Bones Flashcards
Describe vit D pathway
UV + diet
=>
vit D
=> (25-hydroxylase from liver)
calcitriol
=> (1-alpha-hydroxylase from kidney) + PTH
calcitriol
Which hormones control calcium metabolism?
To increase calcium (+ decrease phosphates)
- PTH (parathyroid glands), calcitriol (skin + UV light)
To decrease calcium
- calcitonin (parafollicular cells)
Types of hyperparathyroidism, incl. which calcium imbalance they cause
Primary
- hyperplasia, adenoma/carcinoma
- increased PTH => increased Ca2+
- hypercalcaemia
Secondary
- vit D deficiency, decreased calcium intake
- low Ca2+ => less neg. feedback => increased PTH
- hypocalcaemia
Compare sx of hypo and hypercalcaemia
Hypocalcaemia (CATS go numb)
- C onvulsions
- A rrhythmias (prolonged QT interval)
- T etany (Trousseau’s hand + Chvostek’s cheek)
- P araesthesia (hands, mouth, feet, lips)
Hypercalcaemia (stones, nones, thrones, abdo moans, psychiatric overtones)
- renal stones
- bone pain/damage
- polyuria
- abdo (nausea and constipation pain)
- psych (depression, anxiety)
- also a cause of pancreatitis!!
RFs for primary hyperPTH
HTN
MEN-1 or MEN-2
Signs and sx for secondary hyperPTH
Rickets/osetomalacia
- bowed legs, knock knees, rachitic rosary, bone bossing
Hypocalcaemia
Fractures/bone pain
Fatigue
Proximal myopathy
Ix for hyperPTH
Basic obs
Physical exam
Bloods
- FBC, CRP, U&Es, LFTs, Ca2+, PO43-, PTH, vit D
Imaging
- CT KUB (for stones), cervical US, X-ray/CT
=> primary: pepper pot skull
=> secondary: rachitic rosary, boser’s pseudofractures
State the calcium, phosphate, PTH, vit D and ALP reading for:
a) primary hyperPTH
b) ostemolacia (vit D)
c) osteomalacia (CKD)
d) Paget’s
e) osteoporosis
Readings for calcium, phosphate, PTH, vit D, ALP:
a) high, low, high/normal, normal, high/normal
b) low, low, high, low, high
c) low, high, high, low, high
d) normal, normal, normal, normal, high
e) normal, normal, normal, normal, normal
Mx for hyperPTH
Primary
- acute hypercalcaemia: IV fluids, biphosphonates (if calcium remains high)
- surgical (1st line): totaly parathyroidectomy
- medical: cinacalet (if unsuitable for surgery, calcimimetic drug)
Secondary
- due to CKD
=> treat CKD, calcium, vit D active (alfacalcidol)
- due to vit. D
=> treat hypocalcaemia (IV calcium infusion, calcium gluconate), calcium, vit D inactive (ergocalciferol)
Phases of Paget’s disease
Disorder of bone remodelling
I. Lytic phase
- hyperactive osteoclasts => reabsorption
II. Mixed phase
- compensation by osteoblasts
III. Sclerotic phase
- hyperactive osteoblasts => formtaion
Produces WOVEN bone, not lamellar
Paget’s disease signs + sx
Sx: nerve compression, bone pain (femur, pelvis, skull), otherwise often asymptomatic (until sciatica and sensorineural hearing loss)
Signs: thoracic kyphosis, warm skin over painful area (increased metabolic activity), bone bossing (femur, tibia, skull)
Paget’s disease ix
Basic obs
Physical examination
Bloods
- FBC, CRP, U&Es, PTH, phosphate, calcium, vit D, serum CTX (bone resorption marker), serum P1NP (bone formation marker)
Imaging
- X-rays, bone scan (tec99) => hot spots in lytic areas
Osteoporosis causes
Primary
- postmenopausal
- old age
Secondary
- drugs: thyroxine, steroids
- endo: hyperT, osteomalacia, Cushing’s disease
- cancer: multiple myeloma
- MSK: SLE, RA
- GI: IBD, coeliac disease
Osteoporosis signs, sx and ix
Fractures (often NOF), back pain, thoracic kyphosis
Basic obs, physical exam, bloods (FBC, CRP, U&Es, LFTs (ALP), calcium, phosphate, PTH, vit D), imaging (X-rays, DEXA scan)
What are the DEXA scan ranges?
T-score used to compare to young, healthy adult
Z-score used to compare to age-matched BMD
T-score:
0 - -1 = normal
-1 - -2.5 = osteopaenia
>-2.5 = osteoporosis
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
D. Fasting serum calcium
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 3 L 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. Intravenous saline rehydration
A 78 year old man complains of insidious onset of generalised bone pain. On examination there are no red flags but noted muscle weakness in his lower limbs and a ‘waddling gait’. He has coeliac disease but no history of trauma. Lab resutls show: low calcium, low serum phosphate, high ALP, high PTH, low vit D. What is the most likely diagnosis?
A Osteomalacia
B Osteoporosis
C Paget’s disease
D Multiple myeloma
A Osteomalacia
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. Ricketts
E. Paget’s disease
E. Paget’s disease
A 63 year old man is furious that he has been waiting an hour for his appointment. When he finally talks to the doctor, he admits to generalised bone pain and muscle weakness. His blood results reveal the following: low calcium, low phosphate, normal ALT, high ALP
What is the most likely underlying diagnosis?
A Osteomalacia
B Primary hyperparathyroidism
C Paget’s disease
D Osteomyelitis
E Osteoporosis
A Osteomalacia
A 75 year old woman presents with polyuria, constipation. She admits that her mood has been low over the past few weeks. Her blood results reveal the following: high calcium, low phosphate, normal PTH, normal fasting glucose
What is the most likely underlying diagnosis?
A Osteomalacia
B Primary hyperparathyroidism
C Paget’s disease
D Osteomyelitis
E Osteoporosis
B Primary hyperparathyroidism
An 82 year old man sees his GP because of a 3 month history of progressive deafness. Using a 512Hz tuning fork, the doctor performed both Weber’s and Rinne’s test. There was lateralisation of vibration to the left ear, and air was louder than bone conduction in both ears. His blood results were normal apart from increased ALP.
What is the most likely underlying diagnosis?
A Osteomalacia
B Primary hyperparathyroidism
C Paget’s disease
D Osteomyelitis
E Osteoporosis
C Paget’s disease
A 58 year old woman was diagnosed with a fragility fracture. Her past medical history includes a myocardial infarction at the age of 47, and rheumatoid arthritis for which she is taking oral prednisolone. She is also going through menopause. Her blood results are as follows: normal calcium, normal phosphate, normal ALP
What is the most likely underlying diagnosis?
A Osteomalacia
B Primary hyperparathyroidism
C Paget’s disease
D Osteomyelitis
E Osteoporosis
E Osteoporosis
