Differential Diagnosis for an 8-year-old hit in the side of the head with a baseball

Single most likely diagnosis

• Concussion: This is the most likely diagnosis given the mechanism of injury (hit in the head with a baseball) and the symptoms presented (nausea, vomiting, lethargy). Concussions are common in children who participate in sports or activities where they can be hit in the head, and the symptoms described are classic for a concussion.

Other Likely diagnoses

• Skull Fracture: A skull fracture is possible, especially if the baseball was traveling at a high speed or if the child has a significant swelling or deformity at the site of impact. Symptoms like nausea, vomiting, and lethargy could also be present in the case of a skull fracture.
• Epidural Hematoma: Although less common, an epidural hematoma is a possible diagnosis, especially if the child has a severe headache, vomiting, and signs of increased intracranial pressure. The mechanism of injury could potentially cause a fracture that damages an artery, leading to bleeding.

Do Not Miss diagnoses

• Subdural Hematoma: This is a critical diagnosis not to miss because it can be life-threatening if not promptly treated. Symptoms can be similar to those of a concussion but may progress to include severe headache, confusion, and even loss of consciousness.
• Intracranial Hemorrhage: Any form of bleeding inside the skull is a medical emergency. Symptoms can include severe headache, nausea, vomiting, lethargy, and in severe cases, seizures or loss of consciousness.
• Cerebral Edema: Swelling of the brain can occur after a head injury and can be life-threatening. Symptoms can be similar to those of a concussion but may worsen over time, including increased lethargy, confusion, and potentially life-threatening complications.

Rare diagnoses

• Basilar Skull Fracture: While less common, a basilar skull fracture could occur if the force of the baseball was significant. This type of fracture involves the bones at the base of the skull and can have serious complications, including leakage of cerebrospinal fluid.
• Arteriovenous Fistula: A rare but potential complication of a head injury, where an abnormal connection between arteries and veins can form, potentially leading to serious neurological symptoms or bleeding.

Each of these diagnoses requires careful consideration based on the child's specific symptoms, the mechanism of injury, and potentially, imaging studies like a CT scan of the head. Prompt medical evaluation is essential for any child who has been hit in the head, especially if they are experiencing symptoms like nausea, vomiting, and lethargy.