11 part2.thyroid
DESCRIPTION
surgery lectures slidesTRANSCRIPT
Neck masses thyroid disease
Supervised by: Dr. Mohammad Khammash
Presented by: Nurul Aina Khalid
Embryology The first endocrine gland to develop in embryo .
The gland originates as a proliferation of endodermal epithelial cells on the median surface of the developing pharyngeal floor.
Descends in the neck anterior to the level hyoid bone . Briefly remain connected to the tongue by the thyroglossal duct which obliterates eventually leaving proximal pit (foramen cecum ) in the tongue base .
the parafollicular C cells (calcitonin ),differentiate from the neural crest cells that migrate from the pharyngeal arches to the 4th pharyngeal pouch.
Anatomy largest endocrine organ in the body approximately 20-
25 g in adult . 2 lobes encircles the anterolateral portion of the
trachea overlying the 2nd to 4th tracheal rings ,connected by isthmus (<4mm ).
A pyramidal lobe was found in 55% of individuals . Extends from the isthmus and can reach the level of the hyoid bone. A fibrous tract may extends from the pyramidal lobe
to the hyoid bone and may harbor a thyroglossal cyst.
It’s bordered medially by the trachea and esophagus, laterally by the carotid sheath, anteriorly and laterally by The sternocleidomastoid muscle and the three strap muscles and posteriorly by the longus colli muscles.
Blood Supply & Drainage Superior thyroid artery : a branch of The external
carotid artery . o courses with the superior laryngeal nerve
( landmark ). Inferior thyroid artery : a branch of the
thyrocervical trunk which arises from the subclavian artery. o The RLN may course anterior or posterior to the inferior
thyroid artery(landmark ). Thyroidea ima artery : is found in approximately
3% of individuals and arises from the aortic arch, courses to the inferior portion of the isthmus or inferior thyroid poles. Surgical control of this artery is essential during
thyroidectomy (severe bleeding )
Function Produce Thyroid hormones which are critical
determinants of brain and somatic development in infants and of metabolic activity in adults; they also affect the function of virtually every organ system.
The parafollicular cells (c cells) of thyroid gland secrete calcitonin ( Ca2+ in blood ).
Physiology Primary function of the thyroid gland is the
secretion of thyroid hormones:
T4 is primary released hormone T3 at least 10 times more active
T4 is converted to T3 mostly peripherally.
• Fetal brain and skeletal maturation.
• Increase in basal metabolic rate.
• Positive Inotropic and chronotropic effects on heart.
• Increases sensitivity to catecholamines.
• Stimulates gut motility.
• Increase bone turnover.
• Increase in serum glucose, decrease in serum cholesterol.
Effects of Thyroid Hormone
Approach
History.
Physical exam.
Investigations .
Treatment.
Symptoms of The Thyroid Diseases
Local (mass or swelling).
Endocrine Activity of the Gland.
Local Symptoms (mass)o History
A lump in the neck. Rapid growth of the neck mass. Discomfort During swallowing. Dyspnea. Pain. Hoarseness. childhood head and neck irradiation, total
body irradiation for bone marrow transplantation,
Family history of thyroid cancer, or endocrine ca (MEN)
Symptoms and Signs of Endocrine Dysfunction
Thyrotoxicosis:
• anxiety, emotional lability, weakness, tremor, palpitations, heat intolerance, increased perspiration, and weight loss despite a normal or increased appetite
• hyperdefecation (not diarrhea), urinary frequency, oligomenorrhea or amenorrhea in women, and gynecomastia and erectile dysfunction in men
Hypothyroidism:
Fatigue, Feeling cold , Poor memory and concentration Constipation , Weight gain with poor appetite, Shortness of breath . Hoarse voice , Menorrhagia (and later oligomenorrhea) Paresthesia Dry, coarse skin Cool extremities Hair loss Peripheral edema Carpal tunnel syndrome and Myxedema
Examination Inspection
General look Hands Eyes Neck
Palpation Percussion Auscultation.
Investigations
Investigations
TSH level Free T4 level Free T3 level Thyroid antibodies (anti-thyroglobuline
antibodies, anti-peroxidase antibodies) Thyroid ultrasound Radio active iodine uptake Thyroid biopsy (FNA)
Thyroid US Give good anatomical images
of the thyroid and surrounding structures but unfortunately reveals more thyroid swelling than are clinically relevant.
Cystic vs. Solid lesions
Reveal smaller nodules not felt on exam .
The US will show the size, shape, consistency of the gland and whether its nodular or not.
Isotope scanning
The uptake by the thyroid of a low dose of either: • Radiolabelled iodine ( I 123)• technetium (Tc 99).
Shows isotope uptake and distribution in the gland which reflects it’s activity.
Main value in a toxic patient presented with a nodule, it helps localize the overactivity whether a toxic nodule or toxic multinodular goiter (small nodules )
Fine needle aspiration ( cytology )
Is the investigation of choice for discrete thyroid swelling.
It has excellent patient compliance, is simple and quick to perform in outpatient clinic and readily repeated.
Best done under US guidance.
The only diseases that can’t be differentiated by FNA is follicular carcinoma from follicular adenoma.
Goiter
Goiter Is a non specific term to indicate diffuse
enlargement of thyroid gland.
The most common presentation of a goiter is painless mass in the neck
Patient may be hyper , hypo, euthyroid .
Diffuse ,solitary nodule , multinodular goiter
Classification of Goiter Simple
Diffuse hyperplastic goiter Physiological Pubertal Pregnancy
Multinodular
goiter
Diffuse Graves
disease
Multinodular
Toxic adenoma
Autoimmune Chronic
lymphocytic thyroiditis
Hashimoto’s disease
Granulomatous De Quervain’s
thyroiditis
Fibrosing
Infective
Toxic Inflammatory Neoplastic
Benign
Malignant
Simple Goiter Etiology
Iodine deficiency : Appears in childhood in endemic areas .
Dyshormonogenesis : Enzyme deficiency in sporadic cases , appears in puberty ( increased metabolic demand )
Goitrogens : Cabbage , kale (contain thiocyanate )
Simple Goiter
Diffuse hyperplastic • Because of Persistent growth stimulation by (TSH) due to low (TH) leading to diffuse hyperplasia .
• Low (TH) Mostly due to iodine deficiency.
• Stimulation increase in puberty and pregnancy .
• May persist for a long time but it’s reversible if stimulation stops early .
1. As a result of fluctuating stimulation a mixed pattern of areas of active lobules and areas of inactive lobules develops .
2. Active lobules become more vascular and hyperplastic until hemorrhage , causing central necrosis .
3. Necrotic lobules coalesce to form nodules ( colloid or cellular )
Presentation Painless Goiter (diffuse or palpable nodules)
Euthyroid.
More common in females.
Complications of Neck masses.
Acute development (size or pain )—Hemorrhage
Investigations TFT
Thyriod antibodies to differentiate from autoimmune thyroiditis
Neck & chest x-ray.
US
FNAC
Treatment
Iodine uptake: iodised salt
Thyroxin administration (in hyperplastic stage )
Thyroidectomy (tracheal compression , cosmatic ,
neoplastic )
Toxic diffuse goiter Graves’ Disease
Diffuse goiter Hyperthyroidism Eye signs (exophthalmos ) Myxedema (later on)
Cause : thyroid stimulating antibodies (TSH-RAbs)that bind to TSH receptors site and produce a prolonged effect .
Diagnosis
High T3, T4. Low TSH thyroid stimulating antibodies. Diffuse increased uptake in Isotope scan
Treatment Medical : carbamazole or propylthiouracil
+propranolol (agranulocytosis) Radioiodine ablation. Surgical resection.
Toxic Multinodular Goiter(Plummer's disease) It’s the second most common cause of
hyperthyroidism (after Graves' disease) in the developed world and in areas of endemic iodine deficiency.
Ranges from a single hyperfunctioning nodule within a multinodular thyroid to multiple areas of hyperfunction.
this may progress to hemorrhage and degeneration, followed by healing and fibrosis, Calcification.
Presentation Neck masses.
Hyperthyroidism
Diagnosis & Treatment
TFT Thyroid isotope Scans
Treatment subtotal or total thyroidectomy
Majority present as lump in the neck , mostly euthyroid. Rare: Less than 1% of all malignancies ,If treated appropriately high survival rate Types :
Follicular epithelium
Differentiated Papillary Follicular
Undifferentiated Anaplastic
Not follicular
Medullary Lymphoma Rare secondary
Thyroid carcinoma
History:• Extreme age• Neck radiation.• Family Hx. (thyroid CA or MEN-II)
Symptoms:• Voice changes.• Neck mass• Lymph node enlargement• Dysphagia.
When to suspect ca ?
Signs:• Single Nodule.• Cold nodule.• Increase calcitonin level.• Lymphadenopathy• Hard, Immobile.
When to suspect ca ?
Investigations
FNA TSH US , CT Calcium level CXR
Differentiated: (papillary &follicular): 1. Total Thyroidectomy 2. Radioactive iodine.3. Thyroxin replacement
Undifferentiated: (Anaplastic):• total thyroidectomy • Radiotherapy (palliation)
Treatment
Pre-operative preparation1. the patient should be euthyroid (to decrease the
risk of thyroid storm)2. Give carbimazole or beta-blocker
(propranolol )before surgery3. Check the vocal cords. 4. Patient should be warned for possible nerve
damage intraoperatively .
Postoperative assessment
Thyroxin T4
Thyroglobulin Sensitive indicator for residual or
recurrent tumor
Thyroid scan after 3-4 weeks to check that there is no remnant after total thyroidectomy
Serum calcium
Complication of thyroidectomy
Hemorrhage Laryngeal edema Nerve damage---- recurrent laryngeal nerve,
superior laryngeal nerve (may be reversible or irreversible according to the cut)
Hypocalcaemia (after 4 weeks ) wound infection
Signs of hypocalcaemia
perioral numbness (1st)
Chvostek sign : It refers to an abnormal reaction to the stimulation of the facial nerve
Trousseau sign (when taking blood pressure) Carpal spasm
References Baily and love Up to date Browse’s introduction
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