Synopsis
Treat suspected acute promyelocytic leukaemia as a haemorrhagic emergency, confirm PML::RARA rapidly and deliver risk-adapted differentiation therapy with coagulopathy and differentiation-syndrome control.
- APL is the acute leukaemia where treatment begins on morphological suspicion: give ATRA immediately and stop it later if genetics excludes the diagnosis.
- Confirm with urgent PML::RARA RT-PCR or FISH; conventional karyotyping is useful but is too slow as the only first-hour test.
- Monitor platelets, PT, APTT and fibrinogen at least every 6 hours initially and transfuse actively to the centre target, commonly platelets above 30–50 × 10⁹/L and fibrinogen above 1.5 g/L.
Key red flags
Headache, focal neurology, reduced consciousness, haemoptysis, hypoxia, melaena or haemodynamic bleeding requires immediate imaging, transfusion and source-control escalation alongside APL therapy.
Unexplained fever, weight gain, oedema, pulmonary infiltrates, hypotension or renal injury during ATRA or arsenic requires immediate dexamethasone.
Investigation priorities
Recognise morphology and quantify the haemorrhagic emergency.
Management branches
Abnormal promyelocytes and compatible coagulopathy make APL possible.
- Start tretinoin immediately, admit under acute leukaemia care and send urgent PML::RARA RT-PCR or FISH.
- Monitor coagulation and fibrinogen at least six-hourly and transfuse to the APL platelet and fibrinogen targets.
Key medicines
Tretinoin (ATRA)Give 45 mg/m²/day orally in two divided doses immediately when APL is morphologically suspected; continue within the risk-adapted regimen until complete remission or the protocol maximum, and stop if adequate genetics excludes APL.
Arsenic trioxideFor newly diagnosed low-to-intermediate-risk APL give 0.15 mg/kg IV daily until complete remission, maximum 60 days; consolidate 0.15 mg/kg five days weekly for four weeks on and four weeks off for four cycles.