A 9-year-old girl with autism who resided in a group facility was brought to the emergency department for evaluation. A nurse had examined her after she pointed to her buttocks and said ‘Ow’. The nurse noted these marks on the child (Image 30) and was concerned that another child had sexually abused her on the playground on the day before as children of mixed ages were playing together that day. The adult who was supervising on the playground stated that she did not see any unusual activity and the girl had been playing on the monkey bars alone. Her vital signs were normal. On physical examination, she had scattered bruises of varying colours on her anterior shins, but no other marks or lacerations. Her genital examination was normal for her age. She was cooperative with the examination, but did not speak or make eye contact with the examiner. https://s3-euw1-ap-pe-df-pch-content-public-u.s3.eu-west-1.amazonaws.com/9780429170423/236ca68c-f283-4df8-88b2-3b8ff49bccc9/content/fig30.jpg" xmlns:xlink="https://www.w3.org/1999/xlink"/>

What are potential aetiologies for this injury?

What further investigation would you consider for unexplained bruising in a child?

The presence of bilateral gluteal or perineal bruising in an active child should generate a short list of differential diagnoses, including inflicted trauma, straddle injury or coagulopathy. In this case, though this was a non-verbal child and it was possible that no disclosure of abuse could be elicited, it was likely that she sustained a straddle injury during the course of normal play, given the history and appearance of the bruising. The injuries were bilateral and symmetric, in a single plane and sparing the anus and genitals – consistent with the pelvis making contact with a hard surface. Straddle injuries are about 3% of total playground injuries. 1 In girls, they can cause labial haematoma and/or laceration and urethral injury. In boys, they can lead to scrotal laceration, penile laceration or contusion and even urethral rupture. Perineal injury can be found in both males and females. About 10%–15% of these injuries require surgical repair. 1

The most important initial step for a bruised child without a clear account of injury is to take a very careful history. Depending on the age and development of the child, abuse may be higher or lower on the short list of differential diagnoses, including inflicted trauma, accidental trauma, and/or coagulopathy. A non-mobile infant with unexplained bruising should make the provider think of coagulopathy or abuse. 2 Bruising in a toddler or older child is very common, though location of the bruises may prompt suspicion. Marks on the ears, neck/face (excluding forehead), trunk, buttocks or genitalia are not pathognomonic for abuse, but should arouse more suspicion for inflicted injury. 2 Additionally, patterned bruises without a supporting history (loop shaped or linear, for example) merit consideration for abuse. Patient and family history should focus on coagulopathy (epistaxis, mucosal bleeding, bleeding from circumcision) and genetic anomalies (such as collagen vascular disease). 3 Extensive unexplained bruising in which the aetiology is not abuse includes haemophilia, von Willebrand disease, disorders of fibrinogen, vitamin K deficiency, factor XIII and other factor deficiencies, thrombocytopenia, leukaemia, aplastic anaemia and other bone marrow infiltrative or failure syndromes, platelet function abnormalities, collagen disorders, corticosteroid use and others. 3 A child with concerns for abuse based on bruising should also undergo basic laboratory screening tests, including complete blood count (CBC), coagulation panel (prothrombin time [PT]/activated partial thromboplastin time [aPTT]), testing for Factor VIII/Factor IX levels, and testing for von Willebrand’s disease. A consultation with a haematologist should also be considered, or with medical genetics, depending on history and physical findings. 3