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Anaesthesia in blood disorders — sickle cell disease, porphyria, G6PD and haemophilia
Each blood disorder brings its own ban: in sickle cell disease hypoxia, cold, dehydration and acidosis are avoided; in porphyria — barbiturates; in G6PD deficiency — oxidants such as methylene blue; and in haemophilia factor is replaced before surgery.
Why it matters in the exam
The exam asks what triggers a sickle crisis around surgery, whether to transfuse before surgery (to 10 g/dL in an HbSS patient having intermediate surgery), what acute chest syndrome after surgery is, which drugs are forbidden in acute intermittent porphyria and which are safe, why methylene blue is dangerous in G6PD deficiency, and how a patient with haemophilia or von Willebrand disease is prepared for surgery (factor concentrate, desmopressin).
In sickle cell disease cells deform and stick in small vessels with hypoxia, cold, hypovolaemia, acidosis or slow flow. Acute chest syndrome appears in the days after surgery with fever, chest pain, a new infiltrate and hypoxaemia — treated with oxygen, analgesia, antibiotics and transfusion or exchange. Sickle trait usually requires no change. In porphyria, barbiturates and enzyme-inducing drugs trigger an attack of abdominal pain, weakness and confusion; propofol, opioids, relaxants and local anaesthetics such as bupivacaine are considered safe.
In G6PD deficiency oxidants cause haemolysis — so methylene blue is forbidden for methaemoglobinaemia, and prilocaine and sulphonamides are also avoided. In haemophilia the factor level is raised to 80%–100% before major surgery, and intramuscular injections and neuraxial blocks are avoided without correction. In type 1 von Willebrand disease desmopressin releases the factor from stores. Platelet thresholds: 50 for ordinary surgery, 100 for brain or eye surgery, and 70 or more for a neuraxial block in most cases.
Key points
- Sickle cell: no hypoxia, cold, dehydration or acidosis; transfuse to 10 g/dL before intermediate surgery.
- Acute chest syndrome: fever, chest pain, infiltrate, hypoxaemia.
- Porphyria: no barbiturates; propofol is safe.
- G6PD: no methylene blue or prilocaine.
- Haemophilia: factor to 80%–100%; von Willebrand type 1 — desmopressin.
Summary table
| Disorder | What to avoid | What is done |
|---|---|---|
| Sickle cell disease | Hypoxia, cold, dehydration, acidosis, tourniquets | Transfuse to 10 g/dL before intermediate surgery in HbSS; oxygen, warming, fluids |
| Acute intermittent porphyria | Barbiturates, phenytoin, sulphonamides, prolonged fasting | Propofol, opioids and relaxants are safe; in an attack — hemin and glucose |
| G6PD deficiency | Methylene blue, prilocaine, sulphonamides | For methaemoglobinaemia — alternatives (vitamin C, exchange transfusion) |
| Haemophilia | Intramuscular injections, blocks without correction | Factor to 80%–100% before major surgery |
| Von Willebrand disease | NSAIDs | Type 1 — desmopressin; others — von Willebrand concentrate |
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Sources
- British Society for Haematology guideline: Management of sickle cell disease in the perioperative period, 2021 — Preoperative transfusion and prevention of complications
- Miller's Anesthesia, 9th edition (2020) — Anesthetic Implications of Concurrent Diseases: Hematologic Disorders
- Morgan & Mikhail's Clinical Anesthesiology, 7th edition (2022) — Anesthesia for Patients with Hematologic Disease
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.