ChemPath - ClinChem CPC

Question 1

What is the effect of potassium imbalances on the heart

Answer 1

In hypokalaemia, your myocardium becomes more irritable  leads to arrhythmias (VF)
As potassium rises, myocardium becomes more stable, however, the ultimate stable rhythm = asystole

Question 2

What is a smith’s fracture and how is it treated

Answer 2

posterior displacement of the radius (i.e. radius towards the BACK of the hand)

Falling on a flexed wrist
Treated with manipulation under anaesthesia (MUA) and plaster

Question 3

What is a Colle’s fracture

Answer 3

anterior displacement of the radius (i.e. radius towards the PALM of the hand)

Falling on an extended wrist

Question 4

What is a Pott’s fracture

Answer 4

ankle fracture involving both tibia and fibula

Question 5

What urine abnormality would be seen in the following:
Renal stone
Glomerulonephritis
DKA
Acute rheumatic fever
Bacterial endocarditis

Answer 5

Renal stones: macroscopic haematuria
Glomerulonephritis: microscopic haematuria
DKA: ketonuria
Acute rheumatic fever: proteinuria
Bacterial endocarditis: microscopic haematuria

Question 6

What causes microscopic haematuria in endocarditis

Answer 6

Immune complexes formed by bacteria in the aorta and form tiny infarcts (Roth’s spots, splinter haemorrhages). They cause leaks in the kidney

Question 7

What investigations should be done for abdominal pain with +++ blood on urine dip

Answer 7

Plain AXR
USS abdomen

Question 8

What are the differentials for a high calcium (and PTH levels for each )

Answer 8

Hypercalcaemia of malignancy (PTH H)
Primary hyperparathyroidism (PTH N/L)
Sarcoidosis (PTH L)

Question 9

What causes hyperparathyroidism

Answer 9

85% adenoma

Question 10

What feature in the eye is a sign of chronic hypercalcaemia

Answer 10

Band keratopathy

Question 11

What are the complications of primary hyperparathyroidism

Answer 11

Renal stones
Peptic ulcer disease
Pancreatitis
Skeletal changes
Osteitis fibrosa cystica (i.e. pepper-pot skull)

Question 12

What are the risk factors for renal stones (calcium)

Answer 12

Family history
Dehydration
Hypercalciuria
Hypercalcaemia
Recurrent UTI

Question 13

How do renal stones present

Answer 13

Pain
Haematuria
Recurrent infections (proteus mirabilis)
Renal failure

Question 14

What investigations should be done for renal stones

Answer 14

CT-KUB
Stone analysis
Urine and serum biochemistry

Question 15

What is the management for renal stones

Answer 15

Most stones will pass - painkillers: →PR diclofenac is very good
- Lithotripsy
- Cystoscopy
- Lithotomy

Prevention of RENAL STONES:
- Drink more water
- hypercalciuria (e.g. thiazides)
- Not in parathyroid adenoma
- Hypercalcaemia (reduces calcinuria but increases serum Ca)
- Treat hypercalcaemia

Question 16

What is the management for hypercalcaemia

Answer 16

Urgent it Ca >30

1. Fluids - IV 0.9% saline
2. IV frusemide (prevent pulmonary oedema and to aid calciuresis)

Consider IV pamidronate (bisphosphonate)

Eventually: Surgery (parathyroidectomy)
- Technetium Sesta MIBI and USS performed →shows hyperactive parathyroid
- If both tests concordant → whole neck does NOT need to be opened
If tests not concordant → surgeon needs to view all four glands and take out the largest one-

Question 17

What drug should be avoided in hypercalcaemia

Answer 17

Thiazides (reduces Ca in the urine, but increases serum Ca)

Question 18

What hand changes might be seen in the X-ray of a hand with primary hyperparathyroidism

Answer 18

Often normal
May show cystic changes in the radial aspect at later stages

Question 19

What is the histology for primary hyperparathyroidism

Answer 19

Brown tumours = multinucleate giant cells
- Activated osteoclasts in the bone
- Represents long-standing undiagnosed HPT

Question 20

What makes up MEN-1

Answer 20

Pituitary adenoma
Pancreatic tumour
Parathyroid hyperplasia

Question 21

What makes up MEN-2A

Answer 21

Parathyroid hyperplasia
Phaeochromocytoma
Medullary thyroid carcinoma

Question 22

What makes up MEN-2B

Answer 22

Phaeochromocytoma
Medullary thyroid carcinoma
Mucosal neuromas
Marfanoid body habitus

Question 23

What would sarcoidosis present as on CXR

Answer 23

Bilateral hilar lymphadenopathy

Question 24

What would biopsy of lung tissue show for sarcoidosis

Answer 24

Non-caseating granuloma

Question 25

Explain why sarcoidosis is associated with seasonal hypercalcaemia

Answer 25

Sarcoid tissue expresses 1-a hydroxylase
Macrophages in the lungs express 1-alpha hydroxylase → activate vitamin D
Vitamin D leads to excessive calcium
Patients more likely to become hypercalcaemic in summer months because of increased exposure to sunlight

Question 26

What is the short term management for sarcoidosis

Answer 26

Steroids