Differential Diagnosis for Knee and Lower Leg Swelling and Tenderness
Single Most Likely Diagnosis
- Cellulitis: This is a common and likely diagnosis for knee and lower leg swelling and tenderness, especially if there is a history of trauma, skin break, or recent infection. Cellulitis is a bacterial skin infection that can cause redness, swelling, and tenderness in the affected area.
Other Likely Diagnoses
- Deep Vein Thrombosis (DVT): DVT is a blood clot that forms in the deep veins of the legs, which can cause swelling, tenderness, and warmth in the affected area. This diagnosis is likely, especially if the patient has a history of immobility, cancer, or recent surgery.
- Muscle Strain or Contusion: A muscle strain or contusion can cause swelling and tenderness in the knee and lower leg, especially if there is a history of trauma or overuse.
- Lymphedema: Lymphedema is a condition characterized by swelling in the legs due to impaired lymphatic drainage. This diagnosis is likely if the patient has a history of cancer, surgery, or radiation therapy.
Do Not Miss Diagnoses
- Compartment Syndrome: This is a medical emergency that occurs when pressure builds up in the muscle compartments of the legs, causing severe pain, swelling, and tenderness. Compartment syndrome can lead to permanent damage if not treated promptly.
- Osteomyelitis: Osteomyelitis is a bone infection that can cause swelling, tenderness, and pain in the affected area. This diagnosis is critical to consider, especially if the patient has a history of recent trauma, surgery, or immunocompromised state.
- Septic Arthritis: Septic arthritis is a joint infection that can cause severe pain, swelling, and tenderness in the affected joint. This diagnosis is critical to consider, especially if the patient has a history of recent trauma, surgery, or immunocompromised state.
Rare Diagnoses
- Erythema Nodosum: Erythema nodosum is a rare condition characterized by inflammation of the fat cells under the skin, causing swelling, tenderness, and redness in the affected area.
- Necrotizing Fasciitis: Necrotizing fasciitis is a rare and life-threatening condition that occurs when bacteria infect the tissue under the skin, causing severe pain, swelling, and tenderness in the affected area.
- Kawasaki Disease: Kawasaki disease is a rare condition that affects children, causing inflammation in the blood vessels, which can lead to swelling, tenderness, and pain in the legs.