Medicine Marrow Pg No 905-914 (Endocrinology)
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Questions and Answers

Which anti-thyroid drug is preferred for use during pregnancy?

  • Propylthiouracil (correct)
  • Propranolol
  • Carbimazole
  • Methimazole

    • Agranulocytosis is the most common side effect of anti-thyroid drugs.

    False

    What is the half-life of Carbimazole?

    6-8 hours

    Methimazole is associated with __________ defects.

    <p>teratogenic</p> Signup and view all the answers

    Match the following anti-thyroid drugs with their characteristics:

    <p>Methimazole = Irreversible inhibitor, teratogenic Carbimazole = Preferred over Propylthiouracil Propylthiouracil = Preferred in pregnancy, hepatotoxic Propranolol = Used for symptomatic relief</p> Signup and view all the answers

    Which condition is commonly associated with autoimmune hypothyroidism?

    <p>Hashimoto's thyroiditis</p> Signup and view all the answers

    Congenital hypothyroidism is mostly due to thyroid dysgenesis.

    <p>True</p> Signup and view all the answers

    What are two features of congenital hypothyroidism?

    <p>Open posterior fontanelle and delay in passing meconium</p> Signup and view all the answers

    Lithium is associated with _____ diabetes insipidus.

    <p>nephrogenic</p> Signup and view all the answers

    Match the following types of hypothyroidism with their causes:

    <p>Primary Hypothyroidism = Autoimmune causes Secondary Hypothyroidism = Pituitary dysfunction Consumptive Hypothyroidism = Increased Deiodinase-III expression Congenital Hypothyroidism = Thyroid dysgenesis</p> Signup and view all the answers

    Which antibody is associated with Hashimoto's disease at the highest percentage?

    <p>Thyroid peroxidase antibody</p> Signup and view all the answers

    Transient Hypothyroidism is a confirmed indicator of Hashimoto's disease.

    <p>False</p> Signup and view all the answers

    What is the recommended dose of L-Thyroxine for a symptomatic patient under 60 years old?

    <p>1.6-1.8 µg/kg/day (approximately 100 µg/day)</p> Signup and view all the answers

    The TSH value threshold for confirming Hashimoto's disease is greater than ______ mcu/ltr.

    <p>10</p> Signup and view all the answers

    Match the age group with the appropriate L-Thyroxine dosage:

    <p>&lt; 60 years = 1.6-1.8 µg/kg/day</p> <blockquote> <p>60 years = 25 µg/day Elderly with cardiotoxicity concern = 25 µg/day Young with vague symptoms = &lt; 100 µg/day</p> </blockquote> Signup and view all the answers

    Which of the following is a predisposing factor for thyrotoxic crisis?

    <p>Surgery</p> Signup and view all the answers

    Subacute thyroiditis is commonly associated with viral infections.

    <p>True</p> Signup and view all the answers

    What medication is administered initially in a thyrotoxic crisis?

    <p>Propylthiouracil</p> Signup and view all the answers

    Acute thyroiditis commonly follows a __________ infection.

    <p>Staphylococcus or Streptococcus</p> Signup and view all the answers

    Match the type of thyroiditis with its feature:

    <p>Acute Thyroiditis = Follows Staphylococcus infection Subacute Thyroiditis = Post-viral (no viral association) Chronic Thyroiditis = Painless hard thyroid Postpartum Thyroiditis = Occurs after childbirth</p> Signup and view all the answers

    Which of the following is NOT a classical symptom of 1° hypothyroidism?

    <p>Weight loss</p> Signup and view all the answers

    Myxedema is a potential complication of hypothyroidism.

    <p>True</p> Signup and view all the answers

    What is a primary risk factor for myxedema coma?

    <p>Non-compliance with treatment</p> Signup and view all the answers

    What is the most common cause of Carpal Tunnel Syndrome (CTS) in females?

    <p>Hypothyroidism</p> Signup and view all the answers

    Common symptoms of hypothyroidism in young females include hair loss, irregular menstrual cycle, and __________.

    <p>dry skin</p> Signup and view all the answers

    Clinical relief from hypothyroidism treatment may occur within 1-2 months after TSH levels become normal.

    <p>False</p> Signup and view all the answers

    What is the recommended initial dose of IV L-thyroxine for treatment?

    <p>500 µg OD</p> Signup and view all the answers

    Match the following symptoms with their corresponding descriptions.

    <p>Bowel Movements = Constipation Heart Rate = Slow Menstrual Cycle = Irregular Mental Function = Memory problems</p> Signup and view all the answers

    In cases of steroid-responsive encephalopathy associated with autoimmune thyroid illness, patients can present with __________ and myoclonus.

    <p>seizures</p> Signup and view all the answers

    Match the following presenting features of myxedema coma with their descriptions:

    <p>Decreased consciousness = May present with seizures Bradycardia = Slow heart rate Low voltage complex on ECG = Characteristic ECG finding Hypo-ventilation = Reduced breathing rate</p> Signup and view all the answers

    Which antibody is most important in diagnosing Hashimoto's thyroiditis?

    <p>Thyroglobulin Ab</p> Signup and view all the answers

    Apathetic thyrotoxicosis is characterized by irritability and restlessness.

    <p>False</p> Signup and view all the answers

    What is a common feature associated with Graves' disease?

    <p>Exophthalmos</p> Signup and view all the answers

    In severe thyrotoxicosis, there is an increase in __________ catabolism.

    <p>protein</p> Signup and view all the answers

    Match the following symptoms with their associated conditions:

    <p>Weight loss + good appetite = Graves' disease Weight gain + loss of appetite = Hypothyroid Atrial fibrillation = Elderly thyrotoxicosis Periodic paralysis = Thyrotoxicosis associated</p> Signup and view all the answers

    What is the most common presentation of Hashimoto's thyroiditis?

    <p>Irregular, firm goitre</p> Signup and view all the answers

    Hashimoto's thyroiditis is primarily an autoimmune disease affecting middle-aged men.

    <p>False</p> Signup and view all the answers

    Name one type of cell that is a pathological mediator in Hashimoto's thyroiditis.

    <p>T-cell</p> Signup and view all the answers

    In Hashimoto's thyroiditis, the presence of __________ cells is notable for their hypereosinophilic characteristics.

    <p>Hürthle</p> Signup and view all the answers

    Match the following features of Hashimoto's thyroiditis with their descriptions:

    <p>Autoimmunity = Most common in middle-aged women HLA Association = DR3/DR4/DR5 Common Gland Changes = Irregular and firm goitre Associated Malignancy = Extranodal marginal zone lymphoma</p> Signup and view all the answers

    Which diagnosis shows diffuse thyroid uptake of 75-80%?

    <p>Grave's disease</p> Signup and view all the answers

    Graves ophthalmopathy occurs in 20% of hyperthyroid patients as the initial presentation.

    <p>True</p> Signup and view all the answers

    What is the primary treatment recommendation for patients with Graves' ophthalmopathy?

    <p>Stop smoking and high dose IV steroids</p> Signup and view all the answers

    The ocular sign characterized by lid lag in down gaze is called _______ sign.

    <p>Von Graefe's</p> Signup and view all the answers

    Match the signs of Graves' ophthalmopathy with their descriptions:

    <p>Von Graefe's = Lid lag in down gaze Joffroy = Absent creases in the forehead on superior gaze Stellwag = Incomplete and infrequent blinking Dalrymple's = Widened palpebral fissure during fixation Möbius sign = Convergence</p> Signup and view all the answers

    Which of the following is a primary cause of hyperthyroidism?

    <p>Grave's disease</p> Signup and view all the answers

    The Jod Basedow phenomenon occurs when there is an increased iodine supply in iodine deficient areas.

    <p>True</p> Signup and view all the answers

    What is the Wolff-Chaikoff Effect?

    <p>Excess iodide temporarily inhibits thyroid synthesis.</p> Signup and view all the answers

    In thyrotoxicosis, both free T3 and T4 levels are __________.

    <p>elevated</p> Signup and view all the answers

    Match the following causes of hyperthyroidism with their descriptions:

    <p>Grave's disease = Autoimmune disorder leading to hyperthyroidism Toxic multinodular goiter = Overactive nodules producing excess hormones Struma Ovarii = Ovarian tumor with thyroid tissue TSH secreting adenoma = Pituitary adenoma causing high TSH levels</p> Signup and view all the answers

    Study Notes

    Anti-thyroid Drugs

    • Methimazole (6 mg), Carbimazole (10 mg), Propylthiouracil (100 mg): These are all anti-thyroid drugs used to treat hyperthyroidism.
    • Propylthiouracil: Preferred during pregnancy due to higher plasma protein binding but associated with hepatotoxicity – use with caution.
    • Carbimazole: Preferred over Propylthiouracil, half-life of 6-8 hours.
    • Methimazole: Teratogenic, associated with aplasia cutis and choanal atresia, half-life of 6 hours.
    • Side Effects: Rash (most common), agranulocytosis (most dangerous).
    • Titration Regimen: Re-evaluation every 4-6 weeks, monitor free T3 and free T4 levels.
    • Propranolol: Used as an adjunct therapy, 40 mg every 6 hours.

    Radioactive Iodine

    • Used for relapse cases.
    • Requires a month of anti-thyroid drug pre-treatment to prevent thyrotoxicosis.
    • No established association with cancer risk.

    Surgery

    • Indicated when radiotherapy is not possible or contraindicated.
    • Used for biopsy of suspected malignancy or hyperparathyroidism.

    Disadvantages of Anti-thyroid Drugs

    • Consideration for pregnant and lactating women.
    • Higher risk of eye problems.
    • 10% of patients require lifelong replacement medication with L-thyroxine.
    • Severe ophthalmopathy may require intravenous steroids and Rituximab treatment.

    Primary Hypothyroidism

    • Most commonly caused by autoimmune hypothyroidism (Hashimoto's thyroiditis).
    • Associated with autoimmune polyendocrine syndrome (APS)-1/2.
    • Check for APS-2 before treatment.
    • Risk of adrenal insufficiency if L-thyroxine is given without cortisol supplementation.

    Secondary Hypothyroidism

    • Occurs due to pituitary causes, often with no significant hypothyroidism.
    • Most common cause is lymphocytic hypophysitis.

    Consumptive Hypothyroidism

    • Increased deiodinase-III expression leads to decreased hormones.
    • Associated with hemangiomas.

    Congenital Hypothyroidism

    • Primarily caused by thyroid dysgenesis.
    • Features include open posterior fontanelle, delay in passing meconium, prolonged jaundice, minimal crying, and excessive sleeping.

    Hypothyroidism in Children

    • Can lead to shock.

    Hypothyroidism in Adults

    • Can lead to severe adrenal insufficiency.

    Hypothyroidism Causes

    • Drug-associated thyroid destruction.
      • Lithium (also associated with nephrogenic diabetes insipidus).
      • IFN α (irreversible side effect).
      • Amiodarone (can cause hypo- and hyperthyroidism).
    • Iodine deficiency.
    • Post-surgical complications.

    Confirming Hashimoto's

    • Hypothyroidism: check for autoantibodies to rule out transient hypothyroidism or thyroiditis.
    • If positive: TSH > 10 mcu/ltr confirms diagnosis.
    • Consider TSH between 5-10 mcu/ltr if any of the following are present:
      • Positive TPO antibody.
      • Family history of Hashimoto's.
      • Pregnancy.
      • Severe symptoms.

    Treatment of Hashimoto's

    • L-Thyroxine: 1.6-1.8 µg/kg/day (approx 100 µg/day) for symptomatic patients under 60 years.
    • Dose change: 25-50 µg/day.
    • Elderly (>60 years): 25 µg/day due to cardiotoxicity.
    • Dose change: 25 µg/day.

    Thyrotoxic Crisis

    • Predisposing factors: inadequate treatment before radiotherapy, surgery, illness, arrhythmia.
    • Presenting features: fever with delirium, seizure.
    • Management:
      • Propylthiouracil: 1000mg stat, 250mg Q4H.
      • Steroids.
      • Propranolol: 60 mg Q4H.
      • Oral iodine: 500 mg BD (Wolff-Chaikoff effect).

    Thyroiditis

    • Acute Thyroiditis:
      • Mostly in children, following staphylococcus or streptococcus infection.
      • Site: Piriform sinus.
      • Normal thyroid function tests.
      • Pain is a prominent symptom.
    • Subacute Thyroiditis:
      • Caused by trauma or viral infection.
      • De Quervain's thyroiditis/Subacute thyroiditis/Granulomatous/viral thyroiditis.
      • Post-viral thyroiditis (no viral association).
      • Population: 30-50 years, more common in women than men.
      • Associated with HLA-B35.
      • No uptake on scintigraphy.
    • Chronic Thyroiditis:
      • Riedel's thyroiditis (IgG4-related disease).
      • Painless, hard thyroid.
      • Characterized by dense fibrosis.
    • Postpartum Thyroiditis:
      • Occurs after childbirth.

    Hypothyroidism Treatment

    • Instructions:
      • Take on an empty stomach in the morning (7-7:30 am) with a glass of water.
      • Consume a meal after 30 minutes.
      • Avoid medications such as FeSO4, CaCO3, Al(OH)3, and Sucralfate, as they can inhibit absorption.
    • After 3 months of treatment:
      • Check TSH, free T3, and free T4 levels.
      • Gradually taper medication.
      • Non-compliance can lead to treatment failure.
      • Clinical relief may take 3-6 months after TSH levels become normal.

    Emergency Conditions

    • Myxedema Coma:
      • Mortality rate of 40%.
      • Triggered by non-compliance or other factors.
      • Presenting features:
        • Decreased consciousness (with or without seizures).
        • Bradycardia.
        • Low voltage complex on ECG.
        • Hypoventilation.
        • Hypoglycemia.
        • Hyponatremia.
        • Hypothermia.
    • Steroid Responsive Encephalopathy Associated with Autoimmune Thyroid Illness (SREAT):
      • Can occur in euthyroid status.
      • Autoimmune vasculitis unrelated to thyroid function.
      • Associated with increased anti-enolase antibodies.
      • HLA-B8 is associated with this condition.
      • Presentations:
        • Slow progressive cognitive decline.
        • Altered level of consciousness.
        • Seizures and myoclonus.
        • Stroke-like presentation.
    • Treatment:
      • IV L-thyroxine 500 µg OD → 50-100 µg/day.
      • Steroids.
      • IV T3 5-20 µg.
      • Hypertonic saline (avoid hypotonic saline).

    Classical Symptoms of Hypothyroidism

    • Common in middle-aged individuals.
    • Affects both primary and secondary hypothyroidism.
    • 1° Hypothyroidism:
      • Generalized slowing (↓ BMR).
      • Fatigue/tiredness (most common).
      • Slow speech.
      • Slow gait.
      • Constipation.
      • Memory/concentration problems.
      • Slow heart rate.
      • Poor appetite with weight gain.
      • Delayed DTR (deep tendon reflex).
      • Cold intolerance.
      • Menorrhagia (abnormal uterine bleeding).
      • Infertility.
    • Symptoms predominant in young females:
      • Hair loss.
      • Irregular menstrual cycle.
      • Dry skin.
      • Mood swings.
    • Note: False positive hypothyroidism can result from Addison's disease.

    Complications of Hypothyroidism

    • Myxedema.
    • Hashimoto's.
    • Bradycardia.
    • Pleural effusion.
    • Pericardial effusion.
    • Ascites.
    • Obstructive sleep apnea syndrome.
    • Hypocholesterolemia.
    • Oligomenorrhea/Amenorrhea.
    • Carpal Tunnel Syndrome (CTS):
      • Most common cause in females: Hypothyroidism.
      • Most common cause in males: Amyloidosis.
    • Thyroid Stimulating Hormone-Receptor Ab:
      • Positive in 80-95% of cases.
      • Most important in Graves' disease.
      • Stimulates the thyroid.
    • Thyroglobulin Ab:
      • Positive in 50-70% of cases.
      • Most important in Hashimoto's thyroiditis.
    • TPO Ab:
      • Positive in 50-80% of cases.

    Symptoms/Signs of Hyperthyroidism

    • Common Features:
      • Restlessness.
      • Irritability.
      • Tremulousness.
      • Nervousness.
      • Tachycardia.
      • Sweating.
      • Diarrhea.
      • Polyuria.
      • Warm, moist skin.
      • Oligomenorrhea/Amenorrhea.
    • Other Features:
      • Atrial fibrillation (mainly elderly).
      • Worsening of heart failure.
    • In the elder population:
      • Apathic thyrotoxicosis: Fatigue and weight loss.
    • Severe Thyrotoxicosis:
      • Protein catabolism.
    • Thyrotoxicosis Associated:
      • Periodic paralysis (presents like hypokalemia paralysis)
    • Note:
      • Weight loss with a good appetite suggests Graves' disease.
      • Weight gain with a loss of appetite suggests hypothyroid.
    • Proximal Myopathy:
      • No fasciculations.
      • Fasciculations could indicate anterior horn cell disease.

    Findings of Graves' Disease

    • Severe proptosis and eyelid retraction.
    • Exophthalmos.
    • Thyroid Ophthalmopathy.
    • Thyroid Dermopathy: Pretibial myxedema.
    • Acropachy.
    • Thick nodular skin.

    Graves' Disease Guidelines

    • The symptoms mentioned in the previous section are used as guidelines for diagnosis.

    Hashimoto's Thyroiditis

    • Most common cause of primary hypothyroidism.
    • Autoimmune disease.
    • Most common in middle-aged women.
    • HLA Association:
      • DR3/DR4/DR5 (associated with ANA-positive tests).
      • CTLA-4/PTPN-22: Polymorphism.
    • Gland Changes:
      • Often not enlarged.
      • If goitre is present, it is irregular, firm, heterogeneous, and not tender.
    • Gross Appearance:
      • Fibrosed gland.
      • Pale gland due to lymphoid infiltration.
      • Lymphoid infiltration can lead to germinal center formation.
    • Associated Malignancy:
      • Extranodal marginal zone lymphoma.
      • Papillary carcinoma thyroid.
    • Pathological Mediators:
      • T-cells (CD-8, CD-4).
      • IFN-γ.
      • Plasma cells.
    • Other findings:
      • Hypereosinophilic cells (Hürthle cells).
      • Absence of colloid.
      • Oxyphilic metaplasia.

    Scintigraphy Findings

    Diagnosis Thyroid uptake Toxic adenoma Grave's disease Salivary gland uptake
    Normal Diffuse, symmetrical. Normal uptake 25% Increased in nodule, contralateral reduced Diffuse, uptake 75-80% Normal
    Thyroiditis Low or absent

    Graves Ophthalmopathy

    • Affects approximately 30% of hyperthyroid patients.
    • 40/40/20 rule:
      • 40% of cases: Grave symptoms elsewhere, later presentation with ophthalmopathy.
      • 40% of cases: Grave symptoms with ophthalmopathy at presentation.
      • 20% of cases: Ophthalmopathy as the initial presentation.
    • Mnemonic: IM SLOW (Inferior rectus, Medial rectus, Obliques).
    • Radioactive treatment is contraindicated.
    • Treatment: Stop smoking, high dose IV steroid.

    Eye Signs

    • Von Graefe's: Lid lag in down gaze.
    • Joffroy: Absent creases in the forehead on superior gaze.
    • Stellwag: Incomplete and infrequent blinking.
    • Dalrymple's: Widened palpebral fissure during fixation.
    • Möbius sign: Convergence.

    Management of Graves Disease

    • On investigations: TSH ↓, free T3 ↑, free T4 ↑, T3/T4 >20.
    • Antibody: TSH-(R) Ab +ve.
    • Diagnosis: Graves disease.

    Hyperthyroxinemia

    • ↑ free T3, T4: Thyrotoxicosis.
    • ↑ total T3, T4: Euthyroid Hyperthyroxinemia.

    Causes of Overworking Thyroid

    • Autoimmune Graves' disease:
    • Nodular toxic adenoma:
    • Toxic multinodular goiter:
    • TSH secreting adenoma (Pituitary):
    • Struma Ovarii:

    Other possible causes of Hyperthyroidism

    • Thyroid binding globulin excess:
    • Resistant thyroid hormone:
    • Deiodinase deficiency: Sick euthyroid syndrome

    Normal Thyroid Gland Function Issues

    • Thyroiditis:
    • Thyrotoxicosis factitia:
    • Amiodarone:

    Features of Graves Disease

    • Accounts for 75% of thyrotoxicosis cases.
    • Population at risk: 20-50 years, more common in women.
    • Associations:
      • Smoking.
      • Post-partum period.
      • HAART (Highly active antiretroviral therapy).
      • HLA DR-2, CTLA-4, PTPN-22.

    Effects of Thyroid Issues

    Effect Description
    Wolff-Chaikoff Effect Excess iodide temporarily inhibits thyroid synthesis (5-7 days), followed by escape.
    Jod Basedow phenomenon Patient with Nodular or TSH-R Antibody in iodine deficient area. Increased iodine supply leads to thyrotoxicosis.

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    This quiz covers essential information about anti-thyroid drugs, including Methimazole, Carbimazole, and Propylthiouracil, used in treating hyperthyroidism. It also discusses the use of radioactive iodine and surgical options for patients. Test your knowledge on the side effects, treatment regimens, and indications for these therapies.

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