Pathology
Endocrine System
Endocrine pathology for MBBS and NEET-PG: thyroid swellings and cancer, thyrotoxicosis, diabetes mellitus, hyperparathyroidism and adrenal disorders, mapped to NMC codes PA32.1 to PA32.9.
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Endocrine System
Endocrine pathology for MBBS and NEET-PG: thyroid swellings and cancer, thyrotoxicosis, diabetes mellitus, hyperparathyroidism and adrenal disorders, mapped to NMC codes PA32.1 to PA32.9.
This chapter covers endocrine pathology. It includes thyroid swellings and thyroid cancer, thyrotoxicosis and hypothyroidism, diabetes mellitus and its complications, parathyroid and adrenal disease, and pancreatic and adrenal neoplasms.
High-yield: Endocrine System
- Graves disease is the most common cause of hyperthyroidism and is an autoimmune disease driven by TSH receptor antibodies.
- Graves disease shows diffuse goitre, exophthalmos and pretibial myxoedema, with a diffusely hyperplastic gland.
- Hashimoto thyroiditis is the most common cause of hypothyroidism, with lymphocytic infiltration and Hurthle cells.
- Papillary thyroid carcinoma is the most common thyroid cancer and shows Orphan Annie nuclei and psammoma bodies.
- Follicular thyroid carcinoma spreads haematogenously and is diagnosed by capsular or vascular invasion.
- Medullary thyroid carcinoma arises from parafollicular C cells, secretes calcitonin and may be part of MEN 2.
- Type 1 diabetes mellitus is due to autoimmune destruction of pancreatic beta cells and insulin deficiency.
- Type 2 diabetes mellitus is due to insulin resistance with relative insulin deficiency, linked to obesity.
- Chronic diabetes causes microvascular (retinopathy, nephropathy, neuropathy) and macrovascular complications.
- Primary hyperparathyroidism, often from a parathyroid adenoma, causes hypercalcaemia with bones, stones, groans and psychic moans.
- Cushing syndrome is due to excess cortisol, most commonly iatrogenic steroids, and shows central obesity, striae and hypertension.
- Addison disease is primary adrenal insufficiency causing hyperpigmentation, hypotension, hyponatraemia and hyperkalaemia.
- Phaeochromocytoma is a catecholamine-secreting tumour of the adrenal medulla causing episodic hypertension, and follows the rule of tens.
- Pancreatic ductal adenocarcinoma often presents late with painless obstructive jaundice and carries a poor prognosis.
Thyroid disease essentials
- **Graves disease:** Autoimmune hyperthyroidism; TSH receptor antibodies; exophthalmos.
- **Hashimoto thyroiditis:** Autoimmune hypothyroidism; lymphocytes and Hurthle cells.
- **Papillary carcinoma:** Commonest thyroid cancer; Orphan Annie nuclei, psammoma bodies.
- **Medullary carcinoma:** C-cell origin; secretes calcitonin; part of MEN 2.
NMC competencies in this chapter
- **PA32.1:** Aetiology, pathogenesis and iodine dependency of thyroid swellings
- **PA32.2:** Aetiology, manifestations and course of thyrotoxicosis
- **PA32.3:** Pathogenesis, manifestations and course of hypothyroidism
- **PA32.4:** Epidemiology, pathogenesis, pathology and complications of diabetes mellitus
- **PA32.5:** Aetiology, genetics, manifestations and features of hyperparathyroidism
- **PA32.6:** Pathogenesis, features, complications and metastases of pancreatic cancer
- **PA32.7:** Pathogenesis and features of adrenal insufficiency
- **PA32.8:** Pathogenesis and features of Cushing syndrome
- **PA32.9:** Pathogenesis and morphology of adrenal neoplasms
Frequently Asked Questions
What is the most common cause of hyperthyroidism?
Graves disease, an autoimmune condition driven by antibodies that stimulate the TSH receptor, causing a diffuse goitre and exophthalmos.
What is the most common thyroid cancer?
Papillary thyroid carcinoma, recognised by its Orphan Annie eye nuclei and psammoma bodies, with a generally good prognosis.
How do type 1 and type 2 diabetes differ?
Type 1 is autoimmune destruction of beta cells with insulin deficiency, while type 2 is insulin resistance with relative insulin deficiency, linked to obesity.
What are the features of Addison disease?
Primary adrenal insufficiency causing hyperpigmentation, hypotension, hyponatraemia and hyperkalaemia.
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