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Matt's Path REVERSE > Porphyrias > Flashcards

Porphyrias Flashcards

1
Q

Acute intermittent porphyria

A

Autosomal dominant

HMB synthase deficiency

(Hydroxymethylbilane) synthase

Abdo pain, seizures, psych change, nausea, vomiting, sensory loss, muscle weakness, constipation, urinary incontinence

Neurovisceral symptoms ONLY
No porphyrinogens produced to cause cutaneous lesions

Can CAUSE SIADH –> Hyponatraemia

Diagnosis
Increased ALA (pre-cursor)
Increased PBG in urine (pre-cursor) = “port-wine urine”

Precipitating Factors
ALA synthase inducers (barbituates, steroids, ethanol)
Stress = infection or surgery
Reduced caloric intake
Endocrine (premenstrual)

Tx
IV haem arginate
IV carbohydrate

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2
Q

Non-Acute Porphyrias

A

Skin lesions ONLY

Congenital Erythropoietic Porphyria (CEP)

Erythropoietic Protoporphyria (EPP) = most common in children

Porphyria Cutanea Tarda (PCT)= most common

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3
Q

Acute Porphyrias WITH skin lesions

A

Blistering skin condition AND Neurovisceral

Hereditary coproporphyria (HCP)

Variegate porphyria (VP)

Autosomal dominant

Raised prophyrins in faeces or urine

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4
Q

porphyrins precursors cause…

A

Skin lesions

UV oxidised

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5
Q

5-ALA causes…

A

Neurovisceral symptoms

Toxic

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6
Q

Prophyrinogens

A

= no double bond in joining bridge

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7
Q

Porphyrins

A

= double bond in joining bridge

Gives colour

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8
Q

Most common in children

A

Erythropoietic Protoporphyria (EPP)

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9
Q

Most common Porphyria

A

Porphyria Cutanea Tarda (PCT)

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10
Q

X-linked sideroblastic anaemia

A

ALA Synthase deficiency

NOT a porphyria

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11
Q

ALA Dehydratase Porphyria or Plumboporphyria

A

PBG Synthase deficiency

Increase ALA
But no PBG!

Neurovisceral symptoms
Abdo pain
Coma
Palsy 
Motorneuropathy
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12
Q

Hereditary Coproporphyria (HCP)

A

Coproporphyrinogen oxidase deficiency

Autodomal dominant

Acute neurovisceral attack

Skin lesions
Blistering (back of hands and neck, sun exposed)
Skin fragility

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13
Q

Variegate Porphyria (VP)

A

Protoporphyrinogen oxidase deficiency

Autosomal dominant

Acute attacks

Skin lesions: blistering cutaneous

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14
Q

Why don’t all porphyrias have Neurovisceral Symptoms?

A

ALA responsible for neurovisceral symptoms

Protoporphyrinogen IX and Coproporphyrinogen III are potent inhibitors of HMB synthase –> backlog of PBG –> raised ALA –> neurovisceral symtpoms

In other prophyrias there is no inhibition of HMB, ALA will continually be mtebaolised

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15
Q

Differentiating Acute Porphyrias

A

AIP – no skin lesions

HCP & VP – skin lesions

Urine PBG – raised in all three

Urine and faeces for porphyrins - Raised HCP or VP, but not AIP

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16
Q

Porphyria Cutanea Tarda

A

Inherited or acquired

Uroporphyrinogen decarboxylase deficiency

Formation of vesicles on sun-exposed areas of skin crusting, superficial scarring, pigmentation

Biochemistry:

Urinary (& plasma) uroporphyrins & coproporphyrins increased
Ferritin often increased

Avoid precipitants (alcohol, hepatic compromise)

17
Q

Erythropoietic protoporphyria

A

Photosensitivity only, no blisters

Ferrochetalase deficiency

ONLY non-blistering porphyria

Most common in children

Only erythroid cells affected, therefore need to measure RBC protoporphyrin

18
Q

Non-blistering Porphyria

A

Erythropoietic protoporphyria

19
Q

Autosomal dominant

HMB synthase deficiency

(Hydroxymethylbilane) synthase

Abdo pain, seizures, psych change, nausea, vomiting, sensory loss, muscle weakness, constipation, urinary incontinence

Neurovisceral symptoms ONLY
No porphyrinogens produced to cause cutaneous lesions

Can CAUSE SIADH –> Hyponatraemia

Diagnosis
Increased ALA (pre-cursor)
Increased PBG in urine (pre-cursor) = “port-wine urine”

Precipitating Factors
ALA synthase inducers (barbituates, steroids, ethanol)
Stress = infection or surgery
Reduced caloric intake
Endocrine (premenstrual)

Tx
IV haem arginate
IV carbohydrate

A

Acute intermittent porphyria

20
Q

Skin lesions ONLY

Congenital Erythropoietic Porphyria (CEP)

Erythropoietic Protoporphyria (EPP) = most common in children

Porphyria Cutanea Tarda (PCT)= most common

A

Non-Acute Porphyrias

21
Q

Blistering skin condition AND Neurovisceral

Hereditary coproporphyria (HCP)

Variegate porphyria (VP)

Autosomal dominant

Raised prophyrins in faeces or urine

A

Acute Porphyrias WITH skin lesions

22
Q

Skin lesions

UV oxidised

A

porphyrins precursors cause…

23
Q

Neurovisceral symptoms

Toxic

A

5-ALA causes…

24
Q

= no double bond in joining bridge

A

Prophyrinogens

25
Q

= double bond in joining bridge

Gives colour

A

Porphyrins

26
Q

Erythropoietic Protoporphyria (EPP)

A

Most common in children

27
Q

Porphyria Cutanea Tarda (PCT)

A

Most common Porphyria

28
Q

ALA Synthase deficiency

NOT a porphyria

A

X-linked sideroblastic anaemia

29
Q

PBG Synthase deficiency

Increase ALA
But no PBG!

Neurovisceral symptoms
Abdo pain
Coma
Palsy 
Motorneuropathy
A

ALA Dehydratase Porphyria or Plumboporphyria

30
Q

Coproporphyrinogen oxidase deficiency

Autodomal dominant

Acute neurovisceral attack

Skin lesions
Blistering (back of hands and neck, sun exposed)
Skin fragility

A

Hereditary Coproporphyria (HCP)

31
Q

Protoporphyrinogen oxidase deficiency

Autosomal dominant

Acute attacks

Skin lesions: blistering cutaneous

A

Variegate Porphyria (VP)

32
Q

ALA responsible for neurovisceral symptoms

Protoporphyrinogen IX and Coproporphyrinogen III are potent inhibitors of HMB synthase –> backlog of PBG –> raised ALA –> neurovisceral symtpoms

In other prophyrias there is no inhibition of HMB, ALA will continually be mtebaolised

A

Why don’t all porphyrias have Neurovisceral Symptoms?

33
Q

AIP – no skin lesions

HCP & VP – skin lesions

Urine PBG – raised in all three

Urine and faeces for porphyrins - Raised HCP or VP, but not AIP

A

Differentiating Acute Porphyrias

34
Q

Inherited or acquired

Uroporphyrinogen decarboxylase deficiency

Formation of vesicles on sun-exposed areas of skin crusting, superficial scarring, pigmentation

Biochemistry:

Urinary (& plasma) uroporphyrins & coproporphyrins increased
Ferritin often increased

Avoid precipitants (alcohol, hepatic compromise)

A

Porphyria Cutanea Tarda

35
Q

Photosensitivity only, no blisters

Ferrochetalase deficiency

ONLY non-blistering porphyria

Most common in children

Only erythroid cells affected, therefore need to measure RBC protoporphyrin

A

Erythropoietic protoporphyria

36
Q

Erythropoietic protoporphyria

A

Non-blistering Porphyria

Matt's Path REVERSE (18 decks)

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