Post-Traumatic Amnesia (PTA): This is the most likely diagnosis given the context of trauma. PTA is a state of confusion and memory loss that occurs after a traumatic brain injury, characterized by an inability to form new memories.

Concussion: A concussion is a type of traumatic brain injury that can cause amnesia, among other symptoms. The amnesia can be retrograde (forgetting events before the injury) or anterograde (difficulty forming new memories after the injury).
Traumatic Brain Injury (TBI) with Amnestic Syndrome: TBI can result in various cognitive impairments, including amnesia. The amnestic syndrome associated with TBI can manifest as difficulty in learning new information or recalling past events.
Dissociative Amnesia: Although less common in the context of physical trauma, dissociative amnesia is a condition where individuals forget information about themselves or events, which can be triggered by trauma. However, it's more commonly associated with psychological trauma.

Subdural or Epidural Hematoma: These are serious conditions that can cause increased intracranial pressure and lead to amnesia, among other neurological deficits. Prompt diagnosis and treatment are crucial to prevent severe outcomes or death.
Intracranial Infection (e.g., Meningitis, Encephalitis): Infections within the brain can cause amnesia, along with fever, headache, and other neurological symptoms. Early diagnosis and treatment are vital.
Cerebral Vasculitis or Stroke: Although less common, vasculitis or stroke can cause amnesia, especially if areas of the brain involved in memory are affected.

Transient Global Amnesia (TGA): A rare condition characterized by sudden, temporary memory loss and confusion, which can be triggered by physical or emotional stress, including trauma. It typically resolves within 24 hours.
Hypoxic-Ischemic Brain Injury: This can occur if the brain does not receive enough oxygen, which might happen in the context of severe trauma affecting breathing or circulation. Amnesia can be a part of the cognitive deficits resulting from this type of injury.
Psychogenic Fugue (now part of Dissociative Fugue under Dissociative Amnesia): A rare condition where individuals suddenly forget their personal details and often take on a new identity, sometimes traveling away from home. It's considered a rare manifestation of dissociative amnesia.