What symptom in a 6-year-old after a boating crash raises the most concern for intra-abdominal trauma?

Constant left shoulder pain in a 6-year-old following a boating crash raises the most concern for intra-abdominal trauma due to the phenomenon known as Kehr's sign. This sign refers to referred pain in the shoulder, which can be indicative of splenic injury or other intra-abdominal bleeding, particularly from injuries involving the diaphragm.

When there is significant trauma to the abdomen, such as from a boating accident, the spleen can be damaged, resulting in hemorrhage. The blood can irritate the diaphragm, which shares neural pathways with the shoulder area, leading to pain being felt in the left shoulder. This is particularly pertinent as the left shoulder is associated with the left diaphragm, making constant pain in this area a red flag for potential intra-abdominal hemorrhage or splenic injury that necessitates immediate evaluation and intervention.

Other symptoms like chest pain with deep inspiration, thoracic spine pain, and intermittent shortness of breath can also be concerning. However, they are less specific for intra-abdominal trauma compared to the direct correlation of left shoulder pain with potential organ injury or bleeding within the abdomen. These other symptoms could suggest a variety of other issues, including respiratory or spinal injury, but do not directly point towards the risk of intra-abdominal trauma