Calcium Metabolism Disorders Flashcards

1
Q

hypercalcaemia aetiology

A

Primary hyperparathyroidism
Malignancy

Drugs; Fit D, thiazides 
Granulomatous disease: Sarcoid , TB
Familial hypocalciuric hypercalcaemia 
High turnover: bedridden, thyrotoxic, Paget's 
Tertiary hyperparathyroidism
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2
Q

Primary hyperparathyroidism

A

Primary overactivity of parathyroid gland
-e.g. adenoma

High calcium
High PTH

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3
Q

Secondary hyperparathyroidism

A

Physiological response to low calcium or Vit D

Low calcium
High PTH

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4
Q

Tertiary hyperparathyroidism

A

Parathyroid becomes autonomous after many years of overactivity
(e.g. renal failure)

High Calcium
High PTH

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5
Q

Hypercalcaemia: Genetic syndromes

A

MEN1/ MEN2
- Developed a parathyroid adenoma with hypercalcaemia at young age

Familial isolated hyperparathyroidism

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6
Q

hypercalcaemia clinical features

A

Bones
Stones
Abdominal Groans
Psychic moans

Acute

  • Thirst
  • Dehydration
  • Confusion
  • Polyuria

Chronic

  • Myopathy
  • Fractures
  • Osteopenia
  • Depression
  • hypertension
  • pancreatitis
  • DU
  • renal calculi
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7
Q

Hypercalcaemia Investigation

A
PTH 
CT chest, abdo and pelvis 
Myeloma Screen 
Urine Calcium Excretion 
PET Scan
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8
Q

Hypercalcaemia: Further investigations- from PTH Results

A

Normal/ High PTH

  • Urinary calcium excretion
  • Increased UrCa: Primary/ Tertiary Hyperparathyroidism
  • Decreased UrCa: Familial hypocalciuric hypercalcaemia

Low PTH (high phosphate)

  • Bone Pathology
  • Increased ALP: Mets, Sarcoidosis, Thyrotoxicosis
  • Decreased ALP: Myeloma, Vit D Toxicitiy
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9
Q

Diagnosis of Primary Hyperparathyroidism

A

Raised serum calcium
Raised serum PTH (or inappropriately normal)
Increased urine calcium excretion
- Ensure Vitamin D replete

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10
Q

Familial Hypocalciuric Hypercalcaemia (FHH)

A

Familial (autosomal dominant)

- deactivating mutation in the calcium sensing receptor

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11
Q

FHH diagnosis

A

Mild hypercalcaemia
Reduced urine calcium secretion
PTH (marginally) elevated
Genetic screening

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12
Q

hypercalcaemia of malignancy mechanisms

A

metastatic bone destruction
PTHrp from solid tumours
Osteoclast activating factors

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13
Q

hypercalcaemia of malignancy diagnosis

A

Raised calcium phosphate and alkaline phosphatase
X-ray, CT, MRI, PER
Isotope bone scan

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14
Q

Hypercalcaemia; Acute Treatment

A

Fluids; rehydrate with 0.9% saline 4-6L in 24 hours

Once rehydrated consider loop diuretics (avoid thiazides)

Biphosphonates: single dose will lover Calcium over 2-3 days (maximum effect at 1 week

Steroids occasionally used (for sarcoidosis)

Chemotherapy may reduce calcium in malignant disease (egg, myeloma0

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15
Q

Primary Hyperparathyroidism : Management

A

Cinacalet

  • Calcium mimetic
  • Patient require treatment but unsuitable for surgery
  • Approved for tertiary hyperparathyroidism and parathyroid carcinoma

Surgery
-not always required

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16
Q

Primary Hyperparathyroidism: Indications for Parathyroidectomy

A

Very high calcium (>2.85mmol/l)
Under age 50
eGFR <60ml/min

End organ damage

  • Bone disease
  • Gastric ulcers
  • Renal stones
  • Osteoporosis
17
Q

hypocalcaemia signs and symptoms

A
Paraesthesia: fingers, toes, personal 
Muscle cramps, tetany 
muscle weakness
Fatigue 
Bronchospasm or laryngospasm 
Fits
Chovsteks Sign 
- tapping over facial nerve
Trousseau Sign 
- carpopedal spasm 
ECG
-QT prolongation
18
Q

Acute hypocalcaemia management

A

EMERGENCY

IV calcium gluconate 10ml, 10% over 10 mins (in 50ml saline or. dextrose

infusion: 10ml 10% in 100ml infusatn, at 50ml/h

19
Q

Hypoparathyroidism aetiology

A

Congenital disease
-DiGeorge Syndrome

Destruction
-Surgery, radiotherapy, malignancy

Autoimmune
hypomagnesaemia
Idiopathic

20
Q

Hypocalcaemia long term management

A

Calcium supplement: >1-2 g per day

Vitamin D

21
Q

Hypomagnasaemia (mechanism of action)

A

Calcium release from cells is dependent on magnesium
In magnesium deficiency intracellular calcium isa high
PTH release inhibited Skeletal and muscle receptors less sensitive to pTH
If low replace with calcium and magnesium

22
Q

hypomagnasaemia aetiology

A

Alcohol

Drugs

  • thiazide
  • PPI

GI illness
-malabsorption

Pancreatitis

23
Q

Pseudohypoparathyroidism

A

Genetic defect

  • dysfunction of G-protein (Gs-a subunit)
  • Gene: GNAS 1

Low calcium but elevated PTH
-PTH resistance

24
Q

Pseudohypoparathyroidism signs

A
Bone abnormalities
Obesity
Subcutaneous calcification 
learning disability 
Brachdactyly (4th metacarpal)