Central hypoventilation as the presenting symptom in Hu associated paraneoplastic encephalomyelitis

Central Hypoventilation Is a Key Risk Factor for Mechanical Ventilation During the Acute Phase of Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Objective: Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an acute form of encephalitis of autoimmune etiology. We aimed to evaluate the risk factors that predicted the need for mechanical ventilation during the acute phase of anti-NMDAR encephalitis through an analysis of the clinical characteristics and biochemical test results of the patients with anti-NMDAR encephalitis.

Methods: In this retrospective study, patients who primarily presented with anti-NMDAR encephalitis and exhibited anti-NMDAR antibody positivity in the cerebrospinal fluid (CSF) between November 2015 and February 2020 were included. Data on the clinical characteristics, biochemical test results, and treatment methods selected for the patients were collected for the analysis of factors predicting the need for mechanical ventilation.

Results: Thirty-one patients with a median age of onset of 31 years (inter-quartile range: 21–48 years) were included in this study, of which 15 were male (48.4%). Psychosis (23, 74.2%), seizures (20, 64.5%), and memory deficit (20, 64.5%) were the most common clinical manifestations. At admission, 17 patients (54.8%) presented with pyrexia, of which 12 (38.7%) had a body temperature ≥38°C, and six patients (19.4%) presented with central hypoventilation. All patients received first-line therapy (glucocorticoids, intravenous immunoglobulin, or plasmapheresis alone or combined), whereas two patients (6.5%) received rituximab, a second-line agent, as well. Seven patents required mechanical ventilation. Results of univariate logistic regression analysis revealed that body temperature ≥38°C [odds ratio (OR) = 18, 95% confidence interval (CI): 1.79–181.31, P < 0.05] and central hypoventilation at admission (OR = 57.50, 95% CI: 4.32–764.89, P < 0.05) were the risk factors for mechanical ventilation. Multivariate logistic regression analysis showed that central hypoventilation at admission was the only risk factor predicting the need for mechanical ventilation.

Conclusion: Central hypoventilation at admission is a key risk factor for mechanical ventilation during hospitalization in patients with anti-NMDAR encephalitis.

A 58-Year-Old Man With Episodic Hypercapnic Respiratory Failure

CASE PRESENTATION

A 58-year-old man presented to the ED with a 1-week history of progressive weight loss, generalized weakness, unsteadiness, and dizziness. In hospital, he experienced a witnessed episode of loss of consciousness with no observable respirations that lasted for 15 minutes. His arterial blood gas demonstrated hypercapnic respiratory failure, and he required mask ventilation and vasoactive medications. Similar episodes occurred several more times over the course of the night that required the patient to be intubated. The paroxysmal episodes persisted necessitating continued invasive ventilatory support and admission to the ICU. The episodes occurred in both awake and asleep states and required the ventilator settings to dictate a minimum rate, but minimal ventilatory support otherwise. Further history revealed other symptomatic complaints of vertigo, dysphagia, and hypophonia that had progressed over a 2-month period. The patient's medical history was pertinent for a diagnosis of prostatic carcinoma 3 years previously that was found to be castrate resistant. He had metastases to his hip, ribs, and thoracic spine. Previous treatments had included bicalutamide, docetaxel, and abiraterone; he was receiving leuprolide therapy on presentation.

Sleep Disturbances Associated with Neurological Autoimmunity

Associations between sleep disorders and neurological autoimmunity have been notably expanding recently. Potential immune-mediated etiopathogenesis has been proposed for various sleep disorders including narcolepsy, Kleine-Levin syndrome, and Morvan syndrome. Sleep manifestations are also common in various autoimmune neurological syndromes, but may be underestimated as overriding presenting (and potentially dangerous) neurological symptoms often require more urgent attention. Even so, sleep dysfunction has been described with various neural-specific antibody biomarkers, including IgLON5; leucine-rich, glioma-inactivated protein 1 (LGI1); contactin-associated protein 2 (CASPR2); N-methyl-D-aspartate (NMDA)-receptor; Ma2; dipeptidyl-peptidase-like protein-6 (DPPX); alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-R); anti-neuronal nuclear antibody type-1 (ANNA-1, i.e., Hu); anti-neuronal nuclear antibody type-2 (ANNA-2, i.e., Ri); gamma-aminobutyric acid (GABA)-B-receptor (GABA-B-R); metabotropic glutamate receptor 5 (mGluR5); and aquaporin-4 (AQP-4). Given potentially distinctive findings, it is possible that sleep testing could potentially provide objective biomarkers (polysomnography, quantitative muscle activity during REM sleep, cerebrospinal fluid hypocretin-1) to support an autoimmune diagnosis, monitor therapeutic response, or disease progression/relapse. However, more comprehensive characterization of sleep manifestations is needed to better understand the underlying sleep disruption with neurological autoimmunity.

Anti-Hu paraneoplastic brainstem encephalitis caused by a pancreatic neuroendocrine tumor presenting with central hypoventilation

Paraneoplastic neurological syndromes are rare autoimmune manifestations of malignancies associated with specific antibodies. Anti-Hu associated brainstem encephalitis, a well-described syndrome, usually presents subacutely with preferential involvement of the medulla. Anti-Hu antibodies target intraneuronal antigens and are therefore highly correlated with neurological syndromes when present concomitantly with a neoplasm. Reported is a case of anti-Hu brainstem encephalitis associated with a pancreatic neuroendocrine tumor (PNET) presenting with central hypoventilation. This is the first described case of brainstem encephalitis associated with a well-differentiated PNET as well as the first case of Anti-Hu antibodies associated with a PNET. There are no standardized protocols for the treatment of paraneoplastic brainstem encephalitis however, as in the present case, surgical resection and oncological treatment of the tumor is the first line treatment.

Ondine's Curse: A Case of Anti-Hu Paraneoplastic Syndrome

A 60-year-old patient presented with neurological symptoms which proved to be a paraneoplastic syndrome secondary to a small-cell lung cancer. The investigations and treatment for these syndromes are discussed. The patient improved with high dose steroids and chemotherapy.

Neurologic complications of respiratory disease

The respiratory and central nervous systems are intimately connected through strict control of ventilation by central mechanisms. The exquisite sensitivity of central chemoreceptors and cerebral blood vessels to changes in central nervous system oxygenation mandate this type of control to maintain proper brain function. When diseases of the lung and respiratory system interfere with this fine balance, neurologic symptoms, sometimes severe, may develop. This article deals with the effects of abnormal ventilation on the nervous system.