The main feature of leukemia is an abnormal proliferation of white blood cells in the bone marrow, which ultimately turns the disease into a life-threatening condition. It can be aggressive or slow-progressing and insidious depending on the type of leukemia and its subtypes. However, leukemia diagnosis should take into consideration that there are many other pathologic conditions and diseases in which white blood cells are increased in number. In cases of high white blood cell count, we should rule out infections first, unless there is a dramatic increase along with signs and symptoms.
Acute leukemia has 2 subtypes. They are acute myeloid leukemia, and acute lymphoblastic leukemia and their diagnosis depend on the cells involved, and the progression of the disease. Acute myeloid leukemia can further be subdivided into further 8 subtypes, depending on the maturity of the cells that are proliferating in the bone marrow. They are range between M0 through M7 according to the differentiation of cells. Another way to classify AML is through the genetic alterations that occur in patients, which is the current classification by the World Health Organization. Similarly, an acute lymphoblastic type has 4 types depending on the cell involved in the lymphoid series. The types include B cell ALL, T-cell ALL, and an undifferentiated type.
Similar to acute leukemia, chronic leukemia also has been divided into chronic myeloid and chronic lymphoblastic types and subtypes. Chronic lymphoblastic types include common B cell and Rare T cell CLL. On the other hand, chronic myeloid leukemia has 4 types depending on the presence and absence of the Philadelphia chromosome and the BCR gene.
But, with so many options, types, and subtypes, how can we diagnose them?
How is leukemia diagnosed?
Every ailment manifests with different signs and symptoms depending on the duration and nature of the disease. These clinical features help in making a diagnosis or suspecting the nature of a given disease. However, confirmation is always required to make a diagnosis. This can be achieved by doing various blood tests, radiographic investigations, and cultures.
Clinical features to suspect leukemia include a fever of unknown origin, tiredness, shortness of breath, abdominal discomfort and pain, anorexia, sweating, bone pain, recurrent infections, and easy bruising. Other signs and symptoms include enlarged lymph nodes, pallor, oral thrush, and petechial rashes on the body.
The age group is another important factor in determining the type of leukemia. For instance, AML is common in the pediatric age group and ALL in adults. CML is more common in ages above 50 years, and CLL is usually seen above 65 years old.
Another clue that leads to diagnosis is where people work and their health risks. For example, industrial workers who get exposed to benzene have a higher chance of suffering from leukemia. The same goes for people working in radiology departments or hospitals. We can see leukemia more commonly in whites as compared to other races, and it is more common in patients with a positive family history, identical twins, and immunocompromised individuals. These factors help doctors suspect leukemia and make the appropriate tests for diagnosis.
Once these factors are taken into account, the next thing would be performing a physical examination of the patient. In examining the body, doctors will usually look for pallor, a lethargic look of the patient, bruises on the body, an enlarged and tender abdomen, enlarged lymph nodes, rumbling murmurs at auscultation, and many other leading signs. If there is an active infection, doctors will be able to detect them in some cases, and depending on the signs and symptoms the patient has. After this, confirmatory tests are carried out to make sure if it is leukemia or any other disease process.
For each type of leukemia, there is a protocol designed to diagnose patients. For example: