goiter
DESCRIPTION
Goiter. Dr. Gehan Mohamed. Thyroid enlargement. The term goiter (from the Latin guttur = the throat) is used to describe generalised enlargement of the thyroid gland. NORMAL SIZED THYROID (black lining). ENLARGED GOITER (pink). Causes of Goiter. GOITER. - PowerPoint PPT PresentationTRANSCRIPT
Goiter
Dr. Gehan Mohamed
Thyroid enlargement
• The term goiter (from the Latin guttur = the throat) is used to describe generalised enlargement of the thyroid gland.
NORMAL SIZED THYROID(black lining)ENLARGED
GOITER(pink)
Causes of Goiter
GOITERA goitre may be associated with:
• Normal thyroid hormonal activity (euthyroidism).
• Increased thyroid hormonal activity (hyperthyroidism).
• Decreased or absent thyroid hormonal activity (hypothyroidism).
Classification of Goiter1. Simple (non-toxic ) Goiter a-
Diffuse goitre b-Nodular goitreEither diffuse or nodular goiter can be sporadic or
endemic when more than 10% of any community have goiter
.
2. Toxic Goitre a- Diffuse toxic goiter(Grave’s Disease) b- nodularToxic goiter
Endemic goiter
T3
Hypothalamus
Anterior pituitary
Thyroid
TRH
TSH
T4
Remember this?
Iodide
io
Simple Goiter
Definition :it is goiter with normal thyroid hormonal functions.
Age group: May occur in any age group-from neonate (congenital goiter) to the elderly. Peak age:31 and 40 years. The goiter appears in childhood in endemic areas but, in sporadic cases, it usually occurs at puberty when metabolic demands are high.
Aetiology of goiter• A- deficiency of the thyroid hormones lead to Increased secretion of
TSH which stimulate thyroid to grow: causes of thyroxine deficiency are: 1. Inadequate iodine in diet2. Impaired absorption of iodine from the gut3. Drugs preventing trapping and concentrating of iodine by the thyroid gland 4. Dyshormonogenesis: deficiency of enzymes necessary for oxidising
iodine, coupling of iodine and tyrosine5. Excessive iodine paradoxically interfering with release of hormones from
the thyroid.6. Goitrogens: Well-known goitrogens as cabbage,cauliflower,turnip which
contain thiocyanate which prevent thyroxine hormone production.
Aetiology of goiter B- inappropriate secretion of TSH from a microadenoma in the anterior pituitary
C- Relative Physiological Deficiency: Physiological states such as puberty ,menstruation, pregnancy and lactation there is Increase demand for thyroid hormones due to increase in metabolic activity
Mechanism of enlargment of thyroid in case of Simple Goiter:
The stages in goiter formation are as follows:•1- decrease level of thyroxine hormone secretion stimulate release of excess
TSH which cause growth stimulation and diffuse hyperplasia of the thyroid gland ; all lobules are composed of active follicles and iodine uptake is uniform.
This is a diffuse hyperplastic goiter, which may persist for a long time but is reversible if stimulation ceases.
• 2- Later, as a result of fluctuating stimulation of the thyroid (alternating hyperplasia and involution of the thyroid ), a mixed pattern develops with areas of active lobules and areas of inactive lobules.
• Active lobules become more vascular and hyperplastic untilhaemorrhage occurs, causing central necrosis and leaving onlya surrounding rind of active follicles.• Necrotic lobules coalesce to form nodules filled with either iodine-free colloid or
a mass of new but inactive follicles.• Continual repetition of this process results in a nodular goitre. Most nodules are
inactive, and active follicles are present only in the inter nodular tissue
Diagnosis of simple goiterSymptom: swelling in the neck-a major complaint .Pressure symptoms like difficulty
in swallowing and breathing .
Examination findings on Nodular Goitre• A visible goiter that moves up and down on swallowing• May be small, moderate, large or giant in size and affects one of the two lateral
lobes or the isthmus or all the lobes.• Skin over goiter is often shiny with engorged superficial veins .
Investigations• Imaging: x-ray of the neck including thoracic inlet,, ultrasound, CT scan• Thyroid function test• Direct and indirect laryngoscopy
COMPLICATIONS OF simple GOITER
• Pressure symptoms-dyspnea, dysphagia • Toxicity-secondary thyrotoxicosis may
occur• Malignant change• Infection
ectomy
Management of simple goitrePrevention• Iodine supplementation in foodDrug Therapy• Iodine therapy-Lugol’s iodine or potassium iodide tablets-early
cases of endemic and sporadic goitres especially adolescent hyper plastic goitre
• Thyroxine and its analogues-diffuse hyperplastic goitre.
Surgery :thyroidectomy for simple nodular goitreIndicated for the following reasons:• An increasing growing thyroid• Trachea compression• May become toxic• Malignancy may occur
2- Toxic goiterTypes of Toxic goiter: 1- Graves’ disease (primary toxic goiter ): a diffuse goiter associated with hyperthyroidism.
Age group : usually occurs in younger womenand is frequently associated with eye signs. 50% of patients have afamily history of autoimmune endocrine diseases.
-Mechanism : Graves disease is an autoimmune disease that cause hypertrophy and hyperplasia of the thyroid due to abnormal thyroid-stimulating antibodies (TSH-RAbs) that bind to TSH receptor sites and produce a disproportionate and prolonged effect.-Triad of Graves disease: 1- hyperthyroidism 2- exophthalmos due to deposition of proteoglycans ,edema,lymphocytic infiltrate. 3 – dermopathy in form of pretibial myxedema
Toxic goiter2- Toxic nodular goiter (secondary thyrotoxicosis): A simple nodular goiter is present for a long time before the hyperthyroidism, usually in the middle-aged or elderly, and is very infrequently associated with eye signs.
Diagnosis of toxic goiterA- manifestations due to enlargment of the thyroid•Swollen front of the neck•A tight feeling in the throat•Coughing•Difficulty in swallowing & breathing
B- manifestations of THYROTOXICOSIS
• Symptoms:– Hyperactivity– Irritability– Heat intolerance &
sweating– Palpitations– Fatigue & weakness– Weight loss with
increased appetite– Diarrhea– Polyuria– Sexual dysfunction
• Signs:– Tachycardia– Atrial fibrillation– Tremor– Goiter– Warm, moist skin– Muscle weakness,
myopathy– Lid retraction or lag– Gynecomastia– * Exophtalmus– * Pretibial myxedema
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Exophthalmos associating Graves’ disease
Exophthalmos associating toxic goiter
Graves’ disease :Diffusely enlarged gland , Can weigh up to 200 g ,Richly vascular
Normal Thyroid
colloid
Thyroid epithelial cells
T4 90%T3 10%
TSH
Toxic goiter
Toxic goiter:scalloping of colloid inside thyroid follicles
small sized follicles , lymphocytic infiltration,hypervascularity
Thyrotoxicosis - differential• Graves’disease• Toxic adenoma (solitary)• Toxic multinodular goiter• Subacute thyroiditis• Hashimoto’s thyroiditis (transient hyperthyroid phase)• Thyrotoxicosis factitia(exogenous intake of excess synthetic thyroxine)• Postpartum• Struma ovarii(ovarian tumor contain thyroid tissue secreting thyroxine)• Metastatic thyroid carcinoma• Hydatidaform mole (mass or growth that forms inside the uterus at the
beginning of a pregnancy. It is a type of gestational trophoblastic disease ,thyrotoxicosis occur due to the extremely high levels of hCG, which can mimic the normal Thyroid-stimulating hormone).
• TSH-secreting pituitary tumor• Pituitary resistance to triiodothryonine and thyroxine
Other clinical presentations for patients with goiter
• As we previously mentioned patients with goiter may be :1- euthyroid : normal thyroid functions
2- hyperthyroidism :toxic goiter
3- hypothyroidism: decrease thyroid functions , - hypothyroidism In infants called cretinism - hypothyroidism In adults called myxedema
HYPOTHYROIDISM• Symptoms:
– Tiredness– Weakness– Dry skin – Sexual dysfunction
– Hair loss– Difficulty
concentrating
• Signs:– Bradycardia– Dry coarse skin– Puffy face, hands and
feet– Diffuse alopecia– Peripheral edema– Delayed tendon reflex
relaxation– Carpal tunel syndrome– Serous cavity effusions.
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