Parathyroid Pathology Flashcards
Aetiology of hypoparathyroidism
Parathyroidectomy
Thyroidectomy
AutoimmuneGenetic- DiGeorge Syndrome- undevelopment pharygneal pouches
Aetiology of hyperparathyroidism
85% due to parathyroid adenoma
15% Four gland hyperplasia
MEN
Parathyroid Carcinoma
Aetiology of Hypocalceima
PTH Defiency - parathyroid gland damaged Vit D defiency Renal failure Mg 2+ defiency Infection - HIV Tumours
Aetiology of Hypercalcaemia
90% are either:
- Primary Hyperparathyroidism
- Malignant Hypercalcaemia
Other: MEN Familial Hypocalciuric Hypercalcaemia (FHH) -Drugs e.g. Thiazide diuretic or Lithium Vit D Vit A Sarcoid
How does Hypercalcaemia present?
GI:
- Anorexia
- Constipation
- N&V
CV:
Short QT,
Hypertension
Bradycardia
Neuro
Loss of Conc. & confusion
Renal
Polyuria & Polydipsia +
Nephrolithiasis
MSK - Muscle Weakness & bone pain
BONES STONES GROANS & PSYCHIATRIC MOANS
How does Primary Hyperparathyroidism present?
Its generally asymptomatic but can cause symptoms of hypercalcaemia
What is Familial Hypocalciuric Hypercalcaemia?
An autosomal dominant disorder causing
Calcium-Sensing Receptor (CaSR) defects
Pathophysiology:
Increased Ca2+ reabsorption - therefore lowcalcium in uria
What tests are appropriate for Hypercalcaemia? (hint there’s loads)
- Serum Ca, PO4, PTH & Albumin
- Serum ACE (Sarcoid)
- 24 hour urine collection for calcium (low = FHH)
- U&Es
- ALKP
- Lymph node exam (malignancy)
- Myeloma screen (osteolytic metastases)
- ECG (short QT)
- FH
- Med History
- Abdo US for kidney stones
- Parathyroid US for adedomas etc.
What are the initial tests for hypercalcaemia?
Serum Ca / PO4 / PTH / AlbuminFH & Med history
What are the “levels” of hypercalcaemia?
<3mmol/l - Generally aymptomatic
3-3.5mmol/l -~symptomatic & prompt treatment needed
> 3.5mmol/l - Emergency. Risks Dysrhythmia & coma”
How do you treat hypercalcaemia first?
Rehydration & IV bisphosphonates (inhibit osteoclasts)
What can you give hypercalcaemics when bisphosphonates fail/arn’t tolerated?
Calcitonin- opposes effect of PTH and reduces serum Ca 2+ levels
What treatments are there for lymphoma or granulomatous disease causing hypercalcaemia?
Glucocorticoids e.g. Hydrocortisone
How would we treat Primary Hyperparathyroidism Hypercalcaemia?
Parathyroidectomy OR Calcimetics e.g. Cinacalcet
What is Pseudohypoparathyroidism?AKAalbright hereditary osteodystrophy
A set of disorders in which target organs like kidneys & bone become unresponsive to PTHFeatures:
Shortened 4th and 5th digits
Short
Obese
Developmental delays
At what Serum Ca2+ level do symptoms of hypocalcaemia appear?
Around 1.9mmol/l
How does chronichypocalcaemia present?
Parkinsonism
Dementia
Subcapsular Cataracts
Abnormal Dentition
Dry Skin
Ectopic calcification
How does acute hypocalcaemia present?
Lots of symptoms, main ones are:
- Paraesthesia
- Muscle twitching
- Trosseaus sign (bp cuff)
- Chovstek’s Sign (face)
Prolonged QT
Hypotension
Papilloedema
What tests are appropriate for Hypocalcaemia?
Adjusted Ca,
albumin,
PO4
PTH (High Pseudoparathyroidism vs low Hypoparathyroidism)
Mg (Mg deficiency)
U&Es (renal failure)
Vit D (Vit D deficiency)ECG
Explain how blood tests will appear for the 3biggest causes of hypocalcaemia?
Vit D deficiency - Low Ca, low PO4 & high PTH
Hypoparathyroidism - Low Ca, High PO4 & low PTH
Pseudoparathyroidism - Low Ca, High PO4 and high PTH
How do you treat mild Hypocalcaemia?
Mild meaning >1.9mmol/l and asymptomatic.
Oral Ca2+
Supplements Vitamin D & Magnesium
How do you treat severe hypocalcaemia?
Severe meaning symptoms or <1.9mmol/l
Considered a medical emergency
IV Calcium Gluconate
Then treat cause e.g. 2g IV Magneiusm Sulfate
How to work out adjusted calcium
Some calcium is albumin bound, to find a true serum calcium do serum calcium and serum albumin.
Then add 0.1mmol/l for every 5g/l reduction in Albumin from 40g/l
Management of hyperparathyroidism
Primary hyperparathyroidism:
Parathyroidectomy
Secondary Hyperparathyroidism:
Vitman D
Renal therapy
