Severe ketoacidosis in a patient with spinal muscular atrophy

Paradoxical metabolic acidosis after vomiting in children with spinal muscular atrophy: A report of 9 patients

BACKGROUND

Spinal muscular atrophy (SMA) is a hereditary neuromuscular disease that progresses toward restrictive respiratory failure due to muscle paralysis. We observed that SMA patients presented with a specific clinical and laboratory profile, consisting of severe metabolic acidosis following an episode of mild vomiting. This is an unusual, little-known, and life-threatening situation for these patients, as hyperventilation induced by metabolic acidosis can lead to exhaustion and to death by mixed acidosis.

OBJECTIVE

The aim of our study was to describe this paradoxical acidosis after vomiting in SMA patients and to discuss the physiological basis of this condition.

METHODS

We conducted a retrospective single-center study reviewing the clinical and laboratory data of SMA patients who were hospitalized in the intensive care unit for severe metabolic acidosis after vomiting.

RESULTS

Our cohort comprised 11 cases. On arrival, the median pH of the patients was 7.23 with a median bicarbonate concentration of 11.7 mmol/L and almost half of them (45 %) had ketone bodies in the blood and/or urine. The median correction time was 24 h for pH and 48 h for bicarbonate concentrations after receiving intravenous hydration with a glucose solution.

CONCLUSIONS

We suggest that SMA patients are particularly sensitive to ketoacidosis induced by fasting, even after a few episodes of mild vomiting. Moreover, they have a low buffering capacity due to their severe amyotrophy, which favors metabolic acidosis. They must be quickly hydrated through a glucose-containing solution to avoid exhaustion, mixed acidosis, and death.

Non-diabetic Euglycemic Ketoacidosis in an Adult Patient With Spinal Muscular Atrophy Type II

Spinal muscular atrophy (SMA) is a rare neuromuscular disease that develops as a result of the degeneration of the anterior horn cells in the spinal cord and lower brainstem motor nuclei, resulting in progressive muscle weakness and atrophy. While the initial presentation of this disease involves diffuse muscular atrophy at an early age, patients with an established diagnosis and later-stage disease often present with gastrointestinal symptoms related to metabolic imbalances. Here, we examine the case of an adult patient with SMA type II who presented with complaints of 12 hours of intractable nausea and vomiting. The patient was found to be in euglycemic ketoacidosis (EKA), an uncommon, but not unheard of, metabolic derangement in SMA patients with severely decreased muscle mass.

Serum Ketone Levels May Correspond with Preoperative Body Weight Loss in Patients Undergoing Elective Surgery: A Single-Center, Prospective, Observational Feasibility Study

Although nutritional-risk scoring systems allow the determination of the patient’s malnutrition at admission, additional tools might be useful in some clinical scenarios. Previous medical history could be unavailable in unconscious or demented patients. This study aimed to assess the ketone bodies serum levels in patients undergoing elective surgeries and to determine the possible correlation between ketone bodies serum levels and preoperative body weight loss. The study included 21 patients who underwent elective surgery. Hyperketonemia, defined as ketone bodies over 1 mmol/L, was observed in seven (33.3%) patients. Patients with hyperketonemia had significantly higher preoperative percentage body weight loss (p = 0.04) and higher nutritional risk scores prior to surgery (p = 0.04). Serum glucose and the percentage of body weight loss were associated with increased ketone bodies serum levels (Odds Ratios: 0.978 (0.961–0.996, p = 0.019) and 1.222 (1.0–1.492, p = 0.05), respectively). A significant linear correlation was found between the percentage of body weight loss and both ketones bodies (r² = 0.25, p = 0.02) and albumin serum levels (r² = 0.19, p = 0.04). Our study’s results might suggest a positive association between preoperative body weight loss and ketone bodies serum levels. The observation between increased ketone bodies serum levels in patients and preoperative body mass loss merits further research.

Prolonged fasting-induced hyperketosis, hypoglycaemia and impaired fat oxidation in child and adult patients with spinal muscular atrophy type II

AIM

This study explored hypoglycaemia and metabolic crises, including hyperketosis, in patients with spinal muscular atrophy (SMA).

METHODS

The study comprised four adolescents aged 15-17 and six adults aged 19-37 with SMA type II and eight adult controls aged 21-41, who were recruited by the Rigshospitalet, Denmark, from May 1st to October 30th 2017. We used stable isotope technique and indirect calorimetry to investigate fat and glucose metabolism during a 24-h fast or until hypoglycaemia occurred.

RESULTS

All patients with SMA II developed moderate to severe hyperketosis and 60% had symptoms of hypoglycaemia or blood glucose levels below 3 mmol/L. None of the controls developed hyperketosis or hypoglycaemia. Plasma bicarbonate decreased, in line with increased ketone bodies, indicating the start of metabolic acidosis in patients with SMA II. Increased fat production and utilisation were seen in healthy controls during the fasting period, but were absent in patients with SMA II, indicating blunted fat oxidation.

CONCLUSION

Low skeletal muscle mass was the best explanation for why patients with SMA II had an increased risk of hypoglycaemia, hyperketosis, metabolic acidosis and disturbed fat and glucose metabolism during fasting. These risks have implications for children facing surgery and those with severe illnesses.

A 20-year Clinical and Genetic Neuromuscular Cohort Analysis in Lebanon: An International Effort

BACKGROUND

Clinical and molecular data on the occurrence and frequency of inherited neuromuscular disorders (NMD) in the Lebanese population is scarce.

OBJECTIVE

This study aims to provide a retrospective overview of hereditary NMDs based on our clinical consultations in Lebanon.

METHODS

Clinical and molecular data of patients referred to a multi-disciplinary consultation for neuromuscular disorders over a 20-year period (1999-2019) was reviewed.

RESULTS

A total of 506 patients were diagnosed with 62 different disorders encompassing 10 classes of NMDs. 103 variants in 49 genes were identified. In this cohort, 81.4%of patients were diagnosed with motor neuron diseases and muscular dystrophies, with almost half of these described with spinal muscular atrophy (SMA) (40.3%of patients). We estimate a high SMA incidence of 1 in 7,500 births in Lebanon. Duchenne and Becker muscular dystrophy were the second most frequently diagnosed NMDs (17%of patients). The latter disorders were associated with the highest number of variants (39) identified in this study. A highly heterogeneous presentation of Limb Girdle Muscular Dystrophy and Charcot-Marie-Tooth disease was notably identified. The least common disorders (5.5%of patients) involved congenital, metabolic, and mitochondrial myopathies, congenital myasthenic syndromes, and myotonic dystrophies. A review of the literature for selected NMDs in Lebanon is provided.

CONCLUSIONS

Our study indicates a high prevalence and underreporting of heterogeneous forms of NMDs in Lebanon- a major challenge with many novel NMD treatments in the pipeline. This report calls for a regional NMD patient registry.

Metabolic Dysfunction in Spinal Muscular Atrophy

Spinal muscular atrophy (SMA) is an autosomal recessive genetic disorder leading to paralysis, muscle atrophy, and death. Significant advances in antisense oligonucleotide treatment and gene therapy have made it possible for SMA patients to benefit from improvements in many aspects of the once devastating natural history of the disease. How the depletion of survival motor neuron (SMN) protein, the product of the gene implicated in the disease, leads to the consequent pathogenic changes remains unresolved. Over the past few years, evidence toward a potential contribution of gastrointestinal, metabolic, and endocrine defects to disease phenotype has surfaced. These findings ranged from disrupted body composition, gastrointestinal tract, fatty acid, glucose, amino acid, and hormonal regulation. Together, these changes could have a meaningful clinical impact on disease traits. However, it is currently unclear whether these findings are secondary to widespread denervation or unique to the SMA phenotype. This review provides an in-depth account of metabolism-related research available to date, with a discussion of unique features compared to other motor neuron and related disorders.

Metabolic and Nutritional Issues Associated with Spinal Muscular Atrophy

Spinal muscular atrophy (SMA), the main genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of motor neurons in the anterior horn of the spinal cord, accompanied by muscle wasting. Pathomechanically, SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from the loss of the SMN1 gene. However, emerging research extends the pathogenic effect of SMN deficiency beyond motor neurons. A variety of metabolic abnormalities, especially altered fatty acid metabolism and impaired glucose tolerance, has been described in isolated cases of SMA; therefore, the impact of SMN deficiency in metabolic abnormalities has been speculated. Although the life expectancy of these patients has increased due to novel disease-modifying therapies and standardization of care, understanding of the involvement of metabolism and nutrition in SMA is still limited. Optimal nutrition support and metabolic monitoring are essential for patients with SMA, and a comprehensive nutritional assessment can guide personalized nutritional therapy for this vulnerable population. It has recently been suggested that metabolomics studies before and after the onset of SMA in patients can provide valuable information about the direct or indirect effects of SMN deficiency on metabolic abnormalities. Furthermore, identifying and quantifying the specific metabolites in SMA patients may serve as an authentic biomarker or therapeutic target for SMA. Here, we review the main epidemiological and mechanistic findings that link metabolic changes to SMA and further discuss the principles of metabolomics as a novel approach to seek biomarkers and therapeutic insights in SMA.

Diet in neurogenic bowel management: A viewpoint on spinal cord injury

The aim of this review is to offer dietary advice for individuals with spinal cord injury (SCI) and neurogenic bowel dysfunction. With this in mind, we consider health conditions that are dependent on the level of lesion including skeletal muscle atrophy, autonomic dysreflexia and neurogenic bladder. In addition, SCI is often associated with a sedentary lifestyle, which increases risk for osteoporosis and diseases associated with chronic low-grade inflammation, including cardiovascular and chronic kidney diseases. The Mediterranean diet, along with exercise and dietary supplements, has been suggested as an anti-inflammatory intervention in individuals with SCI. However, individuals with chronic SCI have a daily intake of whole fruit, vegetables and whole grains lower than the recommended dietary allowance for the general population. Some studies have reported an increase in neurogenic bowel dysfunction symptoms after high fiber intake; therefore, this finding could explain the low consumption of plant foods. Low consumption of fibre induces dysbiosis, which is associated with both endotoxemia and inflammation. Dysbiosis can be reduced by exercise and diet in individuals with SCI. Therefore, to summarize our viewpoint, we developed a Mediterranean diet-based diet and exercise pyramid to integrate nutritional recommendations and exercise guidelines. Nutritional guidelines come from previously suggested recommendations for military veterans with disabilities and individuals with SCI, chronic kidney diseases, chronic pain and irritable bowel syndrome. We also considered the recent exercise guidelines and position stands for adults with SCI to improve muscle strength, flexibility and cardiorespiratory fitness and to obtain cardiometabolic benefits. Finally, dietary advice for Paralympic athletes is suggested.

Review article: Ketoacidosis in the emergency department

Diabetic ketoacidosis, a life-threatening complication of type 1 diabetes mellitus, is a common cause of presentation to EDs. Two new drug classes have been found to cause ketoacidosis with distinctive presentations. The sodium-glucose transport protein 2 inhibitors used in the management of type 2 diabetes mellitus may present with ketoacidosis with normal glucose levels. Ketoacidosis with these medications may be prolonged and recur after initial resolution. Checkpoint inhibitors may present with fulminant diabetic ketoacidosis in individuals with previously normal glucose tolerance. Ketoacidosis may also occur as a result of starvation and alcohol excess, as well as a number of rare causes. Other causes of metabolic acidosis with both high and normal anion gap need to be considered in the differential diagnosis of ketoacidosis. Diabetic ketoacidosis may also present with biochemical changes suggestive of myocardial ischaemia and pancreatitis in the absence of these pathologies. The present paper reviews ketone body metabolism, ketone testing and the causes and differential diagnosis of ketoacidosis with particular relevance to emergency medicine.

[Severe ketoacidosis induced by short-term starvation in a patient with spinal muscular atrophy]

We report a case of a 29-year-old woman with spinal muscular atrophy (SMA) type II who developed severe ketoacidosis after short-term starvation. She was hospitalized with lower respiratory tract infection. Although her symptoms improved after administration of intravenous antibiotic agents, her food intake gradually decreased. On the 7th day of hospitalization, she experienced abdominal pain followed by vomiting, after which she was unable to eat. Approximately 12 h later, she suffered from shock, accompanied with disturbance of consciousness, and she was admitted to the intensive care unit. She was diagnosed with ketoacidosis based on arterial blood gas analyses and urine test results. On receiving continuous infusion of glucose and insulin, her ketoacidosis was rapidly resolved and her symptoms completely recovered by the next day. To prevent the recurrence of ketoacidosis, we provided a diet plan based on indirect calorimetry results. However, ketoacidosis recurred twice, at 12 months and 16 months after discharge, both within 24 h of the onset of the fasting state. In addition to insufficient glycogen storage because of chronic malnutrition, poor gluconeogenesis or poor ketone body consumption due to skeletal muscle atrophy was believed to increase the risk of acute-onset, severe ketoacidosis after short-term starvation. Clinicians must note that patients with SMA are prone to ketoacidosis and that they must be promptly treated.

Isolated Starvation Ketoacidosis: A Rare Cause of Severe Metabolic Acidosis Presenting with a pH Less than 7

Anion gap metabolic acidosis (AGMA) occurs when an anion gap exists along with metabolic acidosis, most commonly due to diabetic ketoacidosis (DKA) and lactic acidosis (LA). Isolated starvation ketoacidosis (ISK) is one of the rare causes of AGMA; however, it usually presents with a mild disturbance in pH. We report a rare case of a 45-year-old female with previously diagnosed squamous cell cancer (SCC) of the larynx. She presented to the emergency department complaining of difficulty in breathing following laryngectomy and tracheostomy for SCC. Her laboratory results on admission were consistent for isolated starvation ketoacidosis and the patient responded quickly to the appropriate treatment.

Euglycemic Ketoacidosis in Spinal Muscular Atrophy

Euglycemic ketoacidosis is defined by the triad of high anion gap acidosis, increased plasma ketones, and the absence of hyperglycemia. Apart from diabetes mellitus, the disorder may occur in prolonged fasting, excessive alcohol consumption, pregnancy, and inborn errors of metabolism. Here, we highlight the diagnosis of euglycemic ketoacidosis in a pediatric nondiabetic patient with spinal muscular atrophy (SMA) type 1 (Werdnig–Hoffmann disease), who, subsequently to her postoperative admission to the intensive care unit following a spinal surgery, developed high anion gap metabolic acidosis. We discuss the pathophysiology of acid-base disorders in SMA, along with the glucose and fatty acids metabolism, the necessary knowledge for medical practitioners.