Acute myeloid leukaemia

Blood is renewed without pause, and all that work happens in the bone marrow. In acute myeloid leukaemia the myeloid branch breaks — the one that yields neutrophils, red cells and platelets. The cells stop maturing but carry on dividing, and within weeks they crowd everything else out of the marrow. It is the commonest acute leukaemia in adults.

Where exactly the fault lies

A healthy myeloid cell climbs several steps to become a mature neutrophil or another working blood cell. In leukaemia maturation is cut off halfway: the cell takes damage in its genes, stays a blast and loses its function. Dividing, though, it does better than the healthy ones.

From there it is arithmetic. The marrow is a closed space, and room taken by blasts is stolen from normal production: haemoglobin falls, platelets vanish, working white cells run out. It is that shortfall, not the bulk of the tumour, that shapes the illness.

One name covers more than a dozen variants with different genetic faults. The difference is not academic: both the regimen and the outlook follow from it.

What it looks like from outside

Complaints build over weeks, rarely months, and nearly all come down to a shortage of one blood cell or another.

• draining weakness, pallor, dizziness, breathlessness on effort that used to be easy;
• bruises where nothing was knocked, red pinpoints on the shins, bleeding gums, long nosebleeds, unusually heavy periods;
• fever, chills and night sweats with no cold to explain them, infections that will not clear;
• weight and appetite falling away, a full feeling in the abdomen;
• bone and joint pain, heaviness under the ribs;
• less often, lumps under the skin, overgrown gums, enlarged lymph nodes.

No single sign points to leukaemia. The speed does: if someone has visibly gone downhill in a month and the blood count is off on several measures at once, waiting is no longer an option.

When to call emergency services instead of booking

Some complications move very fast, and here speed matters more than diagnostic precision.

• a temperature above 38 °C in someone on chemotherapy means hospital at once: with neutrophils low an infection reaches sepsis within hours, and the first antibiotic belongs in the first hour;
• bleeding that will not stop, blood in the urine, black tarry stools, vomiting blood;
• a violent headache with a stiff neck, vomiting, confusion or seizures: a brain haemorrhage is possible;
• coughing blood, sudden breathlessness, bluish skin;
• confusion, disturbed vision and drowsiness when the white count is very high: thickened blood stops moving through the small vessels.

Acute promyelocytic leukaemia stands apart. Its danger lies not in how fast the tumour grows but in the way it wrecks clotting, and it can kill by haemorrhage in the first days. Yet it responds better than any other variant if treated in time, which is why a suspicion of it is counted in hours.

Why it arises

In most cases no cause is found, and that is an honest answer rather than a dodge: the fault appears in a single cell as it divides. Only the factors that raise the risk are known with certainty:

• age: the odds climb over the years, and most of those affected are past sixty;
• smoking: benzene and other carcinogens in the smoke reach the marrow through the blood;
• chemotherapy or radiotherapy given earlier for another tumour;
• long occupational contact with benzene and solvents;
• earlier blood disorders such as myelodysplastic syndrome and some chronic ones;
• certain inherited syndromes, Down syndrome among them;
• heavy irradiation.

None of these makes the disease inevitable or explains most cases. Leukaemia is not catching and is not passed down as a family trait.

What is done to sort it out

The first step is a full blood count. It is rarely normal: anaemia, low platelets, an odd white cell number, blasts on the film. Not yet a diagnosis, but reason to refer to a haematologist urgently rather than by waiting list.

The diagnosis is made on the marrow: a needle takes a sample from the pelvic crest under local anaesthetic. It feels like heavy pressure and leaves a bruise for a few days.

The cells are then examined from several angles: counted under the microscope, typed by their surface proteins, screened for chromosome rearrangements and mutations. Genetics sorts the disease into risk groups and decides whether a transplant is needed. Separately the heart, kidneys and liver are checked, and spinal fluid is taken if there are neurological symptoms. Some results come in a day, others in a week and a half; treatment does not wait for all of them.

How it is treated

Treatment runs in two phases. Induction has to clear the blasts and achieve remission. Consolidation is there to stop the disease returning: surviving cells show up neither under the microscope nor in the blood, yet without those follow-up courses they almost always relapse.

Chemotherapy is the backbone of both phases. Intensive regimens mean weeks as an inpatient: while the marrow is empty, a person lives on transfusions of blood and platelets under antimicrobial cover. Anyone who cannot take that load because of age or other illness is given gentler schedules, often as an outpatient.

In some genetic variants targeted drugs against that particular mutation are added. The promyelocytic variant is handled differently, less with chemotherapy than with drugs that force the immature cells to mature, and its results are the best of any form.

A donor stem cell transplant is offered to those at high risk of relapse. It is the most effective way of holding a remission and also the hardest: the marrow is destroyed first, then months pass while the donor marrow takes. Donors are sought among siblings first, then in the registries.

Complications worth knowing about in advance

Some of the trouble comes from the disease and some from the treatment, and telling them apart is hard.

• infection is the chief danger: while neutrophils are low an ordinary cold can turn threatening, which is why any fever is treated as urgent;
• bleeding from a shortage of platelets; the worst are inside the skull, the lungs and the gut;
• the breakdown of a large mass of tumour cells in the first days overloads the kidneys, so fluids are pushed and bloods checked daily;
• nausea, mouth ulcers, diarrhoea, hair loss and heavy fatigue are manageable effects that should be reported straight away;
• infertility: temporary in some, permanent in others, with the risk higher when a transplant is being prepared.

Sperm or egg storage has to be raised before the first course, because afterwards the chance is gone. Live vaccines are not given during treatment; the rest of the schedule, including that of household members, is reviewed with the haematologist.

Online consultation

A remote appointment fits when abnormal blood results need making sense of and the question is how urgently a haematologist is required. The doctor can explain reports already issued, help with side effects between courses, flag which symptoms mean an emergency and put together the questions for the treating team. Marrow sampling, transfusions and drug administration happen only on site: where leukaemia is suspected, a remote appointment replaces not the admission but the wait in the queue.

This material is for information only and does not replace medical advice.