Child’s Nerv Syst (2000) 16:590–594 © Springer-Verlag 2000 Sung Kyoo Hwang Seung Lae Kim Received: 5 November 1999 Revised: 15 January 2000 S.K. Hwang (✉) · S.L. Kim Department of Neurosurgery, Kyungpook National University, School of Medicine, 50 Samdukdong Chungku Taegu, 700-721, Korea e-mail: shwang@knu.ac.kr Tel: +82-53-4205654 Fax: +82-53-4230504 O R I G I N A L PA P E R Infantile head injury, with special reference to the development of chronic subdural hematoma Abstract An infantile head injury has unique features in that infants are totally helpless and dependent on their parents, and biomechanical characteristics of the skull and brain are very different from those of other age groups. The authors reviewed a total of 16 infant head injury patients under 12 months of age who were treated in our hospital from 1989 to 1997. Birth head injury was excluded. The most common age group was 3–5 months. Early seizures were noted in 7 cases, and motor weakness in 6. Three patients with acute intracranial hematoma and another 3 with depressed skull fracture were operated on soon after admission. Chronic subdural hematomas (SDHs) developed in 3 infants. Initial CT scans showed a small amount of SDH that needed no emergency operation. Resolution of the acute SDH and development of subdural hygroma appeared on follow-up CT scans within 2 weeks of injury. Two Indroduction Infants under the age of 12 months are totally helpless and dependent on their parents. Furthermore, the biomechanical characteristics of the skull and brain are very different from those of other childhood age groups. These features give the infantile head injury unique characteristics in clinical features, management, and outcome [8, 9, 17]. Chronic subdural hematoma (SDH) is a relatively common intracranial complication after head inju- of these infants developed early seizures. Chronic SDH was diagnosed on the 68th and 111th days after the injuries were sustained, respectively. The third patient was the subject of close follow-up with special attention to the evolution of chronic SDH in view of our experience in the previous 2 cases, and was found to have developed chronic SDH on the 90th day after injury. All chronic SDH patients were successively treated by subduro-peritoneal shunting. In conclusion, the evolution of chronic SDH from acute SDH is relatively common following infantile head injury. Infants with head injuries, especially if they are associated with acute SDH and early development of subdural hygroma, should be carefully followed up with special attention to the possible development of chronic SDH Keywords Infant head injury · Chronic subdural hematoma ry in infancy. Clinical symptoms and signs can be silent in spite of significant mass effect in the radiological evaluation [1, 14]. The pathogenesis and the method of surgical treatment are controversial. In this regard, the authors retrospectively analyzed a series of infantile head injury with special reference to the development of chronic SDH. 591 12 Table 1 Modified coma scale for infants [5] Male Score Eye opening Spontaneous On speech On pain None 4 3 2 1 Verbal Coos, babbles Irritable cries Cries on pain Moans on pain None 5 4 3 2 1 Motor Normal spontaneous movements Withdraws on touch Withdraws on pain Abnormal flexion Abnormal extension None 6 5 4 3 2 1 10 Female 8 No. of cases Response 6 4 2 0 -2 -5 -8 -12 Age (months) Fig. 1 Age distribution of infantile head injury Table 2 Causes of infantile head injury Materials and method No. of cases Fall Motor passenger Vehicle pedestrian Motorcycle passenger Others 5 5 2 1 3 5 Outcome During the 10-year period January 1988 to December 1997, 16 head-injured patients under the age of 12 months were treated in our hospital. Causes of injury, symptoms and signs, clinical findings and treatment outcomes were reviewed retrospectively with special reference to the development of chronic SDH. The mental state was described with reference to the Modified Infantile Glasgow Coma Scale (MIGCS; Table 1) [5, 15]. Treatment outcome was divided into five grades: good, moderate disability, severe disability, vegetative, and died. Good outcome means no residual neurological deficit that would make it impossible to maintain normal life; moderate disability means mild residual deficit but not such as would prevent the patient from maintaining daily life; severe disability means deficit causing difficulty in daily life; vegetative state means no cognitive functions at all. Causes 4 3 2 1 Results Age and sex distributions are shown in Fig. 1. Between 3 and 5 months was the most prevalent age group. There was a male predominance (62.5%). Falls and motor vehicle passenger accidents were the leading causes of injury, accounting for 5 cases each, followed by vehiclepedestrian and motorcycle accidents (Table 2). The numbers of patients with MIGCS scores of 13–15, 9–12, and 3–8 were 6, 6, and 4, respectively. On initial examination, motor weakness was noted in 6 and early seizures in 7. The diagnoses were linear skull fracture in 4 cases, depressed skull fractures in 5, acute SDH in 9, and acute epidural hematoma in 3. Removal of the acute intracranial hematoma was performed in 3 patients. Elevation for depressed skull fracture was done in 3. Chronic SDH developed in 3 patients. Hydrocephalus developed in 1 patient. In 2 patients with chronic SDH burr hole drainage was performed unsuccessfully and 0 5 10 15 MIGCS Fig. 2 Outcome of infantile head injury. (MIGCS modified Infantile Glasgow Coma Scale, outcome: 1 died, 2 vegetative state, 3 severe disability, 4 moderate disability, 5 good subduro-peritoneal shunt placement was done thereafter. In another case of chronic SDH, subduro-peritoneal shunting was done at the time of the diagnosis. The incidence of development of chronic SDH from acute was 3 out of 16. Of the 6 acute SDHs unoperated because of the small volume, 3 became chronic. Four patients died, for a mortality rate of 25%. Three of the deaths were in patients with MIGCS scores below 6. One patient died of shunt infection. Most of the surviving patients improved to better than mild disability (Fig. 2). 592 Fig. 3A–D Case 1. A This 5-month-old male baby presented with a small amount of acute subdural hematoma on the right frontal area. B A follow-up CT scan taken 2 weeks later revealed widening of subarachnoid space with disappearance of hematoma density. C The chronic subdural hematoma was diagnosed on the 68th day after trauma. D Subduro-peritoneal shunting was done Fig. 5A–D Case 3. A This 4-month-old male patient presented with a small amount of acute subdural hematoma. A CT scan taken 4 days later revealed disappearance of hematoma density. B On the 10th day burr hole drainage was done for the subdural hygroma, and C follow up 4 days later revealed widening of subarachnoid space. According to our previous experience of the delayed development of chronic subdural hematoma, we followed up the patient carefully with special concern about the late development of chronic subdural hematoma. D Follow-up CT scan taken 3 months after injury revealed the chronic subdural hematoma Case histories Case 1 This 5-month-old male baby presented with left hemiparesis and generalized seizures, with an MIGCS score of 12 after falling down. An initial CT scan revealed a small amount of acute SDH in the right frontal area. The mental state and motor weakness improved gradually, and an early follow-up CT scan revealed the disappearance of hyperdense hematoma density and a widening of subarachnoid space. On the 68th day after trauma, a follow-up CT scan revealed chronic SDH with midline shifting although the patient’s condition was good with improved mental state and less pronounced motor weakness. A burr hole aspiration was performed, followed by continuous drainage for 5 days. However, a subduro-peritoneal shunt was needed thereafter because of recurrence. The patient made an excellent recovery without any neurological abnormality. (Fig. 3) Case 2 Fig. 4A–D Case 2. A This 4-month-old female baby presented with status epilepticus and a small amount of acute subdural hematoma. B An early follow-up CT scan revealed widening of subarachnoid space and diffuse low density of white matter and brain atrophy. C Chronic subdural hematoma was diagnosed on the 111th day after initial presentation. D Subduro-peritoneal shunting was done This 4-month-old baby girl presented with status epilepticus, left hemiparesis and MIGCS 8. Initial CT scan showed a small amount of acute SDH in the right frontal area. A CT scan 2 weeks later showed widening of the subarachnoid space and a diffuse low density of the white matter. During the follow-up, the patient’s consciousness recovered and her motor weakness improved. However, even though the patient’s mental state and her motor weakness continued to improve, a CT scan taken on day 111 showed a 593 chronic SDH. Burr hole trephination and continuous drainage of the hematoma failed. Subduro-peritoneal shunting was performed. The patient recovered with moderate disability (Fig. 4). Case 3 This 4-month-old male patient presented with seizure and an MIGCS score of 12 after a traffic accident. The initial CT scan showed an acute SDH and widening of the subarachnoid space. The volume of the hematoma was small, and the patient was managed conservatively. A follow-up CT scan taken 4 days later revealed disappearance of hematoma density. On the 10th day after injury, a subdural hygroma was drained through a burr hole. In view of our previous experience of delayed development of chronic SDH despite early improvement of neurological abnormality, we followed up the patient carefully, especially bearing in mind the possibility of later development of chronic SDH. A CT scan taken 3 months after the injury did indeed reveal chronic SDH. The patient did not look sick and had no neurological abnormality. Subduro-peritoneal shunting was done and had an excellent outcome with no neurological sequelae (Fig. 5). Discussion Pediatric head injury is a relatively common disease entity. However, the actual incidence of head injury below the age of 12 months is not known. A study by McCormick et al. [7] of 4,989 infants under 1 year old showed that 8.6% suffered injuries requiring medical treatment. About one sixth of these children were hospitalized, almost half of them because of head or neck injuries. It has been recognized that there are basic differences in nature between the tissue damage in craniocerebral trauma occurring in infants and that in older children and adults. As a hypothesis, it has been suggested that the relatively large size of an infant’s head compared with the rest of the body accounts for the preponderance of head injuries over trunk and extremity injuries in this age group [17]. The skull is more plastic in infancy and probably permits some movement of the brain within it without damage. The softer texture of the infant brain probably minimizes superficial contusions so that they are less severe than might be seen in adult brains. Epidural hematoma is relatively rare in infancy owing to the dural adherence at the level of the sutures, especially the coronal sutures, and the elasticity of the skull at this age. Rupture of a meningeal artery occurs less frequently in infants than in adults. It can develop without skull fracture. However, the volume of an epidural hematoma in an infant may be great. Hematomas in the subdural space in infants are the most frequent posttraumatic intracranial hematomas. Especially in infancy the trauma may be mild or remain unnoticed. Aoki et al. [2] divided infantile acute SDH into two groups. The first type is the fulminant type, in which the patient rapidly falls into a coma and which may be fatal. The other, mild, type causes only signs and symptoms of mild intracranial hypertension. The development of chronic SDH is caused by the enlargement of a small acute SDH. The SDHs probably become enlarged as a result of repeated bleeding of the fragile vessels of the neomembrane [10]. Chronic SDHs are seldom seen in older children, being much more common in the infant age group. Easy expansibility of the intracranial space owing to a soft consistency of the poorly myelinated cerebrum and pliancy of skull and sutures make the incidence high in infants. Specific traumatic events are sometimes go unrecognized or unreported. The relationship of the subdural or subarachnoid fluid collection to the chronic SDH is not clearly known. Mori et al. [13] reported a series of subarachnoid fluid collections complicated by SDHs. It is not clearly delineated what the nature of the subarachnoid fluid collections is and what role they have in the development of chronic SDH. Yamamoto et al. [18] reported 20 infantile cases with acute subdural hematoma and found subdural membrane formation in 18 out of 19 cases whose dura mater was examined. Miyagami et al. [12] reported 30 infantile cases with SDH shortly after head injury, 19 being caused by major head injuries, such as traffic accidents, and being regarded as acute SDH of adult type. In the other 11 infants the hematomas were caused by minor head injuries, and subdural membrane was identified in all of the 11 patients who were operated on. In our series, early follow-up CT scan showed widening of the subdural space and disappearance of hyperdense hematoma density. According to our experience, early radiological improvement of acute SDH should not exclude the development of chronic SDH in infancy. It is not known whether the patients who developed chronic SDH in our series had had subarachnoid space widening before the trauma. Also, this widening can be the subdural fluid collection after the absorption of the acute SDH, or isodense attenuation of CT density. MRI follow-up may be helpful to define it and predict the possibility of late development of the chronic SDH. Reports on the clinical features of infantile chronic SDH have been surprisingly rare [1, 14]. According to Parent’s pediatric chronic SDH series, macrocephaly, anorexia, lethargy, and seizures were common presenting symptoms [14]. Sometimes the symptoms in infancy are nonspecific and cannot be recognized by the parents without special concern. In our, parents did not complain of any worsening of the symptoms and the diagnosis were made by sequential follow-up CT scan. The treatment of chronic SDH is controversial. Ingraham and Matson [4] initially recommended craniotomy. The original theory was that the membranes that developed in response to the hematoma prevented normal growth and development of the brain by mechanical constriction [6]. At present, there is little support for the theory of brain damage resulting from the presence of membranes. Collins and Pucci [3] discovered that the mem- 594 branes, after the fluid had been shunted to the peritoneal cavity, progressively regressed in thickness, cellularity, and vascularity. Various methods advocated for treating chronic SDHs in infants have noted a remarkably constant frequency of developmental retardation, which indicates that the method of management probably contributes less to successful brain recovery and growth than other factors that cannot be defined [9]. Repeated subdural taps formerly provided the diagnosis and indicated what therapy might be applied. Since the development of CT scanning, however, the subdural tap has no longer been used as a diagnostic procedure. If repeated taps do not resolve the SDH, subduro-peritoneal shunting is usually warranted. Infection is the main complication of repeated subdural tapping and can even predispose to the development of a new SDH [13]. Burr hole drainage in infantile chronic SDH was not successful in our series. Subduro-peritoneal shunting is a good option for the treatment of infantile chronic SDH [11]. Our initial treatment policy for infantile chronic SDH is subduro-peritoneal shunting using a low-pressure valve. Whether or not an operation is indicated depends mainly on the radiological findings, and not on the clinical symptomatology. There are controversies over whether to remove the shunt after improvement. According to Rosenbluth et al. [16], drainage for about 6 weeks is sufficient in most cases. However, later removal may involve the risk of bleeding due to adhesion. Some authors do not make a point of recommending removal of the shunt, but its removal eliminates any chance of infection and other unlikely complications, such as migration or granuloma formation. We did not remove the shunts. References 1. Aoki N (1990) Chronic subdural hematoma in infancy. Clinical analysis of 30 cases in the CT era. J Neurosurg 73:201–205 2. 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