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Academic literature on the topic 'Acidosis, Respiratory, diagnosis'
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Journal articles on the topic "Acidosis, Respiratory, diagnosis"
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Bruno, Cosimo Marcello, and Maria Valenti. "Acid-Base Disorders in Patients with Chronic Obstructive Pulmonary Disease: A Pathophysiological Review." Journal of Biomedicine and Biotechnology 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/915150.
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The authors describe the pathophysiological mechanisms leading to development of acidosis in patients with chronic obstructive pulmonary disease and its deleterious effects on outcome and mortality rate. Renal compensatory adjustments consequent to acidosis are also described in detail with emphasis on differences between acute and chronic respiratory acidosis. Mixed acid-base disturbances due to comorbidity and side effects of some drugs in these patients are also examined, and practical considerations for a correct diagnosis are provided.
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Friis, Ulla G., Ronni Plovsing, Klaus Hansen, Bent G. Laursen, and Birgitta Wallstedt. "Teaching acid/base physiology in the laboratory." Advances in Physiology Education 34, no. 4 (December 2010): 233–38. http://dx.doi.org/10.1152/advan.90197.2008.
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Acid/base homeostasis is one of the most difficult subdisciplines of physiology for medical students to master. A different approach, where theory and practice are linked, might help students develop a deeper understanding of acid/base homeostasis. We therefore set out to develop a laboratory exercise in acid/base physiology that would provide students with unambiguous and reproducible data that clearly would illustrate the theory in practice. The laboratory exercise was developed to include both metabolic acidosis and respiratory alkalosis. Data were collected from 56 groups of medical students that had participated in this laboratory exercise. The acquired data showed very consistent and solid findings after the development of both metabolic acidosis and respiratory alkalosis. All results were consistent with the appropriate diagnosis of the acid/base disorder. Not one single group failed to obtain data that were compatible with the diagnosis; it was only the degree of acidosis/alkalosis and compensation that varied.
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Basok, Anna B., Yosef-S. Haviv, Boris Rogachev, and Marina Vorobiov. "Renal Tubular Acidosis Type I with Prominent Hypokalemia and Nephrolithiasis as a Presentation of Sjögren’s/Systemic Lupus Erythematosus Disease." Case Reports in Nephrology and Dialysis 11, no. 2 (August 12, 2021): 247–53. http://dx.doi.org/10.1159/000515050.
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Female patient, suffering from nephrolithiasis, at the age of 32 was admitted for renal colic caused by a stone obstructing UP junction with left hydronephrosis. Nephrostomy was placed, resulting in brisk diuresis. Severe metabolic acidosis with normal anion gap and urine pH of 6.5 was noted. Potassium level dropped to extremely low level (1.6 mEq/L), causing muscle paralysis and respiratory failure, necessitating mechanical ventilation. The patient was treated by potassium chloride infusion, followed by correction of severe metabolic acidosis by sodium bicarbonate. Diagnosis of distal type renal tubular acidosis type I (dRTA) was made based on normal anion gap metabolic acidosis, alkaline urine, hypokalemia, and nephrolithiasis. Five years later, the patient presented with severe hypoxia, lung opacities, and bronchiolitis obliterans organizing pneumonia which was confirmed by bronchoscopy with lung tissue biopsy. Concurrently, the patient presented with dry mouth, pruritus, skin rash with hypocomplementemia, elevated anti-DNA, anti-Ro, and anti-SmAb. Diagnosis of overlap Sjögren’s/systemic lupus erythematosus disease was done and treatment by hydroxychloroquine, prednisone, and azathioprine was started. Possible presence of Sjögren’s syndrome should be considered in adult patients with unexplained dRTA.
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McGonigle, Reid, and Robert A. Woods. "Take my breath away: a case of lactic acidosis in an asthma exacerbation." CJEM 13, no. 04 (July 2011): 284–88. http://dx.doi.org/10.2310/8000.2011.110236.
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ABSTRACT:A 36-year-old male with a history of chronic asthma presented to an emergency department with shortness of breath consistent with an asthma exacerbation. He had persistent tachypnea following inhaled bronchodilator treatment; thus, the workup and differential diagnosis were expanded. He was found to have a mixed respiratory alkalosis and metabolic acidosis with elevated serum lactate without an obvious cause and was admitted to hospital. His case was reviewed, and the lactic acidosis was thought to be caused by inhaled β2-agonist use. Emergency physicians should be aware of the potential side effects of inhaled β2-agonists as lactic acidosis may complicate clinical assessment and management of asthma exacerbations and lead to unnecessary and potentially dangerous escalations in therapy.
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Najout, Hamza, Mohamed Moutawakil, Abdelghafour Elkoundi, Nawfal Doghmi, and Hicham Bekkali. "Salbutamol-induced severe lactic acidosis in acute asthma." SAGE Open Medical Case Reports 8 (January 2020): 2050313X2096902. http://dx.doi.org/10.1177/2050313x20969027.
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Selective beta-adrenoceptor agonists are worldwide prescribed to manage bronchial obstruction. However, they expose to a potential risk of hyperlactatemia and lactic acidosis even with normal doses. The mechanism still poorly understood and suggested that salbutamol diverts the metabolism of pyruvate acid from Krebs cycle toward lactate formation. We report the case of a 42-year-old patient, admitted to intensive care unit for acute severe asthma. He presented a transient lactic acidosis over the first 48 h, following an excessive use of salbutamol. The metabolic acidosis caused tachypnea, as a compensatory mechanism, leading to respiratory failure. The diagnosis of salbutamol-induced lactic acidosis must be made by elimination and only accepted after deleting the other causes. The main clinical character is the worsening of dyspnea despite regression of bronchospasm. It is transient and usually normalizes within 24–48 h after stopping or decreasing doses of salbutamol.
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Latif, Azka, Aheli Arce Gastelum, Akshat Sood, and Joseph Thilumala Reddy. "Euglycaemic diabetic ketoacidosis in a 43-year-old woman with type 2 diabetes mellitus on SGLT-2 inhibitor (empagliflozin)." BMJ Case Reports 13, no. 6 (June 2020): e235117. http://dx.doi.org/10.1136/bcr-2020-235117.
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We report a case of euglycaemic diabetic ketoacidosis (EDKA) in a 43-year-old woman with type 2 diabetes mellitus who presented to the emergency department with problems of vomiting, cough, shortness of breath and generalised weakness after following a ketogenic diet for 2 weeks. Therapy with sodium glucose transport protein-2 empagliflozin had been started 2 months prior. Initial evaluation revealed high anion gap metabolic acidosis with blood glucose level of 169 mg/dL. Treatment for EDKA with fluid resuscitation, intravenous insulin and dextrose resolved her acidosis and symptoms in less than 24 hours. Empaglifozin was discontinued on discharge. This entity represents a diagnostic challenge since the differential diagnosis is broad with a potentially misleading clinical presentation that can result in delayed diagnosis and adverse outcomes including acute kidney injury, multiple electrolyte abnormalities, cerebral oedema, acute respiratory distress syndrome, shock and death.
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Moore, Darlene. "Medium-Chain Acyl-CoA Dehydrogenase Deficiency: A Case Presentation." Neonatal Network 24, no. 5 (September 2005): 7–13. http://dx.doi.org/10.1891/0730-0832.24.5.7.
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When an infant presents with hypoglycemia, acidosis, hepatomegaly, and respiratory arrest, the neonatal team must be alert to the possibility of a metabolic disorder. Among those to be considered is medium-chain acyl-CoA dehydrogenase deficiency, which occurs in 1 in 10,000–23,000 live births. Recognizing and treating this disorder early could decrease the morbidity and mortality associated with the diagnosis.
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Dernoncourt, A., J. Bouchereau, C. Acquaviva-Bourdain, C. Wicker, P. De Lonlay, C. Gourguechon, H. Sevestre, P. E. Merle, J. Maizel, and C. Brault. "Myogenic Disease and Metabolic Acidosis: Consider Multiple Acyl-Coenzyme A Dehydrogenase Deficiency." Case Reports in Critical Care 2019 (December 22, 2019): 1–7. http://dx.doi.org/10.1155/2019/1598213.
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Background. Multiple acyl-coA dehydrogenase deficiency (MADD) is a rare, inherited, autosomal-recessive disorder leading to the accumulation of acylcarnitine of all chain lengths. Acute decompensation with cardiac, respiratory or hepatic failure and metabolic abnormalities may be life-threatening. Case Presentation. A 29-year-old woman presented with severe lactic acidosis associated with intense myalgia and muscle weakness. The clinical examination revealed symmetric upper and lower limb motor impairment (rated at 2 or 3 out of 5 on the Medical Research Council scale) and clear amyotrophy. Laboratory tests had revealed severe rhabdomyolysis, with a serum creatine phosphokinase level of 8,700 IU/L and asymptomatic hypoglycemia in the absence of ketosis. Electromyography revealed myotonic bursts in all four limbs. The absence of myositis-specific autoantibodies ruled out a diagnosis of autoimmune myositis. Finally, Acylcarnitine profile and gas chromatography–mass spectrometry analysis of organic acids led to the diagnosis of MADD. A treatment based on the intravenous infusion of glucose solutes, administration of riboflavin, and supplementation with coenzyme Q10 and carnitine was effective. Lipid consumption was strictly prohibited in the early stages of treatment. The clinical and biochemical parameters rapidly improved and we noticed a complete disappearance of the motor deficit, without sequelae. Conclusion. A diagnosis of MADD must be considered whenever acute or chronic muscle involvement is associated with metabolic disorders. Acute heart, respiratory or hepatic failure and metabolic abnormalities caused by MADD may be life-threatening, and will require intensive care.
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Mendez, Yamely, Francisco E. Ochoa-Martinez, and Tatiana Ambrosii. "Chronic Obstructive Pulmonary Disease and Respiratory Acidosis in the Intensive Care Unit." Current Respiratory Medicine Reviews 15, no. 2 (December 10, 2019): 79–89. http://dx.doi.org/10.2174/1573398x15666181127141410.
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Chronic obstructive lung disease is a common and preventable disease. One of its pathophysiological consequences is the presence of carbon dioxide retention due to hypoventilation and ventilation/perfusion mismatch, which in consequence will cause a decrease in the acid/base status of the patient. Whenever a patient develops an acute exacerbation, acute respiratory hypercapnic failure will appear and the necessity of a hospital ward is a must. However, current guidelines exist to better identify these patients and make an accurate diagnosis by using clinical skills and laboratory data such as arterial blood gases. Once the patient is identified, rapid treatment will help to diminish the hospital length and the avoidance of intensive care unit. On the other hand, if there is the existence of comorbidities such as cardiac failure, gastroesophageal reflux disease, pulmonary embolism or depression, it is likely that the patient will be admitted to the intensive care unit with the requirement of intubation and mechanical ventilation.
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van Amesfoort, Jojanneke Epke, Dominique E. Werter, Rebecca C. Painter, and Frederik J. R. Hermans. "Severe metabolic ketoacidosis as a primary manifestation of SARS-CoV-2 infection in non-diabetic pregnancy." BMJ Case Reports 14, no. 4 (April 2021): e241745. http://dx.doi.org/10.1136/bcr-2021-241745.
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We present a case of a metabolic acidosis in a term-pregnant woman with SARS-CoV-2 infection.Our patient presented with dyspnoea, tachypnoea, thoracic pain and a 2-day history of vomiting, initially attributed to COVID-19 pneumonia. Differential diagnosis was expanded when arterial blood gas showed a high anion gap metabolic non-lactate acidosis without hypoxaemia. Most likely, the hypermetabolic state of pregnancy, in combination with maternal starvation and increased metabolic demand due to infection, had resulted in metabolic ketoacidosis. Despite supportive treatment and rapid induction of labour, maternal deterioration and fetal distress during labour necessitated an emergency caesarean section. The patient delivered a healthy neonate. Postpartum, after initial improvement in metabolic acidosis, viral and bacterial pneumonia with subsequent significant respiratory compromise were successfully managed with oxygen supplementation and corticosteroids. This case illustrates how the metabolic demands of pregnancy can result in an uncommon presentation of COVID-19.
Books on the topic "Acidosis, Respiratory, diagnosis"
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Thornton, Kevin, and Michael Gropper. Diagnosis, assessment, and management of hyperthermic crises. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0247.
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Malignant hyperthermia, the neuroleptic malignant syndrome (NMS), and the serotonin syndrome are the principal disorders associated with life-threatening hyperthermia in the intensive care unit. While each is a clinically unique entity, all can progress to multisystem organ dysfunction with acidosis, shock, and death. MH usually results from exposure to halogenated volatile anaesthetics and/or succinylcholine and symptoms of increased CO2 production and respiratory acidosis progress rapidly without prompt intervention, including the administration of dantrolene. NMS is a syndrome of rigidity and altered mental status seen most commonly in patients being treated with antipsychotic medications. The serotonin syndrome is seen in patients treated with serotonergic agents including selective serotonin reuptake or monoamine oxidase inhibitors and tricyclic antidepressants. The salient clinical finding is clonus, but agitation, altered mental status and autonomic dysfunction are common. Recognizing the non-specific features of these syndromes presents a challenge as they are life-threatening if not treated promptly and correctly with specific therapies.
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Whitty, Christopher J. M. Diagnosis and management of malaria in the ICU. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0292.
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Falciparum malaria is the commonest life-threatening imported tropical infection. The most important critical care intervention is rapid high-dose antimalarial treatment with artesunate, or if that is not available quinine. The common complications of malaria are different in children and adults. Cerebral malaria may occur in both, for which there is no specific therapy. Renal failure and acute lung injury are much more common in adults, and may occur late in the course of the disease, even after parasites have cleared. In children acidosis, anaemia and Gram-negative sepsis are more common. Renal and respiratory support may be needed in adults. Malaria alone seldom causes shock and if patients are shocked, co-existing Gram-negative sepsis should be considered. In children there is evidence that bolus hydration increases mortality. Most patients make a full recovery even after prolonged periods of unconsciousness.
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Farmer, Brenna M., and Neal Flomenbaum. Management of salicylate poisoning. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0317.
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Salicylates are weak acids that work as neurotoxins. The goal of management is to keep salicylates out of the brain and enhance elimination. Acute salicylate toxicity manifests as tinnitus, nausea, vomiting, and hyperventilation in a patient who takes a single large ingestion. Chronic salicylate toxicity is associated with long-term use, has a more insidious onset, and symptoms tend to be less severe, resulting in delayed diagnosis. It is more commonly seen in elderly patients. Therapeutic interventions for toxicity include gastrointestinal decontamination, serum and urine alkalinization, and haemodialysis. Mechanical ventilation may lead to clinical deterioration and death in a salicylate-poisoned patient due to worsening acidosis from respiratory failure. This results in severe acidosis, cerebral oedema, pulmonary oedema, and cardiac arrest.
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Sever, Mehmet Şükrü, and Raymond Vanholder. Acute kidney injury in polytrauma and rhabdomyolysis. Edited by Norbert Lameire. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780199592548.003.0252_update_001.
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The term ‘polytrauma’ refers to blunt (or crush) trauma that involves multiple body regions or cavities, and compromises physiology to potentially cause dysfunction of uninjured organs. Polytrauma frequently affects muscles resulting in rhabdomyolysis. In daily life, it mostly occurs after motor vehicle accidents, influencing a limited number of patients; after mass disasters, however, thousands of polytrauma victims may present at once with only surgical features or with additional medical complications (crush syndrome). Among the medical complications, acute kidney injury (AKI) deserves special mention, since it is frequent and has a substantial impact on the ultimate outcome.Several factors play a role in the pathogenesis of polytrauma (or crush)-induced AKI: (1) hypoperfusion of the kidneys, (2) myoglobin-induced direct nephrotoxicity, and intratubular obstruction, and also (3) several other mechanisms (i.e. iron and free radical-induced damage, disseminated intravascular coagulation, and ischaemia reperfusion injury). Crush-related AKI is prerenal at the beginning; however, acute tubular necrosis may develop eventually. In patients with crush syndrome, apart from findings of trauma, clinical features may include (but are not limited to) hypotension, oliguria, brownish discoloration of urine, and other symptoms and findings, such as sepsis, acute respiratory distress syndrome, disseminated intravascular coagulation, bleeding, cardiac failure, arrhythmias, electrolyte disturbances, and also psychological trauma.In the biochemical evaluation, life-threatening hyperkalaemia, retention of uraemic toxins, high anion gap metabolic acidosis, elevated serum levels of myoglobin, and muscle enzymes are noted; creatine phosphokinase is very useful for diagnosing rhabdomyolysis.Early fluid administration is vital to prevent crush-related AKI; the rate of initial fluid volume should be 1000 mL/hour. Overall, 3–6 L are administered within a 6-hour period considering environmental, demographic and clinical features, and urinary response to fluids. In disaster circumstances, the preferred fluid formulation is isotonic saline because of its ready availability. Alkaline (bicarbonate-added) hypotonic saline may be more useful, especially in isolated cases not related to disaster, as it may prevent intratubular myoglobin, and uric acid plugs, metabolic acidosis, and also life-threatening hyperkalaemia.In the case of established acute tubular necrosis, dialysis support is life-saving. Although all types of dialysis techniques may be used, intermittent haemodialysis is the preferred modality because of medical and logistic advantages. Close follow-up and appropriate treatment improve mortality rates, which may be as low as 15–20% even in disaster circumstances. Polytrauma victims after mass disasters deserve special mention, because crush syndrome is the second most frequent cause of death after trauma. Chaos, overwhelming number of patients, and logistical drawbacks often result in delayed, and sometimes incorrect treatment. Medical and logistical disaster preparedness is useful to improve the ultimate outcome of disaster victims.
Book chapters on the topic "Acidosis, Respiratory, diagnosis"
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Young, Edwin. "Diagnosis and Treatment of Respiratory Acidosis." In Fluid and Electrolytes in Pediatrics, 257–71. Totowa, NJ: Humana Press, 2009. http://dx.doi.org/10.1007/978-1-60327-225-4_10.
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Seifter, Julian. "A physiological approach to acid–base disorders: The roles of ion transport and body fluid compartments." In Oxford Textbook of Medicine, edited by Timothy M. Cox, 2182–98. Oxford University Press, 2020. http://dx.doi.org/10.1093/med/9780198746690.003.0238.
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The normal pH of human extracellular fluid is maintained within the range of 7.35 to 7.45. The four main types of acid–base disorders can be defined by the relationship between the three variables, pH, Pco2, and HCO3 –. Respiratory disturbances begin with an increase or decrease in pulmonary carbon dioxide clearance which—through a shift in the equilibrium between CO2, H2O, and HCO3 –—favours a decreased hydrogen ion concentration (respiratory alkalosis) or an increased hydrogen ion concentration (respiratory acidosis) respectively. Metabolic acidosis may result when hydrogen ions are added with a nonbicarbonate anion, A−, in the form of HA, in which case bicarbonate is consumed, or when bicarbonate is removed as the sodium or potassium salt, increasing hydrogen ion concentration. Metabolic alkalosis is caused by removal of hydrogen ions or addition of bicarbonate. Laboratory tests usually performed in pursuit of diagnosis, aside from arterial blood gas analysis, include a basic metabolic profile with electrolytes (sodium, potassium, chloride, bicarbonate), blood urea nitrogen, and creatinine. Calculation of the serum anion gap, which is determined by subtracting the sum of chloride and bicarbonate from the serum sodium concentration, is useful. The normal value is 10 to 12 mEq/litre. An elevated value is diagnostic of metabolic acidosis, helpful in the differential diagnosis of the specific metabolic acidosis, and useful in determining the presence of a mixed metabolic disturbance. Acid–base disorders can be associated with (1) transport processes across epithelial cells lining transcellular spaces in the kidney, gastrointestinal tract, and skin; (2) transport of acid anions from intracellular to extracellular spaces—anion gap acidosis; and (3) intake.
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Farne, Hugo, Edward Norris-Cervetto, and James Warbrick-Smith. "Poor urinary output." In Oxford Cases in Medicine and Surgery. Oxford University Press, 2015. http://dx.doi.org/10.1093/oso/9780198716228.003.0028.
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You should ask the nurse: • What the trend is in urine output—has it been gradually decreasing, or suddenly stopped? If the latter, have they checked if the urinary catheter is blocked by flushing it? This is a rapidly reversible cause of poor urinary output. • What the observations are for the patient. Ask for the heart rate, blood pressure, respiratory rate, oxygen saturations, and temperature, so you can get an idea of how unwell the patient is. This will help you prioritize how soon you need to see the patient. Healthy adults have a urine output of about 1 mL/kg/hour. Oliguria refers to a reduced urine output and is defined variously as <400 mL/day, <0.5 mL/kg/hour, or <30 mL/hour. Anuria refers to the complete absence of urine output. Decreased urine output should be taken very seriously as it may be the first (and only) sign of impending acute renal failure. Untreated, patients may die from hyperkalaemia, profound acidosis, or pulmonary oedema due to the kidneys not performing their usual physiological role. Normal urine output requires: • adequate blood supply to the kidneys • functioning kidneys, and • flow of urine from the kidneys, down the ureters, into the bladder, and out via the urethra. Pathology affecting any of these requirements can result in poor urine output, which is why the differential diagnosis for poor urinary output is often classified as shown in Figure 22.1. In practice, as a junior doctor you want to diagnose and treat the prerenal and postrenal causes. If you come to the conclusion that it is a renal cause (by exclusion), call the renal physicians for an expert opinion. This is crucial in determining the diagnosis: • Adequate intake? Remember that an adult of average size will require about 3 L of fluid intake per 24 hours (30–50 mL/kg/day). Febrile patients will require an extra 500 mL for every 1 °C above 37.0 °C to compensate for increased loss of fluids from evaporation and increased respiratory rate.
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Sinharay, Rudy. "Chest Medicine." In Oxford Assess and Progress: Clinical Medicine. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198812968.003.0009.
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Respiratory conditions are common, and the burden of morbidity on the general population is high. You only have to take part in a few general medical takes as a junior doctor to realize this. As the on- call bleep goes off again, you are referred another exacerbation of chronic obstructive pulmonary disease (COPD) or asthma, a breathless patient (is it a pulmonary embolism, pneumothorax, or something less common?), or a patient with haemoptysis and weight loss [is it lung cancer or tuberculosis (TB)?] or productive cough (pneumonia or bronchiectasis?). The number of different respiratory conditions can be bewildering, and it is essential for the developing physician to be able to manage ‘common presentations’, as well as potentially life- threatening situations such as an asthma attack or an acute pulmonary embolism. The nuances of history taking is often key to successfully clinching a diagnosis: ● What chronic conditions, respiratory or otherwise, do your patients have? ● What is the onset of symptoms? Sudden breathlessness may indicate a pneumothorax or pulmonary embolus. A chronic productive cough may indicate COPD or bronchiectasis. ● Social history— do they smoke, what are their living conditions, what is their occupation? Luckily, we have other tools to help us. The age- old art of inspection, palpation, percussion, and auscultation during an examination is essential when assessing the patient. Combined with imaging techniques, including chest radiography, CT scanning, and bedside thoracic ultrasound, the answer is often easily obtained. Keeping an open mind to the less common causes of breathlessness, cough, and haemoptysis is important. Combined with lung function testing, autoimmune blood tests, and bronchoscopy, subtler diagnoses such as interstitial lung disease, fungal lung disease, and autoantibody- induced haemoptysis may be revealed. And a word to the wise— not all breathlessness originates from the lungs! For instance, an increased body mass index will cause a physical restriction on the mechanics of breathing and a compensated metabolic acidosis may cause tachypnoea. As with all chronic diseases, the management of chronic respiratory disease is becoming increasingly complicated with the advent of biologics, immunotherapy, antifibrotic therapy, and a genuinely confusing array of inhalers.
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Lanpher, Brendan. "Urea Cycle Disorders." In Cognitive and Behavioral Abnormalities of Pediatric Diseases. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195342680.003.0043.
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The urea cycle is a series of steps required to generate urea from nitrogen produced by protein catabolism. The cycle was first described in 1932 by Krebs and Henseleit (Krebs and Henseleit 1932). Six enzymes and two transporters are necessary for urea cycle activity. Specific deficiencies have been described with each of these. The process converts nitrogen from ammonia and aspartate into urea, which is freely excreted by the kidney (Brusilow 1995). Embedded within the urea cycle is the nitric oxide cycle. Nitric oxide is generated from arginine by nitric oxide synthase (NOS), producing citrulline (Scaglia et al. 2004). The entire urea cycle is present only in the liver. The proximal cycle (N-acetylglutamate synthase [NAGS], carbamyl phosphate synthetase [CPS], ornithine transcarbamylase [OTC]) is also present in the intestinal tract, whereas the distal cycle (argininosuccinic acid synthase [ASS], argininosuccinic acid lyase [ASL], arginase [ARG]) is active in the kidney. The most common of the urea cycle disorders (UCDs) is ornithine transcarbamylase deficiency, which is inherited in an X-linked manner. All of the others are autosomal recessive. The overall incidence of all urea cycle disorders is estimated at between 1/10,000 to 1/25,000, although patients with incomplete deficiency are likely significantly more common (Nagata, Matsuda et al. 1991). When the urea cycle function is absent or diminished, either by direct enzymatic deficiency or by secondary inhibition of the proximal four steps, nitrogen accumulates in the form of toxic ammonium. In null activity patients, this typically presents in the first days of life with hyperammonemia, resulting in central nervous system (CNS) dysfunction with overwhelming encephalopathy and coma, brain edema, seizures, and potentially death, with severe long-term neurodevelopmental sequelae if not rapidly reversed. The differential diagnosis of severe hyperammonemia includes organic acidemias, herpes-related hepatitis, and other disorders of liver function. Respiratory alkalosis and hyperventilation is classically seen in UCDs, although if encephalopathy progresses, apneas and acidosis may be seen (Burton 1998). If not recognized and reversed immediately, this may progress to fatal cerebral edema and herniation. There are multiple postulated mechanisms for ammonia-related neurotoxicity.