Date post: | 17-Feb-2017 |
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GOITREPRESENTERS: HAMISI MKINDI,MD5 SHIJA CHARLES,MD5 THERESIA LUFYO,MD5
MODERATORS Dr.FASSIL G. Dr.MAYOKA R. Dr.Fr.GINGO
Learning objectives
Definition Surgical anatomy
and embryology of thyroid gland
Etiology Classification Pathophysiology Clinical
presentation
Workup Treatment Complications Prevention
DEFINITION
Goiter can be defined as enlargement of the thyroid gland irrespective of its pathology
THYROID
Derives its name from thyroid cartilage Anterior part of neck 20-25gm Functional unit=lobule Each lobule =24-40 follicles
SURGICAL ANATOMY
BLOOD SUPPLY
NERVE SUPPLY
ARTERIES AND NERVES
EMBRYOLOGYDv from TGD(median bud of pharynx)which
passes from foramen caecum at base of the tongue to thyroid isthmus
First of the body's endocrine glands to develop, on approximately the 24th day of gestation.
2 main structures: the primitive pharynx and the neural crest.
EMBRYOLOGY
The inferior parathyroid glands arise from the dorsal wing of the third pharyngeal pouch.
The initial descent of the thyroid gland follows the primitive heart and occurs anterior to the pharyngeal gut. At this point, the thyroid is still connected to the tongue via the thyroglossal duct.
PHYSIOLOGY
THYROID HORMONES
Mental growth and developmentPhysical growthBMRSensitivity to catecholamines
ETIOLOGY OF GOITRE
Factors associated with goiter formation can be classified as follows:-Hereditary factorsHormonal factorsDietary factorsPharmacological factorsPhysiological factorsEnvironmental factorsPathological factors
Hereditary factorsInherited defect of thyroid hormone
synthesis Enzymatic defect deficiencyDyshormonogenesis
Familial goitre
Hormonal factorsThyroid hormone dysfunction
Hyperthyroidism (overproduction of thyroid hormones)
Hypothyroidism (underproduction of thyroid hormones)
Dietary factors
Dietary iodine deficiencyGoitrogens:-
Cabbage endemic goitre
Pharmacological factorsUse of goitrogen drugs like para-
aminosalicylic acid (PAS), thiocyanate and antithyroid drugs [e.g. thiouracil, carbimazole] hypothyroidism
Physiological factorsIncreased metabolic demand of
thyroid hormones e.g. during pregnancy or puberty physiological goitre
Environmental factors
Exposure to radiations Thyroid cancer
Hypothyroidism
Pathological factorsIntrinsic thyroid gland diseases
Inflammatory goitresNeoplastic goitres-Benign adenoma(follicular adenoma)-MalignantA.Primary
Well differentiated, Poorly differentiated, Arising from parafollicular cells
B.Secondary
CLASSIFICATION
Etiological classificationEpidemiological classificationAnatomical classificationPathological classificationFunctional classificationMorphological classification
Etiological classificationPhysiological goitre
Goitres resulting from increased metabolic demand of thyroid hormones e.g. during pregnancy or puberty
Pathological goitreGoitres resulting from diseases
affecting the thyroid gland e.g. Neoplastic or inflammatory conditions
Epidemiological classificationFamilial goitres
goitres that run in families as a result of Inherited defect of thyroid hormone synthesis
Endemic goitresdefined as thyroid enlargement affecting
a significant number of inhabitants of a particular locality
Sporadic goitresgoitres that run sporadically
Anatomical classification
Cervical goitreGoitre situated on the anterior aspect of
the neckRetrosternal goitre
Goitre extends downward and get situated behind the sternum
Intrathoracic goitreThe type of goitre which extends into
thoracic cavity
Pathological classificationSimple goitresToxic goitres Neoplastic goitresInflammatory goitresMiscellaneous (Other rare types)
Functional classificationToxic goitre
Type of goitre associated with thyroid hyperfunction (hyperthyroidism)
Non-toxic Type of goitre associated with thyroid
hypofunction (hypothyroidism) or normal thyroid function (Euthyroid)
Morphological classificationAccording to the texture of the
glandDiffuse goitreNodular goitre
Solitary nodular goitreMultinodular goitre
PATHOPHYSIOLOGY
The pathophysiological consequences of goitres results from one of the following:-The effect of thyroid hormone
dysfunctionThe effect of enlarged thyroid glandThe effect of primary disease causing
goitre
Effect of thyroid hormone dysfunction
Thyroid hyperfunction (hyperthyroidism)
Features of hyperthyroidism
Thyroid hypofunction (hypothyroidism)
Features of hypothyroidism
Effect of enlarged thyroid gland
Effect on the trachea dyspneaEffect on the esophagus
dysphagiaEffect on the superior venacava
distended neck veinsEffect on the recurrent laryngeal
nerve horsiness of voice
Effect of primary disease causing goitre
The effect depends on the underlying disease
CLINICAL PRESENTATION
History (Symptoms)Physical examination (Signs)
History (Symptoms)Age SexMain complaints
Anterior neck swellingDurationMode of onsetRate of growthAssociated pain
History (Symptoms)… Pressure-related symptoms
Dysphagia, dyspnoea, hoarseness of voice, neck vein engorgement etc
Review of systems to assess toxicityCNS- tremors, irritability, mental
disturbance CVS- palpitation, dyspnoea, orthopnoeaGI- change of appetite, constipation,
diarrhoeaMSS- bone pain, weight change, heat or
cold preference, excessive sweating
History (Symptoms)…….. Past medical history
Previous medication, previous h/o irradiation
Family and social historyH/o goitre in the family or in the
community
Physical examination General examinationLocal examinationSystemic examination
General examinationLook for four cardinal features of
toxicity namely:-ExophthalmosisTachycardiaTremorMoist skin
Local examinationInspectionPalpationPercussionAuscultation
Systemic examinationCentro nervous system Cardiovascular SystemRespiratory system
WORK UP
Laboratory studiesImaging studies Endoscopic studiesHistopathology
Laboratory studiesSerum TSH(0.3-5IU/ml)Serum T3(1.5-3.5nmol/l)Serum T4(55 – 150nmol/l)Disease T3 T4 TSH
Thyrotoxicosis Increased Increased Supressed
T3 toxicosis 2X Normal Suppressed
Hypothyroidism Low/normal Low Increased
Labs cont…
Serum thyroglobulinSerum cholesterolThyroid autoantibody levelsThyroid scintigraphy
Imaging studiesPlain x-ray of the neckThyroid ultrasoundThyroid radioisotope scanCT scan/MRIBarium swallow
Plain x-ray of the neckPlain radiography of the neck may
reveal the following:-Tracheal deviation or
compressionCalcification within the goitre
Thyroid ultrasound Help to determine the
physical characteristics of the goitre and used to:- distinguish solid from
cystic nodules assess whether more
than one nodule exists to assess the exact size
and shape of the thyroid gland
Aid in ultrasound guided FNAC
Thyroid radioisotope scan Used to determine the functional activiity by
distinguishing a nodule as hot, warm, or cold, based on the relative amount of uptake of radioactive isotope Hot nodules take up excessive amounts of
isotope and indicate autonomously functioning nodules
Cold nodules does not radioactive isotope and therefore indicate hypofunctional or nonfunctional thyroid tissue
Warm nodules appear gray and suggest normal thyroid function
The radioactive isotopes that are most commonly include 123-Iodine, 99m-Technetium and 131-Iodine
CT scan/MRIGive excellent anatomical detail of
thyroid swelling but have no role in the first line of investigation
Help to assess recurrence and intrathoracic or retrosternal goitres
Barium swallowTo assess compression of the
esophagus
Endoscopic studiesIndirect laryngoscopy
To assess the mobility of the vocal cord
HistopathologyFine needle aspiration cytology (FNAC)Open biopsy
TREATMENT
Medical treatmentRadioiodine Surgery
Medical treatmentLugol’s iodine
thyroid hormone synthesis vascularity
Antithyroid drugs eg CarbimazoleUsed to restore the patient to a euthyroid
state -adrenergic blockers E.g. propranolol
tachycardia & palpitation Used to restore the patient to a euthyroid It also vascularity
RadioiodineThyroiodine destroys thyroid cells
and as in thyroidectomy reduces the mass of functioning
SurgeryIndicationsPreoperative careIntraoperative care Postoperative care
IndicationsCosmetic purposeSuspected malignancyToxic goitrePressure symptoms
Preoperative careCorrect anemia, mobilize blood donor Treatment of intercurent disease or
infectionsThe thyroid functional status should be
determinedThe patient should be made euthyroid
Preoperative care……Admit the patient a day before
operationAnesthetic visitAn informed written consent for
operation and anaesthesia
Intraoperative careTypes of surgery (Thyroidectomy)
Subtotal thyroidectomyNear-total thyroidectomyTotal thyroidectomyThyroid nodulectomy
Postoperative careIv fluidAnalgesicsAntibiotics Monitor vital signs
COMPLICATIONS
Complications related to enlarged glandComplications related to thyroidectomy
Complications related to enlarged gland
Tracheal obstruction airway obstruction
Secondary thyrotoxicosisMalignant transformation
Complications related to thyroidectomy
Haemorrhage Respiratory obstruction Recurrent laryngeal nerve palsy Thyroid storm Thyroid insufficiency Parathyroid insufficiency Wound infection Hypertrophic scar Keloids
PREVENTION
PrimarySecondaryTertiary