Subdural hemorrhage of infancy: Is it spontaneous?
Correspondence Address: Source of Support: None, Conflict of Interest: None DOI: 10.4103/0028-3886.227329
Source of Support: None, Conflict of Interest: None
Subdural hemorrhage (SDH) occurs in 24 per 100,000 infants. Infants aged less than 4 months are most commonly affected. Nonspecific symptoms often hamper an early diagnosis. Neuroimaging is diagnostic, but the underlying cause needs evaluation. Investigations should be prioritized to rule out nonaccidental head injury. In a sizable proportion, the evaluation for the etiology is unrewarding and a diagnosis of spontaneous SDH has to be concluded. We describe the case of a 16-month old boy with presumed spontaneous repeated SDHs in early infancy.
The index child presented at the corrected age of 4 months with concerns of a progressive increase in head size. He was the first twin, born preterm (32 weeks) to a nonconsanguineous couple. His birth weight was adequate (1400 g), and his neonatal period in the hospital was uneventful. He and his male sibling attained early milestones appropriate for his age. The parents first noticed his large head at the age of 2 months but became concerned at the age of 3.5 months when he additionally started having irritability and inward downward gazing of eyes. There was no history of vomiting, seizures, fever, lethargy, or poor feeding.
On examination, the baby had a large (5 cm × 5 cm) head, bulging, pulsatile anterior fontanelle with prominent scalp veins, and sutural diastasis. His head circumference was 45 cm (at +3 Z-score). The transillumination test was negative, but sunset sign was present. No bruises, abnormal skin, or hair changes were noted. Central nervous system (CNS) examination, including examination of fundi, was unremarkable. A clinical possibility of meningitis with hydrocephalus was considered. Neuroimaging revealed bilateral subdural effusion with mass effect on the brain parenchyma [Figure 1]. Cerebrospinal fluid (CSF) analysis was unremarkable, and the blood culture was sterile. Diagnostic subdural tap showed a hemorrhagic fluid with elevated proteins (2.6 g/dl) and predominant lymphocytic pleocytosis (200 cells/dl). The skeletal survey was unremarkable. Hair microscopy was normal. Serum copper, blood acyl-carnitines, and urine organic acid estimation did not reveal any abnormalities. His vitamin D levels were in an insufficient range (19.56 ng/ml). A diagnosis of chronic SDH of uncertain etiology was concluded. On day 7 of his hospital stay, the baby developed recurrent episodes of vomiting and reduced alertness. A bilateral burr hole drainage of the subdural fluid was undertaken. The postoperative period was uneventful. Three weeks later, the baby was readmitted for recurrence of irritability and a further increase in head circumference to 46.5 cm. The burr hole drainage procedure was repeated. The possibility of a subduroperitoneal shunting was discussed but the parents opted for conservative management. The baby was kept under close follow-up with a watch on symptoms, head size, and serial ultrasounds of the cranium. Serial ultrasounds showed a reduction in the subdural collection. He had no new symptoms during the follow-up visits, and the head circumference did not show any unusual growth. At a 1-year follow-up, the child had normal development similar to his twin sibling and had attained a normal head circumference.
The diagnostic search for any child with a SDH should start with the exclusion of nonaccidental head injury. Examining the circumstances before the symptoms developed, a skeletal survey for fractures of varying age, and assessment of the fundus for retinal hemorrhages are essential components of the neurological evaluation. Other differential diagnoses of SDH in infancy include complicated meningitis; coagulation disorders; sinovenous thrombosis; or, rare inborn errors of metabolism, such as Menke's disease or glutaric aciduria. In the index child, investigations for the above-mentioned causes were unrevealing. The twin sibling of the same sex was asymptomatic and developing normally. Hence, we presumed the cause of SDH in the index child to be idiopathic. A subsequent favorable outcome supports our presumption.
Nevertheless, we believe certain factors may have predisposed this baby to developing a SDH. The child had vitamin D deficiency and possibly arachnoidomegaly. However, the causal role of arachnoidomegaly (also known as external hydrocephalus) in the development of SDH is still debatable. Arachnoidomegaly is a common feature in infants even in the absence of macrocrania, and is considered a characteristic of a normal infant. An association between SDH and arachnoidomegaly was first reported by Mori et al. The authors reported SDH in 3 of 20 cases having an infantile subarachnoid fluid collection in an 8-year period. The authors concluded that infantile subarachnoid fluid collection seems to be prone to complicate SDH. The relationship between a minor trauma and subdural bleed after venous stretching has been proven by multiple mathematical models. In the largest prospective series of idiopathic SDH, 7 of the 16 infants had an arachnoidomegaly. Alternatively, in the immature brain, hypoxia, both alone and in combination with infection, is sufficient to activate the pathophysiological cascade, which culminates in altered vascular permeability and extravasation of blood within and under the dura., Though the index baby was born preterm, he did not have any symptom suggestive of hypoxic-ischemic brain injury or of intracranial infection. It is possible that hypovitaminosis-D predisposed to macrocrania, archanoidomegaly, and subsequent SDH. We postulate that accelerated skull widening with the subsequent rupture of the bridging veins may have had a potential role in the development of spontaneous SDH; this hypothesis requires further exploration.
The management of SDH depends on its etiology as well as the symptomatology caused by blood collection. A conservative management and a close follow-up can be done for minor bleeds, provided the etiological work-up is unrevealing and intentional trauma is excluded. Surgical treatment forms the mainstay of treatment when the subarachnoid fluid collection is complicated by the occurrence of SDH due to arachnoidal rupture or tearing of the bridging veins. A subdural drainage and occasionally a craniotomy have been employed by previous researchers. A recent meta-analysis by Almenawer et al., revealed no significant difference in mortality (P = 0.09) and recurrence (P = 0.99) rates between a burr hole craniostomy and a twist drill craniostomy. The index child had a large bleed and compressive symptoms, compelling the performance of surgical drainage twice in his case. The use of a subdural drain after a burr hole evacuation is associated with reduced recurrence rates and no increase in the incidence of complications.
The prognosis depends on the etiology of SDH, its rapidity of development, and the amount of subdural collection. Majority of the infants, like the index child, do well on a long-term follow-up.
In conclusion, we wish to highlight that spontaneous SDH is an underrecognized and underreported condition. Spontaneous SDH should be included in the differential diagnosis of SDH occurring in infancy after ruling out nonaccidental head injury and other systemic causes. The presence of arachnoidomegaly, macrocrania, minor blunt trauma, and a favorable outcome supports this diagnosis.
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