthyroid patients with a
normal free T4 level .

7. Functional examinations
•Measure the uptake of iodine into the thyroid
gland .
•The iodine isotopes : used to identify nodular
thyroid disease , to determine if these nodules are
hot ( functioning ) or cold ( hypofunctioning ) , to
determine the cause for the hyperthyroid state
( Graves’ disease vs thyroiditis ) and to determine
a dose of radioiodine for treatment .

8. Erythrocyte sedimentation rate
• To confirm the diagnosis of subacute
( viral ) thyroiditis in patients with
tenderness on thyroid palpation .

9. The Role of the History in
Diagnosing Hypothyroidism
• Previous thyroid ablation .
• Elevated thyroid autoantibodies .
• Thyroid surgery .
• Medicatins containing lithium or iodine .
•The most common cause of hypothyroidism
is autoimmune or Hashimoto’s thyroiditis .

10. Signs and Symptoms of
Hypothyroidism
•Less active than usual with loss of interest
in things previously enjoyed .
•Lethargy , and decreased mobility .
•Fatigue .
•Dry skin .

11. Sings and Symptoms of
Hypothyroidism (continued )
•Apathy and psychomotor retardation .
•Weakness , arthralgia , myalgia , coarsening
of the voice , constipation , edema , weight
gain , cold intolerance .
•Alveolar hypoventilation => CO2 retention
and coma .

12. The Physical Examination in
Hypothyroidism
•Hypotension or diastolic hypertension .
•Low body temperature and bradycardia .
•Facial features that are puffy and coarse .
•The skin : dry and cold .
•Carotenemia : An orange or yellow tint
without scleral icterus .

13. The Physical Examination in
Hypothyroidism ( continued )
•Brittle nails and hair , pallor , induration
and thickening of skin , periorbital edema ,
macroglossia , and myxedema .
•Mental status change .
•Delayed relaxation time of deep tendon
reflex .
•Pleural , peritoneal and pericardial
effusion .
•Delirium and psychosis .

14. The Heart in the Hypothyroid
State
•Decreased stroke volume , bradycardia ,
and decreased cardiac output .
•Diastolic hypertension .
•Sinus bradycardia and a prolonged PR and
QT intervals .
•Low voltage , heart block , T-wave
flattening or inversion , Torsades de pointes
, and sudden death .

15. The Heart in the Hypothyroid
State ( continued )
•Echocardiogram may be useful to show
regional wall abnormalities .
•It also will diagnose a pericardial effusion .
•Pericardial tamponade is rare .

16. Laboratory Diagnosis of
Hypothyroidism
•Levels of TSH : high .
•The levels of free T4 : decreased .
• Vitamin B 12 deficiency => macrocytic
anemia .
•Erythropoietin levels also are low => fall in
hematocrit .
•Hyponatremia with low serum osmolality .

17. Laboratory Diagnosis of
Hypothyroidism ( continued )
•Hypoglycemia .
•Cardiac enzymes may be elevated .
• Without AMI , the troponin I level remains
normal .
•Adrenal hypofunction .

18. Laboratory Diagnosis of
Hypothyroidism ( continued )
•Elevation of thyroid microsomal antibodies
is => chronic autoimmune ( Hashimoto’s )
thyroiditis .
•Thyroid antibodies may be associated with :
Grave’s disease , vitiligo , myasthenia
gravis , Addison’s disease , pernicious
anemia , and other autoimmune diseases .

19. The Diagnosis of Myxedema
Coma
• Abnormal TSH and free T4 values :
confirm the diagnosis .( in the presence of
nonpitting edema , hypoventilation ,
hypothermia and stupor )
•Hyponatremia , hypoglycemia , and
associated infection : confirmatory .

20. Precipitating Events for
Myxedema Coma
•Surgery , severe infection , and trauma .
•Sedatives , narcotics , and tranquilizers .
•Missed doses of T4 .

21. Clinical Features of Myxedema
Coma
•Alteration in mental status , presence of a
precipitating factor , hypothermia , and
increased serum CK levels .
•Pale and edematous .
•Respiratory symptoms .
•Ascites , pericardial effusion and pleural
effusion .

22. Clinical Features of Myxedema
Coma ( continued )
•Distant heart sounds , bradycardia , high serum
cholesterol levels and low voltage on the EKG .
•Dyspnea on exertion , fatigue , and edema .
•Distended abdomen , paralytic ileus , and fecal
impaction .
•Myxedema megacolon : pseudomembranous
colitis and intestinal ischemia .

23. Clinical Features of Myxedema
Coma ( continued )
•Disturbance in consciousness : ranging
from delirium to stupor and coma .
•Hallucination ( myxedema madness ) ,
cerebellar signs and somnolence .
•Muscle relaxation times of the deep tendon
reflexes : delayed markedly .
•Hyponatremia => seizure and depressed
level of consciousness .

24. Laboratory Database of
Myxedema Coma
•Serum TSH and free T4 levels , blood
glucose , electrolytes , and arterial blood
gas .
•Serum cortisol .
•Chest films , urinalysis , and blood
cultures .
•CK , and SGOT .
•Serum electrolytes ,creatinine , BUN ,and
glucose should be monitored .

25. Treatment of Myxedema Coma
•Thyroid hormone replacement : the
definitive treatment .
•Intravenous therapy : preferred .
• Give steroids when starting thyroid
replacement => avoid precipitating adrenal
crisis .
•Passive rewarming and maintenance of
appropriate hydration status .

26. Factors Associated with poor
come
•Advantaged age .
•Body temperature lower than 93*F .
•Hypothermia persisting more than three
days .
•Bradycardia less than 44 beats/minute .
•Hypotension , MI ,and sepsis .

27. Initiation of Treatment in ED for
Myxedema Coma
•200-300 mcg ( 4 mcg/kg ) IV bolus
thyroxine , followed by 50-100 mcg QD .
•T3 20 mcg IV bolus ( loading dose 10-25
mcg ) , then 10 mcg Q8-12H for 24-48
hours until the patient is conscious and
taking maintenance T4 .
•Hydrocortisone 100 mg Q8H .

28. Initiation of Treatment in ED for
Myxedema Coma ( continued )
• Evidence of infection =>Antibiotics .
Underlying illness => Supportive care .
•Consider elective intubation .
• Severe hyponatremia => Consider
hypertonic saline .
•Consider appropriate rewarming technique .

29. Recommendation for Admission
for the Hypothyroid Patient
•Clinical diagnosis of myxedema coma =>
ICU admission .
•Body temperature less than 93*F or
bradycardia less than 44 beats /min => ICU
admission .
•Comorbidity : CHF ,cachexia , COPD ,
pneumonia , or any pulmonary problem .

30. Recommendation for Admission
for the Hypothyroid Patient
( continued )
•Underlying disorder : aspiration
pneumonia , urosepsis , MI .
•CNS dysfunction : Seizure , ataxia ,
somnolence , lethargy , confusion , or
coma .
•Behavioral disorders : Disorientation ,
paranoia , or hallucination ( myxedema
madness ) .

31. Recommendation for Admission
for the Hypothyroid Patient
( continued )
•Hypoglycemia : suggesting hypopituitarism
or adrenal insufficiency .
•Hyponatremia less than 128 mEq/L .
•Social factors that jeopardize patient safety .

32. Symptoms and Signs of
Thyrotoxicosis
• weight loss ( the most common ) ,
palpitation , weakness , dizziness and
syncope .
•Alteration in mental status .
•Heat intolerance .
•Nervous or restlessness .

33. Symptoms and Signs of
Thyrotoxicosis ( continued )
•Tracheal compression => SOB, hoarseness ,
wheezing and stridor .( Pemberton’s sign )
•Thyromegaly => wheezing , hoarseness ,
stridor , or dysphagia .
•Myopathy : the proximal muscle groups of
the shoulder and pelvic girdles .

34. Symptoms and Signs of
Thyrotoxicosis ( continued )
•Memory loss , confusion and short attention
span .
•Chorea , delirium , convulsion , stroke ,
cerebral venous thrombosis , and coma .
•Some psychiatric conditions => may be
mistaken for thyrotoxicosis .

35. Physical Findings in the
Hyperthyroid State
•Flushed skin.Hyperhidrosis of the palms
and soles . Alopecia . Fine and brittle hair .
•Fever and tachycardia .
•Lid lag , chemosis , exophthalmosis ,
vasodilation of the conjunctiva , edema of
the lids , and compromised visual acuity .
•Myxedema of the pretibial areas , feet , and
toes .

36. Physical Findings in the
Hyperthyroid State ( continued )
•Diffuse enlargement , bruit , nodules , and
tenderness.
•Abdominal pain or secretary diarrhea .
•Muscle weakness , hyperactive reflexes ,
and tremor .Alteration in mental status .
•Dementia and severe psychomotor
retardation . ( Apathetic hyperthyroidism )

37. The Heart in Thyrotoxicosis
•Diminished diastolic BP . Palpitation
.Decreased exercise tolerance . Dyspnea on
exertion .Elevated systolic BP . Sinus
tachycardia . Atrial fibrillation . Anigina
pectoris .
•EKG : shortening of the PR interval , ST
change , or atrial fibrillation .

38. Laboratory Testing in
Thyrotoxicosis
•Suppressed TSH levels and increased serum
free T4 estimates : clinically evident
thyrotoxicosis ( 95% ) .
•Radioactive iodine uptake => incereased .
•ESR => elevated markedly .
•Serum thyroglobulin => increased .

39. Thyroid Storm
•A life-threatening crisis .
•Estimated mortality : 20-30% .
the result of thyroid surgery .
•Caused more often by antecedent Grave’s
disease .

40. Precipitants of Thyroid Storm
•Surgery .
•Radioiodine therapy .
•Iodinated contrast dyes .
•Thyroid hormone ingestion .
•Diabetic Ketoacidosis .
•Cerebrovascular accident .
•Pulmonary embolism and CHF .

41. Pathophysiology of Thyroid
Storm
•1) An acute decrease in thyroxine-binding
globulin => high levels of free hormone .
•2) Thyroid hormone increases the density of
beta-adrenergic receptors & alters
responsiveness to catecholamines at a
postreceptor level .

42. Diagnosis of Thyroid Storm
•Largely a clinical diagnosis .
•CNS disturbances occur in 90% of patients .
•Atrial arrhythmia and ventricular
tachyarrhythmia may complicate high
output CHF .
•Many of the stigmata of the hyperthyroid
state may be present .

43. Laboratory Diagnosis of Thyroid
Storm
•A combination of low TSH and elevated
free T4 => makes the diagnosis .
•If TSH is lower than normal and free T4 is
normal => free T3 testing is recommended .
ED measurement of thyroglobulin or
thyroid antibodies : No indication .

44. Treatment of Thyroid Storm
•Block hormone synthesis with either :
a) Propylthiouracil 100-600 mg loading
PO or NG , 200-250 mg q4h for total daily
dose of 1200-1500 mg ; or
b) methimazole 20 mg PO ( 10-40 mg
range ) q 4h .

45. Treatment of Thyroid Storm
( continued )
•Inhibit hormone release :
Iodides –Potassium iodide ( SSKI ) 5 drops PO
Q6-8H , or
Lugol’s solution 7-8 drops ( 1 mL PO Q6H ) or
Ipodate 1-3 g daily ( as 1 g Q8H for 24 hours ,
then 500 mg Q12H ) .
If severe iodide allergy , lithium carbonate 300 mg
Q6H .

46. Treatment of Thyroid Storm
( continued )
•Glucocorticoids : Hydrocortisone ( 300 mg
IV , then 100 mg IV q8h ) ; dexamethasone
( 2 mg Q6H ) .
•Adrenergic blockade : Propranolol ( 0.5-3
mg IV over 15 minutes slow IV , then
60-80 mg PO Q4H ) ; Esmolol ( 0.25-0.5
mcg/kg loading , infusion of 0.05-0.1
mcg/kg/min ) .

47. Adjunctive Therapy for Thyroid
Storm
•Treat fever aggressively with
acetaminophen .
•IV fluid containing 10% dextrose are
recommended .
•Administer vitamin supplements , including
thiamine .
•Treat CHF with conventional methods .

48. Adjunctive Therapy for Thyroid
Storm ( continued )
•Identify the precipitating event , including
infection .
•Consider plasmapheresis , hemodialysis or
peritoneal dialysis for removal of
metabolically active hormone .

49. Admission Criteria for the
Hyperthyroid Elderly Patient
• Impending or clinical thyroid storm .
• Clinical hyperthyroidism and :
•a) CNS effects , including agitation , chorea
, delirium , psychosis , seizure , or coma ;
•b) GI effects such as frank diarrhea ,
vomiting , jaundice , dehydration , or
abdominal pain ;

50. Admission Criteria for the
Hyperthyroid Elderly Patient
( continued )
•c) Cardiovascular dysfunction , including
CHF , sinus tachycardia unresponsive to
oral beta blocade in the ED , new onset
atrial fibrillation , or angina pectoris ;
•d) Persistent fever > 100.4*F after rest ,
without source or without easily treatable
source ;
•e) Syncopal episode ;

51. Admission Criteria for the
Hyperthyroid Elderly Patient
( continued )
•f) History of recent radioiodinevtherapy ; or
•g) Thyrotoxic periodic paralysis ( address
hypokalemia ) .
Underlying precipitating cause .