Fatal traffic accident associated to hypercapnic coma due to kyphoscoliosis: a case report

Introduction

Kyphoscoliosis (KS) is defined as a deformity of the spine involving lateral displacement (scoliosis) and anteroposterior angulation (kyphosis). The most common form of KS is idiopathic (present in 80% of cases), although it can also result from various conditions, including those of neuromuscular or traumatic origin. KS maybe associated with acute-on-chronic respiratory failure (ACRF) secondary to restrictive airway disease and reduced vital capacity and often requires some form of ventilatory support. Respiratory failure in patients with KS may result from chronic and slow deterioration of the physiological reserves or be aggravated by acute triggers such as infections, cor pulmonale and miss use of at-home non-invasive ventilation (NIV), among others (1-3).

The severity of KS is usually calculated by the angle formed by both lines of the convex primary curvature, defined as the Cobb angle. Although there is no clear consensus, scoliosis with a Cobb angle >40° is considered severe. Approximately 1 in 1,000 people have some form of KS and severe KS occurs in about 1 in 10,000 people (2-4).

It is generally accepted that with a spinal curvature of 80° or more the incidence of respiratory insufficiency may be as high as 50%. Also, a decline in pulmonary function may be greater in persons with more severe KS (2,5,6).

When severe KS is complicated by ACRF and cor pulmonale, both the immediate and long-term outlook are poor. These patients are often referred to the intensive care unit (ICU) for mechanical ventilatory support. Most deaths attributed to KS with ACRF are associated with hypoventilation and, ultimately, cardiorespiratory failure. ICU outcomes of KS patients are rarely reported in the literature (2,3,5,7).

We present the case of an older patient with severe KS that required ICU hospitalization due to a prolonged and inevitable deterioration of its chronic pulmonary condition without a clear trigger of ACRF, but with all the respiratory hallmark findings associated to this disease. We present this case in accordance with the CARE reporting checklist (available at https://jeccm.amegroups.com/article/view/10.21037/jeccm-24-7/rc).

Case presentation

A 72-year-old male was admitted to our ICU following a traffic accident. His vehicle experienced a frontal impact at low speed during deceleration. He was found in asystole in his car seat, with no signs of trauma, and was given cardiopulmonary resuscitation (CPR) for 15 minutes. He was then intubated and transported to our hospital after return of spontaneous circulation (ROSC).

Significant findings in his medical history include severe traumatic dorsolumbar KS (Cobb angle of 150°) since the age of 6 months, following an accidental fall (Figures 1,2). A severe chronic pulmonary restrictive and obstructive disease with a ventilatory status of forced vital capacity (FVC): 22% (1.18 L); forced expiratory volume in 1 second (FEV₁): 19%; Tiffenau index: 61%, and baseline arterial blood gases (FiO₂ 0.21) showing pH of 7.4; PaCO₂/PaO₂ of 57/52 mmHg; and HCO₃ of 35 mmol/L. He has required nocturnal NIV since the age of 51 years and its use had been progressively intensified in the last years. A control echocardiography (constrained due to a near impossible acoustic window secondary to the thoracic deformity) performed 2 months before the current admission only showed moderate aortic regurgitation and a shortened pulmonary acceleration time, without clear signs of pulmonary hypertension or other significant alterations.

Figure 1 Outpatient control PA thoracic X-ray (7 months prior to admission) showing severe KS. PA, posteroanterior; KS, kyphoscoliosis.

Figure 2 Outpatient control lateral thoracic X-ray (7 months prior to admission) showing severe KS. KS, kyphoscoliosis.

He had several previous admissions to our hospital due to ACRF. Six months before this case report the patient required an almost identical ICU hospitalization necessitating both invasive and non-invasive mechanic ventilation: he was admitted following a traffic accident associated with hypercapnic coma, without a clear additional cause that would worsen the patient’s chronic deterioration.

Upon arrival at our hospital by emergency services, the patient’s initial examination revealed hemodynamic and respiratory stability, a Glasgow Coma Scale (GCS) of 3 without pupillary alterations and no external injuries. However, the thoracic cage was significantly deformed on account of KS, which was evident on the chest X-ray (Figure 3). Echocardiography at admission (limited by a poor acoustic window) did not show any significant alterations.

Figure 3 AP thoracic X-ray showing severe KS with a measured Cobb angle of 150°. Vertebrae are highlighted with a dotted line. AP, anteroposterior; KS, kyphoscoliosis.

The body computed tomography (CT) revealed KS with thoracopulmonary collapse (Figures 4,5) and vertebral horizontalization (Figure 6), a trunk of the pulmonary artery of increased caliber (40 mm) and increased artery/bronchus ratio, suggesting pulmonary hypertension. CT images also showed a sternal fracture with anterior mediastinal hematoma and rib fractures associated with CPR, no other injuries were observed.

Figure 4 Anterior coronal CT scan showing severe KS and pulmonary collapse. CT, computed tomography; KS, kyphoscoliosis.

Figure 5 Posterior coronal CT scan showing severe KS and pulmonary collapse. CT, computed tomography; KS, kyphoscoliosis.

Figure 6 Axial CT showing total horizontalization of at least 4 vertebrae as well as an enlarged pulmonary artery trunk consistent with pulmonary hypertension. CT, computed tomography.

Brain and cervical CT scans at admission were deemed normal, showing no acute or hemorrhagic lesions.

After initiating mechanical ventilation in the ICU, the first arterial blood gas analysis (FiO₂ 0.5) showed pH 7.26; PaCO₂/PaO₂ 77/69 mmHg; HCO₃ 34 mmol/L. No clinical signs (family members do not recall worsening of his disease) or complementary tests suggested an intercurrent infection (blood analysis and nasal swab samples were negative) or other common acute triggers for his respiratory failure.

During the first 24 hours of admission the patient exhibited acute post-hypoxic facial and distal extremities myoclonus. Because of the poor prognosis associated to potential catastrophic brain damage, a full neurological screening was performed.

All tests indicated irreversible brain damage; neuron specific enolase (NSE) measurement on the fourth day of hospitalization was 390 µg/L (normal range, 0.0–16 µg/L). Negative 20 somatosensory evoked potentials (N20 SSEPs) were absent, and a brain magnetic resonance imaging (MRI) performed on the fourth day of hospitalization revealed necrotic lesions and gliosis associated to moderate to severe chronic hypoxia (Figure 7). On day 5 of hospitalization, on account of irreversible catastrophic brain damage, the patient died.

Figure 7 MRI FLAIR showing periventricular demyelination/gliosis and multiple necrotic lesions compatible with moderate to severe chronic ischemia. MRI, magnetic resonance imaging; FLAIR, fluid-attenuated inversion recovery.

All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient’s family for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Discussion

KS is characterized by a restrictive ventilatory disease with diminished chest wall compliance, thoracic muscle weakness, increased dead space ventilation, and impaired respiratory mechanics, leading to progressive hypoventilation, hypercapnia, and chronic respiratory failure. The deformity also causes an abnormal distribution of inspired air, with consequent atelectasis and ventilation-perfusion mismatching (3,5-8).

The respiratory drive is intrinsically normal in KS, but the mechanical abnormalities prevent it from being translated into a normal degree of lung inflation and deflation. Patients may exhibit blunted ventilatory chemosensitivity and suffer from pulmonary hypertension that develops as a result of chronic hypoxic pulmonary vasoconstriction (1,3,5,8).

Studies show an inverse correlation between lung volume and spinal curvature. Patients with a forced vital capacity less than 1.5 L, scoliosis developing before the age of 8 years and a high thoracic curve are at risk of developing respiratory failure, usually in the fourth or fifth decade (5,8).

Likewise, in patients with a spinal curvature of 80° or more, the incidence of respiratory insufficiency may be as high as 50%. However, the use of the degree of curvature and the severity of respiratory failure relation is controversial. There have been no controlled studies with survival as an endpoint in chronic respiratory failure due to chest wall disorders, but in uncontrolled studies these patients exhibit a broad spectrum of cardiorespiratory disfunction, ranging from life-threatening ACRF and cor pulmonale with premature death (median survival of one year after ACRF) to clinically insignificant disease with 1-year survival of 90% and 5-year survival of 80% (3,5,7,8).

Patients with severe KS and ACRF are frequently transferred to the ICU for mechanical ventilatory support. However, there is currently a lack of reports detailing the specific reasons why KS patients with ACRF necessitate ICU admission and mechanical ventilation. Furthermore, both ICU management and long-term post-ICU outcomes are scarcely documented in these patients (2,7).

As we described, our case illustrates typical findings of chronic and severe KS with risk factors associated with ACRF: a dorsolumbar KS with a Cobb angle of 150° resulting from a traumatic injury at the age of 6 months, a significant decrease in forced vital capacity (1.18 L), chronic mixed restrictive and obstructive pulmonary disease (FVC: 22%; FEV₁: 19%; Tiffenau index: 61%) with baseline hypoxemic and hypercapnic arterial gases (PaCO₂/PaO₂ 77/69 mmHg), use of NIV for increased periods of time, and previous hospital and ICU admissions due to ACRF (the previous hospitalization, 6 months before the present case, being of particularly similar circumstances).

Most ACRF episodes in patients with KS are precipitated by acute triggers such as infection or decompensated cor pulmonale (7). However, in our patient, respiratory failure appears to occur as a gradual but fatal deterioration of physiological reserves with no identifiable trigger. Furthermore, clinical findings in this patient demonstrate the chronic progression of the disease, with signs of pulmonary hypertension and chronic hypoxemic brain lesions.

Conclusions

The presented case exemplifies the complex interplay between severe KS and ACRF in a patient that required ICU hospitalization. KS often leads to restrictive ventilatory disease and reduced lung function, predisposing individuals to respiratory complications. The severity of KS, assessed by the Cobb angle, correlates with the risk of respiratory insufficiency, with higher angles associated with increased morbidity, nonetheless the angle of the deformity has yet to be studied as a prognostic/risk factor in case of ICU hospitalization.

Despite the recognition of KS as a significant risk factor for ACRF, there remains a paucity of literature addressing the specific factors driving ICU admission and mechanical ventilation in these patients. Additionally, long-term outcomes post-ICU discharge are poorly documented, highlighting a gap in our understanding of the disease trajectory and optimal management strategies.

Our case underscores the insidious nature of respiratory failure in KS, characterized by the absence of discernible triggers and a progressive decline in physiological reserves culminating in fatal outcomes. Ultimately, this case emphasizes the importance for healthcare providers to recognize and study KS as a potential independent risk and prognostic factor for patients admitted to the ICU.

Acknowledgments

Funding: None.

Footnote

Reporting Checklist: The authors have completed the CARE reporting checklist. Available at https://jeccm.amegroups.com/article/view/10.21037/jeccm-24-7/rc

Peer Review File: Available at https://jeccm.amegroups.com/article/view/10.21037/jeccm-24-7/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jeccm.amegroups.com/article/view/10.21037/jeccm-24-7/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. All procedures performed in this study were in accordance with the ethical standards of the institutional and/or national research committee(s) and with the Helsinki Declaration (as revised in 2013). Written informed consent was obtained from the patient’s family for publication of this case report and accompanying images. A copy of the written consent is available for review by the editorial office of this journal.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Dunford M, Donoghue J, Power G, et al. Managing ventilatory insufficiency and failure in a patient with kyphoscoliosis: a case study. Aust Crit Care 2001;14:165-9. [Crossref] [PubMed]
2. Conti G, Rocco M, Antonelli M, et al. Respiratory system mechanics in the early phase of acute respiratory failure due to severe kyphoscoliosis. Intensive Care Med 1997;23:539-44. [Crossref] [PubMed]
3. Masa JF, Kryger MH. Restrictive Lung Disorders. In: Principles and Practices of Sleep Medicine. 5th edition. Elsevier; 2011:1308-17.
4. Horng MH, Kuok CP, Fu MJ, et al. Cobb Angle Measurement of Spine from X-Ray Images Using Convolutional Neural Network. Comput Math Methods Med 2019;2019:6357171. [Crossref] [PubMed]
5. Libby DM, Briscoe WA, Boyce B, et al. Acute respiratory failure in scoliosis or kyphosis: prolonged survival and treatment. Am J Med 1982;73:532-8. [Crossref] [PubMed]
6. Lorbergs AL, O'Connor GT, Zhou Y, et al. Severity of Kyphosis and Decline in Lung Function: The Framingham Study. J Gerontol A Biol Sci Med Sci 2017;72:689-94. [PubMed]
7. Adıgüzel N, Karakurt Z, Güngör G, et al. Management of kyphoscoliosis patients with respiratory failure in the intensive care unit and during long term follow up. Multidiscip Respir Med 2012;7:30. [Crossref] [PubMed]
8. Shneerson JM, Simonds AK. Noninvasive ventilation for chest wall and neuromuscular disorders. Eur Respir J 2002;20:480-7. [Crossref] [PubMed]