Differential diagnosis
| Condition | Characteristics | Comment |
|---|---|---|
| Non-intentional injury | SDHs are more likely to occur in high impact falls or motor vehicle crashes. Low impact falls (<3 feet) rarely cause SDH. RH is rarely associated with non-intentional injury21 | |
| Neurosurgical complications | SDH commonly reported as a postoperative complication of neurosurgery | |
| Perinatal | Asymptomatic neonatal SDH has been reported in any type of delivery. They predominate in the supratentorial region. They are characteristically small and most resolve by 1 month, all by 3 months29 30 | |
| Cranial malformations | Spontaneous bleeding from vascular malformations—for example, aneurysms. Less serious trauma can result in SDH when arachnoid cyst is present31 32 | |
| Cerebral infections | Meningitis: post-infective subdural effusions are reported33 | Meningococcal septicaemia can be associated RH34 |
| Coagulation and haematological disorders | Leukaemia35 Sickle cell anaemia36 Disseminated intravascular coagulation Haemophilia36 von Willibrand's disease Haemorrhagic disease of the newborn38 Idiopathic thrombocytopenia purpura39 | These disorders will also predispose to RH40 and bruising |
| Metabolic disorders | Glutaric aciduria type 1 is associated with front-temporal atrophy that can predispose to SDH Osteogenesis imperfecta Galactosaemia Menkes kinky hair syndrome | Case reports describe associated retinal haemorrhages in glutaric aciduria41 42 Fractures and RH in osteogenesis43 and vitreous haemorrhage reported in galactosaemia44 Menkes syndrome has associated femoral spurs that can be confused with fractures45 |
| Hypernatraemia | SDH is described in association with salt poisoning, hypernatraemic dehydration hypernatraemia may also be a complication of the intracranial trauma46 | |
| Enlarged subarachnoid space | Benign extra-axial fluid collections of infancy must be differentiated from low attenuation SDH. If this coexists with SDH the cause must be investigated. There is debate in the literature as to whether benign extra-axial fluid of infancy predisposes an infant to SDH47 48 |
RH, retinal haemorrhage; SDH, subdural haemorrhage.