Thyroid Gland Disorders (2.1) PDF

2.1 DISORDERS THYRIOD GLAND HYPOTHYROIDISM DR.ABDISHAKUR 12 May 2024 DR.ABDISHAKUR  SCENARIO Aisha 63-year-old woman ECG was normal. Fasting and complained of mild fatigue, dry skin, postprandial blood sugar a...

2.1 DISORDERS THYRIOD GLAND HYPOTHYROIDISM DR.ABDISHAKUR 12 May 2024 DR.ABDISHAKUR  SCENARIO Aisha 63-year-old woman ECG was normal. Fasting and complained of mild fatigue, dry skin, postprandial blood sugar and CBC and difficulty in losing weight since were within normal limits. last 2 years. Serum TSH and FT4 tests were The past medical and surgical repeated 2 weeks after the first history were uneventful. visit and were found to be 10 mIU/L and 1.4 ng/dL, There was no reported family respectively. history of DM/HTN/IHD. Physical examination results were normal including a non- palpable thyroid gland. 12 May 2024 DR.ABDISHAKUR 2  HYPOTHYROIDISM Hypothyroidism is a failure of the thyroid gland to produce sufficient thyroid hormone to meet the metabolic demands of the body. Syndrome characterized by the clinical and biochemical manifestations of thyroid hormone deficiency in the target tissues of thyroid hormone There is a generalized slowing down of metabolic processes. In newborn infants – Cretinism In adolescents – short stature, mental retardation, precocious puberty In adults – symptoms largely reversible after therapy 12 May 2024 DR.ABDISHAKUR 3 Untreated hypothyroidism contribute to : ✓ Hypertension. ✓ Dyslipidaemia. ✓ Infertility. ✓ Cognitive impairment. ✓ Neuromuscular dysfunction 12 May 2024 DR.ABDISHAKUR 4  TYPES OF HYPOTHYROIDISM I. Primary hypothyroidism - insufficient amount of thyroid hormone secreted by thyroid gland. II. Secondary hypothyroidism – it is due to pituitary gland failure (inadequate secretion of TSH ) III. Tertiary hypothyroidism – it is due to hypothalamus failure ( subnormal secretion of TRH ) IV. Peripheral resistance to the action of thyroid hormone V. Subclinical hypothyroidism – also called mid thyroid failure 12 May 2024 DR.ABDISHAKUR 5/15 Primary (1ry): due to failure of the thyroid gland itself Secondary (2ry): due to hypopituitarism Tertiary (3ry): due to failure of hypothalamus Quaternary (4ry): due to tissue insensitivity to action of thyroid hormone 12 May 2024 DR.ABDISHAKUR 6  PATHOPHYSIOLOGY HYPOTHALAMUS DYSFUNCTION (TERTIARY) THYROTROPIN RELEASING HORMONE DECREASE TRH ANTERIOR PITUITARY PITUITARY DYSFUNCTION (SECONDARY) TSH DECREASED OR NORMAL TSH THYRAID GLAND DESTRUCTION INFLAMMATION (PRIMARY) THYROXINE (T4) TRIIODOTHYRONINE (T3) INCREASED TSH 12 May 2024 DR.ABDISHAKUR 7  CLASSIFICATION Congenital Age of onset Acquired Primary (defect in the thyroid) HPT level Secondary (defect in the hypothalamus or pituitary gland, also called central hypothyroidism) Overt (clinical) Severity Mild [subclinical) Permanent Duration Transient 12 May 2024 DR.ABDISHAKUR 8  PRIMARY HYPOTHYROIDISM Thyroid dysgenesis Destruction of thyroid tissue Chronic autoimmune thyroiditis: atrophic and goitrous forms Radiation: 131I therapy for thyrotoxicosis, external radiotherapy to the head and neck for non-thyroid malignant disease Subtotal and total thyroidectomy 12 May 2024 DR.ABDISHAKUR 9  Infiltrative diseases of the thyroid (amyloidosis, sarcoid, lymphoma, hemochromatosis, scleroderma) Defective thyroid hormone biosynthesis Congenital defects in thyroid hormonal biosynthesis Iodine deficiency Drugs with antithyroid actions: lithium, iodine and iodine containing drugs, radiographic contrast agents 12 May 2024 DR.ABDISHAKUR 10  CENTRAL HYPOTHYROIDISM Insufficient stimulation by TSH of an otherwise normal thyroid gland. Prevalence 1 : 20,000 - 80,000 1 in 1000 hypothyroid patients. 1 in 160,000 → congenital hypothyroidism of central origin. 12 May 2024 DR.ABDISHAKUR 11  pituitary macroadenomas, craniopharyngiomas, Invasive lesion meningiomas, gliomas, metastases, carotid aneurysms Iatrogenic cranial surgery or irradiation, drugs Injury head traumas, traumatic delivery postpartum necrosis (Sheehan syndrome), Infarction pituitary apoplexy 12 May 2024 DR.ABDISHAKUR 12  lymphocytic hypophysitis, circulating anti- Immunologic disease POU1F1 antibodies Infiltrative lesion sarcoidosis, hemochromatosis, histiocytosis X Infectious disease tuberculosis, syphilis, mycoses pituitary transcription factor defects Inherited (occasionally with childhood onset), TSHβ and TRHR mutations Idiopathic Other unknown causes Empty sella syndrome 12 May 2024 DR.ABDISHAKUR 13 CLINICAL MANIFESTATIONS: SYMPTOMS/SIGNS SYMPTOMS SIGNS ▪ Tiredness/ weakness ▪ Cold peripheral extremities ▪ Weight gain with poor appetite ▪ Dry, coarse and yellow skin ▪ Dry skin ▪ Puffiness of face, hands and feet ▪ Hoarse voice ▪ Pretibial non pitting edema ▪ Cold sensation ▪ Hair loss and brittle nails ▪ Hair loss(diffuse alopecia) ▪ Bradycardia/ diastolic ▪ Nail growth is retarded hypertension ▪ Poor concentration/memory loss ▪ Slow relaxation of tendon reflex (woltmans sign) ▪ Constipation ▪ Serous cavity effusions ▪ Menorrhagia(miscarriage). ▪ Normal/enlarged/atrophied ▪ Impaired hearing thyroid gland 12 May 2024 DR.ABDISHAKUR 14  CLINICAL FEATURES 12 May 2024 DR.ABDISHAKUR 15  TSH : Thyroid – Stimulation Hormone 12 May 2024 DR.ABDISHAKUR 16  T4 : Serum Total Thyroxine 12 May 2024 DR.ABDISHAKUR 17  T3: Serum Total Triiodothyronine 12 May 2024 DR.ABDISHAKUR 18  Thyroid Antibodies Antithyroid peroxidase Antithyroglobulin antibodies antibodies Used to diagnose suspected Used to diagnose autoimmune Hashimoto’s thyroiditis in thyroiditis or Graves’ disease in hypothyroidism hyperthyroidism 12 May 2024 DR.ABDISHAKUR 19  Patterns of thyroid function tests during assessment of thyroid function 12 May 2024 DR.ABDISHAKUR 20  TSH MEASUREMENT ALGORITHYM 12 May 2024 DR.ABDISHAKUR 21  MANAGEMENT ❑ The starting dose of levothyroxine in young, healthy adults for complete replacement is 1.6 mcg per kg per day. Instructions: ✓ taken in the morning, 30 minutes before eating. ✓ Calcium and iron supplements should not be taken within four hours ❑ LEVOTHYROXINE ▪ Plasma T4 reaches a peak concentration 2 to 4 hours after oral administration ▪ once daily dose of L-T4 each morning provides stable and relatively constant blood levels of T4 ▪ long half-life (about 7 days) 12 May 2024 DR.ABDISHAKUR 22 ❑ L I O T HYRONINE: ▪ T3 - affinity for the nuclear receptor is 10- to 20-fold that of T4 ▪ The ratio of T4 to T3 in the human thyroid gland is approximately 15:1 ▪ T3 has a relatively short half-life ▪ available formulations of L-T3 are rapidly absorbed ▪ Typically, after T3 administration, supraphysiological serum T3 concentrations were maintained for several hours followed by a rapid decline ❑ USES: ✓ As a second line drug for conditions such as myxedema coma 12 May 2024 DR.ABDISHAKUR 23 12 May 2024 DR.ABDISHAKUR 24 12 May 2024 DR.ABDISHAKUR 25 SUBCLINICAL HYPOTHYROIDISM ❑ Treatment should be considered for patients with: ✓ initial TSH levels greater than 10 mIU per L. ✓ patients with elevated thyroid peroxidase antibody titers. ✓ patients with symptoms suggestive of hypothyroidism and TSH levels between 5 and 10 mIU per L. ✓ patients who are pregnant or are attempting to conceive 12 May 2024 DR.ABDISHAKUR 26 ❑ Increased risk of progression to overt hypothyroidism ❑ may have an increased risk of HF and CHD events and mortality ❑ Risk of CAD increases with the severity of thyroid hormone deficiency and was even higher when TSH values were above 10 mU/L ❑ Studies show increased incidence of HF observed in patients with TSH concentrations of more than 7 to 10 mU/L 12 May 2024 DR.ABDISHAKUR 27  OVERT HYPOTHYROIDISM ❑ should be treated to prevent the risk of progression to a more severe disease and to avoid the risk of adverse cardiovascular events ❑ Untreated overt hypothyroidism can lead to an increased risk of atherosclerosis, CAD, HF, pericardial and pleural effusion, and ventricular arrhythmias ❑ During pregnancy, hypothyroidism should be treated to avoid adverse obstetric outcomes and impaired neuropsychological development in the offspring 12 May 2024 DR.ABDISHAKUR 28 ROCOVERED PATIENT WITH HYPOTHYRODISM 12 May 2024 DR.ABDISHAKUR 29  THANK YOU FOR PAYING ATTENTION 12 May 2024 DR.ABDISHAKUR 30