Fetal gunshot brain injury leading to late postnatal hydrocephalus

Abbreviations

1 Case report

A pregnant mother presented to emergency room at 38 weeks gestation after sustaining a gunshot injury to her abdomen when she was caught in crossfire. Emergent cesarean section was done and a male infant was delivered. He was vigorous at birth and his initial exam was notable for a 1×2 cm laceration on the scalp in the area of anterior fontanelle. CT scan of the head showed a bullet in the inferior aspect of the right temporal lobe (Fig. 1). Other head imaging findings included a small hemorrhage in the region of the right basal ganglia and inferior aspect of the right temporal lobe, an intraventricular hemorrhage (IVH) in the 3rd ventricle while the lateral ventricles were normal in size and the 4th ventricle not visualized due to streak artifact, and diffuse cerebral edema. EEG revealed epileptiform abnormalities in the right temporal region.

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Fig.1

Initial scout film on CT scan showing the bullet location in the right cerebral hemisphere.

Neurosurgery deferred surgical intervention as it would increase the risk of further brain injury. A decision was made to remove the bullet at one year of age. The initial goal was to minimize secondary injury to the rest of the cerebral parenchyma. Cerebral hemostasis was achieved by maintaining mean arterial pressure more than 40 mm Hg. He remained remarkably stable except for intermittent non-focal seizures, which were controlled with phenobarbital. He was discharged home on day 20 of life on full oral feeds and phenobarbital.

Cerebral ultrasounds were performed daily. On day 6 of life, the ultrasound showed increase ventricular dilation, with the right side greater than the left, and a porencephalic cyst on the right parietal region (Fig. 2). At 5 weeks of age, cerebral ultrasound showed significant hydrocephalus and porencephaly, which prompted readmission for VP shunt placement (Fig. 3). During the surgery the neurosurgeon was unable to remove the bullet and only a right-sided VP shunt was placed.

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Fig.2

Cranial US showing ventricular dilation and porencephalic cyst on the right parietal region.

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Fig.3

At 5 weeks follow-up cerebral US showed progressive ventriculomegaly and enlarging porencephalic cyst.

At 13 months of age he was readmitted for VP shunt revision and a second attempt at removal of the bullet. A right occipital craniotomy was performed, which included a small corticectomy with microdissection. The bullet was successfully excised. He developed intraoperative bleeding into the transverse sinus and required shunt revision 2 days later. He continued to have seizure disorder and developed left sided hemiparesis.

Firearm violence contributes substantially each year to premature deaths, illness, and disability in the United States. Examination of CDC data from 2010–2012 revealed that more than 32,000 people died each year from firearm related injury in the United States [1]. Pregnant women and their fetus have not been exempt from the adverse effects of gun violence. Multiple reviews have found that significant trauma complicates about 5–10% of pregnancies, and penetrating trauma accounts for 10% of these injuries [2, 3]. Gunshot wounds to the abdomen is the predominant type of penetrating trauma to the pregnant mother [4, 5]. In one retrospective study, gunshot wounds were found to account for 70% of the penetrating trauma seen in pregnant women [4]. Maternal mortality due to penetrating trauma was around 7–9%, while fetal mortality was around 73%. The huge discrepancy in mortality rates between mother and fetus is explained by the fact that in the second half of pregnancies, the vast majority of penetrating injuries to the abdomen are associated with uterine injury. As the gravid uterus grows larger, it acts to shield maternal abdominal viscera and also diminish the velocity of the missile and its ability to penetrate other organs [6]. Thus a penetrating injury is more likely to impact the gravid uterus, putting the fetus more at risk than the mother.

Cases of newborns with gunshot wounds are rare, and cases of newborns with gunshot wounds to the head are even rarer. In a series of only 30 patients, Coughlan et al., [8] reported that the youngest child hospitalized for a gunshot wound to the head was seven days of age. Our literature review found only one published case of successful survival of the fetus after penetrating trauma to the head in utero since 2006. In that instance, Muzumdar et al., [8] described a fetus who acquired a BB pellet to the head, found to have meningitis and multiple brain abscess following birth, and survived with significant developmental delay. Survival of the fetus with intracranial injury after a penetrating trauma is dependent on many factors including the type of injury, degree of intrauterine asphyxia, maturity of the fetus, and the postnatal course [8]. In our case, the infant was fortunate to have been delivered at 38 weeks and in stable condition with only a minor laceration on the anterior fontanel seen on exam. This is unique given the extent of intracranial injury later found on imaging.

Intracerebral hemorrhage (ICH) and intraventricular hemorrhages (IVH) can cause immediate and delay injury to the brain. The mechanisms of injury include ischemia, hypoxia, white matter injury, periventricular leukomalacia, free radical damage, release of inflammatory cytokines and free radicals to the CSF, gliosis and decreased cerebral perfusion pressure [9]. These effects may culminate and lead to cerebral palsy, seizures, cognitive deficits, hydrocephalus, or death. It is well known that ICH and IVH can lead to hydrocephalus. The prevailing theory explaining acute IVH-induced hydrocephalus is that blood clots and subsequent inflammation and fibrosis obstruct the CSF drainage pathway, typically in the cerebral aqueducts or the fourth ventricular outlets [9]. In ICH, it is generally accepted that inflammation and fibrosis impede fluent CSF flow outward to the sinus, terminally from the arachnoid granulations [10]. In our case, the infant’s hydrocephalus was most likely from obstruction due to both his IVC and ICH. An infectious etiology of his hydrocephalus was also considered, because of the risk of intracranial infections after penetrating gunshot wounds to the head and inability to remove the foreign body immediately. However because our patient showed no signs or symptoms of infections, such as vital instabilities or findings on imaging, and had appropriate antibiotic prophylaxis, infection was not suspected.

Penetrating head injuries constitute only a small part of the total number of traumatic head injuries but belong to the class of most severe traumatic brain injuries. A wide variety of damage can be seen. Head CT and X-ray are useful to demonstrate the extent of the damage. Bi-hemispheric injuries, in which midline structures of the brain are crossed, are the most common patterns but are associated with poor outcomes [11]. As well, injuries with extensive bullet tracts and those that involve the brainstem are also associated with poor outcomes. Other predictive factors of high morbidity and mortality in patients with gunshot wounds to the head include cardiorespiratory instability on admission, coagulation abnormalities, bilateral fixed and dilated pupils, trans-ventricular or bi-hemispheric central type trajectory, and midline shift of brain structures [12, 18]. Surgery should be performed as soon as possible with debridement and proper wound closure. However, if a retained bullet is in an inaccessible location, it should be left undisturbed if removal is likely to be accompanied by more brain damage or neurological deficits [14, 15]. Complications of surgery include CSF leak, diabetes insipidus, seizures, intracerebral abscess and hydrocephalus [7].

Craniocerebral gunshot injuries in children are often associated with long-term sequelae. Permanent neurological deficits and cerebral palsy can result depending on the extent and area of the brain that is injured. Post-traumatic epilepsy is seen with higher prevalence in those with more severe brain injury [16]. In terms of development, Ewing-Cobbs et al., [17] found that gunshot wound patients were significantly more impaired than patients with severe closed-head injuries. Children who were younger than five years of age at the time of injury had more intellectual impairment than children who sustained craniocerebral gunshot injuries at a later age. The interaction of key variables, such as the site and laterality of the lesion, the functional maturation of brain tissue, the age at the time of insult, and environmental factors converge to influence long-term neurodevelopmental outcome [18]. Our neurosurgery team felt that the infant did have a good prognosis for survival given that he had no large intracranial hemorrhage or transventricular breach. There was some obvious right hemispheric injury, but because he was neurologically underdeveloped, it was possible that the baby may be able to lateralize function to the left hemisphere over time.

3 Conclusion

As long as gun violence is still prevalent in our society, pregnant mothers and their fetuses will continue to be at risk for penetrating gunshot injuries during pregnancy. Craniocerebral gunshot wounds in the fetus tend to have fatal outcomes. In our case, the newborn had multiple protective factors that contributed to his survival, including fetal maturity, cerebral involvement that was not associated with a poor prognosis, and access to a multidisciplinary team with close follow-up care.

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