hipotiroidismo is the diminution of the levels of tiroídeas weave and plasma hormones consequently that can be asymptomatic or to cause multiple symptoms and signs of diverse intensity in all the organism.

The patients sometimes, by their larvada presentation, can receive psychiatric treatment or psychological when in fact what they need it is substitute hormonal treatment. He is not easy to diagnose in his initial stages.

In 2006, 1% of the population of the United Kingdom received T4 available ( Tiroxina ) therapy of the hipotiroidismo.

Etiology of the hipotiroidismo

The causes of the hipotiroidismo are multiple, distinguishing mainly the primary hipotiroidismo of the secondary one. The congenital causes appear with a frequency among alive born 1:4000 and 1:9000, whereas the acquired reasons are between 1% and 3% of the population.

Primary Hipotiroidismo

Also tiroideo hipotiroidismo is called, because its cause must to an insufficiency of the own tiroidea gland. It constitutes approximately 95% of all the forms of hipotiroidismo. can as well attend with Goiter or without goiter.

Hipotiroidismo without goiter

Also tiroprivo hipotiroidismo is called. It must to a loss of the tiroideo weave with inadequate synthesis of tiroidea hormone in spite of the maximum stimulation with hormone tirotropa ( TSH ). The destruction or loss of function of the thyroid can be due to multiple causes like:
  • Congenital.

    • tiroidea Disgenesia: is a congenital anatomical lack of tiroideo weave. It can be by agenesia complete or ectópico thyroid lingual. associated to Cretinismo produces congenital Hipotiroidismo frequently .
  • Acquired.

    • Hipotiroidismo iatrógeno : it supposes a third of all the cases of hipotiroidismo. The lack of thyroid gland can be by Tiroidectomía, like for example practiced in the Cancer of thyroid, by Radioactive ablation with iodine 131 before one Tirotoxicosis or by X-ray of tumors of head and neck.
    • idiopático or primary Hipotiroidismo: usually is produced in the majority of the cases by autoimmune hipotiroidismo because is often associated with circulating antitiroideos Antibodies and in some cases it is consequence of the effect of antibodies that block the receiver of TSH . Diabetes can be associated to other upheavals like mellitus, pernicious Anemia, systemic erythematous Lupus, reumatoide Arthritis, Syndrome of Sjögren and chronic Hepatitis . Also adrenal Insufficiency can be associate to, paratiroidea or gonadal . It is the call endocrine syndrome to poliglandular. The autoimmune chronic hipotiroidismo is the most frequent cause of primary hipotiroidismo in the developed countries.
    • transitory Hipotiroidismo: usually is a autolimitado hipotiroidismo of spontaneous resolution, associated to subacute tiroiditis, silente, postpartal after a phase of hyperfunction.

Hipotiroidismo with goiter

It is a hipotiroidismo that can pronounce with increase of the tiroideo size that it is felt and it is seen. Also it can be due to multiple causes like:
  • Congenital.
    • Dishormonogénesis: is a hereditary biosynthetic defect of tiroideas hormones, reason why frequently associated with Cretinismo will cause congenital Hipotiroidismo .
  • Acquired.
    • maternal Transmission: the antitiroideos drug administration like Carbimazol or Metimazol during not regulated Pregnancy suitably, produces hipotiroidismo in the fetus, with increase of the TSH and goiter.
    • dietetic iodine Deficit: as it happens in regions of the interior of the moved away continents of the sea. It is the most frequent cause of hipotiroidismo and Goiter at world-wide level.
    • iatrógeno Goiter: the drugs can prevent the hormonal synthesis ( Tionamidas Amiodarona, Lithium, iodine), alter their absorption ( Colestiramina, ferrous Sulfate ) or increase their degradation metabolic ( Carbamacepina, Rifampicina, Fenitoína ).
    • Tiroiditis de Hashimoto : is a autoimmune tiroiditis and the most frequent cause of hipotiroidismo with goiter, present mainly in areas without iodine deficiency.
    • Effect Wolff Chaikoff : the excess of Iodine in predisposed people, in particular in the neonatal stage, can cause tiroidea hypofunction when inhibiting the organificación and the synthesis of tiroideas hormones. For this reason, certain iodized products (by ex.: iodized antiseptics) must be avoided during the childhood.
    • infiltrativas Diseases : like Amiloidosis, Esclerodermia, Sarcoidosis, Hemocromatosis, Leukemia, Tiroiditis de Riedel and infections can cause hipotiroidismo.

Supratiroideo Hipotiroidismo

Hipofisario Hipotiroidismo

Also secondary hipotiroidismo is called. It less than supposes 5% of all the hipotiroidismos.

It must to a deficit of hormone TSH generally due to an adenoma, more frequently, or to a hipofisario tumor which can be confirmed or discard, generally, by means of a simple x-ray of skull to visualize the Turkish chair.

Before a picture of hipotiroidismo with symptoms additions that are not to him own more and if they are of hormonal origin it is necessary to think about very different a secondary hipotiroidismo what supposes a therapeutic evolution and.

Thus with simultaneous hipotiroidismo and gigantism it would be necessary to discard the presence of a producing adenoma of hipófisis of hormone of the growth in excess, being caused therefore the gigantism, that when growing is destroying the cells of the hipófisis that stimulates the thyroid causing therefore a hipotiroidismo in spite of being the completely healthy thyroid.

Also by hipofisaria Necrosis postpartal ( Syndrome of Sheehan ) can take place secondary hipotiroidismo.

Hipotalámico Hipotiroidismo

Also tertiary hipotiroidismo is called. He is less frequent still and it must to a deficit or inadeacuada secretion of the hipotalámico factor liberating of tirotropina ( TRH ).

Peripheral Hipotiroidismo

Also quaternary hipotiroidismo is called. It must to the peripheral resistance to tiroideas hormones, to circulating Antibodies against tiroideas hormones .


  • Prevalence of the hipotiroidismo varies according to the geographic place and the populations, admitting itself that the 1 enters and 3% of the general population present/display indications of more or less intense hipotiroidismo, with TSH levels or autoimmune tiroiditis.
  • The prevalence of the congenital hipotiroidismo of one each 5000 new born alive ones.
  • The spontaneous hipotiroidismo happens one one each 1000 women year, being more frequent in the woman who in the man in a proportion 1/4.

Group of symptoms of the hipotiroidismo

precocious Symptoms of the hipotiroidismo in the adult are inespecíficos and of insidious beginning. Among them one is the lethargy, Constipation, the intolerance to the cold, rigidity and muscular contractura, Syndrome of the carpiano tunnel and Menorragia .

Hypothyroid Facies

In the exploration of the face it is where more clinical data are appraised and among them it emphasizes:
  • Amimia : filled with paste face or expensive of clown is called to him, due to palpebral swelling, waxen pallor in which emphasizes the reddening to malar (chapetas malares), with manifest inexpresiveness, silly coarse aspect, . Perhaps when he is exaggerated is developed a mixedematoso coma. Also it is necessary to differentiate it from a parkinsoniano syndrome.
  • Blefaroptosis: is the fall of the eyelid superior by paralysis (ptosis palpebral)
  • palpebral or periorbitario Edema, with bags in the eyelids inferiors
  • heavy Lips
  • Macroglosia : it can cause the mordedura of the language frequently and cause Syndrome of obstructiva apnea of the dream . is necessary to distinguish it of Acromegaly
  • hoarse Voice: dull, slow, guttural, deep and sometimes rough
  • Alopecia: usually is of type android, with hair fine, very dry, estropajoso, unpolished, debilitated
  • Fall of the hair of the tail of the eyebrows: is due to autoimmune processes with antibodies against the hair. is necessary to differentiate it from Leprosy
  • thickened Skin : the skin almost appears like orange skin, in which the nasogenianos furrows are marked to much you fold and them

Respiratory apparatus

exists one hypoventilation, due to the diminution of force of the respiratory muscles that causes one respiratory Insufficiency of different degrees declared by:
  • Diminution of the vital capacity forced in Espirometría .
  • Atelectasis, that usually is laminar due to the diminution of the ventilation.
  • pleural Derrame, secondary also to the hypoventilation.
  • carbonic anhydride Retention, that can cause one respiratory Acidosis and lead to a mixedematoso coma.

Cardiovascular apparatus

  • Bradycardia with weak cardiac tones. It can not exist in the hipotiroidismo.
  • pericárdico Derrame that makes worse the prognosis.
  • arterial Hypertension : it appears in 30% of the cases.
  • Inotropismo : variation in the contraction force
  • Diminution of the volume of ejection .
  • Electrocardiographic upheavals like prolonged space PR, Complex QRS of low voltage and can exist blockade auriculo-ventricular.
  • cardiac Insufficiency : ischemic Cardiopathy exists a risk of . In the final phase Cardiomegalia exists one with expanded cardiomyopathy that can bring about the death.

Digestive apparatus

Multiple symptoms like Hiporexia and until Anorexy, in spite of the increase of weight exist; hipoclorhidia in 50% of the patients that brings about heavy digestions, hipoperistaltismo with with íleo sometimes quadriplegic Constipation and and Megacolon, Meteorismo, sluggish biliary vesicle and Ascitis .

Urinary apparatus

An increase of Urea exists, Creatinine, Hiponatremia, hipoalbuminemia, albuminuria, that leads to oliguria by retention of liquids and edemas. A diminution of the renal sanguineous flow with diminution of the filtration to glomerular and the tubular resorption takes place.

Nervous system

The great majority of the neurological symptoms is characteristic of the congenital hipotiroidismo in smaller children of 2 years by defect the maturation of central nervous System .
  • Lethargy: slowing of the intellectual function, bradipsiquia, bradilalia, loss of initiative (loss of energy) and memory (amnesia), drowsiness, apathy. is necessary to distinguish it of Dementia
  • psychiatric Upheavals: happens rarely and it characterizes by paranoiac psychosis or depression (mixedematosa madness) and mental delay
  • Migraine : Turkish Chair also takes place by deficit of tiroideas hormones and by enlargement of because TSH must produce much in cases of primary hipotiroidismo. is necessary to distinguish it of hipofisario Adenoma
  • Diminution and slowing of reflected osteotendinosos .
  • Neuralgias and Parestesias like Syndrome of the carpiano tunnel by compression of the medium nerve
  • Anosmia and Ageusia
  • Hipoacusia
  • Comma mixedematosos: in cases of serious hipotiroidismo of long evolution

Locomotive apparatus

It appears rigidity by muscular contracturas, easy fatigue, muscular cramps, hipotonía sometimes muscular generalized that gets worse with the cold, muscular thickening in pantorrilas and arms, relaxation of reflected osteotendinosos . In addition we can find to the physical examination the miotónico reflection that can be evoked when doing pressure in the third superior of the arm in the biceps, and it loosen pressing towards the examiner. The reflection of Walkman is also very important to the physical examination that is not another thing that a slow return to the neutral posicición after to evoke the aquileo reflection, and that suggests the hipotiroidismo presence strongly.


  • The skin appears pale, heavy, parched, flaky, without sweat, doughy and fries
  • Queratodermia to palmoplantar. Sometimes exists a carotinémico dye by insufficient metabolism of Carotenes * Cloasma, that is a pigmentation and front pómulos like in the pregnant women
  • Heavy, fluted, fragile nails and of slow growth
  • Alopecia, not only of the hairy body but of the rest of the body. The resequedad of the skin and hair must peripheral Blood vessel constriction
  • Mixedema : in hydrophilic serious hipotiroidismos in the fundamental substance of the skin and other weaves exists an accumulation of Mucopolisacáridos, that are surrounded by water and produce thickening of the skin, face characteristics and doughy induración of the skin that gives to the patient an Oedematous aspect generalized that unlike edema of cardiac Insufficiency does not leave Fóvea

Genital apparatus

The hipotiroidismo is a frequent cause of sterility.
  • In women anovulatorios cycles with hipermenorrea exist, abortions, and in some cases amenorrhoea by hiperprolactinemia associated by increase of TRH
  • In the men it produces impotence, diminution of Libido, alterations in Spermatogenesis, Hidrocelede everything

Adrenal glands

In the hipotiroidismo can exist one adrenal Insufficiency associated that does not disappear with facility with tiroxina treatment, reason why at the beginning of the treatment of the hipotiroidismo it is necessary to administer corticoids.

Also a complication exists that must to an insufficiency concerning the called hypothalamus hipofisario hipotiroidismo.

Alteration of the metabolism

  • A diminution of the power metabolism with the diminution of heat production exists
  • Diminution of the basal metabolism
  • Intolerance to the cold and low basal temperature

Alterations in Analysis of blood

  • Anemia : pernicious Anemia can be macrocítica by (12%), microcítica anemia by Hipermenorrea in women, or normocítica by medullary insufficiency of chronic disease and diminution of Metabolism
  • Hipercolesterolemia : mainly by the increase of LDL .
  • Diminution of Eritropoyetina, B12 Vitamin, and in the absorption of Iron
  • Elevation of CPK, muscular as as much cardiac
  • Hiponatremia dilucional
  • Increase of Enzymes aminotransferase
  • Diminution of tiroideas hormones
  • TSH is high in the primary and diminished hipotiroidismo in the secondary and tertiary hipotiroidismo

Treatment of the hipotiroidismo

In the established hipotiroidismo, independent of which it is its cause, is due to resort to Tiroxina. The administration must begin with low doses of 25 to 50 micrograms/day in people majors, to be raising progressively until reaching the dose of 100-300 mcg/day. One is due to begin with low doses to avoid the abrupt increase of the cardiac cost that produces the tiroxina and that can lead to Infarct of myocardium in the people majors.

It must monitor the free T4 and the TSH to value the effectiveness of the treatment:

  • If high normal T4 and TSH exist a subclinical hipotiroidismo.
  • If diminished normal T4 and TSH, exist a tiroxina overdose.
  • If normal normal T4 and TSH, exist a good control of the hipotiroidismo.
  • If elevated T4 low and TSH, insufficient dose of tiroxina.

Also there are extratiroideas causes of increase of the TSH, as the mental alcohol consumption and some diseases, that must be evaluated before establishing that a person must take hormones from by life.


Due to the indirect effect that occur before the diminution of the level of tiroideas Hormones (digestive slowing of the metabolism and processes, etc), it is important that we take care of the feeding habits very well. One of the problems additions in the debut of the hipotiroidismo usually is the increase of weight, is for that reason that is recommended to do one Diet balanced, low in fats and rich in fruits, vegetables and sufficient in proteins and fats of high quality. A very restrictive and hypocaloric diet and with limitation of fats and proteins, will take to many people to a physical worsening. In reference to iodine, one has demonstrated that in the case of the hipotiroidismo of autoinmunitario origin (Hashimoto), a sufficient consumption of the trace element tends to make worse the disease, when increasing the activity and number of antiroideos antibodies, reason why many endocrine ones advise against the increase of the consumption of iodine in these cases. Therefore, the recommendation of iodine consumption will take to many people to a worsening of the pathology, unless their hipotiroidismo is for want of this (very little frequent nowadays).
Random links:Almeida Garrett | Bellegarde-in-Marche | Earthquake of Caucete 1977 | Proclamations of the Central Road of the Ukraine | Selection of soccer sub 17 of Chile

© 2007-2008 speedlook.com; article text available under the terms of GFDL, from fr.wikipedia.org