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Year 3 MedEd > Endo3 > Flashcards

Endo3 Flashcards

Calcium and Bone

1
Q

What is secreted when there is a calcium deficiency?

A

PTH

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2
Q

What organs does PTH directly and indirectly act upon?

A

Bones (directly)
Kidneys (directly)
SI (indirectly)

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3
Q

How does PTH act on the bones?

A

Increases osteoclast activity
Induces bonre resportion
Plasma Ca concentration increases

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4
Q

How does PTH act on the kidneys?

A

Increases Ca resorption and PO4 excretion

Increases 1 alpha hydroxylase activity

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5
Q

How does PTH act on the SI?

A

Increases 1 alpha hydroxylase activity in the kidneys
Converts 25-OH D3 into 1,25-(OH)2 D3 aka calcitriol
Calcitriol acts upon the SI
increases Ca resorption and PO4 resorption

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6
Q

What is the pathway of vitamin D?

A

Vitamin D is converted to 5-OH D3 in the liver
5-OH D3 is converted into 1,25-(OH)2 D3 in the kidneys
1,25-(OH)2 D3 increases Ca and PO4 resorption

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7
Q

What are some causes of hypercalcaemia?

A 
Endocrine:
-1 hyperPTH, 3 hyperPTH (renal failure)
Malignancy:
-PTHrp from SSC/breast Ca
High bone turnover:
-Paget's, MM, hyperthyroidism
Other:
-MEN 1/2a, sarcoidosis
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8
Q

What are some causes of hypocalcaemia?

A 
Endocrine:
-Vit D3 deficiency, hypoPTH
Electrolyte:
-Hyperphosphataemia, hypomagnesaemia
Other:
-Acute renal failure, pancreatitis, iatrogenic, drugs (eg. lithium)
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9
Q

What is the normal range of serum calcium?

A

2.2-2.6mmol/L

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10
Q

What are the signs and symptoms of hypercalcaemia?

A

Stones
-polyuria, thirst, nephrocalcinosis, renal colic, chronic renal failure
Bones
-bony pain
Abdominal groans
-anorexia, nausea, dyspepsia, pancreatitis
Psychic moans
-fatigue, depression, impaired consciousness, coma (if >3)

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11
Q

What are the signs and symptoms of hypocalcaemia?

A 
CATs go numb:
Convulsions
Arrhythmia
Tetany
Paraesthesia

Trousseau’s sign
Chvostek’s sign

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12
Q

What is Trousseau’s sign?

A

Carpopedal spasm
Triggers due to ishaemia
eg. applying a BP cuff

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13
Q

What is Chvostek’s sign?

A

Twitch of the face

Triggered by tapping a facial nerve

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14
Q

What are the investigations for hyper/hypocalcaemia?

A 
Plasma Ca
Plasma Vit D3
Plasma PTH
Plasma PO4
ALP
Radiology
ECG
Bone biopsy
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15
Q

What is the treatment for hypercalcaemia?

A

Fluids
IV bisphosphonates
Haemodialysis
Treat underlying cause eg surgery for Ca

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16
Q

What is the treatment for hypocalcaemia?

A

IV calcium gluconate 10%
Calcium chloride
Vit D/Ca supplements
Treat underlying cause

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17
Q

What is primary hyperparathyroidism?

A

Abnormal secretion of PTH

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18
Q

What is secondary hyperparathyroidism?

A

Abnormal secretion of PTH secondary to hypocalcaemia

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19
Q

What is tertiary hyperparathyroidism?

A

PTH secretion due to long term 2 hyperPTH

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20
Q

What are the common causes of 1 hyperPTH?

A

Adenoma
Parathyroid carcinoma
MEN, radiation

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21
Q

What are the common causes of 2 hyperPTH?

A

Chronic renal failure

Vit D3 deficiency

22
Q

What are the common causes of 3 hyperPTH?

A

Chronic renal failure

23
Q

What are the symptoms of hyperPTH?

A

Insidious onset
Many are asymptomatic
Features of hypercalcaemia

24
Q

What are the investigations for hyperPTH?

A

U+E:

  • Ca raised in 1+3, normal/low in 2
  • ALP slightly raised
  • Vit D low in 2
  • PTH raised
  • PO4 low in 1+3, high in 2
25
Q

What is the treatment for hyperPTH?

A 
Treat acute hypercalcaemia with fluids
Surgical is definitive treatment
If surgery is contraindicated:
-bisphosphonates
-oestrogen
-cinacalcet (PTH carcinoma, 3 hyperPTH)
26
Q

What are the complications of hyperPTH?

A 
Inflammation
Organ deposition
Arrhythmia
Death
Osteitis fibrosa cystica
Surgical complications
27
Q

What is osteomalacia?

A

Vit D deficiency leading to a disorder of bone matrix mineralisation in adults

28
Q

What is Ricket’s?

A

Vi D deficiency leading to a disorder of bone matrix mineralisation in children

29
Q

What are the risk factors for Vit D def?

A 
Dietary
Lack of sunlight exposure
Malabsorption
Liver/kidney disease
Vit D resistance
Renal phosphate wasting eg. Fanconi's syndrome
30
Q

What are the signs and symptoms of osteomalacia?

A 
Bone pain
Weakness
Malaise
Waddling gait
Proximal muscle weakness
Signs of hypocalcaemia
31
Q

What are the signs and symptoms of Ricket’s?

A 
Hypotonia
Growth retardation
Skeletal deformities
Frontal/parietal bossing
Rickety rosary
Bowed legs
Knocked knees
Short stature
32
Q

What are the investigations for Vit D def?

A 
Bloods:
-low/normal Ca
-low PO4
-slightly raised ALP
-high PTH (2 hyperPTH)
ABG- for acidosis
XR
-may show Looser's zone and osteopenia
Bone biopsy after double tetracycline labelling
33
Q

What is the management for Vit D def?

A 
Restore Vit D:
-ergocalciferol
-cholecalciferol
-Ca supplements
If in renal failure:
-alfacalciferol
34
Q

What are the complications of Vit D def?

A 
Bone deformities (permanent in children)
Hypocalcaemia:
-seizure
-arrhythmia
-tetany
Depression
35
Q

What is osteoporosis?

A

Reduced bone density, resulting in bone fragility and increased fracture risk.

36
Q

How is osteoporosis diagnosed?

A

If a Pt’s DEXA is >2.5 S.D’s below the peak bone mass in healthy adults (ie. T score)

37
Q

What is the epidemiology of osteoporosis?

A

> 50yrs

Caucasians > Afro-Caribbeans

38
Q

What are the causes of primary osteoporosis?

A

Idiopathic

39
Q

What are the causes of secondary osteoporosis?

A 
Malignancy- myeloma, carcinoma mets
Endo- Cushing's Dx, thyrotoxicosis, 1 hyperPTH, hypogonadism
Drugs- corticosteroids, heparin
Rheum- RhA, ankylosing spondylitis
GI- malabsorption, liver Dx, anorexia
40
Q

What are the risk factors for osteoporosis?

A

Age, ethnicity, FHx
Alcohol, low Vit D nutrition
Medication

41
Q

What are the signs and symptoms of osteoporosis?

A

Asymptomatic

Usually present after a fracture

42
Q

Which fractures are commonly associated with osteoporosis?

A

Neck of femur fracture
Vertebral fracture
Colles’ fracture (distal radius)

43
Q

What are the investigations for osteoporosis?

A

Bloods- normal in primary
XR- diagnose fractures
Isotope bone scans
DEXA scan

44
Q

What is Paget’s disease of bone?

A

Excessive bone remodelling leading to deformities

45
Q

What is the aetiology of Paget’s?

A

Overactivity of osteoclasts break down bone
Lytic wedges form
Compensatory osteoblast activity lays down trabecular bone, not lamellar bone
Marrow becomes filled with fibrous tissue what is hypervascular

46
Q

What is the presentation of Paget’s?

A

May be asymptomatic
May have insidious onset of bone pain
Headaches/dizziness
Increasing skull size
Bitemporal head enlargement with frontal bossing
Spinal kyphosis
Anterolateral bowing of femur/tibia/forearm
Skin over the affected bone may be warm
Sensorineural deafness (CN VIII compression)

47
Q

What are the investigations for Paget’s?

A 
ALP (very very high)
Ca and PO4 normal
Lytic and sclerotic bone lesions
Skull changes
Radioisotope bone scan- increased activity
48
Q

A 39-year-old man presents with a three-month history of depression. The patient recently lost a family member and around the same period began to feel unwell with constipation and a depressed mood. He has started taking analgesia for a sharp pain in his right lower back that often radiates towards his front. The most appropriate investigation is:

A. Serum parathyroid hormone 
B. Serum thyroid stimulating hormone 
C. Colonoscopy 
D. Fasting serum calcium 
E. MRI scan
A

D. Fasting serum calcium

This patient appears to be suffering from symptoms of elevated calcium levels, these can include depression, constipation and renal stone formation causing abdominal pain.

49
Q

A 50-year-old woman presents to accident and emergency complaining of excessive lethargy. In addition, she mentions that she has been constipated. On examination, there are clinical features of dehydration. Blood tests have revealed a corrected calcium of 3.3 mol/L. Her chest x-ray shows bilateral streaky shadowing throughout both lung fields. She is given 3L of saline in 24 hours after admission. The following day her blood tests are repeated and her corrected calcium level is now 3.0 mmol/L. Results of parathyroid hormone levels and thyroid function tests are still awaited. What is the most appropriate management?

A. Intravenous saline rehydration
B. Intravenous saline rehydration and pamidronate
C. Pamidronate
D. Calcitonin
E. Intravenous saline rehydration plus calcitonin

A

E. Intravenous saline rehydration

Acute hypercalcaemia is an emergency that requires prompt treatment. The treatment of acute hypercalcaemia is saline, saline and more saline! Bisphosphonates (B) and (C) should be reserved for hypercalcaemia of malignancy. The most common causes of hypercalcaemia are hyperparathyroidism and malignancy. In light of the raised calcium, the chest x-ray findings should raise the suspicion of sarcoid or possible lymphangitis carcinomatosis. While a diagnosis of sarcoid must be confirmed with histology, hypercalcaemia in sarcoidosis is an indication for corticosteroid therapy. Therefore, this patient can be given a steroid challenge. If the calcium levels fall following this, it is suggestive of sarcoid. Administering bisphosphonates, however, would complicate the process of making the diagnosis of sarcoid as any correction in calcium following steroid therapy may have been produced by the bisphosphonate. Calcitonin (D) and (E) is seldom used in hypercalcaemia as it has a short- lived action and is painful upon intravenous administration.

50
Q
  1. A 67-year-old man presents to his GP with pain in his pelvis. During the consultation, he mentions that his friends have been commenting that his head appears larger than before. In addition, he has noticed deterioration in hearing in his left ear. On neurological examination, a left-sided sensorineural deafness in detected. Closer inspection of the legs reveals bowing of the tibia. What is the most likely diagnosis?
A. Osteomalacia 
B. Osteoporosis
C. Acromegaly 
D. Ricket's 
E. Paget’s disease
A

E. Paget’s disease

Year 3 MedEd (29 decks)

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