Page 550 - Concise Pathology for Exam Preparation ( PDFDrive )

20 Endocrinology 535

Q. Define thyrotoxicosis. Enumerate the disorders associated with
hyperthyroidism.
Ans. Thyrotoxicosis is a hypermetabolic systemic state which occurs due to increased free
T3 and T4 levels. It is most commonly caused by hyperfunctioning of the thyroid gland;
also known as ‘hyperthyroidism’.

Disorders Associated With Hyperthyroidism

Common
• Diffuse toxic hyperplasia (Graves disease)
• Toxic multinodular goitre (Plummer disease)
• Toxic adenoma

Uncommon
• Acute or subacute thyroiditis
• Hyperfunctioning thyroid carcinoma
• Choriocarcinoma or hydatidiform mole (due to mild thyrotropic effect of HCG)
• TSH-secreting pituitary adenoma
• Neonatal thyrotoxicosis with maternal Graves disease
• Struma ovarii
• Iodide-induced hyperthyroidism
• Iatrogenic (Job–Basedows disease)

Q. Write briefly on the clinical manifestations and diagnosis of
hyperthyroidism.

Ans. Hyperthyroidism is a systemic state in which there is hyperfunctioning of thyroid gland.

Clinical Manifestations of Hyperthyroidism
• Increased BMR (basal metabolic rate), tachycardia, cardiomegaly, arrhythmias and
congestive heart failure (due to increased cardiac contractility) and thyrotoxic dilated
cardiomyopathy (shows lymphoeosinophilic infiltration of myocardium with fatty
change and fibrosis)
• Generalized lymphoid hyperplasia and lymphadenopathy
• Ocular changes, eg, a wide, staring gaze and lid lag (due to sympathetic overstimula-
tion) and true thyroid ophthalmopathy (as seen in Graves disease)
• Increased appetite, but weight loss; increased gut motility, tremors, hyperactivity,
emotional liability, anxiety, inability to concentrate, insomnia and heat intolerance (due
to overactivity of sympathetic nervous system)
• Proximal muscle weakness (caused by atrophy and fatty infiltration of skeletal muscle;
also called thyroid myopathy)
• Warm and moist skin showing flushing and increased sweating (due to peripheral
vasodilatation)
• Bone resorption (causing osteoporosis and increased risk of fractures)
• Fatty liver

Diagnosis of Hyperthyroidism
Hyperthyroidism is diagnosed based on findings of a low serum TSH and increased
free T4.

Q. Describe the etiopathogenesis and clinicopathological features
of Graves disease.
Ans. Graves disease is the most common cause of endogenous hyperthyroidism with a
peak incidence between 20–40 years and a female:male ratio of 7:1. Its genetic basis is

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