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48 Cards in this Set
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P-P-P-P-PLEASE |
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First pyrrole product in pathway? |
porphobilinogen (PBG) |
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First tetrapyrrole product in pathway? |
hydroxymethybilane |
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First oxidized product in pathway? |
protoporphyrinogen IX |
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Prophyrins are activated by what UV range? |
400-410 |
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What are the prophyrias... 9 major products --> 9 diseases, 8 enzymes |
1. XLD protoporphyria (XLDPP)- GOF mutation in ALA synthase
2. ALA dehydratase deficiency porphyria (ALADD)
3. Acute Intermittent Porphyria (AIP)- loss of porphobilinogen deaminase
4. Congenital Erythropoeitic Porphyria (CEP)- decrease in uroporphyrinogen III synthetase
5. Porphyria Cutanea Tarda (PCT)- MC, defect in uroporphyrinogen decarboxylase
6. Hepatoerythropoetic Porphyria (HEP)- defect in uroporphyrinogen decarboxylase (same as PCT, but with increased RBC zinc proroporphyrin)
7. Hereditary Coproporphyria (HCP)- defect in corproporphyrinogen oxidase
8. Variegate Porphyria (VP)- defect in protoporphyrinogen oxidase
9. Erythropoeitic Porphyria (EPP)- defect in ferrochelatase |
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What are the 4P's in AIP? |
Neuro/visceral only!!
pain (episodic abominal) peripheral neurpathy paralysis psychiatric |
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What differentiates Porphyria Cutanea Tarda (PCT) from Hepatoerythropoetic Porphyria (HEP)? |
both are a defect in uroporphyrinogen decarboxylase
same lab profile EXCEPT HEP has an increased RBC zinc-protoporphyrin |
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Red urine in diapers? Defect? |
Congenital erythropoeitic porphyria
Cee Evil Pee (CEP)
Uroporphyrinogen III synthetase |
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Red teeth? Defect? |
Congenital erythropoeitic porphyria
Uroporphyrinogen III synthetase
Ur t33th are colored |
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Red gall stones? Defect? |
Congenital erythropoeitic porphyria
Uroporphyrinogen III synthetase |
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Precipitants of porphyria cutanea tarda? Defect? |
Uroporphyrinogen decarboxylase
ETOH, estrogens, drugs, HCV, HIV, iron overload, hemodialysis, smoking , HCC |
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Two types of PCT? |
Type I- sporadic, MC, decreased uroporphyrinogen decarboxylase in liver only, onset in 40s
Type II- familial, decreased uroporphyrinogen decarboxylase in all dissues, onset in 20s |
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Pathomneumonic lab finding in PCT? |
Isocoproporphyrin in feces |
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Does urine fluoresce in PCT? |
yes!! under Woods lamp |
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Histopathology of PCT? |
cell poor sub epidermal split (THE P3 B3)
catepillar bodies (col IV and VII)
DIF shows IgG/C3 @DEJ and vessel walls |
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Common culprits for pseudoporphyria? |
NSAIDS! mc naproxen lasix TCN amiodarone dapsone PUVA isotretinoin tanning bed hemodialysis |
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Variegate porphyria is common in South Africa... acute attacks are precipitated by... |
fasting, fever, infection, pregnancy, ETOH, meds (barbs, griseofulvin, sulfonamide, estrogen) |
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Erythropoietic porphyria defect? Labs? |
Ferrochelatase
transient fluorescence of greater than 623nm of circulating RBCs
elevated protoporphyrin IX in RBC/stool
no porphyrins in urine (EPP = empty pee pee) |
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Plasma porphyrin fluorescence for variegate porphyria? |
626nm |
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IMPORTANT LAB:
Acute intermittent porphyria |
no stool porphyrins (AIP- ain't in poo) |
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IMPORTANT LAB:
Erythropoeitic porphyria |
EPP
empty pee pee
no porphyrins in urine |
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Ration of urinary uroporphyrins to coproporphyrins in porphyria cutanea tarda? |
URO: COPRO
5-8:1 |
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What do we find in both porphyria cutanea tarda and hepatoerythropoeitic porphyria? |
fecal isocoproporphyrin |
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In which porphyria is the urine devoid of porphyrins? |
erythropoietic protoporphyria |
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Deficiency of protoporphyrinogen oxidase results in? |
variegate porphyria |
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Deficiency of uroporphyrinogen III synthase results in? |
Congenital erythropoeitic porphyria |
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Deficiency of uroporphyrinogen decarboxylase results in? |
porphyria cutanea tarda, hepatoerythropoetic porphyria |
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Coral red fluorescence seen in erythrasma is attributed to:
uroporphyrin III porphobilinogen delta aminolevulinic acid coproporphyrin III protoporphyrin IX |
coproporphyrin III |
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The porphyrin produced by p acnes is: |
coproporphyrin III |
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Which of the following statements is false:
1. fecal coproporphyria is increased in variegate porphyria
2. hepatoerythropoietic porphyria is the homozygous form of PCT
3. acute intermittent porphyria has no skin findings
4. coproporphyrinogen is elevated more than uroporphyrinogen in 24 hour urine samples in PCT
5. in erythropoietic protoporphyria, protoporphyrin IX absorbs in the soret band |
WHAT? |
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Which is caused by an enzymatic defect that occurs in the mitochondria?
PCT AIP CEP EPP HEP |
EPP |
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What porphyria is a/w variable degrees of hematological involvement from mild hemolytic anemia to hydrops fetalis? |
CEP |
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What porphyria may resemble CEP clinically, but does not have the hematologic abnormalities? |
HEP |
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What three porphyrins absorb light intensely in the Soret band? |
uroporphyrin, coproporphyrin and protoporphyrin |
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Where is the enzyme defect in acquired PCT? |
liver only
uroporphyrinogen decarboxylase |
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Where is the enzyme defect in familial PCT? |
all tissues
uroporphyrinogen decarboxylase |
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Histologically, which entity may resemble EPP? |
lipoid proteinosis |
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What is the rate limiting step in heme synthesis? |
ALA synthase |
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What porphyrin in the feces is specific to PCT and HEP? |
isocoproporphyrin |
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What gene defect, outside of the heme pathway, is a/w PCT? |
HFE gene in hemochromatosis |
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What cancer is PCT a risk for? |
hepatocellular carcinoma |
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What is the only oxidized porphyrin? |
protoporphyrin IX |
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What skin finding is seen in patients with EPP and no recent attacks? |
scarring on nose and lips |
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What is the greatest concern in patients with EPP? |
development of cholestasis from rapid accumulation of protoporphyrin in the liver and biliary system. LFTs may be normal until late in the course where liver damage or death may occur. |
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What are the DIF findings in PCT? |
IgG/C3/fibrinogen at the DEJ and around blood vessels in the papillary dermis |
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What urine prophyrins are a/w PCT? |
uroporphyrin I >III, hepta-carboxylated porphyrins III > I |
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What three porphyrias are autosomal recessive? |
ALA D deficiency, CEP, HEP |