WorksheetsDescription of Porphyrias
Total questions: 71
Worksheet time: 36mins
Which statement best defines porphyrias based on the description provided?
A group of infectious diseases primarily affecting the lungs
A rare group of inherited or sometimes acquired metabolic disorders with defective enzymes impairing heme biosynthesis
An autoimmune condition characterized by antibody-mediated hemolysis
A nutritional deficiency leading to reduced iron absorption
In porphyrias, the biosynthesis of heme is impaired due to defective enzymes. Which sites are specifically mentioned as affected by this impairment?
Kidneys and spleen
Pancreas and thyroid
Liver and/or bone marrow
Skin and muscle
In porphyrias, what is the immediate biochemical consequence of decreased enzyme activity in heme biosynthesis?
Reduced heme demand by tissues
Accumulation of intermediates of heme production
Increased hemoglobin degradation
Enhanced iron absorption from the gut
A patient with porphyria shows increased urinary and fecal elimination of certain metabolites. What does this change most directly reflect?
Overproduction of heme
Accumulation of pathway intermediates leading to greater excretion
Enhanced conversion of intermediates to heme
Renal failure causing metabolite retention
Which statement best explains symptom variability among different porphyrias?
Symptoms are unrelated to the biosynthesis pathway
They depend on which heme biosynthesis enzymes are affected and which intermediates accumulate
All porphyrias lead to identical intermediate accumulation
Symptoms occur only when intermediates are not excreted in urine
In the heme synthesis pathway diagram, which substrates combine to form δ-aminolevulinate (δ-ALA) in the first step?
Glycine and succinyl-CoA
Glycine and acetyl-CoA
Succinyl-CoA and acetyl-CoA
Glycine and propionyl-CoA
Serine and succinyl-CoA
Which enzyme introduces Fe2+ into protoporphyrin to form heme?
δ-ALA synthase
Porphobilinogen deaminase
Uroporphyrinogen decarboxylase
Ferrochelatase
δ-ALA dehydratase
According to the pathway, porphobilinogen is formed after which immediate precursor step?
Condensation of δ-ALA molecules
Modification of uroporphyrinogen III
Formation of the porphyrin ring
Insertion of iron into protoporphyrin
Decarboxylation of uroporphyrinogen
Which disease is associated with deficiency of δ-ALA synthase activity?
Porphyria cutanea tarda
Acute intermittent porphyria
Lead poisoning
Sideroblastic anemia
Variegate porphyria
Lead poisoning most directly inhibits which enzyme(s) in the heme synthesis pathway as indicated in the diagram?
Porphobilinogen deaminase only
δ-ALA dehydratase and ferrochelatase
Uroporphyrinogen decarboxylase and ferrochelatase
δ-ALA synthase only
Coproporphyrinogen oxidase
A defect in porphobilinogen deaminase leads to which porphyria according to the figure?
Acute intermittent porphyria
Porphyria cutanea tarda
Congenital erythropoietic porphyria
Hereditary coproporphyria
Sideroblastic anemia
Which enzyme deficiency is linked to porphyria cutanea tarda in the depicted pathway?
Porphobilinogen deaminase
δ-ALA synthase
Uroporphyrinogen decarboxylase
Coproporphyrinogen oxidase
Ferrochelatase
Which criterion is explicitly used to classify porphyrias according to the material?
Age at onset
Inheritance pattern
Response to therapy
Geographic prevalence
Within hepatic porphyrias, which condition is identified as the most common chronic (often cutaneous) type?
Acute intermittent porphyria
Porphyria cutanea tarda
Erythropoietic protoporphyria
Congenital erythropoietic porphyria
According to the classification by organ of accumulation, which statement is correct?
Erythropoietic variants are the most common
Hepatic porphyrias are more common than erythropoietic variants
Only erythropoietic porphyrias can be acute
Hepatic porphyrias are exclusively cutaneous
Which condition is classified as an acute hepatic porphyria and follows an autosomal dominant inheritance pattern?
Acute intermittent porphyria
Doss porphyria
Porphyria cutanea tarda (acquired form)
Congenital erythropoietic porphyria
Which primary porphyria is autosomal recessive among the acute hepatic group?
Hereditary coproporphyria
Porphyria variegata
Doss porphyria
Porphyria cutanea tarda
Porphyria cutanea tarda is categorized as which of the following?
Acute hepatic porphyria, autosomal recessive
Chronic hepatic porphyria, autosomal dominant or acquired
Erythropoietic porphyria, autosomal dominant
Erythropoietic porphyria, autosomal recessive
Which erythropoietic porphyria is correctly matched with its inheritance pattern?
Congenital erythropoietic porphyria — autosomal dominant
Erythropoietic protoporphyria — autosomal dominant
Erythropoietic protoporphyria — autosomal recessive
Porphyria variegata — autosomal recessive
Which statement best describes secondary porphyria?
An inherited defect in heme biosynthesis
An acquired condition due to external or systemic factors
A congenital enzyme deficiency limited to the liver
A purely dermatologic disorder present at birth
Secondary coproporphyria is most directly associated with which of the following example causes listed for acquired porphyrias?
Anemia, alcohol, chronic heavy metal poisoning
Intoxication, hepatic diseases, blood disorders, infections, starvation
Autoimmune thyroid disease and diabetes mellitus
Genetic mutations in ALAS2
A patient presents with features consistent with an acquired porphyria after prolonged alcohol use. Which specific secondary porphyria is most consistent with this trigger?
Secondary coproporphyria
Secondary protoporphyrinemia
Acute intermittent porphyria
Congenital erythropoietic porphyria
Which porphyria has the highest prevalence in the general population?
Acute intermittent porphyria
Porphyria cutanea tarda (PCT)
Hereditary coproporphyria
Variegate porphyria
Erythropoietic protoporphyria
In which age range does porphyria cutanea tarda (PCT) most commonly present?
Childhood (5–12 years)
Adolescence (13–19 years)
Early adulthood (20–29 years)
Middle adulthood (30–50 years)
Older adulthood (>65 years)
Which enzyme has reduced activity in Porphyria Cutanea Tarda (PCT), leading to downstream biochemical changes?
Uroporphyrinogen III decarboxylase (UROD)
ALA dehydratase
Ferrochelatase
Porphobilinogen deaminase
What is the immediate consequence of reduced UROD activity in PCT that contributes to photosensitivity?
Accumulation of uroporphyrin in the skin
Decreased bilirubin production
Increased heme synthesis
Iron depletion in erythrocytes
Sunlight-dependent skin damage in PCT primarily results from which mechanism?
Autoantibody formation against keratinocytes
Release of reactive oxygen species from photoreactive porphyrins
Direct UV-induced DNA crosslinking
Thermal injury due to increased skin temperature
Which statement best distinguishes Type I from Type II PCT?
Type I is inherited and accounts for about 20% of cases; Type II is acquired and accounts for about 80%
Type I is acquired (sporadic) and accounts for about 80% of cases; Type II is inherited (autosomal dominant) and about 20%
Type I causes more severe clinical disease than Type II in all patients
Type II is clinically distinguishable from Type I by unique skin lesions
Which skin areas are most prone to blistering in Porphyria Cutanea Tarda due to increased fragility?
Sun-exposed skin
Moist intertriginous folds
Palms and soles only
Mucosal surfaces
A patient with Porphyria Cutanea Tarda presents with small white cystic lesions after healing of blisters. What are these lesions called?
Comedones
Milia
Xanthomas
Molluscum bodies
Which of the following is a characteristic hair-related finding in Porphyria Cutanea Tarda?
Alopecia areata
Hirsutism of the chest
Hypertrichosis on the cheeks, temples, and eyebrows
Trichotillomania
Which combination best describes the cutaneous spectrum in Porphyria Cutanea Tarda?
Nodules and ulcers on non–sun-exposed skin
Vesicles/bullae with scarring and milia on sun-exposed skin
Pustules and comedones sparing the face
Eczematous plaques limited to the flexures
In Porphyria Cutanea Tarda, which pigmentary change is commonly observed?
Hypopigmentation
Hyperpigmentation
Vitiligo
Cyanosis
According to the clinical image of the hand, which lesion types are typically seen together in Porphyria Cutanea Tarda?
Urticarial wheals and angioedema
Vesicles/bullae, erosions, excoriations, and scars
Papules with central umbilication
Target lesions with central duskiness
The image description notes scarring on the dorsum of the hands with white-grayish lesions and some erythematous erosions. What underlying process most likely led to these scars in Porphyria Cutanea Tarda?
Impaired healing following blistering
Primary bacterial infection
Autoimmune deposition in the dermis
Direct thermal injury
Which statement best links Porphyria Cutanea Tarda lesions to environmental exposure?
Lesions worsen with cold exposure.
Lesions are triggered by pressure points.
Lesions arise on sun-exposed skin due to photosensitivity.
Lesions occur only under occlusion.
In Porphyria Cutanea Tarda, which visible finding on the dorsum of the left hand is specifically highlighted in the image description as a single lesion on the left ring finger?
Hyperpigmented macule
Erosion
Crust
Blister
Which combination best lists the concurrent cutaneous features described together on the back of the left hand in Porphyria Cutanea Tarda?
Papules, nodules, and telangiectasias
Erosions, crusts, scars, and hyperpigmentation
Comedones, pustules, and scale
Livedo reticularis, purpura, and necrosis
In the second image, what is the most prominent lesion described on the index finger?
Pustule
Fluid-filled blister
Hyperkeratotic plaque
Fissure
According to the second image description, which two lesion depths coexist on the back of the left hand?
Deep ulcers and superficial erosions
Subcutaneous nodules and epidermal cysts
Petechiae and ecchymoses
Verrucae and keratoacanthomas
In porphyria cutanea tarda, which of the following is a common lesion location?
Palmar surface of the hand
Dorsum of the hand
Soles of the feet
Anterior surface of the forearm
Lower back
A patient suspected of porphyria cutanea tarda undergoes Wood lamp examination of urine. What characteristic finding supports the diagnosis?
Blue fluorescence of clear urine
No fluorescence in straw-colored urine
Coral pink fluorescence of red-brown (tea-colored) urine
Green fluorescence of cloudy urine
Yellow fluorescence of dark brown urine
Which set correctly lists common sites for PCT lesions?
Palms, abdomen, thighs
Face and neck; dorsum of the hand; extensor surface of the forearm
Scalp, chest, posterior calf
Eyelids, periumbilical area, plantar foot
Inner arm flexor surface, lips, ear canal
Which clinical presentation should prompt consideration of porphyria cutanea tarda (PCT) in an adult?
Blistering rash on sun-exposed areas, particularly the backs of the hands, with a known susceptibility factor
Nonpruritic macules confined to covered areas with no identified risks
Painful nodules on the shins after cold exposure and no other findings
Diffuse alopecia without skin lesions in sun-exposed regions
Why is a high index of suspicion important in diagnosing porphyria cutanea tarda (PCT)?
Because PCT symptoms overlap with several other conditions
Because PCT only occurs in pediatric patients
Because laboratory testing is unnecessary for PCT
Because PCT presents exclusively without skin findings
In suspected Porphyria Cutanea Tarda (PCT), which routine blood study is typically normal?
CBC
AST
ALT
GGT
Serum ferritin
Which set best reflects the liver chemistry pattern that may be seen in PCT on routine testing?
Decreased AST, ALT, and GGT
Normal AST and ALT with decreased GGT
Increased AST, ALT, and GGT
Isolated increase in alkaline phosphatase
Which additional infectious disease screenings are recommended in the routine evaluation when susceptibility factors are present?
Syphilis and EBV
Hepatitis B, hepatitis C, and HIV
Tuberculosis and CMV
HSV and VZV
For first-line confirmatory testing of PCT, which spot urine finding is characteristic?
Marked increase in coproporphyrins
Marked increase in uroporphyrins
Decreased uroporphyrins
Normal porphyrin pattern
In patients with renal failure and impaired urinary excretion, which testing approach is required and preferred for porphyrin evaluation?
24-hour urine porphyrins
Spot urine porphobilinogen
Serum porphyrins
Fecal porphyrins
Which study is categorized as second-line testing in the diagnostic workup for PCT?
Serum porphyrins
Spot urine uroporphyrins
UROD activity analysis and gene mutation detection
Liver chemistries
In Porphyria Cutanea Tarda (PCT), the overarching therapeutic goal is to resolve symptoms by which primary strategy?
Reducing porphyrin levels
Increasing heme synthesis
Eliminating bilirubin
Suppressing immune responses
Which of the following is a recommended general measure for patients with PCT?
Encouraging moderate alcohol intake
Avoiding susceptibility factors such as smoking, alcohol, and exogenous estrogen
Increasing sun exposure to build tolerance
Taking high-dose vitamin D supplements
What photoprotective advice is appropriate for PCT management?
Use narrow-band UV therapy weekly
Reduce exposure to visible light, for example by using large particle sunscreens
Prefer tanning beds over natural sunlight
Rely solely on protective clothing without sunscreen
Phlebotomy in symptomatic PCT is typically performed with what procedure schedule?
Removal of 150 mL of blood weekly
Removal of 450 mL of blood every 2 weeks
Removal of 1,000 mL of blood monthly
Single session removal of 300 mL followed by observation
Which therapeutic targets best indicate adequate response to phlebotomy in PCT?
Serum ferritin ~ 150 ng/mL and plasma porphyrin ~ 10 mcg/dL
Serum ferritin ~ 15 ng/mL and plasma porphyrin ~ 1 mcg/dL
Serum ferritin undetectable and plasma porphyrin 0 mcg/dL
Serum ferritin ~ 50 ng/mL and plasma porphyrin ~ 5 mcg/dL
Low-dose hydroxychloroquine is indicated in PCT under which circumstance?
Patients with severe iron overload
Patients unable to tolerate phlebotomy, such as those with concurrent anemia
All patients regardless of genotype or iron status
Only when plasma porphyrins are already normalized
When using low-dose hydroxychloroquine for PCT, treatment is continued until which endpoint?
Six months have elapsed
Serum ferritin reaches 100 ng/mL
Plasma or urine porphyrins have normalized
Transaminases normalize
In the ongoing management of porphyria cutanea tarda (PCT), when should hepatitis C be treated?
Before any PCT therapy is started
Only if alpha-fetoprotein is elevated
After initiation of treatment for PCT
Only when liver imaging shows cirrhosis
Which combination is recommended for hepatocellular carcinoma screening in patients with porphyria cutanea tarda?
CA-125 and pelvic ultrasound
Alpha-fetoprotein and liver imaging
CEA and colonoscopy
PSA and prostate MRI
Which statement best describes the relative frequency of Acute Intermittent Porphyria (AIP) among porphyrias?
It is the rarest porphyria.
It is the second most common porphyria.
It is the most common porphyria.
Its frequency varies too widely to classify.
At what age range does Acute Intermittent Porphyria (AIP) most commonly present, and which sex is more affected?
10–19 years; males more than females
20–30 years; females more than males
30–40 years; males more than females
40–50 years; females and males equally
Which inheritance pattern best describes the gene mutation responsible for Acute Intermittent Porphyria (AIP)?
Autosomal recessive
Autosomal dominant
X-linked recessive
Mitochondrial
Y-linked
Approximately what proportion of carriers of the AIP gene mutation are asymptomatic?
10–20%
30–40%
50–60%
80–90%
Nearly 100%
A trigger that increases heme demand leads to impaired activity of which enzyme in AIP, resulting in the accumulation of heme intermediates?
ALA synthase
Ferrochelatase
Porphobilinogen deaminase (PBG-D)
Uroporphyrinogen decarboxylase
Cytochrome c oxidase
Which pair of heme precursors accumulates and contributes to symptoms in AIP when enzyme activity is impaired?
Heme and bilirubin
Coproporphyrin and uroporphyrin
Porphobilinogen (PBG) and δ-aminolevulinic acid (ALA)
Protoporphyrin IX and iron
Biliverdin and biliverdin reductase
Which statement best explains why many triggers precipitate acute attacks in Acute Intermittent Porphyria (AIP)?
They directly inhibit hepatic heme production, lowering demand
They increase hepatic heme demand, stimulating heme biosynthesis and accumulating intermediates
They increase renal excretion of porphyrins, reducing feedback inhibition
They suppress cytochrome P450 activity, causing enzyme deficiency
Which medication class is explicitly listed as a trigger due to induction of hepatic cytochrome P450 enzymes involved in heme biosynthesis?
Beta-blockers
Anticonvulsants such as barbiturates and phenytoin
ACE inhibitors
Anticoagulants
A patient with AIP is being evaluated for drug safety. Which of the following is LEAST appropriate due to its potential to trigger an acute attack?
Sulfonamides
Anesthetics
Hormone therapy
Isotonic saline
Inducers of which hepatic enzyme system are emphasized as important medication-related triggers of acute porphyric attacks?
Cytochrome P450
ATP synthase
Glucose-6-phosphate dehydrogenase
Monoamine oxidase
Beyond medications, which factor listed can increase metabolic or hormonal drive and precipitate an acute porphyric attack?
High-fiber diet
Endogenous sex hormones
Regular aerobic exercise
Vitamin C supplementation
