Neurogenic Shock Secondary to Atlantoaxial Subluxation in an Infant With Chondrodysplasia Punctata

A 30‐year‐old gravida 2, para 1 woman with no significant family history was hospitalized for 2 months during early pregnancy because of severe hyperemesis gravidarum. No fetal abnormalities were noted during gestation. A female infant was born via spontaneous delivery at 39 weeks and 5 days' gestation with a birth weight of 2522 g (standard deviation [SD], −1.6) and a length of 42.2 cm (SD, −3.8). Delivery progressed smoothly without any rotational abnormalities; however, the newborn exhibited respiratory insufficiency and hypotonia at birth. A conventional direct laryngoscope was successfully placed in the standard position during the second intubation attempt. Apgar scores were 2 and 3 at 1 min and 5 min, respectively. Following stabilization, the newborn was transferred to our neonatal intensive care unit. The infant presented with thoracic hypoplasia and a markedly depressed nasal bridge (Figure 1a). On postnatal day 30, chondrodysplasia punctata (CDP) was diagnosed based on radiographic findings of punctate calcifications around the spine and proximal femoral epiphyses (Figure 1b). Hypotonia and weak spontaneous respiration did not improve; however, no abnormality was detected during head ultrasonography.

FIGURE 1.

(a) Photograph of the patient at 2 months of age showing a markedly depressed nasal bridge. (b) Plain radiography image showing punctate calcifications around the spine and proximal femoral epiphyses (arrows). (c) Postoperative computed tomography image on postoperative day 8 revealing C1–2 stenosis caused by atlantoaxial subluxation in the neutral position and the C1 markedly displaced anteriorly. (d) Image obtained during T2‐weighted magnetic resonance imaging in the extension position on postoperative day 29 revealing spinal cord compression at C1–2 (arrow) with an intramedullary high‐intensity signal at C3 (arrowhead) suggesting spinal cord injury.

On postnatal day 80, tracheostomy was performed because of extubation difficulty. On postoperative day (POD) 5, fever, impaired consciousness, oliguria, hyperlactatemia, and recurrent intermittent bradycardia (heart rate range, 50–80 beats/min) developed. The patient showed little response to volume loading and steroid administration, and hypotension with approximately 40 mmHg systolic arterial pressure developed. However, the patient responded well to vasopressors, and systolic arterial pressure increased to 60–80 mmHg within a few hours. Fever and hypotension resolved within 2 days; however, visual tracking and social smile were lost. On POD 8, computed tomography revealed a diffuse low‐density cerebrum and C1–2 stenosis caused by atlantoaxial subluxation (Figure 1c). On POD 29, magnetic resonance imaging revealed spinal cord compression at C1–2 and spinal cord injury at C3 (Figure 1d) as well as findings consistent with severe hypoxic–ischemic encephalopathy (HIE). These imaging findings and the clinical course suggested that HIE was caused by cerebral ischemia resulting from hypotension attributable to neurogenic shock secondary to atlantoaxial subluxation. At > 1 year of age, the patient was bedridden because of severe psychomotor developmental delay and tetraparesis.

CDP comprises a group of disorders characterized by abnormal punctate calcifications in the cartilage observed on radiography and is classified based on genetics or etiology [1, 2]. In this case, genetic and chromosomal tests did not identify any specific cause, and blood tests ruled out inborn errors of metabolism. Because of the mother's history of severe hyperemesis gravidarum during early pregnancy, maternal vitamin K deficiency was considered the cause. CDP associated with maternal vitamin K deficiency can resemble X‐linked recessive CDP‐1 [3], which is a genetic classification.

Severe cervical spine lesions are observed in approximately 20% of patients with X‐linked recessive CDP‐1 [4]. Persistent respiratory insufficiency and hypotonia observed from birth in our patient may have been manifestations of spinal shock resulting from prenatal atlantoaxial subluxation and cervical spinal stenosis. Additionally, atlantoaxial subluxation was likely aggravated by a combination of spontaneous delivery, endotracheal intubation, postnatal positional changes, and tracheostomy. In particular, during tracheostomy, adequate cervical spine protection and immobilization to obtain sufficient surgical exposure may not have been maintained, resulting in excessive neck extension. Because hypotension developed following tracheostomy, the cervical spinal cord injury was considered more likely associated with tracheostomy positioning than with the initial endotracheal intubation or other factors.

We attributed postoperative hypotension to neurogenic shock in our patient. Neurogenic shock, which involves disruption of sympathetic outflow and subsequent parasympathetic dominance that leads to hypotension and bradycardia, generally occurs following high‐level spinal cord injury. Several case reports describe cervical spinal cord injury at birth [4, 5]; however, to our knowledge, progression to neurogenic shock in patients with CDP has not been reported. Infection and other types of shock—including cardiogenic, hypovolemic, and obstructive shock—were ruled out based on laboratory and imaging findings. We consider that prolonged neurogenic shock particularly that prior to vasopressor administration, led to decreased cerebral perfusion and eventual HIE development. If spinal shock had also occurred at that time, then neurogenic shock would have been more likely to coexist; however, determining whether spinal shock also occurred was difficult because the patient exhibited hypotonia and tetraparesis since birth.

CDP should be considered when fetal ultrasonography reveals characteristic features such as a depressed nasal bridge or punctate calcifications in the long bone epiphyses, which can be recognizable in the second trimester [2, 5]. Fetal magnetic resonance imaging can enable spinal canal evaluations to facilitate decision‐making regarding cesarean delivery to protect the fetal cervical spine [5]. When CDP is suspected postnatally, early evaluation of the spinal canal, restriction of cervical spine motion by careful patient handling and cervical collar use, and decompressive surgery (as needed) are crucial. Additionally, during surgical procedures such as tracheostomy, adequate monitoring and avoidance of excessive neck extension are essential. This case highlights the importance of careful management of CDP, particularly in the cervical spine, throughout the fetal and postnatal periods.

Author Contributions

S.S., H. Adachi, and A.K. treated the patient; S.S. prepared the first draft; H. Adachi supervised the preparation of the manuscript and critically reviewed it for important intellectual content; A.K. and H. Arai critically reviewed the manuscript. All authors have read and approved the final manuscript.

Funding

The authors have nothing to report.

Consent

Informed consent was obtained from the patient's parents for the publication of this report.

Conflicts of Interest

The authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available from the corresponding author upon reasonable request.