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Diagnosis and tests

Symptoms of APL and emergency features

The related article (“APL: symptoms, emergency signs and diagnosis”) explains why the bone marrow is examined. This topic looks closely at the symptoms of a special subtype of AML, acute promyelocytic leukaemia (APL), and why it is an emergency.

Last updated: ~1 min read
A scale with a clot and a drop.
Figure 1.The clotting balance is lost.

01Short answer

APL is a subtype of AML caused by the t(15;17) translocation and the PML::RARA fusion gene. Its main danger is a disturbance of blood clotting: the abnormal promyelocytes switch on both clotting and clot breakdown at the same time (disseminated intravascular coagulation, DIC). This creates a risk of both bleeding and clots. Symptoms include sudden, widespread bruising, petechiae, nose and gum bleeds, heavy periods, and blood in the urine or stool; rarely, bleeding in the brain causes a sudden severe headache or confusion. Other AML signs such as tiredness and infections may also be present. The good news: when recognised early and treated urgently, APL is one of the types of leukaemia with the best outcomes.

02Simple explanation

A clotting disturbance: the main danger.

Bleeding: bruises, nose, gums.

Urgent: same-day treatment.

03Scientific explanation

DIC: fibrinogen falls and clotting tests are prolonged, so when APL is suspected, clotting tests and support with blood products are needed at once.

Early risk: in APL the main risk in the first days is bleeding; when APL is suspected, treatment starts without waiting for genetic confirmation.

04What happens in the body?

Balance lost

The balance between clotting and bleeding is disturbed.

Emergency care

Suspected APL needs urgent hospital care.

A glowing emergency entrance.
Figure 2.An emergency department entrance.

The promyelocyte

The abnormal cells carry many granules and Auer rods.

A cell with Auer rods.
Figure 3.A promyelocyte with granules.

05The urgent path in APL

Four steps.

Bruising — Appears suddenly.1BruisingAppears suddenly.
Bleeding — Nose, gums.2BleedingNose, gums.
Call — Emergency services.3CallEmergency services.
Treatment — The same day.4TreatmentThe same day.

06Symptoms of APL

SymptomHow urgent
Widespread bruising, petechiaeSeek care the same day
Nose or gum bleeding that will not stopUrgent
Blood in urine or stoolUrgent
Sudden severe headache, confusionCall emergency services
Tiredness, feverSeek care quickly

07Key terms

APL
Acute promyelocytic leukaemia.
PML::RARA
The fusion gene in APL.
DIC
Disseminated intravascular coagulation.
Fibrinogen
A clotting protein.
Promyelocyte
An immature myeloid cell.

08Key points

  • APL is a special type of AML.
  • The main danger is a clotting disturbance.
  • Signs of bleeding are urgent.
  • Treatment may start before confirmation.
  • With early treatment, outcomes are very good.
  • If in doubt, get help at once.

09Frequently asked questions

Why is APL so urgent?

In the first days there is a high risk of serious bleeding; prompt treatment lowers it.

How does APL differ from AML?

APL is a subtype of AML with different genetics and treatment (“How APL is diagnosed”).

Does it occur in children?

Yes, but rarely.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Why is APL so urgent?

  2. How does APL differ from AML?

  3. Does it occur in children?

My questions

12Sources

  1. National Cancer Institute (NCI). Adult AML treatment (PDQ), patient version
  2. National Cancer Institute (NCI). Definition: FISH
  3. MedlinePlus. Blood smear
  4. National Human Genome Research Institute (NHGRI). DNA Sequencing Fact Sheet
  5. National Cancer Institute (NCI). NCI Dictionary of Cancer Terms: reference range
  6. National Cancer Institute (NCI). Surgical Pathology Reports
  7. American Cancer Society. Understanding Your Pathology Report
  8. American Cancer Society. Biomarker and Tumor Marker Tests
  9. Testing.com. Reference Ranges and What They Mean
  10. Blood Cancer United (formerly The Leukemia & Lymphoma Society). Acute myeloid leukemia (AML) diagnosis
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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