lec#3 surgery
TRANSCRIPT
-
7/29/2019 Lec#3 surgery
1/18
Thyroid
Thyroid Anatomy :
-
7/29/2019 Lec#3 surgery
2/18
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.
-
7/29/2019 Lec#3 surgery
3/18
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
-
7/29/2019 Lec#3 surgery
4/18
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
-
7/29/2019 Lec#3 surgery
5/18
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
-
7/29/2019 Lec#3 surgery
6/18
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 .
-
7/29/2019 Lec#3 surgery
7/18
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.
-
7/29/2019 Lec#3 surgery
8/18
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
-
7/29/2019 Lec#3 surgery
9/18
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
-
7/29/2019 Lec#3 surgery
10/18
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)
-
7/29/2019 Lec#3 surgery
11/18
- 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
-
7/29/2019 Lec#3 surgery
12/18
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 .
-
7/29/2019 Lec#3 surgery
13/18
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 .
-
7/29/2019 Lec#3 surgery
14/18
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.
-
7/29/2019 Lec#3 surgery
15/18
-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 .
-
7/29/2019 Lec#3 surgery
16/18
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
-
7/29/2019 Lec#3 surgery
17/18
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 .
-
7/29/2019 Lec#3 surgery
18/18
For give me for any mistake
Done by Haitham Nasser Oweis