Surgery of the thyroid gland

(Maily Jugulo-

Digastric)

(Maily Jugulo-

Omohyoid)

Surgery of the Thyroid Gland

1-Anatomy & Embryology:- -Emberyologically Formed in the floor of the mouth.

-Middle Thyroid veins may be present and they drain to

the internal jugular vein.

-Thyroida-Ima artery may be present as one of the 4

branches of the Arch of Aorta.

-The External Laryngeal nerves migrates away deeply

as it progress together with the superior thyroidal towards the

median line.

-Lymphatic Drainage:- Deep Cervical Lymph nodes

Upper half:- upper deep cervical LNs + Tracheal LNs.

Lower half:- Lower deep cervical LNs + Mediastinal LNs.

Upper

Isthmus

Lower

Isthmus

Congenital Anomalies: 1- Lingual Thyroid (Inside Tongue).

2- Retro-Sternal Thyroid. 3- Thyro-glossal Fissure. 4- Thyro-glossal Cyst (not fistula). 5- Aplasia (Hypoplasia: Failure to develop)

N.B:- A-The Thyro-glossal Duct is lined by simple columnar epithelium, its

patency is not of congenital origin but due to:-

1- Infection 2- Inadequate removal of previous cyst

B-Thyroid Gland is originated from the 2nd Pharyngeal pouch, while the

Parafollicular C-cells are originated from the Ultimobronchial body, while

the parathyroid glands develop from the 3rd & 4th Pharyngeal pouches.

Blood Supply:-

-Superior thyroid Artery External Carotid artery

-Inferior thyroid Artery Subclavian artery or thyrocervical trunk

-Superior thyroid Vein Internal Jugular vein

-Inferior thyroid Vein Subclavian veins

-Both laryngeal nerves are originated from the Vagus nerve.

-Superior laryngeal Nerve gives External & Internal laryngeal nerves.

-Relations:-

1-Trachea:- Compression Leads to Stridor & Orthopnea but not

Dyspnea.

-Stridor:- Upper Respiratory Tract obstruction.

-Dyspnea:- Lower Respiratory Tract obstruction.

-Orthopnea:- Dyspnea on lying flat corrected by standing.

2-External & Recurrent Laryngeal Nerves:-

-They supply the muscles that move the vocal cords.

-Compression on the recurrent laryngeal nerve leads to

hoarseness of voice (Abduction-Adduction Movement).

-Compression on the external laryngeal nerve leads to loss

of high tension voice (patient can only whisper).

3-Oesophagus:- very rare symptom

-Infiltrative compression may lead to Dysphagia as the

thyroid’s special character is moving during swallowing.

4-Common Carotid Arteries:-

-Compresion of both internal carotid arteries may lead to

Fainting attacks.

5-Superior Mediastinum:- only in retrosternal extension

-Compression of one or both subclavian arteries, in case

only one subclavian artery is compressed (mainly the

right) it will lead to unequal pulse in the upper limbs.

-Compression of the subclavian veins will lead to marked

seen of 4 veins on the neck:-

a- 2 External jugular veins.

b- 2 Anterior jugular veins.

NB:- Wircow’s Lymph node:- is the left supraclavicular lymph

node (one of the Mediastinal lymph nodes) which is only

enlarged during ovarian carcinoma metastasis.

-Thyroid Gland moves with deglutition because it’s attached

to the pretracheal fascia so it moves during contraction of

the mylohyoid muscle.

2-Physiology & Biochemistry:-

-the levels of T3 & T4 in the blood are affected by levels of protein

carrier produced by the liver.

-TSH affects the thyroid gland only 1.5-3 h/day, while TSI effect is 24h

-Stages of Thyrogenesis:- 1-Trapping 2- Oxidation

3- Organification 4-Binding 5-Coupling

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3-Pathology:-

-Causes of pain:- 1-Thyroiditis 2-Hemorrhagic cyst

-Differentiation of malignant swelling from non-malignant:-

1-Relative to swelling:-

-Rapidly progressive.

-They grow by infiltration while benign tumors grow

by expansion.

2-Relative to surrounding structures:-

-More Complications of the surrounding structure.

3-Relative to Lymph nodes:-

-They Metastasis by lymph nodes first.

Tyrosine + Iodine Mono-iodotyrosine

(T3) Tri-iodothyronine Di-iodotyrosine

(T4) Tetra-iodothyronine more active during

Emergencies

(TSH) Peripheral conversion in tissues

Thyroid Stimulating Hormone from anterior pituitary

(TRH) Thyroid releasing Hormone from hypothalamus

Negative

Feed-Back

4-Investigations of the Thyroid Gland:- -Diagnosis:- 1-Anatomical Diagnosis (Place)

2-Pathological Diagnosis (Type)

-Types of Investigations:-

1-To confirm your diagnosis (TFT, Ultrasonography).

2-To Prepare the Patient for the anesthesia (ECG, X-ray).

3-To Determine stage (FNAC, Cancer grading).

-Specific Investigations for the thyroid Gland:-

1-Thyroid Function Test (TFT):-

a- Free T3, Free T4, TSH Toxic

b- Free T3, Free T4, TSH Euthyroid

- Free T3 & T4 to prevent the count of globulin-bound hormones

which are affected by the number of globulin carriers produced

by the liver. N.B:- Normal TSI titre is 1:100

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2-Neck Ultrasound:-

a- Multinodular.

b- Diffused.

Normal Neck Ultrasound Normal Anatomical View

Nodular Diffused

Sympathetic Trunk

Strap

Muscle

3-Technitium Scan:-

a- Toxic more uptake Black (Hot).

b- Euthyroid normal uptake Gray (Warm).

c- Hypothyroidism less uptake White (Cold).

- Photography is by Gamma δ – Camera

- Technetium scan is safer & cheaper than Iodine 121 Scan.

- A total body scan should be performed for revealing metastasis

in case the thyroid is normal with proved malignancy.

- Also used in cases of secondary hyperthyroidism to gain

background about the interstitial active tissue and sites of

nodules which are going to be removed by the surgeon.

-If the Patient is Euthyroid with –ve TFT, this is mainly a malignant tumor and

tests number 4 & 5 must be performed.

-If the Patient is Toxic with +ve TFT, This mainly a benign tumor and no use of

tests number 4 & 5 and shouldn’t be performed.

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4-Fine Needle Aspiration Cytology:-

-It confirms malignancy but doesn’t differentiate carcinoma in situ

from infiltrative carcinoma.

-In +ve tests (malignant cases):-

a- Increased mitotic activity & mitotic figures are seen.

b- Increased Nuclear/ Cytoplasm Ratio.

c- Increase number of nuclei.

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5-Grade Classification of the Cancer:-

a- Grade:- Differentiated – Undifferentiated.

b- Stage:- Size of Tumor – LNs Metastasis – Body Metastasis

TNM (T1,T2,T3) (N0,N1,N2) (M)

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6-Computed Tomography of the Neck (CT Scan):-

- X-rays are used every 1Cm of the Neck.

- Used in malignancy, recurrent goiters, retrosternal extension.

- Positron emission tomography can be also used.

Normal

Technetium

Scan

Investigations of the thyroid

Diagnosis Tests

Anatomical

Pathological TFT + Neck Ultrasonography

+ve -ve -ve

Toxic Hypothyroidism Euthyroid

Conf. by Technetium Scan

Benign FNAC + Grade

Malignant

Neck CT on need

Goiter -Definition:- Enlargement of the whole thyroid gland

-Solitary:- Single nodular enlargement of the thyroid gland not Goiter.

Toxic Goiter Euthyroid Goiter

Def:- Enlargement of the whole of the Def:- Enlargement of the whole of the

thyroid gland with symptoms of thyroid gland without symptoms

thyrotoxicosis (hypersecretion) of thyrotoxicosis

Causes:- Sudden Decrease in

T3,T4 leading to sudden

increase in TSI,

leading for feed-back

T3,T4. Simple Goiter Neoplastic Inflammatory

Goiter Goiter بيقلوا كتير

Def:- Enlargement

of the whole of the Benign (rare)

Primary Diffused Toxic Goiter thyroid gland without

(Grave’s Disease) symptoms of thyro- Malignant

toxicosis which is

neither Neoplastic (less common)

Secondary Multinodular Toxic Goiter nor inflammatory

Simple Diffused Goiter

Simple Nodular Goiter

(Most common)

- Benign enlargement but never -Benign enlargement but could be

transformed into malignancy transformed into malignancy.

due to genetic causes.

1-Simple Goiter:-

A-Simple Diffused Goiter (Physiological Goiter):-

1-Causes:- Increase Demand on T3 & T4 leading to mild subclinical

increase of the level on TSH leading to slight enlargement

of the thyroid gland, only seen in females during Menarche

& Pregnancy.

2-Both cases resolve spontaneously but some people prefer to take T3

injection as a rapid treatment of goiter.

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B-Simple Multinodular Goiter:-

1-Causes:- Mild frequency of TSH secretion due to:- شوية يزيد و شوية يقل

a- Change of residence from oasis to sea many times.

b- Frequency of Iodide intake in food.

c- Emotional Distress (Hypothalamic disorders).

d- Goiterogenic Drugs – foods – calcium – paramino

salicylic acid.

e- Alb-mountain communities (Endemic).

2-Complications:-

a- Turn Into Malignant:-

-By turning into Follicular Goiter

-Known through:- -rapid progressive changes.

-Metastasis to LNs & Body.

-Complications to the surroundings.

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b- Turn into Thyrotoxicosis:-

1-Toxic Multinodular Goiter TSI Dependant:-

-Due to formation of Long acting Thyroid Stimulators =

LATS = Thyroid Stimulating Immunoglobulins = TSI

-They lead to marked stimulation of internodular tissue

which doesn’t depend on TSH anymore.

-The hyperactive internodular tissue now depends on

TSI (IgG) in the Serum.

Black (Hot) on Technetium

Scan with Gray(Warm)

Background

2-Autonomus Toxic Nodule Formation (Toxic Ad.):-

-One of the nodules (not the internodular tissue) turn

into toxic of unknown etiology, which doesn’t depend

on TSI nor TSH.

-Sub-total thyroidectomy is done (leaving 8 gm thy. tissue)

lobectomy + Isthmictomy

-To Differentiate between the 2 previous types

technetium scan must be performed, as each has

different treatment & Surgical Procedure.

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c- Cystic Degeneration:-

-Due to Hydropic degeneration of the cells leading to

cysts formation.

-May be solid type (no cysts) FNAC Used.

-May be accompanied by hemorrhage and pain (pain is

not a sign of malignancy) aspiration reveals altered blood.

NB:- Recent rapid increase of the thyroid volume in days Cyst

Recent rapid increase of the thyroid volume in months Malignancy

cysts are found in:Follicular (adenoma – carcinoma), papillary carcinoma, discrete swellings.

3-Investigations:-

TFT Euthyroid Neck Ultrasonography Diffused

Toxic Nodular

Signs of Thyrotoxicosis

Technetium Scan

Progression of the thyroid

Autonomus Toxic Multinodular

Very rapid Rapid FNA Cytology

No Treatment Cyst formation Malignant

Benign

4-Treatment:- 1-Surgical:- Total or Partial Thyroidectomy.

2-Coserve:- Just to follow up the patient and treat causes.

3-Drugs:- Oral T3 Tablets (not mainly used).

2-Toxic Goiter:-

A-Primary Diffused Toxic Goiter (Grave’s Disease):

1-Causes:- Formation of Thyroid Stimulating Immunoglobulins (TST),

causing relative increase in the levels of T3 + T4 and

decrease the level of TSH.

-The Direct effect of TSI on the normal gland causes

Diffused enlargement not nodular enlargement.

-Thyrotoxic effect starts parallel to the enlargement, while

in the secondary Multinodular toxic goiter the

enlargement precedes the thyrotoxic effect which comes

later as one of the complications.

2-Symptoms:- 3-Signs:-

-Eye:- Prominent Exophthalmos (Staring look) -Tachycardia Mainly during sleep

Lid Lag, Diplopia (the only prominent sign)

-Heart:- Tachycardia (Palpitation) -Water Hammer Pulse

Arrhythmias (may be absent)

-Pre-tibial Myxedema -Increased Excitability

-Loss of weight (Despite good appetite) -Joffroy’s Sign

-Cold sensation (High Basal Metabolic Rate) -Mobius Sign

-Severe Muscle Weakness (Thyromyopathy) -Von Gravis Sign (Lid-Lag)

-Tremors, Insomnia, Dysmenhorrea, Impotence, Decreased Libido.

NB:- 1-TACHYCARDIA:- T3,T4 doesn’t have a direct effect on the heart but they

increase the β-receptors sensitivity to the catecholamines.

Circulating T3,T4 β-receptors stimulation Tachycardia

Catecholamines

The Systolic Pressure Increased Stroke

Increases Volume

The Cardiac Output Increases

& Peripheral Resistance Decreases

Water Hammer Pulse Diastolic Pressure Decreases

2-EYE:-

a-Exophthalmos:- due to retro-ophthalmic infiltration and deposition of

mucopolysaccarides.

b-Lid Lag:- Spasm of the levator palpebrae superioris muscle during eye

movement, so that eye movement and lid movement doesn’t

occur at the same time.

3-Pre-tibial Myxedema (Misnomer):- thickening of the skin over tibia after

trauma due to deposition of hyalouronic acid,

(Non-Pitting Edema).

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B-Secondary Multinodular Toxic Goiter:-

1-Causes:- Toxic transformation of Simple Multinodular Goiter under

the effect of TSI.

2-Symptoms:- 3-Signs:-

-The same as primary type -same signs but cardiac

but less Incidence. signs are more

prominent and heart

failure is a very common

complication.

C-Investigations:-

1-Thyroid Functions Test: High T3.T4 / Absent TSH (due to high TSI)

2-Neck Ultrasonography:- Diffused (Primary), Nodular (Secondary)

3-Technitium Scan:- Internodular tissue, Autonomus Nodule

D-Treatment:-

1-Medical Treatment:- Anti-thyroidal Drugs Interfere with oxidation & coupling

a-Carbimazole:- 3 tab/8h (6 month-2 years) (1 tab=5mg)

b-Propylthiouracil:- given during pregnancy to avoid cretinism in

fetus as Carbimazole can pass the BPB, but T3 tablets should be taken in case of

pregnancy to avoid the “transmitted Propylthiouracil goiter” in the fetus, as T3

can also pass the BPB.

-Side Effects:- 1-Immediate:- Agranulocytosis due to bone marrow

depression, so CBC must be performed 3 days

after start of the treatment.

2-Later:- Chronic Renal Failure.

-Causes of treatment failure:- -Patient loses hope in treatment,

called lack of compliance.

-Drug Intoliractability.

-If drugs failed Subtotal Surgical

removal is done.

2-Surgical Treatment:-

a-Near total thyroidectomy:- total thyroidectomy except the tissue

around the recurrent laryngeal nerve.

b-Total thyroidectomy

NB:- 1-Thyrotoxic Crisis:- may occur due to separation of a part of an active

thyrotoxic gland during surgery into the blood causing thyrotoxic manifestations

due to active T3,T4, so it’s avoided by making the patient Euthyroid during the

preparation of the surgery.

2-Patient Preparation for the Surgery:- 2 steps must be performed, the first

is clinical treatment of al the thyrotoxic symptoms, the second is Propranolol

medication to control the tachycardia (patient pulse must be 90b/min during day,

and 80b/min during sleep) also to decrease transformation of T4 into T3 (so we

gain high T4 and low T3), but the patient with Bronchial asthma shouldn’t be

medicated Propranolol as it blocks β2-receptors in the bronchi.

3-Patients with Retrosternal Extension:- are prepared with Propranolol &

Lugol’s Iodine only but not Anti-thyroidal drugs as they increase the size of the

gland by inhibition of T3,T4 release causing sudden feed back stimulation of TSH

secretion which induces thyroid enlargement.

4-During Surgery:- Bleeding is very common due to high vascularity of the

thyroid gland, so Lugol’s Iodine is indicated 12 drops/day for 10-14 days, but

prolonged use may cause rebound action, also prevents release of T3 & T4.

5-After Surgery:- Stoppage of the Carbimazole should be gradually with

continuation of Propranolol use.

– Complications of thyroidectomy:-

1- Removal of the parathyroid glands causing hypoparathyroidism

2- Cutting the laryngeal nerves

3- Suffocation from hematoma (cause of death)

4- Recurrence

5- Thyrotoxic crisis

6- Scar formation

7- Thyroid in sufficiency

8- Parathyroid insufficiency

9- Wound infection

10- General complications of surgery

-How to make the patient fit for the surgery?

1- Make him Euthyroid.

2- Prevent Transformation of T4 into T3.

3- Control of Tachycardia (90beat during wake, 80beat during Sleep).

4- Control of high vascularity.

3-Radio Active Iodine I125:- -Given only for the patients over 25

(Radio Isotope Therapy) years old.

-It’s contraindicated in pregnancy.

-Side Effects:- 1-Myexedema with prolonged use (more than 10y)

2-Teratogenic in pregnant.

3-Carcinogenic in infants.

E-Choose of Treatment:-

1-Grave’s Disease or Interactive Tissue:- Medical – Surgical –

Radio Active Iodine.

2-Secondary Thyrotoxic Goiter:- Surgery – Radio Active Iodine.

3-Huge Goiter:- Surgery is the best.

4-Small Goiter:- Radio Active Iodine is the best.

5-Recurrence After Surgery:- Radio Active Iodine is the best.

6-If Patient is Under 25 Y:- Medical Treatment is the best.

3-Inflammatory Goiter:- Very Rare ( High T3,T4,TSH)

A-Hashimoto Disease:- It’s Chronic Lymphatic Thyroiditis

it can precipitate Thyroid Lymphoma.

B-De Quervain’s Disease:- Subacute Thyroiditis.

C-Reidel Thyroiditis:- Chronic Thyroiditis.

De Quervain’s disease: could occur as a complication of post viral infection mainly

mumps.

metastasis

from other

places as

Breast cancer

(very rare)

Medullary

Carcinoma

by Both Blood &

LNs Met.

5%

Papillary 60%

(Commonest)

Follicular 20%

by LNs & blood met.

Thyroid

Lymphoma

5%

Blood Met. Mainly

to bones as skull

Anaplastic

by Local Met.

10%

They Come Clinically from Discrete Thyroid Swellings

(most common)

4-Tumors of the Thyroid:- Benign Malignant

Follicular Adenoma Primary Secondary

Follicular cells Parafollicular cells C Lymphocytes

Differentiated

Undifferentiated

- Papillary carcinoma more metastasis by blood.

- Follicular carcinoma more metastasis by lymph nodes.

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5-Discrete Thyroid Swellings:- It’s not a Goiter (more in females 3:1)

Investigations FNAC + Ultrasonography + TFT + Technetium scan

Solitary Thyroid nodule Dominant Nodule

Malignancy Tr. 15% 7%

Causes

1-Simple Thyroid Cyst:- the Patient is Euthyroid with neck

ultrasound cyst swelling.

2-Tumors of the Thyroid Gland 3-Toxic Adenoma:- By Technetium scan, but no place for medical

treatment, TFT reveals high T3,T4 / low FSH

Treatment

If small in size:- Just follow up the patient.

If Large in size:- Aspiration + Ultrasound after 3 months reveals

Malignancy or cystic transformation, and surgical

thyroidectomy is needed.