Table 2 EMBASE search undertaken 23/1/2015 and Medline search undertaken 29/1/2015

1. exp Delayed Diagnosis/

2599

6141

2. delayed presentation.mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]

1306

1627

3. late presentation.mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]

1653

2246

4. exp Cerebral Hemorrhage/ or exp Intracranial Hemorrhages/

56224

91897

5. (intracranial haemorrhage or intracranial hemorrhage or intracerebral haemorrhage or intracerebral hemorrhage).mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]

15271

22369

6. (skull fracture or brain contusion or basal skull fracture).mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]

1899

11318

7. exp Craniocerebral Trauma/

124238

225415

8. (head injur* or brain injur*).mp. [mp=title, abstract, original title, name of substance word, subject heading word, keyword heading word, protocol supplementary concept word, rare disease supplementary concept word, unique identifier]

76828

150849

9. 1 or 2 or 3

5352

9752

10. 4 or 5 or 6 or 7 or 8

192518

322486

11. 9 and 10

168

382