15 CARACTERISTICAS DEL PLAN RECOMENDADO
15.6 Costos marginales de largo plazo de generación
2
© BRIHASPATHI ACADEMY ׀ SUBSCRIBER’S COPY ׀ NOT FOR SALE
• Increased motility of the GIT due to increased smooth muscle tone
• Weakness of skeletal muscles due to protein breakdown & decreasing muscle myoglobin
• Excessive sweating due to stimulation of adrenergic nerve fibers to sweat glands
• Neuritis leading to nervous irritability
EVALUATION OF THE THYROID History
• The thyroid gland can cause two groups of symptoms
1. Those connected with the swelling in the neck
2. Those related to the endocrine activity of the thyroid gland
Neck Symptoms
H/O a lump in the neck
H/O discomfort during swallowing
H/O dyspnoea
H/O pain
H/O change in the voice (Hoarseness)
Eye Symptoms
The patient may complain of staring of protruding of the eyes
H/O difficulty in closing eyelids
H/O double vision
H/O pain in the eyes
Symptoms of Thyrotoxicosis
Nervous symptoms: Nervousness, irritability, insomnia, nervous instability, tremor of the hands
Cardiovascular systems: Palpitations, dyspnoea on exertion, swelling of the ankles and chest pain
Metabolic & GIT symptoms: High in appetite but loss of weight, change in bowel habit usually diarrhea, preference of cold weather
With excessive sweating and intolerance of hot weather. Changes in menstruation usually amenurrhoea.
Symptoms of Myxoedema
Increased weight with deposition of fat across the back of the neck
Slow thought, speech and action
Intolerance of cold weather
Loss of hair lag, ophthalmoplegia, chemosis
• Examine the neck always; check that the lump moves with swallowing
• Palpate the cervical lymph nodes
Investigations
• Synthesis and liberation of thyroid hormones is controlled by TSH from the anterior pituitary 1. Measurements of thyroid hormones in blood
Total serum thyroxin (T4) (55-150 mmol/l)
Estimation of free hormone level is more accurate as total serum level is under the influence of carrying proteins:
2. Estimation of serum TSH
This test is routinely done with estimation of thyroxin as it is,
o Elevated in hypothyroidism o Below normal in thyrotoxicosis 3. Tests using radioactive iodine I123
Radioactive iodine uptake
Thyroid scanning
DISEASES OF THE THYROID
• Goiter (Gutter – throat) is the word used to describe enlargement of part or all of the thyroid gland
• Goiter may be classified clinically as follows I. Euthyroid
A. Diffuse Euthyroid types 1. Endemic goiter 2. Physiological goiter 3. Simple goiter 4. Thyroiditis
B. Nodular Euthyroid types 1. Single Nodular 2. Multi Nodular
II. Hyperthyroid
A. Diffuse (Graves Disease) B. Nodular (Hyperthyroid)
1. Single Nodular 2. Multi Nodular
III. Other classifications according to toxicosity A. Thyroiditis
1. Subacute Thyroiditis (De Quervains Disease)
2. Hashimoto’s Disease 3. Riedel’s Disease
NODULAR ENLARGEMENT (Euthyroid) The Solitary Nodule (SN)
• S.N. is the common clinical problem and significant percentage of cases represent some form of cancer.
Clinical History and Examination
Age, sex, place of birth, family history and H/O radiation
H/O: Showed specifically emphasize the duration of the swelling, recent growth and local symptoms (dysphagia, pain, changes of voice)
O/E: The clinician must systemically palpate the thyroid to determine whether there is solitary nodule or mulitnodular goiter and whether there are palpable lymph nodes
Causes of solitary nodule in the thyroid gland 1. Multinodular goiter
2. Haemorrhage into nodule
3. Adenoma
4. Carcinoma (papillary or follicular) 5. Enlargement of the whole of one lobe
(Usually Hashimoto’s thyroiditis)
Treatment
Conservative treatment indicated in patient with multinodular goiters and Hashimoto’s thyroiditis.
Indicators for surgery are, 1. Suspicious of cancer 2. Symptoms of pressure 3. Hyperthyroidism 4. Substernal extension 5. Cosmetic deformity 6. Patient expose to radiation 7. Family history
Multinodular Goiter
• The aetiology of this common type of thyroid swelling is unclear. Often the disease is sequel to previous simple or endemic goiter.
• Goiter may occur early in the life as consequence of congenital defect in thyroid hormones product.
• Symptoms are usually awareness of neck mass, dyspnoea, dysphagia or symptoms caused by interference with venus return.
• Thyroid function studies (T4, T3) normal TSH increased and thyroid antibodies normal.
Radioactive iodine uptake on scanning, may be increased.
Pathological Complications
Cyst formation
Haemorrhage into cystadenoma may lead to compression of the trachea
Calcification
Infection
Intrathoracic extension
Toxicity (secondary thyrotoxicosis) common at the age of 30 years
Pressure effects
Malignancy may develop in at least 10% of long standing cases
Treatment
If there are no clinical signs of malignancy and the gland is not symptomatic, conservative treatment as thyroxine
General Surgery Thyroid Diseases
4
© BRIHASPATHI ACADEMY ׀ SUBSCRIBER’S COPY ׀ NOT FOR SALE therapy and simple observation is
appropriate
Surgery, if there is any above complication (Subtotal Thyroidectomy)
TOXIC GOITER (Diffuse) (Primary Thyrotoxicosis or Graves Disease)
• Graves Disease is thought to be autoimmune disease resulting from defect in cell mediated immunity especially in view of,
The presence of circulating thyroglobulin and microsomal antibodies in many patients with Graves Disease
Lymphocytic infiltration of the gland
• There is often increase in IgG and the substance known long-acting thyroid stimulators (LATS)
• Graves Disease usually occurs in the twenties and thirties and affects females more often than males
Clinical Presentation
• Since the excess thyroxine affects all the cells of the body, the symptoms are varied.
General Symptoms
• The increased metabolism causes,
Loss of weight with increased appetite
Intolerance of warm weather with excess sweating
Warm sweating hands
Nervous Symptoms
• Nervousness and irritability with disturbance
• Fine tremors
Cardiovascular Systems
• Palpitation and tachycardia
• Elevation of the pulse rate of the sleeping patient
• Atrial fibrillation
Gastrointestinal Disturbances
• Increased appetite for food and drink
• Loose stools with diarrhoea and distention
Genitourinary Symptoms
• Polyuria
• Menstrual disturbances
• Infertility with impotence
Skeletal Effects
• Muscular weakness
• Bone pain
Eye Signs
• Lid retraction
• Protussion of the eye ball (exopthalmos)
Management
Medical Treatment
• The preferred method of treatment is medical since the disease has tendency to remit spontaneously after 1-2 years in adults or 3-6 months in children
• Antithyroid drugs altering various stages of iodine metabolism:-
Propylthiouracil and methimazole
Iodine in high concentration (Lugol’s Iodine)
Propranalol
o Prolonged therapy is required otherwise, incidence of recurrence is high if drugs are stopped
Radioactive Iodine Therapy
• 131I may be given safely after othe patient has been treated with antithyroid drugs and has become Euthyroid
• Radioactive Iodine is indicated in elderly or poor risk for surgery patient or patient with recurrence
• Contraindication: Children and pregnant women should not be treated with radioactive iodine
Surgery (Sub total Thyroidectomy) Indications
1. Failed medical treatment 2. Very severe disease
3. Large goiter with pressure symptoms 4. Ophthalmic complication
5. Compensated thyrocardiac fibrillation 6. Social and economic circumstances
Pre-operative Preparation
For at least 2 weeks; it consists , o Complete physical and mental
rest o Sedation
o Lugol’s Iodine ten drops TDS in milk or orange juice for 10-15 days before surgery
o Antithyroid drugs in severe cases should be stopped 2 weeks before surgery
o Propranalol (Inderal) 10-40 mgms TDS for 4 days before surgery and one day after surgery
Postoperative Complications Immediate
1. Haemorrhage
2. Recurrent laryngeal nerve damage 3. Thyroid crisis
4. Parathyroid tetany
Late Complications 1. Hypothyroidism 2. Recurrent thyrotoxicosis 3. Keloid scars
PLUMMER’S DISEASE (Toxic Nodular Goiter/
Secondary Thyrotoxicosis)
• Secondary thyrotoxicosis differs from primary thyrotoxicosis in the following:
Diffuse Grave’s disease
Nodular Plummer’s
disease
Age Young age Elderly
Onset Abrupt Gradual
Course Remissions &
exacerbations Steady course Nervous
symptoms +++ +
Metabolic
manifestations +++ +
Eye signs +++ + false
CV
manifestations + +++
Thyroid gland Diffuse Nodular
HYPOTHYROIDISM
• Deficiency of thyroid hormones in infancy leads to cretinism where as in adult, it leads to myxoedema
Cretinism
• Cretinism is congenital deficiency of thyroid function which may be associated with aplasia of the thyroid or with goitrous gland (Cretinoid Goiter)
• Clinically the child is sluggish constipated and post-bellied with pale puffy face, protruding tongue, thick lips, flattered nose, short neck and thick short hands
• In adolescence, the patient is dwarfed and mentally retarded with dry wrinkled skin
• The thyroid gland may or may not be palpable
• Treatment: Thyroid extract should be given daily for life.
Myxoedema
• This common disease is important to the surgeon because there are other causes than surgery can cause it like Hashimoto’s Disease, De Quervain’s Thyroiditis, Iodine deficiency and Irradiation
• Most patients are women and the commonest age at menopause
Clinical Symptoms
Voice: Deepening
CVS: Slow pulse, cardiomegaly
Neurological: Mental slowness o Delayed reflex relaxation o Carpal tunnel syndromes
Skin: Dry , Coarse, loss of hair; Periorbital swelling
Genital symptoms: Menorrhagia
GIT: Increased weight and constipation
Medical Treatment
Thyroxine - the initial dose should be 0.05 mg daily; increased gradually until the serum thyroxine level is stabilized
THYROIDITIS
• Diseases in which circulating thyroid antibodies can be demonstrated with common features such as lymphocytic infiltration of the gland.
General Surgery Thyroid Diseases
6
© BRIHASPATHI ACADEMY ׀ SUBSCRIBER’S COPY ׀ NOT FOR SALE
• The macroscopic appearance of the thyroid in autoimmune disease is hard and pale and microscopically.
• Most of the gland may be replaced by sheets of lymphocytic cells.
1. De Quervain’s Disease
Virus infections which usually affect middle age women, often in course of influenza or mumps
The gland became enlarged and painful with fever, pain on swallowing and radiating to the ears.
The onset is sudden but the condition subsides spontaneously in about 3-6 months
Most cases required no treatment apart from analgesics in severe cases giving short course of steroids for about a month.
2. Hashimoto’s Disease
The etiology of this disease is not known and the most common form of thyroiditis.
It is characterized by enlargement of the thyroid with or without pain and tenderness
It is common in women and in most often seen at the time of the menopause.
Hashimoto’s thyroiditis is believed to be autoimmune disease in which patients became sensitized against their own thyroid tissues and form antithyroid antibodies disease hypothyroidism become more common
Treatment appropriate for most patients consists of giving suppressive doses of thyroid hormones.
Operation is indicated for marked pressure symptoms, suspected malignancy and for cosmetic reason.
3. Riedel’s Thyroiditis
This very rare disease is grouped with the autoimmune thyroid diseases only because of tradition and for convenience
Thyroid antibodies are not present in the blood and histological examination of the gland shows dense fibrosis and no lymphatic infiltration
Clinical presentation usually occurs in middle age and common in men than women and may related to other ill understood diseases such as mediastinal fibrosis and sclerosis, cholangitis and may cause pressure symptoms such as cough, dyspnoea or dysphagia
The gland is usually stony hard
The condition is difficult to distinguish from thyroid malignancy and is only differentiated by biopsy.
Treatment replacement therapy is indicated if there is evidence of hypofunction of the thyroid. Steroids may arrest fibrosis in the early stages of the disease
Surgery resection of the isthmus is needed both to confirm the diagnosis and relieved symptoms.
ACUTE SUPPURATIVE THYROIDITIS
• Uncommon; caused by haematogenous spread of microorgansims into the thyroid
• Clinical presentations: Characterized by sudden pain, accompanied by dysphagia, fever, and chills and swelling and redness area one or both lobes. Usually follow upper respiratory tract infection
• Organisms: Most of them are streptococci and staphylococci. It may be associated with piriform fistulae. Barium swallow recommended
• Diagnosis by needle aspiration with appropriate bacteriological studies
• Treatment is by open drainage or localized resection with administration of antibiotics
THYROID CANCER
• Thyroid cancer can be primary or secondary.
• The primary divided into benign and malignant tumours
Benign Tumours of the Thyroid
• Mostly are adenomas, usually solitary and encapsulated and compress the adjacent thyroid
• The major reasons for removal are
Suspicious of cancer
Functional overactivity
Cosmetic disfigurement
Malignant Tumours
• These are rare and usually come from adjacent structures
PAPILLARY CARCINOMA
• This is the commonest type of tumour seen in children and in young adult and usually arises in solitary adenoma or cystadenoma
• It grows slowly but usually attains a large size forming soft cystic mass
• This type is relatively less malignant than other variety
• The tumour has special tendency to invade the lymph nodes and the patient may present with enlarged LN while the primary growth is still impalpable
Operation of choice is total thyroidectomy with removal of involved lymph node
The patient is treated by thyroxine as maintenance and suppression TSH secretion
• Are common in endemic goitre regions
• The invasive type characteristically spread by blood stream to bone and ultimately to the lungs.
• Typically the tumour presents either as solitary lump in the thyroid gland or as pathological fracture, it take up radioactive Iodine as do its metastasis
• The prognosis is not as good as with the papillary type
• Treatment by total thyroidectomy. This is followed by ablation dose of radioactive iodine
MEDULLARY CARCINOMA
• The rarest variety 2-5% of the thyroid tumour
• It has the following characteristics
It arises from the para-follicular (C) cells which is derived from the ultimobranchial body which secrete calcitonin
It is tumour which tend to present in young adult as autosomal dominant in some families
May be associated with bilateral pheochromocytoma and hyper parathyroidism known as Sipple syndrome or (Type II MEA).
The diagnosis can be made by demonstration of raised serum calcitonin level and serum calcium level normal.
Doesn’t respond to the treatment by radioactive
Clinical Features
• Swelling: The thyroid enlarges rapidly with short duration
• Pain is common with pressure symptoms with dyspnoea, dysphagia and changes in the voice
On Examination
• The thyroid swelling feels hard irregular and does not move freely on deglutition; late cases the skin becomes fixed
• Glandular metastasis occurs 1st in the prelaryngeal, pretracheal LN later in the deep cervical and mediastinal glands
• Distant metastasis are common in the bone Eg:
Vertebrae, skull and long bones
Treatment
• By total thyroidectomy with modified neck dissection
• External beam radiotherapy is useful when it is impossible to remove fully the tumour
• Maintenance therapy for life with thyroid hormones
ANAPLASTIC CARCINOMA
• This is the rarest variety usually affect elderly people and carried extremely poor prognosis
• The tumour grow rapidly and characteistic features are the early invasion of the adjacent structures with early distant metastasis by blood and lymphatics
General Surgery Thyroid Diseases
8
© BRIHASPATHI ACADEMY ׀ SUBSCRIBER’S COPY ׀ NOT FOR SALE Treatment
• Partial removal of the gland or splits the isthmus, if there is airway compression.
• Radiotherapy is the treatment of choice for relieving the distress
MALIGNANT LYMPHOMA
• Non Hodgkin’s lymphoma of the thyroid is unusual disease which predominates in women and is more common in middle age
• It presents with swelling of the thyroid gland usually in association with involved regional lymph node
• There is evidence that Hashimoto’s thyroiditis is sometimes precursor of this type of thyroid tumour
Treatment
• The treatment of choice is - Radiotherapy or Chemotherapy
• The prognosis is poor
Comparison of Malignant varieties
Spread
Differen-tiation Cell of
Origin
% of Total Type
Lymphatic Well
Epithelial 60%
Papillary
Haematog enous Well
Epithelial 25%
Follicular
Direct, lymphatic and haematog enous Poor
Epithelial 10%
Anaplastic
Lymphatic and haematog enous Moderate
Para follicular 5%
Medullary