This document discusses hypothyroidism, including its causes, signs and symptoms, and clinical manifestations. It begins by listing various causes of primary and secondary hypothyroidism such as autoimmune disorders, iatrogenic causes, congenital disorders, and infiltrative disorders. It then describes the common signs and symptoms of hypothyroidism which affect the skin, eyes, cardiovascular system, gastrointestinal tract, neurological and neuromuscular systems, and other body systems. The document also discusses laboratory abnormalities seen in hypothyroidism and compares features of primary and secondary hypothyroidism.
10. Primary –
autoimmune – hashimotos thyroiditis,atrophic thyroiditis
Iatrogenic
;I131 treatment ,subtotal or total thyroidectomy; external
irradiation of neck for lymphoma or cancer
Drugs-
iodine excess(including iodine containing contrast media
and amiodarone)lithium ,antithyroid drug,p-amino salisalic
acid,interferon alpha
Congenital hypothyroidism-
absenteectopicthyroid,dyshormonogenesis,tsh-r mutation
iodine defieciency
Infiltrative disorder-
amylodosis,sarcoidosis,hemochromatosis,scleroderma,
cystinosis, riedels thyroiditis
11. Transient-
silent thyriditis,including post partum thyroididtis
Subacute thyroiditis
Withdrawl of thyroid treatment in indiviual with intact
thyroid
Secondary-
hypopituitarism:tumour ,pituatry surgery or irradiation,infiltrative
disorder,sheehans syndrome,trauma,genetic form of combined
pituatryhormone deficiencies
Isolated Tsh deficiency or inactivity
Bexaretone treatment
12.
13. Signs and symptom of hypothyroidism
Symptoms
Tiredness,weakness
Dry skin
Feeling cold,hairloss
Hair loss
Difficultyconcentratin
g and poor appetite
Dysponea
Hoarse voice
Menorrhagia(later
oligomenorrhea)
Signs
Dry coarse skin cool
periphral extremities
Puffy face,hands,and
feet (myxedema)
Diffuse alopecia
Bradycardia
Peripheral edema
Delayed tendon
reflexation
Carpal tunnel
syndrome
14. Clinical Manifestations of Hypothyroidism --
Skin
Cool and pale skin blood flow
Dry roughness of skin the epidermis has an
atrophied cellular layer and hyperkeratosis
Decreased sweating calorigenesis and acinar gland
secretion
Generalized nonpitting edema (myxedema) in severe
hypothyroidism infiltration of the skin with
glycosaminoglycans and associated water retention
15. Clinical Manifestations of Hypothyroidism -- Eyes
Periorbital edema -- as a manifestation of
generalized nonpitting edema or Graves'
ophthalmopathy.
Graves' ophthalmopathy may persist or worsen
when hypothyroidism develops after treatment of
Graves' hyperthyroidism. Patients will have
variable degrees of stare, protrusion of the eyes,
and extraocular muscle weakness.
16. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Bradycardia reductions in heart rate
Impaired muscular contractility
Reduced cardiac output decreased exercise capacity
and shortness of breath during exercise
ECG: low voltage of QRS complexes and P and T waves
CXR: cardiomegaly interstitial edema, myofibrillary
swelling, LV dilatation, pericardial effusion
17. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Myxedema induces coronary artery disease ??
CAD more common in p’ts with hypothyroidism
Symptoms and signs of congestive heart failure are
usually absent in patients who have no other cardiac
disease
Congestive heart failure or angina may worsen when
hypothyroidism develops in patients with heart
disease
18. Clinical Manifestations of Hypothyroidism --
Cardiovascular System
Hypertension peripheral vascular resistance
In normotensive patients, BP increases are small
(<150/100 mmHg).
The BP of patients with established hypertension
may increase further with the development of
hypothyroidism.
19. Clinical Manifestations of Hypothyroidism --
Gastrointestinal Disorders
Constipation, even ileus gut motility
Decreased taste sensation
Gastric atrophy presence of antiparietal cell
antibodies. Pernicious anemia occurs in 10% of
patients with hypothyroidism caused by chronic
autoimmune thyroiditis.
Weight gain decreased metabolic rate +
accumulation of fluid (nonpitting edema) that is rich
in glycosaminoglycans
Ascites, rare
20. Clinical Manifestations of Hypothyroidism --
Neurological Dysfunction
General depression of central nervous system function
Sleepiness, inability to concentrate
Sluggish thought processes
Respond slowly to questions
Less able to retrieve information from memory
Agitated psychosis, rare (“myxedema madness”)
PET: 23% reduction in cerebral blood flow and a 12%
reduction in cerebral glucose metabolism
21. Clinical Manifestations of Hypothyroidism --
Neuromuscular Abnormalities
A delay in the relaxation phase of deep tendon
reflexes
Carpal tunnel syndrome
Paresthesia
Asymptomatic elevation in serum CPK level to
muscle hypertrophy (which may be accompanied
by muscle cramps) to proximal muscle weakness
to, in rare cases, rhabdomyolysis.
22. Clinical Manifestations of Hypothyroidism --
Metabolic Abnormalities
Hyponatremia may result from a reduction in free
water clearance
Reversible increases in serum creatinine occur in 20 ~
90% of hypothyroid patients
lipid clearance may be decreased, resulting in an
elevation in the serum concentrations of free fatty
acids and total and low-density lipoprotein cholesterol
Plasma homocysteine concentrations are increased in
some hypothyroid patients,
23. Clinical Manifestations of Hypothyroidism --
Respiratory System
Fatigue, shortness of breath on exertion, and
decreased exercise capacity impaired respiratory
function + cardiovascular disease
Hypoventilation (shallow and slow respirations)
respiratory muscle weakness + reduced pulmonary
responses to hypoxia and hypercapnia
Obstructive sleep apnea macroglossia
24. Clinical Manifestations of Hypothyroidism --
Renal Function
Decreased glomerular filtration rate (GFR )
Impaired ability to excrete a water load
The drug clearance (ex, antiepileptic,
anticoagulant, hypnotic and opioid drugs), is
decreased. Drug toxicity may occur if drug
dosage is not reduced.
During T4 replacement, drugs that are
administered at effective doses in patients who are
hypothyroid may become less effective.
25. Clinical Manifestations of Hypothyroidism --
Anemia
Impaired hemoglobin synthesis thyroxine
deficiency
Iron deficiency increased iron loss with
menorrhagia + impaired intestinal absorption of iron
Folate deficiency impaired intestinal absorption of
folic acid
Pernicious anemia vitamin B12-deficient
megaloblastic anemia
26. Clinical Manifestations of Hypothyroidism --
Reproductive Abnormalities
Women with hypothyroidism may have either oligo-
or amenorrhea or hypermenorrhea-menorrhagia.
Decreased fertility
Increased likelihood for early abortion
Hyperprolactinemia may occur, and is occasionally
sufficiently severe to cause amenorrhea or
galactorrhea
The serum sex hormone-binding globulin
concentration may be low in hypothyroidism. This
will lower serum total but not free sex hormone
concentrations.
27.
28. features Primary secondary
skin Thick and without wrinkle Thick with fine wrinkle
Hair coarse fine
Menstrual irregularities menorrhagia amenorrhea
Secondary sexual changes Normal poor
Heart size May be enlarged small
Goitre May be present absent
Soft tissue edema Marked absent
Blood pressure Normal or high low
cholestrol increased normal
TSH high low
Plasma cortisol normal low
TRHstimulation test Exaggerated response No response
Thyriod auto anti bodies May be present absent
hypothyriodism
29. Hashimoto’s Thyroiditis
Chronic lymphocytic thyroiditis
Probably the most common cause of
hypothyroidism
With goiter(younger patients) or without goiter
(older patients – atrophy gland after destruction by
immunologic process)
High titer of autoantibodies to thyroidal
antigens (Thyroglobulin Ab, Thyroperoxidase
Ab = TPO Ab = Antimicrosomal Ab = AMA)