EMQ on Clinical chemistry

Question 1

A 30-year-old man complains of polyuria and polydipsia.

His fasting blood glucose is 4.7 mmol/l.

Biochemical investigations reveal
Na 140 (135-145)
K 4.2 (3.4 – 5.0)
Ca 2.85 (2.20 – 2.65)
Phosphate 0.4 (0.8-1.4)
PTH 4.2 (1.1 – 6.8)

Answer 1

4. primary hyperparathyroidism

Question 2

A 50-year-old Asian woman complains of tingling in her hands and feet.

When checking her blood pressure, her hands reveal carpal spasm.

Her fasting blood glucose is 4.9 mmol/l.

Biochemical investigations reveal
Na 141 (135-145)
K 4.1 (3.4 – 5.0)
Ca 1.85 (2.20 – 2.65)
Phosphate 1.4 (0.8-1.4)
PTH 80 (1.1 – 6.8)

Answer 2

7. Secondary hyperparathyroidism

very high PTH.

Question 3

A 50-year-old Asian woman complains of nocturia and dizziness.

Her fasting blood glucose is 3.9 mmol/l.

Biochemical investigations reveal
Na 131 (135-145)
K 6.1 (3.4 – 5.0)
Ca 2.75 (2.20 – 2.65)
Phosphate 1.0 (0.8-1.4)
PTH 1.3 (1.1 – 6.8)

Answer 3

B. Addison’s disease

LOW NA, HIGH K, SOMETIMES HIGH CA and suppressed PTH

Question 4

A 60-year-old man complains of pain in his knee, and examination reveals an effusion.

Withdrawal of fluid and microscopy reveals crystals, which on viewing under polarised light are positively-birefringent.

Answer 4

5. Pseudogout

POSITIVE BIFRINGEMENT

Question 5

Occurs in patients with Lesch-Nyhan syndrome.

Answer 5

A. Acute gout

Question 6

Occurs in patients with osteomalacia

Answer 6

7. Secondary hyperparathyroidism

Question 7

A 30-year-old man complains of polyuria and polydipsia.

His fasting blood glucose is 4.7 mmol/l.

Biochemical investigations reveal
Na 157 (135-145)
K 4.2 (3.4 – 5.0)
Ca 2.35 (2.20 – 2.65)
Phosphate 1.2 (0.8-1.4)
PTH 4.2 (1.1 – 6.8)

Answer 7

D. Diabetes insipidus

Clearing lost of water just leaving salt

Question 8

Paget’s disease causes:

A.Nerve deafness

B.Conductive deafness

C.Has no effect on hearing

D.Both nerve and conductive deafness

Answer 8

D. Both nerve and conductive deafness

Paget’s disease of the ossicles (Malleus, Incus and Stapes) will cause a conductive deafness.

Bone conduction will be normal if you put the tuning fork on the mastoid process…

Of the skull can compress the VIIIth cranial nerve and also cause nerve deafness.