Differential Diagnosis for Leg Pain in Kids

When considering leg pain in children, it's crucial to approach the diagnosis systematically to ensure that no critical conditions are overlooked. The differential diagnosis can be categorized as follows:

• Single Most Likely Diagnosis

  • Growing Pains: This is the most common cause of leg pain in children, typically occurring in the calf or thigh. It's characterized by recurrent, bilateral leg pain that usually occurs at night and resolves by morning. The exact cause is unknown, but it's thought to be related to the growth and development of bones and muscles.

• Other Likely Diagnoses

  • Muscle Strains: Common in active children, muscle strains can occur due to overuse or acute injury, leading to pain, swelling, and limited mobility.
  • Shin Splints (Medial Tibial Stress Syndrome): This condition is common in children who engage in running or jumping sports. It causes pain in the front or side of the lower leg due to inflammation of the muscles, tendons, and bone tissue.
  • Osgood-Schlatter Disease: A condition that affects the knee, causing a painful lump to form below the kneecap. It's due to inflammation of the patellar tendon and is common in adolescents during growth spurts.
  • Sever's Disease (Calcaneal Apophysitis): This condition causes heel pain in children, typically during periods of rapid growth. It's due to inflammation of the growth plate in the heel.

• Do Not Miss Diagnoses

  • Osteomyelitis: A bone infection that can cause severe pain, fever, and swelling. It requires prompt antibiotic treatment to prevent long-term damage.
  • Septic Arthritis: A joint infection that can cause severe pain, swelling, and limited mobility. It's a medical emergency requiring immediate antibiotic treatment.
  • Child Abuse: Non-accidental trauma can cause leg pain and should be considered, especially if the history is inconsistent or there are other signs of abuse.
  • Neurological Conditions (e.g., Peripheral Neuropathy, Neurofibromatosis): Certain neurological conditions can cause leg pain and should be considered if the pain is persistent, severe, or accompanied by other neurological symptoms.

• Rare Diagnoses

  • Leukemia: Although rare, leukemia can cause bone and joint pain in children due to the infiltration of malignant cells into the bone marrow.
  • Bone Tumors (e.g., Osteosarcoma, Ewing's Sarcoma): Primary bone cancers can cause persistent pain, swelling, and limited mobility. They are rare but critical to diagnose early.
  • Chronic Recurrent Multifocal Osteomyelitis (CRMO): A rare condition characterized by recurring episodes of bone inflammation, often without an identifiable cause.
  • Ehlers-Danlos Syndrome: A group of genetic disorders that affect the body's connective tissue, potentially leading to joint hypermobility, pain, and other musculoskeletal issues.

Each of these diagnoses has distinct clinical features and requires a thorough history, physical examination, and sometimes additional diagnostic tests for accurate identification and management.