Acute respiratory failure due to unilateral dorsolateral bulbar infarction

Case report: Central alveolar hypoventilation in a survivor of cardiopulmonary arrest

Introduction

Ondine's curse is a rare respiratory disorder that is characterized by central alveolar hypoventilation (CAH) during sleep. It is most commonly congenital. However, it can also be acquired very rarely. Herein, we report a young survivor who developed CAH following cardiopulmonary arrest.

Case presentation

A 35-year-old man was admitted to the Intensive Care Unit following unwitnessed cardiopulmonary arrest. Following resuscitative interventions, he remained comatose. Early diagnostic testing showed elevated neuronal specific enolase (28.7 ng/ml), absent cortical responses on evoked potential testing and MRI evidence of restricted diffusion in the cerebellum, hippocampi, juxtacortical white matter, superior cerebellar peduncles, dorsal pons, dorsolateral medulla, and upper cervical spinal cord. Ten days following admission, the patient remained comatose and underwent tracheostomy. He subsequently began to emerge from coma but had persistent unexplained hypotension and bradypnea necessitating ongoing vasopressor and respiratory support. Repeat MRI on hospital day 40 revealed residual FLAIR hyperintensities in the medulla within the nucleus tractus solitarius (NTS). After being discharged to long-term acute care facility, he was successfully liberated from mechanical ventilation 70 days post arrest.

Conclusion

We report the first survivor of cardiopulmonary arrest who was complicated by CAH and hypotension with MRI verified ischemic injury to the bilateral NTS regions. Despite this injury, ventilator and vasopressor dependency resolved over a period of 10 weeks. Our case highlighted the essential functions of NTS in regulating the respiratory and cardiovascular systems.

Progression rates of medulla oblongata infarcts in clinical follow-up: A retrospective study

OBJECTIVE

To determine clinical progression rates in patients with medulla oblongata infarction (MOI).

MATERIALS AND METHODS

The data of patients diagnosed with MOI were analysed retrospectively. Dermographic characteristics of the patients; Age, gender, history and stroke etiology were evaluated. Radiological imagings were reviewed retrospectively. Intensive care unit (ICU) requirement, number of intubation days, failed extubation and death rates, good clinical outcome at discharge and 3 months [modified Rankin Scale (mRS 0-2)] and poor clinical outcome (mRS 3-6) rates were evaluated. In addition, the clinical results of patients with medial medullary infarction (MMI) and lateral medullary infarction (LMI) were compared.

RESULTS

33 patients were included in the study, 22 (66.7 %) were male. The mean age of the patients was 72.0 (43.0-85.0). The characteristics of the patients (dermographic features, comorbidities, clinical symptoms, infarct localization, etc.) were evaluated. The results of MMI and LMI patients were compared. The intubation rate was 4 (44.4 %) in the MME group, while it was 8 (33.3 %) in the LME group. There was no statistically significant difference between the two groups in terms of failed extubation, tracheostomy, hospitalization and mortality rates. However, while discharge mRS was statistically significant between the two groups, the mRS at 3 months was not statistically significant. Twelve (36.4 %) of all patients were intubated due to severe clinical progression. In the clinical follow-up, 6 (50.0 %) of the intubated patients died, 3rd month mRS of 6 (50.0 %) patients who survived was 5. In all patients 3-month good clinical outcome rate was % 48,5.

CONCLUSION

It should not be forgotten that life-threatening clinical progressions may develop at a considerable rate during the early treatment process of patients diagnosed with MOI.

Disordered breathing in severe cerebral illness - towards a conceptual framework

Despite potentially life-threatening symptoms of disordered breathing in severe cerebral illness, there are no clear recommendations on diagnostic and therapeutic strategies for these patients. To identify types of breathing disorders observed in severely neurological comprised patients, to direct further research on classification, pathophysiology, diagnosis and treatment for disordered breathing in cerebral disease. Data including polygraphy, transcutaneous capnometry, blood gas analysis and radiological examinations of patients with severe cerebral illness and disordered breathing admitted to the neurological intensive care were analyzed. Patients (15) presented with acquired central hypoventilation syndrome (ACHS), central bradypnea, central tachypnea, obstructive, mixed and central apneas and hypopneas, Cheyne Stokes respiration, ataxic (Biot's) breathing, cluster breathing and respiration alternans. Severe cerebral illness may result in an ACHS and in a variety of disorders of the respiratory rhythm. Two of these, abrupt switches between breathing patterns and respiration alternans, suggest the existence of a rhythmogenic respiratory network. Polygraphy, transcutaneous capnometry, blood gas analysis and MRI are promising tools for diagnosis and research alike.

Stroke and breathing

Stroke remains a leading cause of neurologic disability with wide ranging effects, including a variety of respiratory abnormalities. Stroke may influence the central control of the respiratory drive and breathing pattern, airway protection and maintenance, and the respiratory mechanics of inspiration and expiration. In the acute phase of stroke, the central control of breathing is affected by changes in consciousness, cerebral edema, and direct damage to brainstem respiratory centers, resulting in abnormalities in respiratory pattern and loss of airway protection. Common acute complications related to respiratory dysfunction include dysphagia, aspiration, and pneumonia. Respiratory control centers are located in the brainstem, and brainstem stroke causes specific patterns of respiratory dysfunction. Depending on the exact location and extent of stroke, respiratory failure may occur. While major respiratory abnormalities often improve over time, sleep-disordered breathing remains common in the subacute and chronic phases and worsens outcomes. Respiratory mechanics are impaired in hemiplegic or hemiparetic stroke, contributing to worse cardiopulmonary health in stroke survivors. Interventions to address the respiratory complications are under researched, and further investigation in this area is critical to improving outcomes among stroke survivors.

Clinical and Radiological Characteristics Associated with Respiratory Failure in Unilateral Lateral Medullary Infarction

BACKGROUND

The prognosis for unilateral lateral medullary infarction (ULMI) is generally good but may be aggravated by respiratory failure with fatal outcome. Respiratory failure has been reported in patients with severe bulbar dysfunction and large rostral medullary lesions, but its associated factors have not been systematically studied. We aimed to assess clinical and radiological characteristics associated with respiratory failure in patients with pure acute ULMI.

MATERIALS AND METHODS

Seventy-one patients (median age 55 years, 59 males) with MRI-confirmed acute pure ULMI were studied retrospectively. Clinical characteristics were assessed and bulbar symptoms were scored using a scale developed for this study. MRI lesions were classified into 4 groups based on their vertical extent (localized/extensive) and the involvement of the open and/or closed medulla. Clinical characteristics, bulbar scores and MRI lesion characteristics were compared between patients with and without respiratory failure.

RESULTS

Respiratory failure occurred in 8(11%) patients. All patients with respiratory failure were male (p = 0.336), had extensive lesions involving the open medulla (p = 0.061), progression of bulbar symptoms (p=0.002) and aspiration pneumonia (p < 0.001). Peak bulbar score (OR, 7.9 [95% CI, 2.3-160.0]; p < 0.001) and older age (OR, 1.2 [95%CI, 1.0-1.6]; p=0.006) were independently associated with respiratory failure.

CONCLUSIONS

Extensive damage involving the open/rostral medulla, clinically presenting with severe bulbar dysfunction, in conjunction with factors such as aspiration pneumonia and older age appears to be crucial for the development of respiratory failure in pure ULMI. Further prospective studies are needed to identify other potential risk factors, pathophysiology, and effective preventive measures for respiratory failure in these patients.

Medicine in the future - with subspecialists in medullary neurology and brain dentistry

The solitary tract nucleus of the medulla with its limited watershed vascular capacity may occasionally be the focus of transient ischemia caused by the increased metabolic demands associated with frequent and intense neuronal stimulation from other organs and other parts of the brain. Case reports have suggested that these ischemic changes may sometimes result in the initiation of intense autonomic discharges, which can occasionally be fatal. Therapeutic interventions for the medulla oblongata are hampered by its limited accessibility. Systemically administered pharmaceuticals may have some usefulness in future years. Previous experience with vagus nerve stimulation in the treatment of epilepsy suggests that it may have some usefulness in stabilizing medullary autonomic discharges. Computerized electronic stimulation of other cranial nerves may be helpful as well, especially the chorda tympani nerve, and may be most easily accomplished from implanted dental appliances, especially molar modules, transmitting signals via secondary transmitters procedurally placed on cranial nerves. Future technology may enable wireless signaling from the implanted dental appliance to the secondary transmitter placed at the nerve site. By the year 2050 subspecialists in medullary neurology and brain dentistry may use computerized electronic stimulation of cranial nerves to prevent sudden unexpected death and treat “chest pain from the brain”.

Sudden unexpected death owing to unilateral medial medullary infarction with early involvement of the respiratory center

A 64-year-old woman was found dead in her home. At autopsy, although relatively fresh bruises were found on her body, no lethal injury was observed in an internal observation. Mild edematous swelling of the right half of the medulla oblongata was observed. There was acute medial medullary infarction (MMI), which mainly involved the nucleus hypoglossi, medial lemniscus, hypoglossal root, inferior olivary nucleus, and pyramidal tract. Subacute infarction of the lower part of the cerebellum was also found, and severe atherosclerosis of the right vertebral artery containing thrombi was found as the culprit lesion. Immunohistochemistry using amyloid precursor protein (APP) was positive in neuronal tissue in the nucleus ambiguus, despite not showing coagulative necrosis in the nucleus. Therefore, acute ischemic necrosis of the nucleus ambiguus, which is considered to be a component of the dorsal respiratory group, may be a significant finding for her expected death. Immunohistochemistry of APP may be useful for confirming the precise extent of acute ischemia in brain stem infarction, such as unilateral MMI.