Leukemia and Knee Pain: Could Joint Discomfort Be an Early Warning Sign?

Unexplained knee pain in children is often dismissed as a normal part of growth spurts, but it could actually be an early indicator of something more serious—like leukemia. In some pediatric cases, persistent knee or sternum pain serves as the first noticeable symptom of this blood cancer. Unlike typical growing pains that come and go, leukemia-related discomfort tends to linger and worsen over time. If a child experiences ongoing knee pain for more than four weeks without improvement, even after standard treatment, it's crucial to consider underlying conditions such as leukemia.

Why Leukemia Can Cause Knee and Bone Pain

Leukemia originates in the bone marrow, where blood cells are produced. As abnormal white blood cells multiply uncontrollably, they can overcrowd healthy cells and infiltrate surrounding bone tissue. This buildup often leads to pressure and inflammation within the bones, particularly in areas with high marrow activity—such as the knees, legs, and sternum. Consequently, many children with early-stage leukemia report deep, aching pain in their joints or bones, especially at night.

The Importance of Sternum Tenderness in Diagnosis

In addition to joint discomfort, another telltale sign of leukemia is tenderness when pressing on the breastbone (sternum). This occurs because the sternum contains a large amount of active bone marrow, making it a common site for leukemic cell accumulation. When combined with persistent knee pain, sternal tenderness should prompt immediate medical evaluation.

Comprehensive Evaluation: What Parents and Doctors Should Look For

If leukemia is suspected, a thorough physical examination is essential. Physicians should assess whether there are signs of organ enlargement—particularly the liver, spleen, or lymph nodes—which may indicate systemic involvement. Additionally, clinicians should check for other symptoms such as unexplained bruising, frequent infections, fatigue, pallor, or fever, all of which can accompany childhood leukemia.

Blood Tests: The First Step Toward Accurate Diagnosis

A complete blood count (CBC) is one of the most valuable tools in detecting leukemia early. Abnormal levels of white blood cells, low red blood cell counts (anemia), and reduced platelet counts (thrombocytopenia) are common findings in patients with this condition. While a CBC alone cannot confirm leukemia, significant irregularities typically warrant further testing, such as a bone marrow biopsy, to reach a definitive diagnosis.

Early detection dramatically improves outcomes for children with leukemia. That's why any persistent, unexplained joint or bone pain—especially when paired with other systemic symptoms—should never be ignored. Parents are encouraged to seek prompt medical advice and advocate for comprehensive screening if concerns arise. Awareness and timely action can make a life-saving difference.