Porphyrias Flashcards
Porphyria cutanea tarda usually presents during the first and second decades of life
False third to fourth , usually not before puberty
Acquired type 1 PCT represents 75% of cases, presenting in middle age
True
Type II is familial UROD gene mutation accounting for 25%
True
Risk factors for PCT
Alcohol UROD deficiency Hepatocellular ca Dialysis in renal failure Iron overload H63D/C282Y Hep B, Hep C Male Age >50 Hereditary haemochromatosis OCP and exogenous oestrogens in females Exogenous agents such as halogenated hydrocarbons
Biochemical findings of PCT
Urine - uroporphyrin III
Faeces- Isocoporphyrin
Peak plasma fluorimetry 615-620nm
Natural course of PCT
Blisters first remit 2-3 mo
Fragility takes 6-9 mo
Porphyrins take 12 mo to normalise
Hypertrichosis, sclerodermoid changes take years
Aims of PCT treatment and targets
Induce mild Fe deficiency to reduce triggering haem synthesis
Aim of Hb 110-120
Fe <25
These can take 13 mo to achieve
Features of congenital ERYTHROPOETIC porphyria
Presents with hydrops details, through to severe disease starting in infancy, but mild forms can present later in life
- first sign might be noting brown discolouration of amniotic fluid at onset of labour or pink/brown/violet porphyrins staining (red orange under Wood lamp)
- severe photosensitivity begins in infancy
- = blisters develop on minimal sun exposure
- exposed skin is fragile
- erythrodontia may be evident
CEP biochemical findings
Urine - uroporphyrin I
Faeces - coproporphyrin I
Red cell - zinc and free protoporphyrin , uroporphyrin I, coproporphyrin I
Extracutaneous features of CEP
Eyes- keratoconjunctivitis, cataracts, scarring alopecia eyelashes and eyebrows, corneal ulcers
Bones and teeth - teeth almost always stained brain , decr bone density are seen with pathological fractures
Haemolytic anaemia - due to marrow hyperplasia
Erythropoetic porphyria inheritance
Newly classified AR - previously AD with incomplete penetrance
EPP develop significant blisters in the first few years of life
False - oedema and pain
Late onset of EPP is common
False - rare
EPP 5% liver failure
True
Hereditary coprophyria develop acute attacks without blisters
False, do get blisters
HC Is autosomal dominant
True
Deficiency in HC is ferrochelotase
False, coproporphyrinogen oxidase . Ferrochelotase is deficient in EPP
HC has incr uro and coproporphyrin concentrations in urine and incr coproporphyrin in faces
True
Variegate porphyria is autosomal recessive
False, dominant
Risk of offspring developing VP is 50%
True as it is autosomal dominant
Protophyrinogen oxidase is the deficiency in VP
True
VP usually presents in infancy or childhood
False - adolescence or young adulthood
VP indistinguishable from PCT
True
VP biochemical findings
Urine coprophyrinoge, faecal coprophyrinogen , plasma fluorimetry is diagnostic with peak at 626nm
Symptoms of an acute porphyria attack
GI - colicky abdo pain, nausea , vomiting, hyponatraemia
Neurologic - seizures, psychosis, coma, paraesthesias, motor neuropathy, anxiety, muscle and back pain
Cardiopulmonary - tachycardia, HTN, respiratory paralysis
Management of acute attack
Key is early diagnosis
Avoid attack inducing drugs
Supportive Tx —> analgesia, usual tx safe ie. aspirin, morphine, ondansetron, 300mg CHO, B blockers for tachycardia and HTN, fluid balance and rehydration, correct hyponatraemia
What can trigger an acute porphyria attack
P450 drugs (SHOEBAGS) Hormones Stress Fasting - need to advise carry sweets Surgery Infection
DRUGS: Sulfur Hormones OCP Epileptics Barbiturates Antimalarials and amphetamines Griseofulvin Sedatives
Pseudoporphyria drugs
NAT CL NSAIDs Tetracyclines Lasix Amiodarone Ciprofloxacin
