Hyperthyroidism
Graves' disease is also not a usual cause (it causes hyperthyroidism), but C is the clearest.
Treatment at a glance
- Carbimazole
- Propranolol for symptoms
Hyperthyroidism
- Hyperthyroidism is characterized by excessive production of T3 and T4, leading to an accelerated metabolic state.
- Graves' Disease : An autoimmune disorder where Thyroid-Stimulating Immunoglobulins (TSIs) mimic TSH, causing diffuse goiter and exophthalmos.
- Toxic Multinodular Goiter : Multiple nodules produce excess hormone independently of TSH.
- Thyroid Adenoma : A benign localized tumor secreting excess hormones.
- Clinical Features : Weight loss, tachycardia, heat intolerance, tremors, and palpitations.
Read this in Gastric Acid Secretion and Thyroid Disorders
Hyperthyroidism
- Description : Overproduction of thyroid hormones, which is the second most prevalent endocrine disorder.
- Common Cause : Often due to autoimmune conditions like Graves' disease .
Read this in LECTURE 4: Thyroid Hormones
What our notes say
- Graves' disease is also not a usual cause (it causes hyperthyroidism), but C is the clearest. (Internal Medicine 4th Year Endocrinology CAT: 30 MCQs)
- A patient in her first trimester of pregnancy is diagnosed with hyperthyroidism. (Internal Medicine (MBIM 4100) main exam, Paper One: 3 July 2019)
- Hyperthyroidism with a diffuse goitre and eye signs (exophthalmos) is Graves disease, caused by TSH receptor-stimulating antibodies. (Endocrinology and Gastroenterology Question Bank: 12 Clinical MCQs)
- Such a TSH secreting pituitary adenoma is an uncommon cause for hyperthyroidism. (Chemical pathology and Endocrine pathology — Past Paper Questions & Answers)
- Hyperthyroidism may be transient, and most persons are euthyroid. (Chemical pathology and Endocrine pathology — Past Paper Questions & Answers)
- The historical findings here are consistent with hyperthyroidism and suggest that this teratoma also has thyroid tissue, known as struma ovarii when the majority of the teratoma is composed of thyroid tissue. (Female system — Past Paper Questions & Answers)
Study material on Hyperthyroidism
- ENDOCRINE PATHOLOGY
- Chemical pathology and Endocrine pathology
- Chemical Pathology MCQs: Clinical Chemistry, Endocrine & Renal
- Chemical Pathology MCQs
- Internal Medicine 4th Year Endocrinology CAT: 30 MCQs
- Endocrine LAqs and SAqs
- LECTURE 4: Thyroid Hormones
- Bipolar and Related Disorders
- Internal Medicine (MBIM 4100) special/supplementary exam, Paper Two: 14 August 2019
- Cardiovascular system examination revised 2012
- Year 3: Endocrine and Metabolic Pathology
Practice questions on Hyperthyroidism
patients with hyperthyroidism
- Typically have increased serum T3 and T4 levels
- Typically have decreased TSH levels
- May have elevated thyroid antibodies
- All of the above
Answer: D. Hyperthyroidism is characterized by excessive production of thyroid hormones (T3 and T4), leading to suppressed TSH levels. In autoimmune causes like Graves' disease, thyroid antibodies are often present.
Patients with hyperthyroidism
- Typically have increased serum cholesterol levels
- Often have decreased total T4 and free T4 levels
- May exhibit bradycardia
- Often have decreased serum T3 and free T3 levels
Answer: D. In hyperthyroidism, thyroid hormone levels (T3 and T4) are elevated. This leads to an increased metabolic rate, often causing tachycardia, weight loss, and heat intolerance. Decreased serum T3 and free T3 levels would be seen in hypothyroidism. Increased cholesterol is more typical of hypothyroidism, and bradycardia is also a feature of hypothyroidism.
patients with hyperthyroidism
- Tend to have lower serum cholesterol levels.
- Tend to have higher serum cholesterol levels.
- Have normal serum cholesterol levels.
- Have significantly elevated triglycerides.
Answer: A. Hyperthyroidism accelerates metabolism, leading to increased catabolism of cholesterol and a tendency towards lower serum cholesterol levels (both LDL and total cholesterol). Conversely, hypothyroidism is associated with elevated cholesterol levels.
A 28-year-old woman develops sudden severe neutropenia (ANC 100) and fever 2 weeks after starting carbimazole for hyperthyroidism. She has no lymphadenopathy or organomegaly. Bone marrow shows absence of mature myeloid cells with preserved erythroid and megakaryocytic lineages. Most likely diagnosis?
- Aplastic anemia
- Drug-induced agranulocytosis
- Acute myelogenous leukemia
- Myelodysplastic syndrome
Answer: B. Sudden severe neutropenia after starting a drug (carbimazole) + selective absence of mature myeloid cells in marrow + preserved other lineages = drug-induced agranulocytosis. Carbimazole, clozapine, and methimazole are classic culprits. ---
Thyroid storm (thyrotoxic crisis) is differentiated from uncomplicated hyperthyroidism by
- T3 levels
- T4 levels
- TSH suppression
- Clinical scoring (Burch-Wartofsky) and marked fever/tachycardia
Answer: D. Laboratory values do not reliably distinguish; clinical criteria (Burch-Wartofsky score) are used. ---
Thyroid storm is a life-threatening complication of hyperthyroidism precipitated by
- Gradual withdrawal of antithyroid drugs
- Stress, surgery, infection, or radioiodine in uncontrolled hyperthyroidism
- Hypothyroidism treated with excess thyroxine
- Iodine deficiency
Answer: B. Thyroid storm: hyperpyrexia, tachycardia/arrhythmias, agitation, vomiting, high-output cardiac failure. Mortality ~20–30%. Treatment: propylthiouracil (blocks synthesis AND T4→T3 conversion) + Lugol's iodine + propranolol + steroids + supportive care. ---