THYROID GLAND
description
Transcript of THYROID GLAND
THYROID GLAND
Begashaw M (MD)
Anatomy
Goiter
Generalized enlargement of the thyroid gland which is normally impalpable
Classification
1. Simple-Euthyroid _Diffuse hyper plastic
_(Multinodular)2. Toxic_Diffuse - Grave’s disease_Nodular_Toxic adenoma
3. Neoplastic _ Benign _Malignant4. Inflammatory _Autoimmune_Infectious_Acute –bacterial/viral_Chronic -tuberculous
Thyroid lesions
Simple Goiter
Patho - physiology enlargement of the thyroid glandstimulation of the thyroid gland by high
levels of circulating TSH common in Females
Etiology
_Iodine deficiency _Goitrogenscabagge_Drugs iodine,lithium_Defective hormone synthesis_peripheral resistance to thyroid hormone
Diffuse hyper-plastic goiter
Persistent stimulation by TSH causes diffuse hyperplasia of the thyroid gland
Soft, diffuse & largeUsually occurs at puberty , pregnancy Areas of active lobule & inactive lobules
Goiter –simple
Nodular goiter Nodular goiter -solitary -multinodular Nodule -colloid when filled with colloid -cellular Secondary changes -cystic degeneration -hemorrhage -calcification
Diagnosis
Clinical presentation_Discrete swelling in one lobe -Solitaryisolated -Dominant noduleabnormality Elsewhere_smooth, firm_painless _moves with swallowing _ euthyroid
Investigation
TFT T3, T4, TSH CXR/Thoracic inlet x-rayscalcification,
tracheal deviation & compression Thyroid antibody titers FNACytology
Complications
Compression stridor, dysphagia, pain, & hoarseness
Secondary thyrotoxicosisCarcinoma malignant changes of the
follicular type
Retrosternal goiter
Prevention
Introduction of iodized salt Thyroxin of 0.1mg dailyNodular stage is irreversible
Indication of surgery
CosmeticTracheal compressionWhen malignancy cannot be excluded Options of surgery _Near total thyroidectomy _Subtotal thyroidectomy
Toxic goiters
Thyrotoxicosis - increased metabolic rate due to high level of circulating thyroid hormone
8X more commonly seen in females than males
Clinical features
symptoms _Loss of weight in spite
of good appetite_preference of cold_Palpitation_Tiredness_Emotional liability
signs_excitability_presence of goiter_hot & moist palms_exophthalmus in
primary type_tachycardia with
cardiac arrhythmia
Diffuse Toxic GoiterGraves Disease
Is a diffuse vascular goiter appearing at the same time as symptoms of hyperthyroidism
Occurs in younger womenFrequently associated with eye signsHypertrophy & hyperplasia are due to
abnormal TS antibodiesF > M = 7:1
Graves disease
Toxic nodular goiter
A simple nodular goiter is present for a long time before hyperthyroidismsecondary thyrotoxicosis
Seen in middle aged/elderly people Less frequently associated with eye signsNodules are inactive Intermediate thyroid tissue is involved in
hyper secretion
Toxic nodule
Solitary hyperactive nodule which may be part of a generalized nodularity or a true toxic adenoma
is autonomous not due to TS antibodiesnormal thyroid tissue surrounding the
nodule is suppressed & inactive
Diagnosis
Clinical picture T3,T4,TSH Isotope scanning
TreatmentAntithyroid drugsSurgeryRadioiodine
Anti thyroid Drugs
used to resume the patient to a euthyroid state maintain this for a prolonged period
cannot cure a toxic nodule
Surgery
Preoperatively, the patient must be prepared with antithyroid drugs so that the patient becomes euthyroid
Subtotal thyroidectomy
Post-operative complications
HemorrhageRespiratory obstructionRecurrent laryngeal nerve paralysisThyroid insufficiencyParathyroid insufficiencyThyrotoxic crisis (storm)Wound infection
Thyroid Tumour BenignFollicular adenoma Malignant Primary - EpithelialFollicular,Papillary,Anaplastic- Para follicularMedullary- Lymphoid cellslymphoma Secondary- Metastatic- Local infiltrations
Benign Tumours
Follicular adenomas-solitary nodules -distinction between a follicular carcinoma &
adenoma can only be made by histological examination
-Treatment Lobectomy
Malignant Tumors
Clinical feature-Thyroid swelling-Enlarged cervical lymph node -papillary
carcinoma-Recurrent laryngeal nerve paralysis –locally
advanced disease-Anaplastic-hard, irregular, infiltrating
Thyroid Cancer
Investigations
TFTT3,T4,TSHFNAAntibody assayRadio isotope scanning
Treatment/Prognosis
_Surgerytotal thyroidectomy_Prognosis Histological type, age, extra
thyroid spread, & size of tumor_ Males > 40 yrs of age & Females >50 yrs
have worse prognosis_Distant metastatic diseaseworse prognosis
Anaplastic Carcinoma
Mainly in elderly womanLocal infiltration Epread by lymphatics & blood streamExtremely lethal tumors with death occurring in
most cases within month Present in advanced stages with tracheal
obstructionRadiotherapy