Aplastic anemia

Aplastic anaemia is a form of bone-marrow failure in which the marrow — the factory that makes blood cells — becomes empty and hypoactive, so it cannot produce enough new cells. Because all the blood cell lines are affected, the result is pancytopenia: low red cells (anaemia), low white cells, particularly neutrophils (raising infection risk), and low platelets (raising bleeding risk). In most cases the cause is thought to be autoimmune — the body's own immune cells attack and destroy the marrow's stem cells. It can also be triggered by certain drugs and toxins, some viral infections, radiation, and, rarely, is inherited (as in Fanconi anaemia). The illness may come on gradually or quite suddenly, with fatigue, breathlessness and pallor from the anaemia, repeated or unusual infections from the low white cells, and easy bruising, nosebleeds, bleeding gums or petechiae (pinpoint skin spots) from the low platelets. The diagnosis is confirmed with a bone-marrow biopsy showing an empty, hypocellular marrow, once other causes of low counts are excluded. It ranges from mild to severe, and severe aplastic anaemia is life-threatening, but modern treatment — immune-suppressing therapy or a stem-cell (bone-marrow) transplant — has greatly improved outcomes.

• Haemoglobin — low (anaemia).
• Platelets — low (bruising and bleeding risk).
• Neutrophils / white cells — low (infection risk); pancytopenia is the hallmark.
• Reticulocytes — low, showing the marrow is not producing new red cells (unlike haemolysis, where they are high).
• Bone-marrow biopsy — the confirming test, showing an empty, hypocellular marrow.

• Tiredness, breathlessness and pallor (from anaemia)
• Frequent, severe or unusual infections (from low white cells)
• Easy bruising, nosebleeds and bleeding gums (from low platelets)
• Petechiae — pinpoint red or purple spots on the skin
• Sometimes a gradual, sometimes a fairly sudden onset