Lec#3 surgery

7/29/2019 Lec#3 surgery

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Thyroid

Thyroid Anatomy :


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the thyroid is an endocrine gland usually extend from C-5 to T-1, this structure is a highly

vascular structure and its weight is from 20 to 30 gram . this we can see in this pic that the

thyroid gland has 2 lobes one on the right side and the other on the left, and we have the

connection between both sides thats called the Isthmus1.25 cm x 1.25 cm , you can see asmall extension from this isthmus upward to the thyroid cartilage and this is what we callPyramidal lobe , its not present in all patients but sometimes its there its present in about

33% of the population and its located anterior to the tchyroid cartilage .

The isthmus usually is against the tracheal rings number 2 ,3 and 4 and this is the most

important landmark anatomy during surgery for us , so the isthmus of the thyroid gland is

against the second, the third, and the fourth tracheal rings this is very important, and its

very rare to see a thyroid gland without isthmus.

the function of the thyroid gland is the secretion of the thyroxin and we will talk about the

pathophysiology of this hormone which is very important in the basic metabolism in the body

.

This pic show to us a patient with the Goiter of the thyroid and we can see enlargement of both

lobes the right and left with the isthmus between them and the Pyramidal lobe with the smallextension .

Something very important about the anatomy of thyroid gland is that both lobes are attached

laterally by a ligaments to the cricoid cartilage the landmark of cricoid cartilage ? how to

identify its location on yourneck ? its like this, hyoid bone is the most bony prominence after

the submental notch , the thyroid cartilage is the second bony prominence after the submental

notch while the cricoids cartilage is the third bony prominence after submental notch so the

cricoid cartilage is usually at the level of C-6 .

About the medial attachment of the thyroid gland usually its attached to the larynx andtrachea.


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This pic is very important

This pic refer to blood supply of thyroid gland ?

superior thyroid artery the first branch of the external carotid artery

the inferior thyroid artery branch thyrocervical trunk branch of

subclavian artery

very rare blood supply to the thyroid gland we call it the thyroid Ima arteryand its a branch

directly from the aorta not all people have this rare artery only a small percentage of them 10 %

The Dr ask questions and he said they are very important

Question one: isthmus usually is against the tracheal rings what are the numbers of

these rings ?

ans : number 2 ,3 and 4

question two: superior thyroid artery which supply thyroid gland branch from which

artery

external carotid artery

the inferior thyroid artery

direct branch from : thyrocervical trunk


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Thyroid Histology :

Thyroid Embryology :

What about the embryology of the thyroid gland ? the thyroid gland is usually derived from the

first branchial pouch and it ascend around the hyoid bone and it will be located against the

trachea , any abnormal thyroid tissue can be through the coarse from hyoid bone to the cricoid

cartilage. very important to know that the Parafollicular C Cells are different in the origin

from the main cells ( thyroid follicle ) that secret the thyroxin of the thyroid gland , this C cells

are usually originated from the ultimobranchial apparatus near inferior portion of pharyngeal

pouch .

Thyroid Physiology :

Usually the thyroid gland secret important hormones , one of them is the T-4 which is the

major hormone of the thyroid gland . another hormone is called T-3 and this is the active part

of the thyroid hormone , 90 % of the T-4 will be converted into T-3 peripherally and the action

is usually through T-3.

the regulation of secretion of thyroid hormones T-3 and T-4 are under the mechanism of

feedback

thyroid stimulating hormone ( TSH ) secreted from the anterior pituitary gland

thyroid releasing hormone ( TRH ) secreted from hypothalamus

Histologicaly, the thyroid gland have some of the important cells that secret the hormones ,

one of these cells is the thyroid follicle which is the functional unit of the thyroid gland , these

cells are lumen lined by cuboidal epithelium containing colloid and the main function of the

thyroid is to secret the hormones like T-3 , T-4 . and another important cells in the thyroid gland

is the C cells or the Parafollicular or what we call it the clear cells , this cells are important

and they secret calcitonin which is an important hormone for the metabolism of the calcium

which is important in bone resorption and the level of calcium is the serum


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Diagnostic Issues :

What about the diagnostic issues that are used to control any pathology of the thyroid gland ?

usually we started to major the level of T-3 and T-4 and TSH and sometimes the TRH. Another

test usually used is the RAIU isotope scan of the thyroid gland and we will talk about all of these

tests

It is very impotant

* Hashimotos Thyroiditis ---- antimicrosomal and antithyroglobulin antibodies

* Graves Disease ---- TSH Receptors Antibodies

Xray

to detect retrosternal thyroid extension ,thyroid calcification ,bony or mediastinal LN & lung

metastases

dr didnt talk about MRI AND CT ONLY IT IS JUST TO DETCT

metastasis from the thyroid gland .

Thyroperoxidase (TPO) mediates: conversion of iodide to iodine coupling of iodine to tyrosine and TG (colloid)

TSH joins follicular cell receptor, then: cAMP mediates:

active transport of iodide synthresis of thyroglobulin (TG) by ER

Lysosymes release T4/T3


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Ultrasound :

Ultrasound is important and easy , its not invasive there is no radiological exposure and the

same is MRI , while we all know the in CT scan there is a radiological exposure by the x-rays .

Ultrasound is usually used to differentiate between cystic and solid masses for any structure .

so in the thyroid in order to differentiate that there is a cystic or solid nodules we can ask about

ultrasound , also its used to differentiate if these nodules are single or multiple . so ultrasound

is a useful investigation that we use it even in the out patient clinic in order to see any cystic or

solid masses , sometimes a lot of ladies come to our clinic with a small or large nodule of the

thyroid and we can see that this is a cystic nodule and through the ultrasound we can aspirate

the cystic nodule and we can relief all the problem in the out patient clinic .

Radioisotpe scan :

Its another test we can use , we give radio active iodine to the patient either by inhalation or

by injection then we expose the patient to a gamma camera to see and to detect the radiation

through this gamma camera, an example of the radio isotope scan important in order

to differentiate between hot nodules and cold nodules .

Normal thyroid scan hot nodule cold nodule

when we speak about hot nodules it means a nodule that secrete too much of the thyroid

hormones T3 and T4 ( over functioning ) while cold nodule doesnt secrete T3 or T4 ( non -

functioning ) . so in radioisotope scan the idea is to differentiate like in ultrasound but more

specifically between multiple and single nodules . it can differentiate between cold and hotnodules and its very important to know that 20% of cold nodules are malignant while hot

nodules are rarely malignant , so cold nodules is more dangerous than hot nodules .


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What does thyroid gland means to you ? what is the importance of the thyroid gland ?

First of all it produces 2 hormones as I told you before the Thyroxin which is usually the T4 and

the Thyronin which is usually the T3. The importance of the thyroid hormones is to control the

metabolism of the body and this metabolism through these hormones affect the cells and we

will speak about that later . so we can see that the thyroid hormone affect any part of the body

starting from the eyes from the brain to the skin to the kidney to the GIT to the heart and

uterus . slide (25)

What does thyroid gland means to you ? what is the importance of the thyroid gland ?

What Does Your Thyroid Gland Do for You?

First of all it produces 2 hormones as I told you before the Thyroxin which is usually the T4 and

the Thyronin which is usually the T3. The importance of the thyroid hormones is to control the

metabolism of the body and this metabolism through these hormones affect the cells and we

will speak about that later . so we can see that the thyroid hormone affect any part of the body

starting from the eyes from the brain to the skin to the kidney to the GIT to the heart and

uterus .

FNA (Fine needle aspiration ) :

this is very important investigation and this is one of the simple investigation that can be used in order

to detect some pathologies specially malignancy or types of malignancy before we start the surgery.

Its used to aspirate either from the thyroid gland itself or if there is any nodule detected clinically or by

ultrasound then we can take aspiration from this nodule , and logically by FNA you can differentiate

whether this nodule is a cystic or a solid because if you aspirate a serous fluid or a blood so this is a

cystic nodule while if it is hard or firm and there is no fluid this means that it is a solid lesion or nodule .

If the lesion is solid and even if its cystic we send a samples after aspiration, so if there is a cystic mass in

the thyroid gland and we aspirate a fluid we take a fluid and we send it for cytology, for a culture and

sensitivity .. and also if its a solid we send these pieces of cells for cytological examination and

pathological examination .

Usually we do fine needle aspiration in clinic or we send the patient to pathological department that

they usually have the facility to do FNA.


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pathology of the thyroid gland

hypothyroidism - Hypothyroidism

- Hypothyroidism :

we will start to speak about hypothyroidism usually in hypothyroidism there is a decrease in

the secretion of T3 and T4 , and as I told u before this will affect all parts of the body,

so the patient usually come to the hospital or to the clinic with lethargy, with hoarseness,with hearing loss, with thick and dry skin , constipation , cold intolerance and

sometimes stiff gate.

Very important that some patient because of the severity of the hypothyroidism and the

chronicity , they presented with what we call Myxedema or coma secondary to hypothyroidism

, and these patient usually they are hypothermic ,bradycardia , plural effusion associated with

electrolyte imbalance , seizures and hypoventilation. So the severe case of hypothyroidism

we call it myxedema coma.THE effect of hypothyroidism in all organs of the body

1:the intestine the patient usually presented with constipation

2:in the productive system they have decrease fertility ,

Refer to slide 28 to know the other effect


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Very important

What are the most common causes of hypothyroidism ?

Primary: abnormalities of the gland Secondary: abnormalities of the pituitary gland Tertiary: abnormalities of the hypothalamus (rare) Peripheral: end organ resistance

- c -erb A gene of chromosomes 17 and 3 code for cellular hormone receptors

The last one is some of the congenital and the genetic abnormality which means that we have

end organ resistance , what means of end organ resistance ? that the thyroid gland secrete T3and T4 but the peripheral organs is resistant to these hormones so sometimes it can be

manifested as hypothyroidism and one of the chromosomal abnormality at the level of 60 is the

c-erbgen.

The most common cause of hypothyroidism even in our country is autoimmune disease , or

what we call it the Hashimotos Thyroiditisit's not an infectious process so the patient at the

first stage in the first 2 to 3 weeks they presented with high T3 and T4 " mild hyperthyroidism"

but any inflammation of the thyroid gland usually it will finish by fibrosis and this fibrosis will

decrease the function of the thyroid gland resulting in hypothyroidism and this is what we

called it Hashimotos Thyroiditis.Iatrogenic causes are the next most common causes :

A patient come to us has a problem and we do a surgery for him like total thyroiectomy so the

patient sometimes will end with hypothyroidism due to this surgery .

Radioiodine ablation is associated with hypothyroidism and some times we have some of the

drugs that can be associated with the decreased of the function of the thyroid gland like the

lithium(Li) , the iodide and the amiodarone and this is one of the antihypertensive drugs.

Dr dont take anything about slide 32


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Treatment :

If you have a patient with hypothyroidism what are we going to do ?

We give thyroxine so the treatment starting with thyroxine and usually we give it after the

patient become euthyroid , so how we know that the patient is euthyroid ? if the T-3 and T-4

are low and the TSH is secondary to the feedback mechanism so we give him thyroxine.

It's not important to know about the dose .

What we call congenital hypothyroidism ? cretinism .

What are the symptoms of hypothyroidism in general ?

- cold intolerance

- bradycardia

- constipation

- depression

TSH cheacked every 12-18 months

liothyronine(T3) is an alternative

elderly patient with ischemic heart disease

starting at 25ug & dose every fortnight

(to avoid tachyarrhythmias & cardiac failure)


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- Hyperthyroidism (thyrotoxicosis )

Definition: any tissue start to expose high level of T3 and T4 it will mean that we have a

thyrotoxic stage or disease.

The symptoms that found in hypothyroidisim are the opposite in hyperthyridisim so these

patients are usually presented with nervousness ,tremors, sweating, heat intolerance ,

palpitation, weight loss , abnormal uterine bleeding and weakness, so these are the majors

symptoms or signs that we can see in thyrotoxicosis .

The most important causes of thyrotoxicosis are :

* First ( most common ) : Graves disease, which is a diffuse goiter.

* Second : toxic multinodular goiter .

* Third : toxic adenoma .

and of course there are rare causes like pituitary abnormality like if you have pituitary adenoma

that secrete high level of TSH this result with effect on the thyroid gland to secrete more T3 and

T4 , and this is what we call it secondary hyperthyroidism , while in graves disease , toxic

multinodular goiter , and toxic adenoma they are primary thyrotoxicosis or primary

hyperthyroidism .

symptoms

Nervousness Irritability difficulty Sleeping Bulging Eyes Unblinking Stare

Goiter Rapid Heartbeat Increased Sweating Heat Intolerance

Unexplained Weight Loss Scant Menstrual Periods Frequent Bowel Movements

Fine Tremor of Fingers Warm, Moist Palms


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Graves' disease :

Its an autoimmune disease like hashemotto thyroiditis . usually we have IgG antibodies that

usually will go to attack TSH receptors at the level of pituitary gland , so this will cause

stimulation of the TSH which will cause secretion more of the TSH which will result in more

effect on the thyroid gland to secret more T-3 and T-4 resulting in thyrotoxicosis .

Usually this patient with graves disease have a goiter which is enlargement of the thyroid gland

, in these patients the thyroid usually is soft because there is a diffuse enlargement of the

thyroid gland , its not multinodular or simple nodule its diffused enlargement of the thyroid

gland and this is logically because we have high TSH and TSH will affect all of the thyroid gland

and not part of it .

Histology: too many follicular cells, too little colloid

Treatment

Usually its very rare to see someone with this disease , usually we see it in females, young

ladies and young men too and they have this autoimmune disease , sometimes they are

associated with other autoimmune diseases like rheumatoid arthritis or crones disease ,

ulcerative coritis ( crones and ulcerative are chronic inflammatory powel disease ) , and as I said

its not common to see graves disease.

So how to treat this patients with graves disease ? I will start from the bottom of the slide ,

usually we need to monitor this patients well , this patients have a tachycardia or hypertensionso we start to give Beta blockers witch is very important in order to stabilize the patient .

Second we give antithyroid medications , anything against T-3 and T-4 and for example for

these is carbimazol , methimazol , propothyouracil , iodide , and actually this medications

inhibit the organification and the proteolysis ending with the inhibitionofangiogenesis , ok ?

but also in some cases beta blockers and antithyroid medications are not effective at all for the

patient so either we do surgery for them for removal of all of the thyroid gland or sometimes

we give radio iodine ablation therapy to destruct the thyroid gland .

Radioiodine ablation:

What is the radio iodine ablation ? this is the most common procedure that used for treatment

of graves disease in the USA, its usually indicated in patients that dont response to the

medical treatment , you know any disease at the beginning we start to treat it medically by

giving drugs , once you have a disease like graves witch is resistant to the medical treatment

we start to give radio iodine ablation .


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sometimes in patients specially in Europe and in our country we prefer to do the surgery for

these patients so in graves disease either u have one school that give you the chance to do

radio iodine ablation or sometimes you do the surgery with called the total or subtotal

thyroidectomy .

in totalThyroidectomy its the removal of all of the thyroid gland witch mean the right lobe, left

lobe , the isthmus and every other part of the gland while in the subtotal Thyroidectomy we

remove one of the lobes completely and about 80 85 % of the other lobe leaving about 10-15

% which means small grams of the thyroid in order not to secret too much and have

hyperthyroidism . and very important before to do any surgery , the patient should be

idothyroid which means we dont send the patient to the surgery directly when he has a high

level of T-3 and T-4 and low TSH secondary to the thyrotoxicosis , you should stabilize the

patient before starting with giving the medications usually from 6 to 8 weeks starting with

beta blockers and other drugs once the patient is stable and ready for the surgery then we

send him to do it.

Toxic Adenoma :

The second cause of thyrotoxicosis as I told you before is Toxic Adenoma . simply there is small

nodules or large nodules inside the thyroid gland that is highly active and secret too much of

T-3 and T-4 resulting in thyrotoxicosis . in graves disease the thyroid gland is all enlarged and

active while in toxic adenoma there is a simple nodule thats highly active and secrets high

amounts of T-3 and T-4 .

As I said before usually the TSH in thyrotoxicosis is low , so TSH is very important test for us, its

an indication to tell us either the patient hypo or hyper thyroidisim . so in toxic adenoma its

usually caused be a hot nodule and this nodule will result in causing thyrotoxicosis , usually this

nodule is larger than 3 cm , in the investigation we have low or absent TSH and high T-4 and

when we do a radioactive iodine to these patients or uptake which is one of the radiological

tests you can see this hot nodule and I show you before a picture for a hot nodule in this test .

and the treatment is usually to start medically in order for patient to become eothyroid and if

he is not responsive we give the radio active iodine ablation and sometimes we do surgery likein graves disease .


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Toxic Multinodular Goiter :

Its a goiter containing multiple nodules NOT a single nodule like in the previous pathology so

we have multiple nodules that secret too much hormone resulting in thyrotoxicosis . its

common in area with iodine deficiency and usually these patients have high T-3 and T-4 and low

TSH like in toxic adenoma and graves disease and usually there are multiple hot nodules not a

single nodule .

The treatment is usually starting with medical treatment in order to transfer the patient into

eothyroid state then you start giving either a radio active ablation therapy or you do surgery,

and the surgery in Toxic Multinodular Goiter is the same as graves disease which is

Total/Subtotal Thyroidectomy .

Summary :

Whats the most common cause of hyperthyroidism ? its graves disease

Second is toxic adenoma , third is toxic multinodular goiter.

How to diagnose thyrotoxicosis ? you ask for T-3 , T-4 and TSH level , so the diagnosis of hyper or

hypo is just serum level of T-3, T-4 and TSH and sometimes you can ask about TRH in order to

differentiate between primary or secondary or tertiary thyrotoxicosis .

Thyroiditis

Its the inflammation of the thyroid gland . what types of thyroiditis we have ?

Acute suppurative Painful (de Quervains) Postpartum Hashimotos Fibrous (Reidels)

- Acute suppurative thyroiditis : means bacterial infection , usually S. aureus or S. pneumo.

Usually preceded by trauma . the treatment of any suppurative process is to give IV antibiotics

and of course any formation ofabscess in general you treat it by drainage and incision even for

dentistry if you have a problem in teeth associated with abscess you have to drain it and incise

it.


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-Painful Thyroiditis (de Quervains): usually its secondary to upper respiratory

tract infection , its usually unknown virus , patients usually have a painful thyroid and any

thyroiditis will start with hyperthyroidism and end eventually with hypothyroidism because at

the beginning there is inflammation of the tissue witch will result in secreting more T-3 and T-4

so you will have a stage of thyrotoxicosis then inflammation will finish ending with fibrosis , this

fibrosis will damage the thyroid ending with non-functional thyroid and this will lead to

hypothyroidism .

Slide (45) is not important for you and Hashimotos Thyroiditis we already talked about it

Just know that Postpartum occur after delivery

Thyroid cancers :

Now we will talk about Thyroid cancers in these few last slides .

The incidence of thyroid cancer is 40 for each 1000,000 person per year . sometimes we speak

about The Good, The Bad and The Ugly thyroid cancer . ( remember this ! )

- The good one is : Papillary Thyroid Cancer- The bad one is : Follicular Thyroid Cancer- The intermediate one is : Medullary Thyroid Cancer- The ugly one is : Anaplastic Thyroid Carcinoma

Papillary Thyroid Cancer : 2: 1 f:m age 30 -40

In Papillary Thyroid Cancer the prognosis is good for patients when you discover it early and

then you remove the tumor, in general any thyroid cancer its treatment is total thyroidectomy,some patients have worse prognosis than other patients , for example when the patient is older

than 45 , larger size nodules , disorganized tumor and metastases and just to know its also

worse in male patients than females . the mortality is 0.5 % , it means 5 for each 1000 persons

will die and as I mentioned its the good one .


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Follicular Thyroid Cancer : in blood stream

usually Papillary Thyroid Cancer will cause invasion locally and it goes to the surrounding

structures and to the cervical lymph node, while in Follicular Thyroid Cancer, before it give localinvasion to the lymph node it will give metastasesand thats why its bad .

So in Follicular Thyroid Cancer its 3:1 F:M , the average age is about 50 and for diagnoses as we

know we do fine needle aspiration ( FNA) to any nodules , and in 20% when we have follicular

nodules they are cancer .

Something important in these cases , when patients presented with nodules of the thyroid

gland and we take FNA , the FNA will give us media containing follicular cells and its very

important to know that FNA cantdifferentiate between benign or malignant follicular nodes

because the differentiation depends on the invasion of basement membrane and this cant bedetected by FNA , so what we do usually is something called frozen suction biopsy during the

surgery , if I have nodules on the right lobe and I took FNA and it gives follicular cells but I dont

know either they benign or malignant so I do a surgery and I remove the right lobe of the

thyroid and I send it as a frozen suction biopsy ( while patient is unconscious ), after 20 minutes

the pathologist will tell us if its benign or malignant , if its benign then we finished the problem

but if its malignant we need to continue to total thyroidectomy .

the prognosis is worse with: age over 50, larger, disorganized tumor, vascular invasion and

metastsis outside thyroid . and the mortality rate is about 15% at 10 years.

Medullary Thyroid Cancer (intermediate) :

Its uncommon and can run in families , it has good cure rate and usually this cancer is very rare

to see. Land mark of it is calcitonin level will incrise

Anaplastic Thyroid Carcinoma : age 60-70

Very rare 1%

Its very uglytumor and usually no patient can survive from it , its highly invasive locally

and it will cause destruction to the trachea and the larynx and even if you do here total

thyroidectomy , this patients usually have very high recurrence rate and sometimes there is

nothing to do except ventilation and support . Anaplastic Thyroid Carcinoma is an ugly

tumor and most of the patients will die form it


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Complication of thyroid surgery :

The last slide and usually we bring a question about this slide . and I think its very important

slide for your future .

1) Damage to recurrent laryngeal nerve.. leading to palsy & causing hoarseness." and that why om kalthom refuse to do this surgery

We have two recurrent laryngeal nerves , right and left, during the surgery if we cut by mistake

one of these laryngeal nerves ( unilaterally ) we will cause hoarseness of voice while if the

surgeon cut the bilateral laryngeal nerve this will result in suffocation of the patient because

those recurrent laryngeal nerves are responsible for the vocal cords and these vocal cord have

an intrinsic muscles so if you cut these nerve supply the vocal cords will become closed

completely and the patient will suffocate so sometimes you need to do trachiostomy in order

to let the patient survive .

# Unilaterally --- hoarseness

## Bilaterally --- suffocation

2) Damage to external branch of superior laryngeal nerve leading to palsy

" in opera

3) Hypocalcaemia caused by damage to parathyroids

Its one of the complication of total thyroidectomy because we spoke about the parafollicular

cells and C - cells that secret calcitonin ( have the same effect like vitamin D , increase the

absorption of calcium ), which is important in the regulation of the serum calcium level so

some patients end with hypocalcaemia .

Calcitonin will cause resorption from the bone and will increase the calcium serum level so once

you have cutting of calcitonin it will decrease the resorpion resulting in hypocalcaemia .

4) Haemorrhagecausing laryngeal oedema & respiratory compromise.

And finally haemorrhage , if the surgeon had a problem and he did a major haemorrhage from

the thyroid gland specially if there is any destruction to the carotid arteries or to the internal

jugular veins or subclavian veins , this will end in intra operative haemorrhage and its very

sever and sometimes can lead to death .


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For give me for any mistake

Done by Haitham Nasser Oweis

Lec#3 surgery

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