Differentials
Accidental head trauma
SIGNS / SYMPTOMS
History of trauma: in infants, significant trauma such as a serious fall or motor vehicle accident will usually be witnessed and documented by police or paramedics.
Physical exam will usually reveal bruising related to a fall, although in some cases scalp bruising may be deep and therefore not visible externally.
Ophthalmologic exam is usually completely negative, although in crush injuries or instances where the eye received a direct blow there may be a small number of retinal hemorrhages.
INVESTIGATIONS
CT head: although skull fracture and subdural hemorrhage may be present, it is rare for accidental household falls to result in significant brain injury.
Birth trauma
SIGNS / SYMPTOMS
If a birth-related hemorrhage is severe enough to cause symptoms, this will occur in the newborn period. The new onset of symptoms and signs of inflicted traumatic brain injury in a child who was asymptomatic at birth is not consistent with birth-related subdural hemorrhage.
Retinal hemorrhages are seen in 30% to 50% of births, are generally few in number, and present in the intraretinal layer. They can be bilateral and widespread; most resolve within 1 to 2 weeks, and the remainder are gone in 6 to 8 weeks.[39][55][56] Widespread retinal hemorrhages after 6 to 8 weeks of age are of concern for abusive head trauma.
INVESTIGATIONS
Distinguishing between inflicted injury and birth trauma is based on historical factors of the birth as well as the current presentation of injury.
Central nervous system infection: meningitis and encephalitis
SIGNS / SYMPTOMS
Fever and clinical signs of meningism.
Generally, parents give history of progressively worsening illness.
INVESTIGATIONS
Lumbar puncture and cerebrospinal fluid analysis: increased number of WBCs, visualization of bacteria on microscopy, low glucose, high protein, positive culture for organism, positive serology for viruses.
Subdural bleeding into benign enlargement of the subarachnoid space (BESS)
SIGNS / SYMPTOMS
Preexisting condition of BESS may predispose infants to the occurrence of subdural bleeding with minor trauma.
Usually asymptomatic, absence of retinal hemorrhages; no other signs of abuse.
INVESTIGATIONS
Cranial imaging: enlargement of subarachnoid space with subdural bleeding that is often unilateral, not space-occupying, or associated with signs of brain edema or injury such as contusion, diffuse axonal injury, or tissue shearing.
Glutaric aciduria type I
SIGNS / SYMPTOMS
Positive family history (autosomal recessive), classic radiologic findings on brain imaging, macrocephaly, motor delay, and learning difficulties are usually present.[32][44][45] Retinal hemorrhages may be present in the setting of glutaric aciduria type I.
A genetics/metabolism team should be consulted if there is any possibility of glutaric aciduria type I.[32]
INVESTIGATIONS
CT head: frontotemporal brain atrophy, subdural fluid collections that sometimes contain blood.
Urine screen: increased levels of glutaric, glutaconic, and 3-hydroxyglutaric acids.
Osteogenesis imperfecta
SIGNS / SYMPTOMS
Positive family history (autosomal dominant), history of fractures after minor trauma, discoloration of the sclera to a blue-gray color (types 1 and 3), poor muscle tone.
INVESTIGATIONS
DNA analysis from blood testing confirms mutations associated with osteogenesis imperfecta. Quantitative or qualitative differences in collagen detected after skin biopsy and fibroblast culture.
Mutation analysis of COL1A1 and COL1A2 genes from fibroblast RNA may also be performed.
Rickets
SIGNS / SYMPTOMS
Nutritional insufficiency or deficiency of vitamin D is common if children are breastfed without vitamin D supplementation; however, radiologic findings of rickets are rare.
Bone deformities of the forearms and posterior bowing of the distal tibia can occur in infants.
INVESTIGATIONS
Typically low calcium and vitamin D levels in hypocalcemic rickets, in association with elevated parathyroid hormone and findings of osteopenia and widened metaphyses on x-ray.
Vitamin K deficiency
SIGNS / SYMPTOMS
Hemorrhagic disease of the newborn due to vitamin K deficiency can be clinically indistinguishable from shaken baby syndrome.
History of lack of administration of vitamin K at birth; drugs taken by mother including warfarin and certain anticonvulsants or antibiotics; or the presence of other medical conditions (intractable diarrhea, alpha-1 antitrypsin deficiency, hepatitis or biliary atresia, cystic fibrosis, or the use of antibiotics) that result in poor absorption of oral vitamin K.[57]
INVESTIGATIONS
Prolonged prothrombin time and activated partial prothrombin time.
Sudden infant death syndrome
SIGNS / SYMPTOMS
Clinical absence of retinal hemorrhage and skeletal injury.
INVESTIGATIONS
Autopsy negative for other causes of death.
Intracranial venous thrombosis
SIGNS / SYMPTOMS
Superior sagittal venous thrombosis is a rare but serious disease in infants. This may result from dehydration, infection, coagulation disorders, or other medical disorders.
It is important to note that cases of abusive head trauma may result in localized thrombosis in the bridging veins, so it is helpful to have the input of neuroradiology and neurology about whether the venous thrombosis is a result of trauma or a cause of the clinical presentation.
INVESTIGATIONS
CT or MRI with venogram is often the most helpful study. Hematology may be consulted to assess for coagulation defects.
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