Heme Metabolism - Goueli

Question 1

How does B6 deficiency leads to microcyctic, hypochromic anemia?

Answer 1

delta-ALA synthase requires pyridoxal phosphate

–>PLP requires B6 as co-factor

–>slowed heme production ===ANEMIA (ahhh shucks, shoulda ate more bacon)

Question 2

B6 deficiency symptoms

Answer 2

Peripheral neuropathy, CNS effects, and anemia

Question 3

B6 deficiency and Isoniazid?

Answer 3

Isoniazid drug in TB tx.

-causes B6 def so add B6 supplements

Question 4

Pt has TB and is treated with isoniazid, now have trouble with their nerves and are anemic. Why?

Answer 4

B6 deficiency dude!

Question 5

Increased unconjugated (indirect) bilirubin levels?

Answer 5

HEMOLYSIS

Question 6

Increased conjugated (direct) bilirubin levels?

Answer 6

Biliary obstruction!

btw, bilirubin is conjugated in the liver.

Question 7

Porphyria Cutanea Tarda

Answer 7

Def of hepatic uroporphyrinogen decarboxylase (URO-D)

• most common porphyria
• increased iron stores (may be due to down-regulation of hepcidin)

Hereditary or ACQUIRED forms

Question 8

Porphyria Cutanea Tarda sporadic form and Hepatitis C?

Answer 8

> 50% of patients with sporadic form are HCV positive

Question 9

Porphyria Cutanea Tarda Symptoms

Answer 9

• BULLOUS DERMATOSIS
• Scarring
• Hyperpigmentation
• Hypertrichosis (lots of hair growth all over)

Question 10

PCT diagnosis and tx

Answer 10

Dx: bullous lesions in sun exposed areas w/out nerovisceral symptoms
-elevated urine total porphyrins

Tx: avoid precipitating factors
-Phlebotomy