🫶Differentiated Thyroid Cancer (DTC) + Hyperthyroidism + Thyroglossal cyst Flashcards

Question

Radical Neck Dissection ( RND)

Answer 1

- **Removal of all ipsilateral cervical LN groups extending from the inferior border of the mandible superiorly to the clavicle inferiorly.** - Medial border: Lateral border of the sternohyoid muscle, hyoid bone, and contralateral anterior belly of the digastric muscle. - Lateral Border: Anterior border of the trapezius muscle. LN level 1 to 5. Spinal accessory nerve (SAN), IJV, and SCM muscle are also removed.

Answer 2

- Preferred method - Type I : RND but spared SAN - Type II : RND but spared SAN & IJV - **Type III :RND but spared SAN, IJV & SCM (most common)** - SAN for shoulder function, IJV to avoid facial edema, SCM to protect vessels

Answer 3

- Preservation of one or more LN groups that are routinely removed in RND. - Removal Level 6 including pre tracheal LN up to innominate artery. Divided into: - **Anterior (Central) neck dissection** ( Level VI ) - **Supraomohyoid** ( Levels 1 - 3 + submandibular gland) - **Anterolateral** - Jugular ( Level 2 - 4) - **Posterolateral** neck dissection ( Includes Levels 2 - 5, post-auricular nodes, suboccipital nodes, and external jugular nodes)

Answer 4

Removal of one or more additional LN groups or non-lymphatic structures, or both, not encompassed by the RND

Answer 5

Prognostic Scoring divide patient into high or low risk - AGES (Age, Tumor grade, Extent, Size) - GAMES (Grade, Age, Mets, Extra, Size) - AMES (Age, Mets, Extra, Size) - MACIS (Mets, Age, Completeness, Invasion, Size) - For PTC only

Answer 6

To Estimate the risk of recurrence

Answer 7

- **Macroscopic**: Solid, White, Firm, often Multifocal (20%), Encapsulated (10%) or Infiltrative with Variable cysts, fibrosis, calcification. - **Microscopic**: papillae and / or follicles. Can be totally follicular. Psammoma bodies. - **Extrathyroidal extension can be readily apparent, if deep (muscles, trachea) or evident only on microscopy (muscles, perithyroidal fat)** - Diagnosis lies in nuclei – large, oval, crowded nuclei (Orphan Anne eye). Nuclear pseudo inclusion. - Can be diagnosed in **FNAC**.

Answer 8

- **Macroscopic**: Capsulated. Solitary nodules. Tan to brown solid cut surface, can have cystic changes and hemorrhage - **Minimally invasive**: usually single encapsulated nodule, with thickened and irregular capsule - **Widely invasive**: extensive permeation of capsule or no capsule. - All capsule with adjacent tissue needs to be submitted for histological evaluation - **Microscopic**: Microfollicular architecture is uniform with cuboidal cells lining follicles. PTC features absent. - Diagnosis lies in capsular invasion to differentiate adenoma from carcinoma. - 🚨**Require HPE for diagnosis.** **If no colloid, means cancerous, if abudant of colloid means benign**

Answer 9

**TSH Targets:** -**🚨High risk:** < 0.1 mU/L -**🌪️Intermediate risk:** 0.1 - 0.5 mU/L -Low risk patients who have undergone remnant ablation and have low level serum Tg levels: 0.1 - 0.5 mU/L -Low risk patients who have undergone remnant ablation and have undetectable serum Tg levels: 0.1 - 0.5 mU/L -Low risk patients who have undergone lobectomy: 0.5 - 2.5 mU/L -DTC receptor responds to TSH stimulation → Thyroglobulin & ↑ Cell growth so once suppressed → prevent growth of any residual thyroid. -**Side effects:** - Subclinical thyrotoxicosis – may worsen Angina, AF & Osteoporosis. - Patient with side effects should aim for TSH replacement rather than suppression. ( Thyrogen)

Answer 10

- **Active surveillance every 6 - 12 months ** - protocol popularized by Japanese group - Age is an independent predictor for significant tumor growth ( >3mm) and LN involvement - 35% in age < 30 - 15% in age 30 -50 - 5 % in age > 50

Answer 11

Tumour < 4cm if unifocal no ETE no LN involvement * Hemithyroidectomy reduce complication by 50% especially RLN injury ( 0.5 -5 % in TT) as well as no need for lifelong thyroxine replacement *This approach is associated with low rate of recurrence which can be safely managed by completion surgery without changes in survival ( Level 3 evidence , approach with caution)

Answer 12

**Given post total thyroidectomy for several reasons;** 1. **To eliminate thyroid remnant and ensure undetectable serum Tg (follow up).** This practice is challenge in past decade due to reduce usage of iodine scintigraphy. Cervical ultrasound and serum Tg are the most sensitive method to detect persistent or recurrent disease. 2. **Eradicate foci of neoplastic tissue with aim to reduce recurrence.** Recent guidelines advice against generalized use of RAI, proposed risk stratification approach 3. **Treat residual or persistent disease**

Answer 13

In patients with thyroid cancer who require radioactive iodine (RAI) treatment or diagnostic imaging, a high level of thyroid-stimulating hormone (TSH) is necessary to stimulate any remaining thyroid tissue to absorb the iodine. Preparation for Remnant Ablation, TSH stimulation is achieved by: **Thyroid hormone withdrawal:** - T4 withdraw for 3 - 4 weeks before RRA or - liothyronine (LT3) substituted for LT4 initial 2 - 4 weeks, then withdrawn for next 2 weeks. - Thyroxine therapy (with or without LT4 for 7 - 10 days), resumed on the second or third day after RAI administration. - 🏹**Goal: TSH > 30mIU/L.** 🍎**Remnant ablation, WBS & Serum Tg measurement requires TSH stimulation & low iodide level to facilitate uptake of RAI** Therefore, investigation usually done together: - Aim to achieve TSH level >30mU/L - Low iodine diet (<50mcg/day) for 2 weeks before and 2 days after 131I - Avoid iodinated contrast for CT & drugs like amiodarone

Answer 14

**Thyrogen (generic name: thyrotropin alfa) is a synthetic form of human thyroid-stimulating hormone (TSH)** - Patients unable to generate an elevated TSH with thyroid hormone withdrawal. - Patients with H/o stroke, TIA, or underlying heart disease, especially heart failure which makes thyroid hormone withdrawal medically contraindicated. - Patients who have a tumour adjacent to central nervous system. - Patients with a H/o or active psychiatric disorders. - Patients who have previously experienced a serious medical or psychiatric complication of short term hypothyroidism. - Patients with severe compromise of overall performance status. - Patients on medications with a narrow therapeutic index as clearance is impaired. - Patients with hypopituitarism or who have previously been unable to achieve an adequate increase in endogenous TSH levels. - Patients who have a positive T4 Tg test, who otherwise would require a battery of diagnostic imaging procedures. Normally, TSH levels can be elevated by stopping thyroxine (thyroid hormone) therapy, causing the body to become hypothyroid. **However, hypothyroidism can worsen conditions like ischemic heart disease (IHD) and increase the risk of stroke by slowing the heart rate, increasing blood pressure, and promoting fluid retention—all of which put additional stress on the cardiovascular system.** 💉 **Administration:** Two IM injections of Thyrogen on Day 1 and Day 2 RAI given or Tg measured on Day 3

Answer 15

**RAI dosage is guided by the risk of recurrence based on risk stratification:** - Low dose (30mCi) mainly for remnant ablation and high dose (100mCi) use for treatment purpose - **To optimize radioisotope uptake, TSH level ideally must be 30 mIU/L (not routinely measure)** - It can be achieved by thyroxine withdrawal for 4-5 weeks or injection of rhTSH (0.9mg OD x 2/7) - Thyroxine withdrawal therapy preferred in metastatic disease but injection rhTSH is better tolerated by patients due to less effect of prolonged hypothyroidism

Answer 16

- ESTIMABL -2 - IoN trial

Answer 17

**Salivary gland** : Inflammation, obstruction, loss of taste **Amenorrhea**: Avoid pregnancy for 6 months (washout RAI). **Oligospermia**: Suggest sperm banking or wait up to 1 year. **Urinary tract**: obstruction (advise to drink more water) **GI symptoms**: nausea, vomiting, diarrhea **Secondary malignancy**: leukemia, CRC, salivary tumor Patients who receive a cumulative 131 I activity in **excess of 500mCi to 600 mCi** should be informed that they may have a mildly increased risk of developing leukemia and solid tumours in the future. - **Post therapy WBS 131I done 1 week after RRA to visualize metastasis.** - Peak of 131I therapy action is between 6 and 12 months with most ablated patients having no evidence of disease or demonstrating some response to this therapy in this time frame.

Answer 18

**Stimulates Tg**: patient stopped L Thyroxine for 4 weeks **Suppressed Tg**: patient still on Thyroxine ( excellent response : <0.1ng/dl)

Answer 19

- **Metastasis that has no RAI uptake**; either from initial or loss of ability to concentrate RAI - 1 or more metastatic lesion with no RAI uptake - **Progressive disease despite on RAI for RAI uptake lesion after 6-12 months of RAI therapy** - 🚨Cumulative RAI dosage of **>600mCi**

Answer 20

- Patient characteristic ( Age > 40 year old) - Tumor Characteristic ( Aggressive histology , local invasion, presence of metastasis) - **Images : FDG-PET/CT positivity, no iodine uptake** - **Markers: Tg doubling time < 1 year**

Answer 21

🍎**DECISION** trial : Sorafenib 🍊**SELECT** trial : Lenvatinib these trial showed better PFS and overall response rate with systemic therapy but no significant different in term of OS

Answer 22

* Sensitive marker for thyrocytes but cannot discriminate between normal and malignant thyrocytes * Undetected level has high NPV, but detectable value can be false positive *** Concomitant measurement of Thyroglobulin antibody (TgAb) is mandatory as it is associated with false negative serum Tg** * 2 methods to assess serum Tg: a) **Suppressed- Basal Tg (also known as On-LT4 Tg)** b) **Stimulated Tg;** endogenous stimulation with thyroxine withdrawal or exogenous with rhTSH * If initial stimulated Tg <1ng/ml, it indicates excellent response and subsequent stimulated Tg is not necessary * Alternatively, basal Tg <0.2ng/ml also represent excellent response * Patient with negative imaging study but has detectable serum Tg classified as indeterminate or biochemical incomplete response group * For this group, serial serum Tg is needed. Increasing trend serum Tg has high PPV for recurrence disease * In case of hemithyroidectomy, increase serum Tg and TgAb may indicate persistent or recurrent disease

Answer 23

* Patient risk status should be assessed for first time at 6-18 months post completion of primary treatment * Aim of this assessment is to stratify patient according to response to treatment and detect recurrence * **75% of patients has recurrence within the first 5 years** * Clinical assessment, serum Thyroglobulin (Tg), neck ultrasound and other imaging are used during follow up and surveillance *** Serum Tg and neck ultrasound is the mainstay modalities during surveillance** * 2015 ATA guideline stratify patients into several groups according to response to treatment into excellent, indeterminate, biochemical incomplete and structural incomplete response * Each of the subgroup carry different risk of recurrence and reflected in the interval of surveillance * If recurrence detected, it can be managed by active surveillance, RAI or surgery

Answer 24

* Most effective tool to detect structural disease in post-operative period * **Ultrasound and serum Tg have diagnostic accuracy reaching 100%** * Disadvantages; operator dependent, high frequency of nonspecific findings and limited role in case of FTC * For FTC, ultrasound only use for locoregional assessment due to hematogenous spread of the disease * **Abnormal ultrasound findings are divided into indeterminate or suspicious findings**

Answer 25

* Indicated when locoregional or distant metastasis suspected (increase level Tg or nonspecific USG) * **WBS with RAI has low sensitivity (25-50%) with high uptake (90-100%) which could be false positive** * For this reason, WBS with RAI is not considered as standard diagnostic tool during follow up * **FDG-PET CT has high sensitivity/specificity (95%/85%) for persistent or recurrent disease** * It is indicated when metastasis suspected especially if negative cross-sectional imaging, serum Tg >10ng/ml and aggressive histology subtype. * FDG uptake can predict poor prognosis as well as RAI refractoriness * **FDG-PET CT is the 1st line isotope imaging technique in RAI refractory disease** * Conventional cross imaging studies mainly use to assess anatomic region * CECT neck and thorax mainly use to assess locoregional disease * **RAI therapy should be deferred at least 6 weeks after administration of iodinated contrast agent (ICA)** * **ICA will compete with radioisotope iodine thus reducing the effect of RAI** * MRI offer another option for cross imaging study. * It is used to assess neck region, liver, brain and bone metastasis * Low availability and high motion artefact preclude its routine use

Answer 26

🍎**Low risk without incomplete structural and intermediate risk with excellent response:** - **Serum Tg and TgAb** every 1-2 years - **USG neck** if indicated if low risk and optional 3-5 years in intermediate group with excellent response - Low normal **TSH suppression** is acceptable (0.5-2 mu/ml) 🍊**Intermediate and high risk with indeterminate or incomplete biochemical response:** - **Serum Tg and TgAb** every 6-12 months - **USG neck** every 6-12 months  other imaging modalities if indicated - Mild **TSH suppression** (0.1-0.5mu/ml) and low normal TSH (0.5-2 mu/ml) in high risk with excellent response 🚨**If presence of structural incomplete response in any risk group:** - **Serum Tg and TgAb** every 3-6 months - **USG neck** + other imaging every 3-6 months - **Suppressed TSH** (<0.1mu/ml) - Consider local therapy or systemic treatment

Answer 27

**Cause: can occur in combination as well** - **Anti-Tg antibody** - Microscopic remnants of normal tissue or metastatic disease not visible with diagnostic I-131 - Macroscopic metastatic disease that has mutated to lose **NIS (Negative Iodine Scintigraphy)** - Serum heterophile antibodies (suspected and sought when the Tg level does not equate with the clinical and imaging findings and does not increase and decrease appropriately with TSH elevation and suppression) - **Inadequate serum TSH stimulation** - Macroscopic metastatic disease that has mutated to lose NIS

Answer 28

- **Locoregional**: LN or contralateral thyroid gland. - **Distant metastasis:** most common in lung and bone. **Incidence** - Most common – 1st 5 years after initial treatment. - In PTC: 20-year recurrent rate is: 5.5% after TT, 9.8% after hemi T. - Recurrent lower in those underwent prophylactic regional LN dissection. **Etiology** - Residual tumor. Micro metastasis. **Clinical** - Usually asymptomatic, detected by - ↑ sTg, 131I WBS. - Locoregional: recurrent neck swelling, LN enlargement, hoarseness of voice. - Distant: bone pain and lung. **Investigation** - Preoperative CT or MRI - for Operability and resectability. **Treatment**: - Surgical excision if Resectable followed by Radioiodine Remnant Ablation (RRA) with 131I - Completion thyroidectomy if in first surgery only hemi-thyroidectomy. - MRND: For resectable disease. Require expert familiar with dissection. - Medical: TSH suppression therapy: aim at TSH level <0.01 - **Radio-iodine ablation** - Effective especially for node <1cm. Patient must have total thyroidectomy done. - Can give multiple times till no residual uptake noted. - FDG PET avid disease is unlikely to respond to RAI

Answer 29

- < 10% of all DTC - **Mainly seen in aggressive histology type, vascular invasion, large primary tumor and gross ETE** - Common sites for metastases are lung (50%), bone (25%), brain and liver - Mortality rates at 5 years (65%) and 10 years (75%) **Diagnosed based on clinical symptoms, suspicious biochemical and imaging studies** - Recurrence and metastatic disease in general have indolent behavior - It is primarily managed with RAI after TSH stimulation - RAI dosage ranging 100-200mCi every 6 months. Regime varies depending on radio-oncologist. **Locoregional therapy should be administered to delay the systemic therapy as long as possible** Choice of locoregional therapy depends on site of metastasis: - **bone metastasis**: EBRT, bisphosphonate and RAI - **liver lesions**: chemoembolization, RFA - **surgical locoregional control.**

Answer 30

- Disease control - Surgery is still preferred if possible followed by RAI - Symptom control - **Surgery considered for patient with single resectable distant metastasis.** - **5 year survival after lung metastatectomy was 65%.** - **Options of treatment:** - **RRA** : less effective than initial treatment. - **External Beam Radiotherapy (EBRT)** - resistant disease or symptom control. - **Percutaneous ethanol injection** - cervical nodal metastases. - **RFA** - cervical, osseous, and pulmonary metastases - alternatives for poor surgical candidates and whose metastases do not concentrate radioiodine. - **Palliative embolization** - bone metastases may reduce symptoms or be used prior to surgery. - **Lung mets** - RRA every 6 – 12 months as long as disease respond - **Bone mets** - Complete surgical resection of isolated mets improved survival - RRA - Skeletal pain & fracture → EBRT with steroid. - Other options: palliative embolization, RFA, zolendronate infusion - **Brain mets** - Complete surgical resection improve survival - Not resectable → EBR - WBRT & Spine RT if multiple metastasis present.

Answer 31

- Despite locoregional and distant metastasis, the overall survival in well DTC is still good - **10- year survival : 40% to 50%**

Answer 32

- Best prognosis. Most do not die of their disease. - Soft tissue invasion: ↑ risk of death 5-fold - Tumor size: Smaller better - **Mutation: BRAF V600E poorer.** - Multicentricity

Answer 33

- Age: < 40 years better prog. 10-year survival 95% - Stage to stage prognosis similar to PTC in pt < 40 years old - Tumor size: Smaller better - Vascular invasion - **Capsular extension: Minimally Invasive FC better than Widely Invasive FC** - Distant metastasis: Depends on degree of metastasis. - **Hürthle cells: Poorer prognosis. 10-year survival 70%** - Insular cancer (ITC): Poorly differentiated. Poor prognosis.

Answer 34

Hurtle cell carcinoma (oncocytoma) -**Highly eosinophilia stain - bright red due to rich in mitochondria** - Hurtle cell can be found in salivary gland as well - Hurtle cell can be found in toxic MNG which might not be malignancy - Hurtle cell concentration in a slide decide the risk of malignancy - **Hurtle cell variant of FTC or PTC, prognosis no good due to risk of metastasis, 30% LN, vascular invasion, not Radioiodine avid** - **Difficult to monitor due to not producing Tg**

Answer 35

* Propylthiouracil (PTU) act at peripheral conversion from T4 to T3, good for thyroid storm, more toxic (agranulocytosis, hepatotoxicity-mortality 100% if occur), bitter taste tablet, 50mg/ tablet max 600mg **Indication of PTU: Pregnancy, T3 thyrotoxicosis** * carbimazole act in thyroid nodule ( block iodine organification by inhibiting thyroid peroxidase - TPO) - Contraindicated in Pregnant, breastfeeding patient **The half-life of T4 is 5-7 days; the half-life of T3 is only 1 day**

Answer 36

- Grave autoimmune VS autonomous TNG - Grave young pt VS TNG old (long standing to get toxic) - Main diff from history taking (swelling or toxic come first - Ix thyroid function test, anti thyroglobulin, anti thyroidperoxidase,

Answer 37

* indication - plan for surgery later if TFT difficult to control * how to do it, high dose carbimazole 15-20mg TDS -> TCA 1month -> euthyroid/ hypothyroid, start thyroxine 100mcg, -> go for surgery (must aim for surgery, no more TCA! ) * **problem - pt will develop huge thyroid (during 4 months treatment) causing compressive symptoms (airway obstruction)**

Answer 38

* carbimazole change to PTU * give dexamethasone - steroid can prevent peripheral conversion ( TFT normal in 2days with carbimazole and dexa) (4mg BD for 2/7) Problem, uncontrolled sugar level

Answer 39

- wolff chaikoff effect, reduce size and vasculature, firm thyroid easier for op

Answer 40

🍊**indication**: - small thyroid nodules - Outcome 30mci/30% success rate /30% recurrent - No response, required second dose of RAI - Hypothyroid 1%every year cumulative (20years20%) 🍎**contraindication** - Pregnant - Breast feeding - Ophthalmopathy - relative contraindication, can cover with steroid

Answer 41

- Ideal means Cure the problem without need of medication - Subtotal thyroidectomy, issue-recurrence - Predictor for recurrence: size of remnant, near total 1g, subtotal 4g -If recurrence -> RAI - Best surgical option is total thyroidectomy

Answer 42

1) Monitor calcium level ( As hyperthyroidism in Toxic MNG can cause hypocalcaemia - bone reabsorption of calcium - like hungry bone syndome) , **ideally 16 hours post opt** 2) Shouldnt off propanolol (Beta blocker) first ( as cardiac protection and prevent thyroid storm) 3) Restart back thyroxine after 1 week 4) off the carbimazole

Answer 43

- Most common cause of hyperthyroidism - 70%–84%. - F : M = 10 : 1. - Peak 30 – 40 years, can occur at any age with no obvious goiter. - Graves’ disease can co-exist with toxic adenoma and is termed as Marine–Lenhart syndrome. **Pathophysiology** - Autoimmune disease, TSH receptor antibodies bind to TSH receptor & mimic action of TSH → ↑ production of thyroid hormone. - Yersinia enterocolitica infection has been associated with Graves’ disease. **Clinical signs (Grave’s triad)** - **Hyperthyroidism** (90%) - fine tremors, - **Grave’s ophthalmopathy** (40%) - TRab target retroorbital tissue → T cell inflammation → fibroblast growth & deposition → Proptosis, lid lag, exophthalmos, conjunctival irritation. - **Dermopathy** (4%) - Activation of fibroblast → ↑ hyaluronic acid & chondroitin sulfate - Pretibial myxedema due to TRab deposition - Occasional vitiligo

Answer 44

1) **Blood Tests** **Thyroid Function Tests:** - **TSH**: Typically very low or undetectable due to negative feedback from excess thyroid hormones. - **Free T3 and Free T4**: Elevated in Graves’ disease, confirming hyperthyroidism. 2) **Thyroid Antibody Tests:** - **Thyroid Stimulating Immunoglobulin (TSI) or TSH-Receptor Antibodies (TRAb):** Their presence is diagnostic for Graves’ disease as these antibodies stimulate the thyroid gland to produce excess hormones. - **Anti-Thyroid Peroxidase (TPO) and Anti-Thyroglobulin Antibodies:** These may also be elevated, supporting the autoimmune nature of the condition. 3) **Imaging Studies** - **Radioactive Iodine Uptake (RAIU) and Scan:** This test involves ingesting a small amount of radioactive iodine. In Graves’ disease, the thyroid shows a diffusely increased uptake, which is a key finding. - **Ultrasound (with Doppler):** Can evaluate the gland’s size and vascularity, which is often increased in Graves’ disease. - **Doppler Ultrasound of Thyroid Blood Flow:** This may be particularly useful when radioactive iodine uptake is not advisable, such as during pregnancy or breastfeeding. Besides measuring thyroid-stimulating immunoglobulins (TSI) or TSH receptor antibodies (TRAb), **another key confirmatory test for Graves’ disease is the radioactive iodine uptake (RAIU) test. This test involves ingesting a small amount of radioactive iodine and then assessing how much the thyroid gland absorbs.** In Graves’ disease, the uptake is typically diffusely high across the entire gland, which helps differentiate it from other causes of hyperthyroidism, such as thyroiditis (which shows low uptake) or toxic nodular goiter (which usually has focal uptake).

Answer 45

**Medical** **30 - 40 % will undergo complete remission.** **Indications**: mild disease, small goiters and negative or low-titer TRAb, Patients with previously operated or irradiated necks, Moderate to severe active Graves’ ophthalmopathy (GO). **Contraindications**: Previous known major adverse reactions to ATDs. **MMI (Methimazole) / carbimazole** - Initial starting dose is usually 0.5–1 mg/kg/day, with a maximal dose of 30 mg/day. - 0.2–0.5 mg/kg daily, 10–30 mg daily to restore euthyroidism, and titrated down to a maintenance level (generally 5–10 mg daily). - After 2–4 weeks, when thyroid hormone levels have normalized, initial dose should gradually be reduced by 30%–50%. - When more rapid biochemical control is needed in patients with severe thyrotoxicosis, an initial split dose of MMI (15 or 20 mg twice a day) maybe more effective than a single daily dose because the duration of action of MMI may be less than 24 hours. **Propylthiouracil** has a shorter duration of action, starting with 50–150 mg three times daily, depending on the severity of the hyperthyroidism to a maintenance PTU dose of 50 mg two or three times daily. - If ATD is chosen as the primary therapy should be continued for approximately 12–18 months, and then discontinued if TSH levels are normalized. - Side effects of ATDs - Minor - Rash, Pruritus, Hives, Hair loss, Nausea, Decreased taste, Joint paint, Arthralgia. - Severe - Agranulocytosis, Neutropenia, Thrombocytopenia, Steven-Johnson syndrome, Cholestatic jaundice, Hepatitis. **β blocker** - Recommended in all patients with symptomatic thyrotoxicosis, especially in elderly patients and thyrotoxic patients with resting heart rates in excess of 90 beats per minute or coexistent cardiovascular disease. - Atenolol, Propranolol, or Metoprolol. - **Also inhibit conversion of T4 to T3** **Lugol's Iodine**

Answer 46

**RAI** - Goal of RAI therapy in GD is to control hyperthyroidism by rendering patient hypothyroid. - 131I (ß energy cause cellular death in 6 – 18 weeks) - a single dose **10 - 15mci (370–555 MBq)** - Low-iodine diet (e.g. seaweeds) for at least 3 to 5 days before. - Iodinated radiocontrast avoided at least 4–6 weeks prior to RAI therapy. - **Status post RAI**: Remission 80%, Hypothyroid 20%, Hyperthyroid 1% relapse. - Discontinue any **MMI** or **Carbimazole** 2–3 days prior in healthy and clinically well compensated patients despite significant biochemical hyperthyroidism. - Elderly patients or in those with underlying cardiovascular disease, resuming MMI or carbimazole 3–7 days after RAI administration should be considered and generally tapered as thyroid function normalizes. - Patients who might benefit from adjunctive MMI or carbimazole in view of a hyperthyroid relapse include those who tolerate hyperthyroid symptoms poorly, having free T4 at 2–3 times upper limit of normal. - Patients who are allergic to ATDs, duration of hyperthyroidism may be shortened by administering **iodine** (e.g. saturated solution of potassium iodide [SSKI]) beginning a week after RAI administration. - RAI treatment can cause a transient exacerbation of hyperthyroidism, beta-blockade should be considered even in asymptomatic who are at an increased risk for complications due to worsening of hyperthyroidism. - **Substantial comorbidity at greater risk of worsening**: cardiovascular complications (atrial fibrillation, heart failure, or pulmonary hypertension) and renal failure, infection, trauma, poorly controlled diabetes mellitus, and cerebrovascular or pulmonary disease - rendered medically stable before the administration. **Contraindications:** Grave Ophthalmoplegia (exacerbate), Thyrotoxicosis, Pregnancy, Lactation, Coexisting or suspected thyroid cancer. **Toxic Nodular Goiter** : most appropriate therapy - Dose required to achieve euthyroidism in TMG is larger than that needed in Graves’ for a similar size gland, because the 24-hour uptake of iodine is lower than in Graves‘. Uptake is dependent on number and size of autonomous nodules and iodine intake at the time of the uptake. - Response 50%–60% by three months and 80% by six months. - 15 and 25 mCi.

Answer 47

**Indication**: - Symptomatic compression or large goitres (>80 g) - Relatively low uptake of RAI - When thyroid malignancy is documented or suspected (e.g. suspicious or indeterminate cytology) - Large thyroid nodules, especially if greater than 4 cm or if nonfunctioning, or hypo functioning on 123I or 99mTc pertechnetate scanning - Coexisting hyperparathyroidism requiring surgery - Especially if TRAb levels are particularly high - Patients with moderate-to–severe active Graves’ Ophthalmopathy (GO) **Contraindications**: - First (increased risk of fetal loss) and third (increased risk of preterm labour) trimesters of pregnancy also due to teratogenic effects associated with an aesthetic agents, - Substantial comorbidities such as cardiopulmonary disease, end-stage cancer, or other debilitating disorders. - **Near total** or **Subtotal thyroidectomy** - for patients refusing life long thyroxine, 8% chance of persistence or recurrence at 5 years - **Total thyroidectomy** - 0% risk of recurrence.

Answer 48

- Remnants of the embryonic thyroglossal duct occurring anywhere from base of tongue to thyroid gland. Thyroid arise as an out pouch from floor of primitive pharynx, at the base of the tongue (foramen cecum). Cells migrate downwards along midline of neck until they arrive at the final position of the thyroid gland Along the path thyroid cells travel through or goes just above or just below the hyoid bone. Thyroglossal tract usually becomes obliterated. **Location**: Below hyoid - 65%, Above hyoid - 20% At the level of hyoid - 15% Lingual - 1-2%. - If fails to descend - **Lingual thyroid** forms at tongue base. - Persistent remnants of thyroglossal tract - **Thyroglossal cyst** - Rupture, drainage, incomplete removal of cyst - **Thyroglossal sinus** Histology: - Lined by squamous epithelium / pseudostratified ciliated columnar epithelium. - Ectopic thyroid tissue is present in 1.5 to 62 %, salivary gland tissue also found. Presentation: - Childhood, young adult. - Located anyway between foramen caecum to manubrium, to the left of midline. - Painless, smooth, and cystic and moves upwards with protrusion of the tongue. - If infected present with pain, redness, and tenderness **Differential diagnosis** - Dermoid cyst, Sebaceous cyst, Lipoma, LN, Hypertrophic pyramidal lobe, Choristoma. **INVESTIGATION** **USG** – to asses cyst and for the presence of normal thyroid gland. **Thyroid isotope scan** – to exclude lingual thyroid, to ascertain cyst is not the only place with ectopic thyroid tissue. Management: - Indication – recurrent infection, cosmetic, pressure symptoms and to eliminate the risk of development of a carcinoma (though rare all types of thyroid cancer can be found, Papillary, mixed follicular-papillary, squamous, follicular, anaplastic, and Hurthle cell carcinoma). - **Infected cyst** - should not be incised or excised. Resolve infection with antibiotics followed by surgery. - **In doubt of midline swelling diagnosis pre or intraoperative** – Sistrunk procedure. - **Thyroglossal sinus** – excise ellipse of skin around sinus then Sistrunk procedure.

Answer 49

Thyroglossal duct cysts (TGDCs) are generally benign, but in rare cases, they can undergo malignant transformation. **The risk of malignancy in a thyroglossal cyst is estimated to be about 1% or less.** Here are some key points regarding the malignancy risk: **Types of Malignancy in Thyroglossal Cysts** **1) Papillary Thyroid Carcinoma (PTC) (~80%)** The most common malignancy found in thyroglossal duct cysts. Has a relatively good prognosis when treated properly. **2) Squamous Cell Carcinoma (~5-10%)** Arises from the epithelial lining of the cyst. More aggressive than PTC. **3) Other Rare Malignancies** Follicular carcinoma Hürthle cell carcinoma Anaplastic carcinoma (very rare but aggressive) **Risk Factors for Malignant Transformation** - Persistent cyst growth despite treatment - Older age (>40 years) at diagnosis - Irregular, firm, or fixed mass in the midline neck - Rapid enlargement of the cyst - Cervical lymphadenopathy (enlarged lymph nodes) - Recurrent infections or previous incomplete excisions

Answer 50

🔥Supine, neck extended, arm by side, clean from nose to chest. Nasal intubation. 🔥**Collar incision over cyst, or ellipse to include sinus**. Deepened to subcutaneous tissue, platysma, **raise sub-platysmal flap** below to lower margin of cyst, above ½ way between body of hyoid & symphysis menti. 🔥Hold skin edge with self retaining retractor. 🔥Separate sternohyoid by dividing deep cervical fascia. 🔥Expose cyst, dissect around cyst. 🔥Upward extension of cyst identified, followed upward, to hyoid. 🔥Separate hyoid from thyrohyoid membrane. 🔥Center 1 cm of bone cleared of muscle attachment. 🔥Excise bone with bone nibbler. 🔥Assistant put finger orally & push tongue downward. 🔥Dissection proceed into tongue toward foramen caecum. 🔥Tract often disappear at this level, entry into oral cavity is unnecessary. 🔥Extend core 2cm deep to mylohyoid (foramen caecum), till separated from mouth by mucous membrane, divide and ligate with absorbable suture. 🔥Hemostasis, vacuum drainage, close strap, close platysma, close skin.

Answer 51

Sympathetic overdrive due to excessive thyroid hormone release leading to life threatening organ dysfunction. Diagnosis made clinically: - Cardinal features: - High fever > 40 degrees - Altered mental status - CVS (AF, heart failure) - Diarrhea **Summary of the Pathophysiological Features of Thyroid Storm:** - Hypermetabolic state (increased BMR, hyperthermia, tachycardia). - Sympathetic hyperactivity (tachycardia, tremors, sweating). - Cardiovascular overload (heart failure, arrhythmias, shock). - CNS dysfunction (agitation, confusion, coma). Precipitating events (infection, surgery, trauma).

Answer 52

Definition: **Thyroid storm** is an extreme, life-threatening manifestation of thyrotoxicosis, characterized by a sudden, exaggerated hypermetabolic state due to massive excess of circulating thyroid hormones and heightened adrenergic activity. It leads to rapid multisystem decompensation. Triggering event --> Acute surge of thyroid hormone effect --> Massive Beta-adrenergic stimulation + Metabolic overdrive --> Multiorgan dysfunction

Answer 53

**Emergency Therapy:** **ABC** : High flow **Oxygen**, cardiac monitoring & **IV fluids** replacement Rapid cooling with **Ice** pack, **PCM** 325–650 mg PO/PR 4–6 h (**aspirin contraindicated it releases thyroxine from protein binding sites**) **PTU (propylthiouracil)**: Preferred over MMI, fast acting & inhibit peripheral conversion - 500–1000 mg loading, then 250 mg, 4–6 hourly, Can be given via NG or PR. - T3 levels drop by 45% within one hour **MMI (methimazole)** 60–80 mg/day, a single dose or divided into two equal doses - T3 levels drop by only 10%–15% after MMI Rectal PTU or MMI can be used with the dose and frequency similar. - PTU enema: 400 mg of PTU in 90 mL of sterile water - PTU suppository: Polyethylene glycol base (200 mg of PTU in each) **Beta blocker**: to control heart rate and inhibit other peripheral action of thyroid hormone. - Recommended in all patients with symptomatic thyrotoxicosis, especially in elderly patients and thyrotoxic patients with resting heart rates in excess of 90 beats per minute or coexistent cardiovascular disease. - **Propranolol IV** in slow 1–2-mg boluses, may be repeated every 10–15 min. - For less toxic- 40–80 mg PO 3–4 to 6 times/day - **Esmolol** or **Diltiazem** can be used to control heart rate when there are contraindications to β-adrenergic receptor antagonists. **Lugol’s iodine/saturated solution of potassium iodide, SSKI**: - 5–10 drops PO every 6 h for the first 10 days or - 10 drops of Lugol’s iodine 8 hourly for the first 10 days - Given at least 1 hour after administration of antithyroid drugs. - Should not be given beyond 10 days or else this would lead to escape from the Wolff-Chaikoff phenomenon. - Can be administered via rectal or nasogastric routes in critically ill patients or taken diluted in water or with bread to avoid mucosal irritation. **Corticosteroids:** inhibit both thyroid hormone synthesis and peripheral conversion of T4 to T3. - **IV Hydrocort** 100 mg, 6 hourly - Dexamethasone 2 mg, 6 hourly. - With the improvement in clinical condition, doses should be reduced and tapered off to prevent adverse effects. **Cholestyramine** - 1–4 g/every 6 hourly, after conjugation in liver thyroid hormone excreted into intestine and re absorbed, cholestyramine sequesters free hormone in intestine and excretes by reducing enterohepatic recycling. **Nutrition**: glucose, multivitamins, thiamine, and folate (deficient secondary to hypermetabolism) **Total plasma exchange (TPE)** - In patients with severe thyroid storm, rapid clinical worsening or failure or contraindications to standard multimodal therapy within 24–48 hours of standard multimodal therapy. - Total plasma exchange with 40–50 mL/kg of replacement fluid associated with improved outcomes and resolution. - Two types of replacement therapy: - Fresh frozen plasma (FFP) - preferentially used as it contains thyroid binding globulin (TBG) that will better enhance removal of TBG bound thyroid hormones) - Albumin **Continuous hemodiafiltration (CHDF)** is sometimes used in parallel with TPE in hemodynamically compromised patients. **Definitive therapy:** - All patients with thyroid storm should have early definitive therapy with **RAI**. - In patients with large obstructing goiter or contraindications to RAI, **early thyroidectomy** should be considered instead.

Answer 54

A **"moth-eaten" or irregular**, scalloped appearance on a thyroid ultrasound, often described as a "giraffe skin" appearance, is a characteristic finding in Hashimoto's thyroiditis, an autoimmune condition causing inflammation and scarring of the thyroid gland

Answer 55

📚 **Huins Classification of Retrosternal Goiters**: * Grade 1: Goiter extends below the thoracic inlet but remains above the aortic arch. * Grade 2: Goiter extends to the level of the aortic arch. * Grade 3: Goiter extends below the aortic arch, reaching the pericardium or right atrium ⚠️ **Limitations of Chest X-Ray:** * CXR is suggestive, not definitive. * CT neck + thorax is needed to fully assess extent, relation to vessels, and surgical planning.

🫶Differentiated Thyroid Cancer (DTC) + Hyperthyroidism + Thyroglossal cyst Flashcards

(84 cards)