- Helen Thadani, specialist registrara,
- Allan Deacon, consultant clinical scientistb,
- Timothy Peters, professor (email@example.com)c
- a Department of Chemical Pathology and Endocrinology, Guy's and St Thomas's Trust, St Thomas's Campus, London SE1 7EH
- b Department of Clinical Chemistry, King's College Hospital, London SE5 9RS
- c Department of Clinical Biochemistry, Guy's, King's, and St Thomas's Medical Schools, King's College Hospital, London SE5 9RS
- Correspondence to: T Peters, Department of Chemical Pathology, Guy's, King's, and St Thomas's Medical Schools, King's College Hospital, London SE5 9RS
Although porphyria is a relatively uncommon condition, it should be considered in patients presenting with an atypical medical, psychiatric, or surgical history. Acute attacks are associated with a substantial morbidity and mortality; there is a need for rapid and accurate diagnosis of the neuropsychiatric porphyrias, particularly because haem arginate can induce a definite remission if given early in an attack. Additionally, porphyrias may present with skin lesions or photosensitivity.
The porphyrias form a group of inherited disorders of haem biosynthesis of which there are seven main types
Porphyrias can be classified into acute (neuropsychiatric), cutaneous, and mixed forms
Acute forms can be life threatening, but attacks can be aborted by early administration of haem arginate
The acute porphyrias are often misdiagnosed; most commonly they present as acute abdominal pain or as neurological or atypical psychiatric symptoms
Patients with porphyria should be referred to specialist centres and be advised to avoid precipitating factors, such as certain drugs
When a patient is diagnosed with an acute porphyria the whole family needs to be screened
What are the porphyrias?
The porphyrias form a heterogeneous group of inherited disorders of haem biosynthesis, and they are often missed or wrongly diagnosed. A partial deficiency of one of the seven enzymes in the pathway causes characteristic clinical and biochemical features. These disorders are due to a specific alteration in the pattern of accumulation of porphyrin and porphyrin precursors (table). Each type of porphyria is defined by a unique pattern of accumulation and excretion of haem precursors, as well as a reduction in the relevant enzyme activity. Correct interpretation of the appropriate biochemical investigations is essential for accurately diagnosing and managing the porphyrias, as clinical features alone are not sufficiently specific either to confirm a diagnosis or to distinguish between the various forms.