Dr prabhat agrawaal Pg department ofmedicine Snmc agra

Primary – autoimmune – hashimotos thyroiditis,atrophic thyroiditisIatrogenic;I131 treatment ,subtotal or total thyroidectomy; external irradiation of neck for lymphoma or cancerDrugs-iodine excess(including iodine containing contrast media and amiodarone)lithium ,antithyroid drug,p-amino salisalic acid,interferon alphaCongenital hypothyroidism-absenteectopicthyroid,dyshormonogenesis,tsh-r mutation iodine defieciencyInfiltrative disorder-amylodosis,sarcoidosis, hemochromatosis,scleroderma,cystinosis, riedels thyroiditis

Transient-silent thyriditis,including post partum thyroididtisSubacute thyroiditisWithdrawl of thyroid treatment in indiviual with intact thyroidSecondary-hypopituitarism:tumour ,pituatry surgery or irradiation,infiltrative disorder,sheehans syndrome,trauma,genetic form of combined pituatryhormone deficienciesIsolated Tsh deficiency or inactivityBexaretone treatment

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,andfeet (myxedema)

Diffuse alopecia Bradycardia Peripheral edema Delayed tendon

reflexation Carpal tunnel

syndrome

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

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.

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

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

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.

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

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

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.

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,

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

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.

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

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.

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

Chronic lymphocytic thyroiditis Probably the most common cause of

hypothyroidism With (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)

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EUTHYROIDSUB-CLINICAL

HYPERTHYROID

NON THYROIDILLNESS - NTI

NTI or Pt.on ELTROXIN

SUB-CLINICALHYPOTHYROID

SECONDARYHYPERTHYROID

SECONDARYHYPOTHYROID

PRIMARYHYPERTHYROID

PRIMARYHYPOTHYROID

LOW NORMAL HIGH

THYROID STIMULATING HORMONE - TSH