Bicarbonato de sodio intravenoso ¿Cuándo, cómo y por qué utilizarlo? / Intravenous sodium bicarbonate. When, how and why to use it?

Severe metabolic acidosis is defined by a pH < 7.2 with HCO3− < 8 mE- q/L in plasma. Its best treatment is to correct the underlying cause. However, acidemia produces multiple complications such as resistance to the action of catecholamines, pulmonary vasoconstriction, impaired cardiovascular function, hyperkalemia, immunological dysregulation, respiratory muscle fatigue, neurological impairment, cellular dysfunction, and finally, it contributes to multisystemic failure. Intravenous NaHCO3 buffers severe acidemia, preventing the associated damage and gains time while the causal disease is corrected. Its indication requires a risk-benefit assessment, considering its complications. These are hypernatremia, hypokalemia, ionic hypocalcemia, rebound alkalosis, and intracellular acidosis. For this reason, therapy must be "adapted" and administered judiciously. The patient will require monitoring with serial evaluation of the internal environment, especially arterial blood gases, plasma electrolytes, and ionized calcium. Isotonic solutions should be preferred instead of hypertonic bicarbonate. The development of hypernatremia must be prevented, calcium must be provided for hypocalcemia to improve cardiovascular function. Furthermore, in mechanically ventilated patients, a respiratory response similar to the one that would develop physiologically, must be established to be able to extract excess CO2 and thus avoid intracellular acidosis. It is possible to estimate the bicarbonate deficit, speed, and volume of its infusion. However, the calculations are only for reference. More important is to start intravenous NaHCO3 when needed, administer it judiciously, manage its side effects, and continue it to a safe goal. In this review we address all the necessary elements to consider in the administration of intravenous NaHCO3, highlighting why it is the best buffer for the management of severe metabolic acidosis.

Alcalosis respiratoria grave, la transformación de un cuadro funcional en orgánico. Caso clínico

Severe respiratory alkalosis is a life-threatening condition, as it induces hypo- calcaemia and extreme adrenergic sensitivity leading to cerebral and myocardial vasoconstriction. We report a 37-year-old woman with previous consultations for a conversion disorder. While she was infected with SARS-CoV-2 (without pulmonary involvement), she consulted in the emergency room due to panic attacks. On admission, she developed a new conversion crisis with progressive clinical deterioration, hyperventilation, and severe respiratory alkalosis (pH 7.68, Bicarbonate 11.8 mEq/L and PaCO2 10 mmHg). Clinically, she was in a coma, with respiratory and heart rates 55 and 180 per min, a blood pressure of 140/90 mmHg, impaired perfusion (generalized lividity, distal coldness, and severe skin mottling) and tetany. She also had electrocardiographic changes and high troponin levels suggestive of ischemia, and hyperlactatemia. She was managed in the hospital with intravenous benzodiazepines. The clinical and laboratory manifestations resolved quickly, without the need for invasive measures and without systemic repercussions.

Trastorno grave del medio interno por fístula enterovesical, a propósito de un caso clínico / Severe metabolic disorder associated with an enterovesical fistula: report of one case

Enterovesical fistula (EVF) is a fistulous communication between the intestine and the bladder. It is uncommon and its classic clinical manifestations are the presence of pneumaturia, fecaluria, suprapubic pain and recurrent urinary infections. Surgical repair of EVF leads to rapid correction of both diarrhea and metabolic abnormalities. We report a 73-year-old diabetic woman with a neurogenic bladder secondary to a spine meningioma. She presented with diarrhea, vomiting, impaired consciousness and metabolic acidosis. She developed hypernatremia, hypokalemia, hypocalcemia, and hypophosphatemia, which were successfully corrected.

Desempeño comparativo de ecuaciones de estimación de excreción urinaria de creatinina

Background: 24-hour urine collection accuracy is generally evaluated based on the values of urine creatinine (UCr) excretion, usually using ranges adjusted by weight. UCr excretion depends on several factors. Equations to estimate UCr in 24-hour collection (UCr/24h) that consider these factors have been developed. However, these formulas have not been evaluated in a sample of Latinamerican origin. Aim: To evaluate the performance of the existing UCr/24 h estimation equations in a sample of Latinamerican origin. Material and Methods: 24-hour urine collections from 181 ambulatory patients were analyzed. Measured UCr/24h was compared with estimated UCr (eUCr) through the equations of Ix (CKD-EPI), Gerber-Mann, Goldwasser, Cockcroft-Gault, Rule, Walser, Kawasaki, Tanaka and Huidobro. Performance of the nine equations to estimate UCr/24h was evaluated with the Pearson correlation and Lin concordance coefficients, and Bland-Altman method. Bias, precision, and accuracy (percentage of collections within 30% of measured UCr or P30) were also calculated. Results: Measured UCr/24h in the 181 patients was 1236 + 378 mg. Correlation coefficient (Pearson) of the eUCr/24h with the equations of Walser, Ix and Huidobro and the measured UCr/24h was strongly positive. Rule and Kawasaki equations had the lowest positive correlation coefficients. Bias was similar using the formulas of Walser, Goldwasser, Kawasaki, Ix and Huidobro. Walser, Ix, Huidobro, Cockcroft-Gault and Goldwasser equations had good accuracy (P30 > 85%), while Gerber-Mann, Tanaka, Rule and Kawasaki formulas had a P30 < 65%. Conclusions: Walser, Ix and Huidobro equations had the best performance to estimate UCr/24h excretion in a population of latinamerican origin.

Síndrome hemolítico urémico asociado a toxina Shiga con hipocomplementemia en edad atípica. Caso clínico

The Shiga toxin associated (Stx) hemolytic uremic syndrome (HUS) is an important cause of acute renal failure (ARF) and the most common cause of thrombotic microangiopathy (TMA) in pediatrics. Primary atypical HUS (aHUS) is a rare disease due to a genetic defect in the alternative complement pathway. Both diseases may share clinical and laboratory elements, making differential diagnosis difficult, such as the presence of diarrhea in aHUS or complement alterations in HUS-Stx. The treatment and prognosis of both diseases is completely different. We report a 15-year-old male with severe HUS. After a self-limited diarrheal syndrome, he had a severe TMA and ARF, requiring renal replacement therapy. An extensive etiological study was carried out, ruling out the main causes of TMA. Alterations in complement factors were observed. Finally, the diagnosis of HUS-Stx was established. The patient evolved favorably with recovery of renal function.

Insuficiencia renal aguda secundaria a rabdomiolisis como manifestación de infección por SARS-CoV-2 / Acute kidney injury caused by rhabdomyolysis as a SARS-CoV-2 infection manifestation: report of one case

SARS-CoV-2 infection has a wide spectrum of clinical manifestations secondary to the impairment of different organs, including kidney. Rhabdomyolysis is produced by disintegration of striated muscle and the liberation of its contents to the extracellular fluid and bloodstream. This may produce hydro electrolytic disorders and acute kidney injury. We report a 35-year-old female with a history of SARS-CoV-2 infection who was hospitalized because of respiratory failure and developed renal failure. The etiologic study showed elevated total creatine kinase levels and a magnetic resonance imaging confirmed rhabdomyolysis. The patient required supportive treatment with vasoactive drugs, mechanic ventilation and kidney replacement therapy. She had a favorable evolution with resolution of respiratory failure and improvement of kidney function.

Nueva ecuación para la estimación de la natriuresis diaria a partir de parámetros en plasma y orina aislada en población chilena / A new equation to estimate daily natriuresis from parameters in plasma and spot urine sample in the Chilean population

Background: Excessive sodium intake is associated with increased cardiovascular morbidity and mortality. Daily sodium intake is usually inferred from sodium excretion in a 24-hour urine collection, which is cumbersome and prone to errors. Different formulas have attempted to estimate 24-hour urinary sodium from a spot urine sample. Unfortunately, their concordances are insufficient and have not been tested in our population. Aim: To develop an equation to predict 24-hour urine sodium from parameters in plasma and spot urine samples. To validate the equation and compare it with other formulas in Chilean population. Material and Methods: Analysis of 24-hour urine collections, plasma sample and spot urine sample from 174 adult outpatients (81% females) with an estimated glomerular filtration rate (eGFR) ≥ 60 mL/min/1.73m2. These were collected between 2015 and 2019 using standardized methods and educating patients about the correct method to collect 24 h urine samples. In all these patients, creatinine and electrolytes were measured in plasma and urine. A new equation was developed using a multiple linear regression model. Results: Twenty-four-hour urine sodium excretion was significantly correlated with age, weight, height, eGFR, plasma osmolarity, urine electrolytes and parameters obtained from spot urine sample, among others. The new equation had a linear correlation with 24-hour natriuresis of 0.91 and the concordance was 0.9. The predictive capacity of the new equation was better than the existing formulas. Conclusions: We developed a formula to accurately predict daily natriuresis in the Chilean population.

Análisis de sobrevida en pacientes incidentes de hemodiálisis en Chile, 2013-2019

Background: Renal replacement therapies, especially hemodialysis (HD) in end-stage kidney disease, avoid an inevitable death caused by the disease. However, in elderly patients with multiple comorbidities, this therapy could derive in a comparable survival than conservative management. Considering that HD represents a high cost for the health system, it is worth analyzing the effects of HD on survival. Aim: To analyze the survival and mortality of all national health security system's patients (FONASA) admitted to HD in Chile from 2013 to 2019. Material and Methods: We requested to the Ministry of Health information about all patients affiliated to the public health insurance system that started dialysis between 2013 and 2019. We evaluated the influence of age when starting HD, sex, presence of hypertension, presence of diabetes mellitus (DM), the region of residence, and year of admission on mortality. Results: A total of 24,113 patients aged 61 ± 15 years (45% women) were analyzed. Forty five percent of patients were aged > 65 years. After 5 years of follow-up, the median survival in this age group was 36.1 months. Among patients who started HD at age > 85 years, the median survival was 14.8 months. Diabetic patients had a median survival of 52.3 months. Advanced age and DM were associated with higher annual mortality. Also, the region of residence and year of admission were associated with higher mortality at 3 and 12 months. Conclusions: The median survival of patients on HD is dependent on age and the presence of comorbidities, among other factors. We performed an analysis to determine if starting HD in older patients with comorbidities has a real benefit over conservative management in terms of survival.

Metahemoglobinemia, una entidad de diagnóstico complejo. Reporte de un caso

Methemoglobinemia is a rare condition with serious consequences if not diagnosed. We report the case of a 64-year-old woman with a history of allergy to sulfa drugs and a recent diagnosis of a small vessel vasculitis (ANCA-p) who started induction therapy with corticosteroids and rituximab. Due to the need for infectious prophylaxis, and considering her history, dapsone was administered instead of cotrimoxazole after ruling out glucose-6-phosphate dehydrogenase deficiency. During the admission to the hospital for her second dose of rituximab, and while being asymptomatic, she persistently presented a pulse oximetry ≪ 90% despite the administration of O2. Therefore, the infusion was postponed to study the patient. The arterial gasometric study by direct potentiometry revealed an O2 saturation of 98%, with a saturation gap > 5%. Considering the use of dapsone, a methemoglobinemia was suspected and confirmed by co-oximetry (methemoglobinemia 9%). Dapsone was suspended and one week later, her methemoglobinemia was absent.

Nefropatías secundarias a paraproteína: perfil clínico a partir de hallazgos histológicos

Background: One of the devastating consequences of monoclonal gammopathies is the development of end-stage kidney disease, which can be prevented with an early diagnosis. Renal involvement can be secondary to saturation of paraproteins with intratubular precipitation or the glomerular deposition of paraproteins with secondary inflammation and destruction. These conditions can also be associated with monoclonal gammopathies that do not meet hematological treatment criteria, called monoclonal gammopathies of renal significance (MGRS). Aim: To report a retrospective analysis of patients who underwent a renal biopsy and whose final diagnosis was a form of monoclonal gammopathy. Material and Methods: We reviewed the clinical and laboratory features and response to treatment of 22 patients aged 63 ± 12 years (55% women) with a pathological diagnosis of a nephropathy associated with paraproteinemia. Results: The most common hematological diagnosis was amyloidosis in 50% of patients, followed by cast nephropathy. The predominant clinical presentations were proteinuria (without nephrotic syndrome) and nephritic syndrome. Classic criteria such as erythrocyte sedimentation rate > 100 mm/h and protein-albumin gap were unusual. Serum light chain quantification was the test with the best yield to detect paraproteins. Conclusions: In this group of patients, light chains tend to affect the kidney more commonly than heavy chains. The prognosis of multiple myeloma is much worse than MGRS.

Intoxicación por ácido acetilsalicílico, fisiopatología y manejo / Physiopathology and management of acetylsalicylic acid intoxication

Acetylsalicylic acid (ASA) intoxication is potentially lethal. After ingestion, AAS is rapidly transformed into salicylic acid that dissociates into an hydrogen ion plus salicylate. Salicylate is the main form of AAS in the body and produces multiple alterations. Initially, the stimulation of the ventilatory center promotes a respiratory alkalosis. Then, the mitochondrial dysfunction induced by salicylate, will generate a progressive metabolic acidosis due to the accumulation of ketoacids, lactic acid and dicarboxylic acids among others. Another alterations include hydro electrolytic disorders, gastrointestinal lesions, neurological involvement, ototoxicity and coagulopathy. The correct handling of acetylsalicylic acid intoxication requires an thorough knowledge of its pharmacokinetics and pharmacodynamics. Treatment consists in life support measures, gastric lavage, activated charcoal and urinary alkalization to promote the excretion of salicylates. In some occasions, it will be necessary to start renal replacement therapy as soon as possible.

Efectos del programa gubernamental vida sana en marcadores metabólicos y capacidad física en mujeres Chilenas / Effects of the government's healthy living program on metabolic markers and physical capacity in Chilean women

RESUMEN Objetivo Determinar los efectos del plan gubernamental vida sana en marcadores metabólicos plasmáticos y capacidad física en mujeres sedentarias de Villa Alemana. Métodos Participaron 63 mujeres (41,2 ± 11,2 años) que fueron sometidas a 12 meses de intervención multi e inter-disciplinaria (médico, nutricionista, psicólogo(a) y profesor de educación física) (180 minutos de ejercicio por semana). En el análisis estadístico descriptivo se utilizaron la media y desviación estándar, la prueba T de muestras relacionadas se usó para determinar los efectos del programa, el nivel de significancia se estimó con un valor p<0,05. Resultados Se apreció una disminución en el colesterol total (p=0,003) y colesterol LDL (p=0,048), mejora en el test de 6 minutos (p=0,000) y número de sentadillas en treinta segundos (p=0,000) con un efecto positivo en el delta de recuperación de la frecuencia cardíaca (p=0,001). Conclusión La estrategia gubernamental produjo una disminución en el riesgo cardiovascular debido a una mejora en los marcadores metabólicos y capacidad física de las mujeres.(AU)

ABSTRACT Objective To determine the effects of the government's healthy living plan on metabolic markers and physical capacity in sedentary women from Villa Alemana, Chile. Materials and Methods 63 women who participated in the study (41.2±11.2 years) underwent 12 months of multi- and interdisciplinary intervention (doctor, nutritionist, psychologist and physical education teacher) of 180 minutes of physical activity per week. Mean and standard deviation were used for statistical analysis, while the t-test of related samples was used to determine the effects of the program. The level of significance was estimated with a value of p<0.05. Results There was a decrease in total cholesterol (p=0.003) and LDL cholesterol (p=0.048), improvement in the 6-minute test (p=0.000) and number of squats in thirty seconds (p=0.000) with a positive effect on delta recovery heart rate (p=0.001). Conclusions The government's strategy resulted in a decrease of cardiovascular risk due to improved metabolic markers and women's physical capacity.(AU)

Síndrome hemolítico urémico atípico / Atypical hemolytic uremic syndrome

Atypical hemolytic uremic syndrome (aHUS) is a rare thrombotic microangiopathy, characterized by microangiopathic hemolytic anemia, thrombocytopenia and renal involvement. It causes end stage renal disease requiring dialysis in most affected patients. It mainly affects young adults (contrary to what was thought years ago). When aHUS is primary, the cause is a genetic mutation in the alternative complement pathway. Instead, secondary aHUS is caused by external factors that trigger the disease by themselves or in combination with a genetic vulnerability. The type of mutation determines the severity of the disease, prognosis, response to therapy and renal transplantation. Advances in the understanding of renal diseases associated with complement defects and the development of specific biologic therapies changed the course of this disease. Eculizumab is internationally approved for the treatment of primary aHUS. Its inhibitory action on the complement cascade leads to hematologic remission and restoration of renal function. We present a review of aHUS detailing its etiology, pathogenesis, clinical presentation, diagnosis and treatment.

Síndrome hemolítico urémico atípico en tratamiento con eculizumab: casos clínicos / Atypical hemolytic uremic syndrome: report of two cases treated with Eculizumab

Hemolytic uremic syndrome (HUS) is a type of thrombotic microangiopathy where organic damage predominates in the kidney. Atypical HUS (aHUS) is a rare disease that affects young adults and causes terminal chronic renal failure ending in dialysis, in most cases. It also recurs after kidney transplantation. aHUS is associated with genetic defects of the alternative complement pathway or its activation by other factors such as drugs, autoimmune diseases, infections, malignant hypertension and ischemia-reperfusion. We report two women aged 17 and 25 years old with catastrophic aHUS. In both cases, complement amplifying factors (drugs and infections) were added and acted on a genetic vulnerability to precipitate complement activation and produce aHUS. Both patients developed terminal renal failure and had to undergo hemodialysis. Fortunately, after a broad etiological study, it was possible to make the diagnosis of aHUS and start treatment with Eculizumab, a monoclonal antibody that changed the natural history of aHUS. It inhibits complement activity controlling microangiopathy and preventing the development of end-stage renal disease. It also improves the success rate in kidney transplantation. In the case of our patients, both discontinued dialysis after chronic treatment with Eculizumab.