What is the diagnosis for a 17-year-old patient with sharp left forearm wrist pain, exacerbated by movement and activity, particularly after a boxing match, with a pain scale of 9/10, and worsened by morning activities due to increased movement during sleep?

Wrist Sprain: The sharp pain with movement, worsening after a boxing match, and exacerbation with any activity suggests a mechanical injury to the wrist, making a wrist sprain the most likely diagnosis. The timing and character of the pain also support this diagnosis.

Triangular Fibrocartilage Complex (TFCC) Injury: The location of the pain (left forearm wrist) and the sharp pain with movement could indicate an injury to the TFCC, which is a common injury in athletes, especially those involved in sports that involve wrist rotation and flexion.
Ganglion Cyst: Although less likely given the acute onset and relation to a specific event (boxing match), a ganglion cyst could cause sharp pain, especially if it is located near a joint or tendon, affecting movement.
Tendinitis (e.g., De Quervain's Tenosynovitis): This condition, which affects the tendons on the thumb side of the wrist, could be considered given the sharp pain with movement, especially if the activities involved repetitive wrist and thumb motions.

Scaphoid Fracture: Although the patient does not report a specific fall onto an outstretched hand, a scaphoid fracture is a critical diagnosis not to miss due to its potential for complications, such as avascular necrosis, if not promptly treated.
Infection (e.g., Septic Arthritis): While less likely given the lack of systemic symptoms or signs of infection, septic arthritis or an infectious process could present with severe pain and must be considered, especially if the patient has a fever, redness, or swelling.
Nerve Entrapment (e.g., Carpal Tunnel Syndrome): Although the symptoms do not perfectly align with classic carpal tunnel syndrome, nerve entrapment could cause sharp pains and must be considered, especially if there are any sensory changes or weakness.

Kienböck's Disease (Avascular Necrosis of the Lunate): This rare condition could cause wrist pain but typically presents in a more chronic fashion and might not directly relate to an acute event like a boxing match.
Gout or Pseudogout: Although rare in a 17-year-old, these conditions could cause severe, acute wrist pain and should be considered if other diagnoses are ruled out, especially if there's a history of similar episodes or a family history of these conditions.