PORPHYRIAS

PORPHYRIAS

1. METABOLIC DISORDERS

   • HEME Biosynthesis pathway
     • caused by
       • defect and abnormal function of ezymes
         • Accumulation of prophyrins, that are organic compounds
         • cause chronic neurophaty and acute neurovisceral attacks
     • HEME
       • component of
         • hemoglobin
         • myoglobin
         • catalase
         • peroxidase
         • P450 liver cytochromes

2. ACUTE PORPHYRIAS

   • AIP
     • most common porphyria
       • mostly in females
     • skin never affected
     • Acute intermittent porphyria
   • VP
     • Variegate porphyria (VP)
   • HC
     • skin lesions
     • acute attack
     • hereditary coproporphyria
   • ADP
     • ALA dehydratase porphyria
       • neurophaty
       • acute attack
   • clinical features
     • symptoms
       • minor behavioral changes
         • anxiety
         • restlessness
         • insomnia
       • tachycardia
   • ACUTE ATTACK
     • could be life threatening
       • severe neurological complications such as motor paralysis.
     • severe abdominal pain
     • neuropsychiatric symptoms
     • autonomic neuropathy
     • electrolyte disturbances
     • nausea
     • vomiting
     • pathogenesis
       • ALA and/or PBG overproduced by the liver are neurotoxic
         • The autonomic and peripheral nervous systems are vulnerable to their action because do not have barrier protection
       • the synthesis of hemoproteins in either the nervous system or the liver may be compromised.
         • A decreased activity of hepatic tryp- tophan dioxygenase has been reported,
           • could increase brain tryptophan levels and increase the turnover of serotonin
     • treatment
       • analgesia
       • opiates
         • antiemetic
           • ANXIETY
             • RESTLESSNESS
         • phenothiazine
       • Diet
         • careful management of fluid balance and avoiding large vol- umes of hypotonic dextrose.
         • properly calories adecuation

3. Cutaneous porphyrias

   • Hepatic bullous porphyrias:
     • PC
       • MOST COMMON
         • solely accociated with skin symptoms
     • VP
       • abdominal pain
         • neurological symptoms
     • HC
     • skin fragility
       • a mini-mal trauma is followed by a superficial erosion that is soon covered by a crust.
       • hypertrichosis
         • upper cheeks
         • ears
         • arms
     • symptoms
       • porphyrins in
         • URINE
           • Urine porphobilinogen (PBG) is the most important first-line screening test
             • highly sensitive and highly specific
         • FECES
           • determination of ALA, PBG, and porphyrin levels
         • PLASMA
           • The plasma fluorescent spectrum is the best initial test for cutaneous porphyrlas
       • The porphyrin excretion profile assessed by high-performance liquid chromatography (HPLC) is the standard sensitive method for differentiating the types of porphyria
     • Precipitating factors
       • a partial inactivation of hepatic UROD in sPC
         • fPC. PC occurs when the residual hepatic UROD decreases to a rate-limiting level
       • estrogens
       • hepatitis C
       • alcohol abuse

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