Hypothyroidism hypothyroidism-hypothyroidism-is-a-clinical2911
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Transcript of Hypothyroidism hypothyroidism-hypothyroidism-is-a-clinical2911
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)
LO
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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