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MEDICAL DISCLAIMER: The contents are under continuing development and improvements and despite all efforts may contain errors of omission or fact. This is not to be used for the assessment, diagnosis, or management of patients. It should not be regarded as medical advice by healthcare workers or laypeople. It is for educational purposes only. Please adhere to your local protocols. Use the BNF for drug information. If you are unwell please seek urgent healthcare advice. If you do not accept this then please do not use the website. Makindo Ltd.

Acute Porphyrias

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🩸 Acute porphyrias are hereditary disorders of haem biosynthesis (prevalence ~1 in 75,000). They can cause severe, potentially life-threatening neurovisceral attacks. ⚠️ The BNF advises: if no safe alternative exists, essential drug treatment should not be withheld even in patients with acute porphyria.

📖 About

🔗 Disruption of the haem synthetic pathway.
☠️ Accumulation of haem precursors causes neurotoxicity and systemic symptoms.
💊 Extreme care required when prescribing — always check safe drug lists.

🌐 National UK Links

🧬 Types of Acute Porphyria

Type	Details
🩺 Acute Intermittent Porphyria (AIP)	Most common. Deficiency of porphobilinogen deaminase. Presents with abdominal pain, neuropsychiatric features, and autonomic dysfunction.
☀️ Hereditary Coproporphyria (HCP)	Deficiency of coproporphyrinogen oxidase. Similar to AIP but can cause photosensitivity.
🌞 Variegate Porphyria (VP)	Deficiency of protoporphyrinogen oxidase. Acute neurovisceral attacks + blistering photosensitivity.
🧪 ALAD Deficiency Porphyria (ADP)	Rare. Deficiency of delta-ALA dehydratase. Mainly neurological symptoms.

⚠️ Precipitants

💊 Unsafe drugs (barbiturates, sulfonamides, hormonal contraceptives).
🍷 Alcohol, 🚫 fasting, 🩸 hormonal changes (e.g. menstruation).
🦠 Infection, stress, dehydration.

🚫 Drugs to Avoid (check full list in BNF/UKPMIS)

❌ Barbiturates
❌ Sulfonamides, Co-trimoxazole
❌ Tricyclics & MAOIs
❌ Hormonal contraceptives, HRT
❌ Imidazole & Triazole antifungals (oral/IV)
❌ Protease inhibitors, NNRTIs
❌ Taxanes, Cytotoxics
❌ Diclofenac, Rifampicin, Metronidazole, Chloramphenicol

🩺 Clinical Features

🔴 Severe abdominal pain (pain out of proportion to exam).
🧠 Neurological: weakness (may involve respiratory muscles), delirium, psychosis, hallucinations, progressive paralysis.
❤️ Autonomic: tachycardia, hypertension.
😵 Fatigue, constipation, irritability.
☀️ VP/HCP: blistering photosensitive skin lesions.
🧪 Urine: dark red-brown colour during attacks.

🔍 Investigations

Test	Use
🧪 Urine PBG	Most important initial test — elevated in AIP attacks.
🧪 Urine ALA	Also elevated during acute attacks.
💡 Plasma fluorescence	Diagnostic for VP & HCP under UV light.
💩 Stool porphyrins	Helps confirm VP/HCP.
🧬 Genetic testing	Confirms mutation and porphyria subtype.
🧪 Enzyme activity	Useful in AIP (PBG deaminase deficiency).
🩺 LFTs	Assess hepatic involvement and monitor long-term risks (HCC).

💉 Treatment: In the UK, haem arginate (hemin) is given IV during acute crises (via NAPS at Cardiff or King’s College London). IV dextrose is also used to suppress haem synthesis.

🛠️ Management (UK Practice)

🚑 Emergency: ABC, monitoring, admit to quiet darkened room.
❌ Stop precipitating drugs/triggers.
💉 IV glucose (to suppress ALA synthase).
🩸 IV haem arginate via NAPS for severe/prolonged crises.
💊 Symptom relief: opioids for pain, antiemetics, beta-blockers for tachycardia.
🧾 Long-term: trigger avoidance, liver monitoring (↑ HCC risk), genetic counselling.

🛡️ Prevention

🚫 Avoid alcohol, starvation, unsafe drugs.
☀️ For VP/HCP: avoid sun exposure, use high-factor sunscreen.
🩺 Regular liver surveillance for hepatocellular carcinoma.

📚 References

Clinical cases

💊 Case 1 – Age 26: Young woman presented with severe, diffuse abdominal pain, vomiting, and dark-red urine. No peritonism on examination. Neurological review revealed mild limb weakness and anxiety. Investigations: Urine turned red on standing; raised urinary porphobilinogen confirmed acute intermittent porphyria (AIP). Management: IV hemin and high-carbohydrate infusion given; precipitating factor identified as oestrogen-containing oral contraceptive, which was discontinued. Teaching point: Acute intermittent porphyria is precipitated by drugs, hormones, or fasting — neurovisceral symptoms without peritoneal signs are classic clues.
⚡ Case 2 – Age 34: Male factory worker developed abdominal pain, tachycardia, and proximal muscle weakness after starting phenobarbital for epilepsy. Mild hyponatraemia and dark urine noted. Investigations: Elevated urinary ALA and porphobilinogen consistent with an acute porphyric attack. Management: Immediate withdrawal of phenobarbital, IV glucose, and hemin therapy. Teaching point: Many enzyme-inducing drugs (barbiturates, sulphonamides) trigger porphyric crises by increasing hepatic haem synthesis.
🩸 Case 3 – Age 29: Female with recurrent abdominal pain, vomiting, and mood disturbance. During one episode, she developed flaccid paralysis and respiratory distress requiring ICU care. Investigations: Porphyrin analysis confirmed variegate porphyria. Management: Supportive care with ventilatory support, IV hemin, and avoidance of porphyrinogenic medications. Teaching point: Variegate and hereditary coproporphyria share similar acute neurovisceral attacks but may also cause cutaneous photosensitivity — mixed features should raise suspicion.

PLEASE NOTE LEGAL ADVICE: The contents are under continuing development and improvements and may contain errors of omission or fact. Feedback vital and always welcome at drokane at gmail.com. This is not to be used for the assessment, diagnosis or management of patients. It should not be regarded as medical advice. It is only for educational purposes. Please adhere to your local protocols. If you are unwell please seek healthcare advice from your doctor. This does not replace senior or specialist advice. If you do not accept this then please do not use the website. If you need medical advice, please consult a doctor or other appropriate medical professional. If you are a medical professional and you need advice then speak to your senior or colleagues.

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