Metabolic Dan Flashcards
T/F
Hereditary coproporphyria causes skin disease only
False
Skin + acute attacks
T/F
Porphyria cutanea tarda (PCT) is the most common type of porphyria
True
T/F
Acute intermittent porphyria (AIP) causes acute attacks only
True
no skin disease
AIP is alone in this group
Which porphyrias cause skin disease only?
Porphyria cutanea tarda (PCT)
Congenital erythropoietic porphyria (CEP)
Erythropoieic protoporphyria (EPP)
Which porphyrias cause skin disease and acute attacks?
Hereditary coproporphyria (HC) Variegate porphyria (VP)
T/F
Porphyrias all result from a total deficiency of one of the enzymes required for the biosynthesis of haem
False
from a partial deficiency of one of the enzymes
T/F
‘Bullous porphyrias’ includes all the skin disease causing porphyrias
False
EPP causes pain and erythema on sun exposure not bullae
T/F
All of the porphyrias except AIP cause cutaneous disease
True
T/F
Porphyrins absorb photons of infrared light, with wavelength peak at 408nm
False
visible violet light with peak at 408nm = the Soret band
T/F
Most types of porphyrias are inherited
True
T/F
Most patients with an inherited porphyria get symptoms eventually
False
Most remain asymptomatic
T/F
Accumulation of hydrophobic porphyrins leads to blistering skin disease on light exposure
False
Hydrophilic porphyrins accumulate in skin causing blistering
T/F
Accumulation of lipophilic protoporphyrins leads to an immediate cutaneous burning sensation after exposure to light, accompanied by erythema, and oedema
True
this occurs in EPP
T/F
Variegate porphyria causes immediate cutaneous burning sensation after exposure to light
False
In VP hydrophilic (uro- and copro-) and hydrophobic (proto-) porphyrins accumulate but the blistering skin disease predominates clinically
T/F
Acute porphyria attack is an acute and potentially fatal illness
True
T/F
In liver, a small proportion of available haem is incorporated into cytochrome P450 proteins
False
this is the main fate of haem in the liver
T/F
Acute porphyria attacks are caused by penicillins
False
not one of the main causes but can be true for individuals
What are the triggers of acute attakcs in porphyrias?
FIG BEANS Fever/ Infection Griseofulvin Barbiturates (o)Estrogen Alcohol Nutritional (fasting) Sulfonamides
Or 5 M’s Medication Menstruation(Oe) - esp luteal phase of cycle Maladie Malnutrition (fasting) Merlot (alcoholism)
What are the features of acute attacks in porphyrias?
6 P’s
Porphobilinogen deaminase deficiency and build up of Porphobilinogen
Precipitated by the 5 M’s
Pain in abdomen – in 95% of cases
Psychological symptoms – anxiety/agitation, hallucination, delirium, depression
Peripheral neuropathy – patchy numbness and paraesthesias
Pee Problems – dysuria, retention, Port-wine (dark purple) urine on standing/UV light
T/F
Haem is synthesised from Glycine + AcetylCoA
False
Glycine + SuccinylCoA
What are the substrates involved in the haem biosynthesis pathway?
‘Glycine & SuccinylCoA All Placed high in Urine Cup Produces Protoporphyrin 9’
Glycine + SuccinylCoA δ Aminolevulinic acid Porphobilinogen Hydroxymethylbilane Uroporphyrinogen (III) Coproporphyrinogen(s) Protoporphyrinogen IX Protoporphyrin IX (Haem)
T/F
The enzyme deficiency in PCT is Uroporphyrinogen decarboxylase (UROD)
True
T/F
The main substrate that builds up in PCT is coproporphyrinogen
False
Uroporphyrinogen (III)
What are the enzymes involved in the haem biosynthesis pathway?
‘All Sin All hyde, Porphos Uses Urine Cups on Poor Ferrets’ Ala Synthase Ala Dehydratase Porphobilinogen (PBG) deaminase (AIP) Uroporphyrinogen (III) synthase (CEP) Uroporphyrinogen decarboxylase(PCT) UROD Coproporphyrinogen oxidase (HC) Protoporphyrinogen oxidase (VP0 Ferrochelatase (EPP)
What are the porphyrias and associated enzymes involved in the haem biosynthesis pathway?
Enzymes - (All Sin All hyde,) Porphos Uses Urine Cups on Poor Ferrets’
Porphyrias - All Congenital Porphyrias Have Variable Presentations
Porphobilinogen deaminase (AIP) Uroporphyrinogen (III) synthase (CEP) Uroporphyrinogen decarboxylase(PCT) Coproporphyrinogen oxidase (HC) Protoporphyrinogen oxidase (VP0 Ferrochelatase (EPP)
T/F
The first 2 enzymes in the haem biosynthesis pathway dont cause porphyrias if they are deficient
False
Cause rare porphyrias - dont need to know about these
Ala Synthase (X-linked dom porphyria) Ala Dehydratase (ALA-dehydratase deficiency porphyria - rare, no skin disease)
T/F
Urinary porphobilinogen deaminase is raised during acute attacks of porphyria
False
Urinary porphobilinogen is raised
porphobilinogen deaminase is the deficient enzyme
T/F
Acute intermittent porphyria (AIP) is the most rare acute porphyria
False
Most common
T/F
Most inherited porphyrias are AR
False Most are AD CEP is AR rare cases of EPP are recessive PCT is 75% acquired (type 1), almost 25% AD (type 2) and a tiny proportion types 3 (familial, inheritence unknown) or 'toxic' acquired type due to halogenated aromatic hydrocarbons in herbicides
What are the high risk factors for developing hepatocellular carcinoma in PCT pts?
male
age >50 at presentation
symptoms longer >10yrs prior to treatment
severe changes on liver bx at presentation
Hep C infection
T/F
There are two types of PCT
False
2 man types account for the vast majority but there are other;
Type I - sporadic acquired
Type II - AD
Type III - rare familial, inheritence unknown
Toxic type
Also Hepatoerythropoietic porphyria (HEP) - Pt is homozygous for gene mutation so >90% reduction in UROD - NB mutation diffrent to those seen in type II
What are the histo features of PCT (and other bullous porphyrias)?
Cell-poor subepidermal bulla
festooning
caterpillar bodies in epi
PAS +ve, diastase resistant thickening (hyalinization) of upper dermal vessels and BM (reduplication of BM)
IMF +ve for IgG +/- IgM, complement + fibringoen at DEJ
T/F
CEP is a common mild porphyria
False
very rare AR, congenital onset of symptoms
mutilating ‘warewolf’ type
severe cutaneous photosensitivity, blistering, erosions, crusts, ulcerations
Extensive scarring and deformation of hands
Also;
Brown stained teeth
osteopenia and fractures
haemolytic anaemia and splenomegally
Hypertransfusion inhibits endogenous haem synthesis but iron overload becomes problematic
T/F
>50% of PCT pts have increased total body iron stores
True
60%
T/F
80% of PCT pt have inherited hameochromatosis
False
20% in USA and N europe
T/F
Homozygous haemochromatosis mutation increases the risk of developing PCT by 20x
False
60x increase
T/F
Iron overload in PCT pts who do not have haemochromatosis is due to excess dietary iron
False
cause unknown
T/F
Heterozygous haemochromatosis mutation increases the risk of developing PCT by 20x
False
risk unknown if heterozygous
T/F
Hep C infection amongst PCT pts is highest in Southern Europe
True
then USA
then N Europe
T/F
20% of alcoholics with cirrhosis develop PCT
False
2%
T/F
Alcohol is an important trigger for PCT in susceptible pts
True Main triggers are; Subclinical genetic haemochromatosis HepC Acohol Oestrogens (OCP or HRT)
T/F
Ingested oestrogens are the sole risk factor for PCT in most female pts
False
sole risk factor for PCT in >25% of female pts
T/F
15% of PCTs pts have cirrhosis
True
Must investigate liver
What are the causes of Phrynoderma
Toad-like skin Vit A, C or E deficiency B-complex deficiency Essential fatty acid deficiency general malnutrition.
T/F
Medications that induce symptoms of Pellagra include:
Isoniazid
True
Isoniazid, 5-FU, 6-mercaptopurine, azathioprine, phenytoin, chloramphenicol, sulfonamides, antidepressants.
T/F
Medications that induce symptoms of Pellagra include: Systemic 5-fluorouracil
True
Isoniazid, 5-FU, 6-mercaptopurine, azathioprine, phenytoin, chloramphenicol, sulfonamides, antidepressants
T/F
Medications that induce symptoms of Pellagra include: 6-Mercapto Purine
True
Isoniazid, 5-FU, 6-mercaptopurine, azathioprine, phenytoin, chloramphenicol, sulfonamides, antidepressants
T/F
Medications that induce symptoms of Pellagra include: Sulphonamides
True
Isoniazid, 5-FU, 6-mercaptopurine, azathioprine, phenytoin, chloramphenicol, sulfonamides, antidepressants
T/F
Regarding Porphyria’s: Photosensitivity is seen in Variegate Porphyria
True
T/F
Hypertrichosis is seen in Hepato-Erythropoietic Porphyria
True
T/F
Lithium is safe in patients with acute hepatic Porphyria
True
T/F
Frusemide is safe in patients with acute hepatic Porphyria
False
T/F
10% of Porphyria Cutanea Tarda patients present in childhood
False
childhood presentation very rare
T/F
Regarding dystrophic calcification, it is more commonly associated with adult onset Dermatomyositis over Juvenile
False
Juvenille>adult
T/F
Regarding dystrophic calcification, calcification tends to go within the first year of disease onset
False
rarely nodules improve spontaneously after many years in dermatomyositis cases
T/F
Regarding dystrophic calcification, the buttocks are frequently affected
True
elbows, knees, shoulders, buttocks
T/F
Regarding dystrophic calcification, calcified nodules may improve spontaneously
True
rarely nodules improve spontaneously after many years in dermatomyositis cases
T/F
Regarding dystrophic calicification, calcinosis has been described in all clinical subsets of Lupus Erythematosus
True
T/F
Coproporphyrins are lipophilic
False
uro- and copro-porphyrins are hydrophilic
protoporphyrins are lipophilic
T/F
In EPP, protoporphyrin accumulates in RBCs mainly
True
What tests should be done on blood samples for porphyria?
plasma porphyrins and red cell porphyrin analysis + plasma spectrofluorometry if available
T/F
Protoporphyrin accumulates in the red cells in PCT
False
red cells are normal in PCT
Protoporphyrin accumulates in red cells in EPP
Where is the plasma fluorometry peak in PCT?
615-620 nm
same for;
PCT, CEP and HC
T/F
Biochemical findings are the same in HEP as in PCT
False
largely the same but also have red cell zinc-protoporphyrin
What are the biochemical findings in PCT?
Urine - Uroporphyrin III Feaces - Isocoproporphyrin Red cell porphyrins - normal Plasma porphyrins - Uroporphyrin III Plasma spectrofluorometry peak - 615-620nm
T/F
plasma and urine porphyrins are increased in renal failure
True
In renal failure it is essential to send faecal sample