Bilateral acetabular fractures induced by an epileptic seizure in a paediatric patient: a unique case and its management

Abstract

Bilateral acetabular fractures following epileptic seizures are a rare but known occurrence in adults, with an 18.5% mortality rate. These fractures occurring post epileptic seizures have not been previously documented in children. We report a case of a 13-year-old boy who presented to hospital via ambulance following two violent generalised tonic–clonic seizures in a postictal state, metabolically acidotic and a low haemoglobin. Acute abdomen was suspected and the patient underwent a CT scan which showed bilateral acetabular fractures with central dislocations of both femoral heads and free fluid in the abdomen. The patient underwent initial damage control intervention with insertion of bilateral distal femur skeletal traction. Definitive fixation of the acetabular fractures occurred 1 week later with an open reduction internal fixation with novel supra-pectineal plates using a Pfannenstiel incision. We use this report to increase awareness of significant pelvic injuries in paediatric patients post epileptic seizures.

Background

Epilepsy is a common condition affecting 0.5%–2% of the population, characterised by the incidence of two or more unprovoked seizures.¹ A spectrum of injuries resulting from epileptic seizures have been documented in literature, including submersion injuries, motor vehicle accidents, burns and head injuries.¹ Acetabular fracture dislocations do not typically result from epileptic seizures, and are usually associated with external, high-energy trauma, such as high-speed road traffic accidents and direct impact from falls.² Nonetheless, at least 26 cases of acetabular fractures resulting from epileptic seizures have been described in literature since 1970s in adults, diagnosis often being delayed due to a low index of suspicion in the absence of high-impact trauma.² On the other hand, there have been zero incidents reported in the paediatric population.

Acetabular fractures are associated with considerable morbidity and mortality as a result of massive blood loss, with surgical fixation being the standard treatment in displaced fractures.²

Here we report a case of bilateral acetabular fractures with central dislocation of both femoral heads in a child following an epileptic seizure. We also describe the management of these fractures with bilateral open reduction internal fixation with supra-pectineal plates using a Pfannenstiel incision with separate 7 cm iliac crest incisions (using a modified stoppa/lateral window approach).

Case presentation

The patient was a 13-year-old boy with a medical history of autistic spectrum disorder (attended mainstream school), chromosome 9q duplication with two genes deleted (thought to be benign copy variation) and focal epilepsy, normally on carbamazepine 300 mg two times per day.

On the evening prior to admission he had a violent generalised tonic–clonic seizure which self-terminated. He complained of bilateral hip pain afterwards but subsequently went to sleep and had another seizure the following morning, after which he was transferred by ambulance to a local district general hospital. On arrival he was noted to be metabolically acidotic with a pH of 7.1, unable to walk and complaining of abdominal pain. The patient was intubated and ventilated and fluid resuscitated with 2 L of crystalloids; a surgical review and CT imaging of the abdomen was conducted querying an acute abdomen. The CT image demonstrated a rare abnormality—bilateral acetabular fractures with central dislocations of both femoral heads and free fluid in the abdomen (figure 1A, B, C).

Figure 1.

(A) Axial CT slice demonstrating bilateral acetabular fracture dislocations. (B) Three-dimensional reconstruction showing bilateral acetabular fracture dislocations. (C) Three-Dimensional reconstruction of pelvis demonstrating the posterior column on this patient with acetabular fracture (left).

The child was subsequently transferred to a major trauma centre, where he was haemodynamically unstable on arrival with a sinus tachycardia between 140–160 beats/min and a blood pressure of 80/40. Haemoglobin was 90 g/L and lactate was 2.6; a major haemorrhage protocol was initiated and the patient was resuscitated with two units of red blood cells and had 1 g of tranexamic acid. A CT angiogram showed the above-mentioned acetabular fractures, an extraperitoneal pelvic haematoma and no active bleeding; haemodynamic stability was achieved post blood transfusion.

The patient was taken to theatre for insertion of bilateral distal femur skeletal traction pins. Bilateral reduction of the central dislocations was achieved under intraoperative fluoroscopy. Digital rectal examination, which demonstrated no palpable fracture fragments and no blood per rectum confirmed a closed fracture. The patient was admitted to paediatric intensive care unit postoperatively and was extubated 4 days later and stepped down to the ward.

On day 2 postoperatively the patient started spiking fevers at 38.3°C and had a rise in creatine kinase to 80 000, from 7000 on admission with an associated acute kidney injury. This was managed with intravenous fluids and empirical antibiotics; no infection source was found on repeated cultures and imaging. He continued to spike fevers and antibiotics were escalated to a complex regimen of Tazocin, vancomycin and gentamicin as per microbiology advice—on day 7 of admission a stool sample came back as Clostridium difficile toxin positive. The antimicrobial regimen was rationalised further to treat C. difficile colitis and the patient completed 8 days of Tazocin, 2 weeks of high-dose oral vancomycin and 10 days of intravenous metronidazole.

On day 7 of admission the child was taken back to theatre for bilateral acetabular open reduction internal fixation. Pfannenstiel incision with separate 7 cm iliac crest incisions were made, using a modified stoppa/lateral window approach. On the left side a Starr frame was used to pull the femoral head out, then a five-hole buttress plate, 10-hole anterior column plate and 4.5 posterior column screw were used to fix the acetabulum. On the right side, a Stryker supra-pectineal plate was used to achieve fixation. A routine postoperative CT pelvis demonstrated no immediate complications. A postoperative X-ray is shown in figure 2.

Figure 2.

Pelvic X-ray post bilateral acetabular open reduction internal fixation.

Investigations

1. CT trauma series.

2. Postoperative CT.

Differential diagnosis

• Bilateral native hip dislocations.

• Bilateral acetabular fractures.

Outcome and follow-up

The child’s postoperative course was further complicated by ileus, which required decompression with a flatus tube and a nasogastric tube, 2 days postoperatively.

Profound vitamin D deficiency was also found with a vitamin D level of less than 10 and treated with vitamin D replacement.

A neurology opinion was sought with regards to epilepsy and arrangements were made for an electroencephalogram and for an outpatient review in view of recent increase in seizure frequency.

The child continued improving clinically and was discharged to a local hospital 3 weeks postoperatively for ongoing rehabilitation.

Weight bearing restrictions were placed for 6 weeks postoperatively with wheelchair mobilisation only. Weight bearing on left lower limb was allowed for transfers only.

The patient was reviewed in clinic at the 6-week mark at which point he was allowed to fully weight-bear on both sides, however it was noted that he did develop bilateral fixed-flexion knee contractures. These were treated conservatively with physiotherapy.

Following a further review in clinic 6 months later, the right knee contracture resolved and the left had a fixed flexion contraction of 50°. At this point he was mobilising with a zimmer frame and continues having physiotherapy in view of his improving flexion deformity.

Furthermore he has since been seen in a neurology clinic and has remained seizure free following his hospital stay.

Following admission a safeguarding alert was put out due to concerns about fractures and whether they were consistent with injuries post an epileptic seizure. The case was discussed thoroughly. As signs of any outside force were not identified, the fractures were symmetrical and the sacroiliac joints were intact, the injuries were in-keeping with being post an epileptic seizure. A strategy meeting was held and safeguarding was subsequently closed a few days post admission.

Discussion

Patients with epilepsy have an increased risk of sustaining a fracture compared with the general population, with up to 3% of people with epilepsy acquiring injuries as a result of epileptic seizures.^{3 4} Nilsson et al reported that the high incidence of fractures is more likely to be explained by the high incidence of bone disease among epileptics, rather than seizure activity itself.⁵ He reported a greater incidence of osteoporosis, osteomalacia and hyperparathyroidism as a result of treatment with antiepileptic drugs among patients with epilepsy, with bone biopsy samples revealing an increased amount of osteoid and increased resorptive activity of osteoclasts among these patients, compared with controls.⁵ Conversely, Vestergaard et al reported that the increase in fractures among patients with epilepsy was related directly to epileptic seizures, rather than biochemical incompetence.⁶ He described the bone mineral density deficit in epilepsy patients as too small to explain the difference in fracture risk, attributing the link to seizures themselves.⁶ In the absence of a definitively known underlying mechanism, we do know that antiepileptic drugs themselves have been found to be an independent risk factor associated with fractures, supporting the reduced bone density hypothesis.⁷ Furthermore, looking beyond the causes associated with epilepsy or its treatment directly, other factors such as use of long-acting benzodiazepines, high caffeine intake and previous fractures are some of the factors associated with increased fracture risk.⁷ It is also important to mention that the sedative effects associated with antiepileptic drugs can increase the risk of falls, further increasing the risk of a fracture.

It is crucial to understand the aetiology of the fractures described in this case. The iliopsoas muscle arises from the iliac fossa and lumbar spine and then inserts onto the lesser trochanter of the femur. Severe contraction from a tonic–clonic seizure pulls on the femoral head, medialising through the tri-radiate cartilage of the acetabulum and into the pelvis. Tri-radiate cartilage closes between 12–14 years of age and thus it is relatively weak in children. This repeated impact on an already weak point can cause a fracture to occur.

It is useful to think of fractures related to seizures in terms of their aetiology, which can be divided into direct and indirect (table 1). Gill et al described direct fractures as more likely to occur where large muscles groups contract together, commonly found in proximal upper and lower limbs and in the thorax.⁸ Indirect fractures meanwhile are more commonly found in the face and distal limbs, which are more susceptible to trauma.⁸ This classification can be useful when thinking about the mechanism of injury in patients, where there is a history of epilepsy.

Table 1.

Aetiology of fractures related to seizures

Direct	Due to action of powerful tonic–clonic muscle contractions, overcoming bone strength
Indirect	Due to trauma: (A) Loss of voluntary motor function (eg, fall from standing) (B) Flailing limb striking a solid object

When considering children, literature is sparse when it comes to reporting fractures after ictal activity. There are isolated case reports of non-traumatic injuries, including one describing a left trans-epiphyseal fracture of the femur in a 7-month-old child post a generalised tonic–clonic seizure.⁹ When thinking about the factors that can influence the risk of fractures and reduce risk, Drezner et al recommended that all patients initiated on an anticonvulsant should be commenced on prophylactic vitamin D supplementation.¹⁰ Furthermore, calcium intake of at least 600–1000 mg/day should be ensured.¹⁰ In a patient with a known bone density disorder however, higher vitamin D doses and in some cases Bisphosphonates should be considered.¹⁰

In terms of acetabular fracture fixation, a recently developed supra-pectineal plate was used in our case for fixing the anterior column with quadrilateral surface disruption for the right acetabulum. This was developed to prevent medial displacement of the femoral head post fixation and demonstrated no intra-articular screw placement in a retrospective study involving 30 plates.¹¹

In conclusion, central acetabular fracture dislocation is an uncommon but known complication post epileptic seizures in adults. Due to the significant morbidity and 18.5% mortality associated with this condition, a high index of suspicion and active screening for this complication is advised on presentation, in both adults and children.² Our report describes a case of bilateral acetabular fracture dislocations in a child and successful management by surgical fixation involving the use of a supra-pectineal plate. We present this case to increase awareness of significant pelvic injuries in paediatric patients post epileptic seizures.

Learning points.

• Bilateral acetabular fractures need to be a differential diagnosis in children presenting with hip and abdominal pain following a seizure. A high index of suspicion is important due to high morbidity and mortality.

• Various factors can combine together to cause acetabular fractures in children with epilepsy—the use of antiepileptic drugs which present an independent risk factor for a fracture, a weak tri-radiate cartilage and the mechanical action during a seizure.

• Bone health is crucial for children and adults with epilepsy to avoid such fractures. It is vital to screen patients to check vitamin D levels and for supplementation to be offered.