Leukaemia
How a single blood-forming cell escapes normal control, why leukaemic cells crowd out normal production to cause anaemia, infection and bleeding, and how acute and chronic, myeloid and lymphoid leukaemias differ.
By the end, you can
- Describe normal haematopoiesis from stem cell to mature blood cells.
- Explain how acquired mutations produce a leukaemic clone, and distinguish acute from chronic leukaemia.
- Explain how marrow failure causes anaemia, infections and bleeding.
- Relate enlargement of the spleen, liver and lymph nodes, and bone pain, to infiltration.
- Outline the four main types and a defining feature of each.
- Recognise the classic blood film and marrow features, classifications and tests of the main leukaemias, and explain how chemotherapy, targeted drugs, immunotherapy and transplantation act on the leukaemic clone.
What it is
Leukaemia is a cancer of blood-forming cells in which a clone of abnormal white cell precursors multiplies in the bone marrow and usually spills into the blood. It is classified by the speed of the disease (acute: immature blast cells accumulate; chronic: more mature cells accumulate) and by the cell line (myeloid or lymphoid).
4 types to tell apart
- Acute myeloid leukaemia (AML)
- Myeloid blasts fail to mature. Commonest acute leukaemia in adults, more frequent with age.
- Acute lymphoblastic leukaemia (ALL)
- Lymphoid blasts; the commonest cancer of childhood, with a peak at two to five years.
- Chronic myeloid leukaemia (CML)
- Myeloid cells at all stages accumulate, driven by the BCR-ABL1 fusion gene (Philadelphia chromosome).
- Chronic lymphocytic leukaemia (CLL)
- Mature-looking but abnormal B lymphocytes accumulate; usually in older adults and often found by chance.
US spelling: leukaemia → leukemia, haematopoietic → hematopoietic.
Normal function
Making blood in the marrow
Blood cells are made in red bone marrow, which in adults lies mainly in the spaces between the of spongy bone in the pelvis, vertebrae, ribs, sternum and skull. Every day it makes billions of new cells to replace those that wear out.
All blood cells descend from a small population of haematopoietic stem cells. These divide to renew themselves and to produce progenitors of two main lines: myeloid (red cells, platelets, neutrophils, monocytes and other granulocytes) and lymphoid (B and T lymphocytes and natural killer cells).
Growth factors and contact with marrow cells control how many cells are made and ensure they mature before release: immature blasts normally make up only a few per cent of marrow cells and are rarely seen in the blood.
- NormalHaematopoietic stem cellSelf-renewing
- NormalMyeloid progenitorNormalLymphoid progenitor
- maturation in the marrowNormalRed cells, platelets, neutrophils, monocytesNormalB and T lymphocytes, NK cells
Simplified; there are several intermediate progenitor stages.
Underlying change · Step 1 of 4
A clone escapes control
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 2 of 4
Normal blood production is crowded out
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Disrupted function · Step 3 of 4
Infiltration beyond the marrow
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Consequences · Step 4 of 4
Acute and chronic leukaemia present differently
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Symptoms and signs
Symptoms, signs and findings
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Exam detail
Exam detail
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Treatment
How treatment works
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Recap
Recap
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .
Self-check
Check your understanding
The full lesson is part of Student Pro
It takes you through all 4 steps of the mechanism, explains the symptoms, signs and findings each step causes, adds the exam detail and how treatment works where the lesson has them, then recaps it and lets you check yourself with 10 self-check questions. The full pathophysiology library: guided lessons with self-check questions comes with Student Pro, with 100 tutor answers a month and the full available catalogue.
Free to read: the introduction and .