porphyria Flashcards
rare disorders that affect heme synthesis
porphyria
if enzyme missing/defiant=
no heme made or decreased amounts
buildup of precursors =
causes lots of symptoms
what does porphyria affect
nervous or cutaneous system or BOTH
can be inherited or acquired
porphyria
how does a porphyria begin
triggered by stress, antibiotics, toxic substances, pregnancy, alcohol
what is the most sig buildup
porphobilinogen
uroporphyrinogen
protoporphyrinogen 3
structure of porphyria
alternating double bonds
4 chiral rings joined together
porphyria absorbs visible light
purple or dark red
cause RBC and teeth to fluorescent
chelate metal ions and cause symptoms
pathological
many who have gene don’t express porphyria illness
can be triggered
how is it diagnosed?
excretion of metabolites
-check urine or feces for increases of porphyrin
where is uroporphyrin excreted
urine
where is protoporphyrinogen excreted
feces
where is coproporphyrinogen excreted?
urine and feces
where is ALA delta aminolevulinic acid
urine
enzyme early on in pathway
nervous system
enzyme further down in pathway
cutaneous symptoms –
photosensitivity 1st common symptoms
acute porphyria
neurological
symptoms come on acutely
-acute abdominal pain
-muscle weakness
extreme case: coma and death
syndrome of inappropriate antidiuretic hormone (vasopressin)
increases in amounts of antidiuretic hormone
decreases in Na– leads to G.I symptoms and neurological chains
-makes you retain water
last days to weeks
how to treatment acute porphyria
no medication to cure due to enzyme lack
-stay away from trigger!
1 type of acute porphyria
acute intermittent porphyria
seen in: sweden, netherlands
what is defect in acute intermittent porphyria
buildup of ALA and porphobilinogen= urine
porphyrin absorb visible light= reddish/purple urine– port wine color
cutaneous porphyria
buildup of porphyrin in skin
photosensitivity absorb visible light= #1 symptom
what happens in cutaneous
blisters and sunburns
increase facial hair due to defect in heme synthesis chain
most common cutaneous porphyria
porphyria cutanea tarda
what happens in porphyria cutanea tarda
blister on skin
hypopigmentation and disfiguring of extremities (most exposed to light)
how is porphyria cutanea tarda obtained
inherited and acquired
acquired- hep. c and contraceptives and iron overload
liver involvement in porphyria cutanea tarda
buildup of hemosiderin and necrosis of the liver
erythropoietic protoporphyria
accumulate in RBC
-look at RBC and flursconct due to absorb visible light
buildup of protoporphyrinogen(onset adults)
congenital erythropoietic is also called
gunther’s disease
congenital erythropoietic
-hereditary and see in infancy
in sun and UV lights babies will scream
will develop pain and blisters
vampire!!
characteristics of congenital erythropoietic
teeth like a vamp
misshapen heads
erythrodontia= teeth absorb UV light and turn red
congenital erythropoietic excret
copro and uro
hemolytic anemias
increase in porphyrins and lead to splenomegaly
variegate porphyria (w/ variety)
cutaneous and neurological symptoms independently of each other
autosomal dominant inheritance
misdiagnosed with buildup of metabolites depending on symptoms
variegate porphyria neurological
porphobilinogen
variegate porphyria cutaneous
proto and coproporphyrinogen
secondary porphyrias
no genetic components due to exposure of certain chemicals and looks like porphyria
what is the #1 secondary porphyria
lead poisoning from paint chips
lead poisoning
occupational hazard for painters and being around lead based pipes
-lead can stay in bones, teeth, tissues for long time
can a preg lady give lead poisoning to her baby
yes
lead poisoning inhibits
heme chain at ALA and ferrochelatase enzyme and stops iron going into Hgb
HGB molecule needs something in core: replace iron with zinc
what do you end up with in lead poisoning
zinc protoporphyrin
(erythrocyte zinc)??
detect lead poisoning by
basophilic stippling
hypochromic, microcytic RBC’s resembles IDA– its not do not want more iron
body during lead poisoning
iron increases buildup not getting in
transferrin decreases bound with iron
% saturation increases because more iron
total binding Fe capacity decreases (no room)
how to differentiate with IDA and lead poisoning
% saturation (IDA will be low)
look at lead levels –chelation therapy preformed
lab testing porphyrias
look at increases in analytes present in urine or stool
also ALA increased (neurological)
urine for testing porphyrias
must be in dark container and not exposed to light before testing bc will absorb light
what test helps differentiate porphyrias
watson-schwartz
urobilinogen- normal
porphobilinogen- porphyria
how to perform watson-schwartz? screening
urine sample– add ehrlich’s reagent
screen turns red= may have uro or porp present
stays yellow= done
if light colors– add sodium acetate to enhance color
once urine is red add
spilt into 2 tubes
add butanol in one
add chloroform in the other
butanol will float to top because density is lighter than urine
chloroform sinks to the bottom
how to read watson-schwatz test
if in both tubes red remains in area added= urobilinogen
if red remains in urine part= porphobilinogen
