Concussion: This is the most likely diagnosis given the mechanism of injury (fall and hitting the head). A concussion is a type of traumatic brain injury caused by a blow to the head or body, a fall, or another injury that jars or shakes the brain inside the skull. Though it might not always involve loss of consciousness, it typically results in a variety of physical, cognitive, and emotional symptoms.

Nasal Fracture: Given the impact to the nose, a nasal fracture is a plausible diagnosis. Symptoms can include pain, swelling, bruising, and difficulty breathing through the nose.
Lacerations or Cuts: The impact could result in lacerations or cuts to the face, including the nose and surrounding areas, which would require immediate attention for cleaning and possibly suturing.
Subdural Hematoma or Epidural Hematoma: Though less common than a concussion, these are possible diagnoses, especially if the patient exhibits worsening symptoms such as severe headache, vomiting, confusion, or loss of consciousness.

Subarachnoid Hemorrhage: This is a life-threatening condition that requires immediate medical attention. It involves bleeding into the space between the brain and the tissue that covers it (the subarachnoid space). Symptoms can include a sudden, severe headache, vomiting, and loss of consciousness.
Cervical Spine Injury: Any fall that results in a head injury also carries the risk of a cervical spine injury. It's crucial to assess for neck pain, numbness, tingling, or weakness in the arms or legs.
Basilar Skull Fracture: This type of fracture can be associated with a fall and head injury. Symptoms might include clear fluid leaking from the nose or ears (indicating a cerebrospinal fluid leak), severe headache, and facial paralysis.

Le Fort Fractures: These are rare but serious facial fractures that result from significant trauma to the face. They can involve the nasal, maxillary, and orbital bones and require surgical intervention.
Cerebral Vasospasm: This is a rare but potentially deadly complication of subarachnoid hemorrhage, where the blood vessels in the brain constrict, leading to reduced blood flow and potential further brain damage.
Traumatic Arteriovenous Fistula: A rare condition where a connection forms between an artery and a vein due to the trauma, potentially leading to various neurological symptoms depending on the location.