ENDOCRINOLOGY Flashcards
What does PTH do?
Increases serum calcium
Increases osteoclast activity to increase bone turnover releasing calcium and phosphaye
Increasesvitamin D3 production
Increases uptake of calcium in the kidneys
What are the causes of Primary Hyperparathyroidism?
Cancer of the parathyroid gland
80% Solitary Adenoma
(multifocal disease, hyperplasia, multiple adenoma, parathyroid carcinoma)
What are the clinical features of Primary Hyperparathyroidism?
- Elderly females with unquenchable thirst with inappropriately normal or raised parathyroid hormone*
Signs of hypercalcaemia
HTN
Raised ALP
How is Primary Hyperparathyroidism managed?
Fluids prevents stones
Total parathyroidectomy (remove the parathyroid glands) if:
- High blood calcium: Serum Calcium >1mg/dL above noral
- High urine calcium: Hypercalciuria >400 mg/day
- Life threatiening hypercalcaemia
- Nephrolithiasis
- > 50 y/o
- Neuromuscualr symptoms
- Reduction in bone mineral density
Calcimimetic agents: cinacalcet if not suitable for surgery
What causes Secondary Hyperparathyroidism?
Parathyroid gland HYPERPLASIA due to LOW CALCIUM due to CKD
What are the clinical features of Secondary Hyperparathyroidism?
Few symptoms
Eventually bone disease
Soft tissue calcification
How is Secondary Hyperparathyroidism managed?
Manage medically, indications for parathyroidectomy:
- Bone pain
- Persistent pruritis
- Soft tissue calcification
What are the causes of Tertiary Hyperparathyroidism?
Ongoing hyperplasia of all 4 glands after CKD is corrected
What are the clinical features of Tertiary Hyperparathyroidism?
Metastatic calcification Bone pain and/or fractures Nephrolithiasis Pancreatitis Raised ALP
How is Tertiary Hyperthyroidism managed?
Only treat after 12 month persistance because it usually resolves
Remove culprit gland or all
What are the causes of Malignant Hyperparathyroidism?
PTH related-peptide produced by some Squamous cell Lung cancers, Breast cancers and renal cell carcinomas
What are the hormone levels in the hypeparathyroidisms?
1’ Raised: PTH Calcium
Low: Phosphate
2’ Raised: PTH Phosphate
Lowered: Calcium Vitamin D
3’ Raised: PTH Calcium
Lowered: Phosphate Vitmain D
Malignant: Raised: Calcium
Lowered: PTH (because PTHrp is raised)
What are the causes of primary hypoparathyroidism?
Gland failure
- AI
- Di geoge syndrome
- Thyroid surgery
What are the features of primary hypoparathyroidism?
Hypocalcaemia
High phosphate
How is primary hypoparathyroidism manged?
Calcium supplements
Calcitriol
Synthetic pTH
What are the causes of secondary hypoparathyroidism?
Radiaiton
Surgery
Hypomagensia
What is pseudo hypoparathyroidism?
Target cells are insensitive to PTH (due to a G protein abnormality) so PTH is actually high (calcium is low)
- Low IQ
- Short stature
- Short 4th abd 5th metacarpals
- Calcified basal ganglia
What is pseudopsuedo hypoparathyroidism?
Same features but normal biochemistry
What do the zones of the Adrenal Cortex produce?
Zona Glomerulosa- Mineralcorticoids
Zona Fasiculata- Glucocorticoids
Zona Reticularis- Sex steroids
What is Cushing’s syndrome?
CLINICAL STATE reduced by chronic EXCESS of GLUCOCORTICOIDS, loss of normal feedback mechanism and loss of CORTISOL secretion circadian rhythm
What are the causes of Cushing’s syndrome?
ACTH independent:
the adrenal gland is making too much cortisol and the ACTH is low. ADRENAL TUMOUR or bilateral adrenal hyperplasia
ACTH dependent:
- Cushing’s disease: Bilateral adrenal hyperplasia from PITUITARY ADENOMA secreting ACTH
- ECTOPIC ACTH production e.g. Small cell lung cancer
What are the symptoms of Cushing’s syndrome?
Acne
Mood changes (depressed, lethargic irritable, psychosis)
Hirsutism
Increased weight
Acanthiosis Nigricans (brown velvety skin discoloration e.g. in axilla)
Erectile dysfunction/Irregular menses
Recurrent achilles tendon rupture
What are the signs of Cushing’s syndrome?
Infections Moon face Buffalo hump Central obesity Purple striae Poor healing Skin and muscle hypertrophy Bruising Osteoporosis
What are the tests for Cushing’s syndrome?
1st line:
- overnight DEXAMETHASONE SUPRESSION TEST (should suppress to <50nmmol/L
or
- 24 hour urinary free cortisol
2nd line:
48 hour dexamethasone suppression
High-dose DMST differentiates between pituitary and non-pituitary causes