Hypernatremia, azotemia, and dehydration ue to high-protein tube feeding

Sodium and Potassium Dysregulation in the Patient With Cancer

Sodium and potassium disorders are pervasive in patients with cancer. The causes of these abnormalities are wide-ranging, are often primary or second-order consequences of the underlying cancer, and have prognostic implications. The approach to hyponatremia should focus on cancer-related etiologies, such as syndrome of inappropriate antidiuretic hormone, to the exclusion of other causes. Hypernatremia in non-iatrogenic forms is generally due to water loss rather than excessive sodium intake. Debilitated or dependent patients with cancer are particularly vulnerable to hypernatremia. Hypokalemia can occur in patients with cancer due to gastrointestinal disturbances, resulting from decreased intake or increased losses. Renal losses can occur as a result of excessive mineralocorticoid secretion or therapy-related nephrotoxicity. The approach to hyperkalemia should be informed by historical and laboratory clues, and pseudohyperkalemia is particularly common in patients with hematological cancers. Hyperkalemia can be seen in primary or metastatic disease that interrupts the adrenal axis. It can also develop as a consequence of immunotherapy, which can cause adrenalitis or hypophysitis. Tumor lysis syndrome (TLS) is defined by the development of hyperkalemia and is a medical emergency. Awareness of the electrolyte abnormalities that can befall patients with cancer is vital for its prompt recognition and management.

Polyuria in adults. A diagnostic approach based on pathophysiology

Polyuria is a common clinical condition characterized by a urine output that is inappropriately high (more than 3 L in 24 h) for the patient's blood pressure and plasma sodium levels. From a pathophysiological point of view, it is classified into two types: polyuria due to a greater excretion of solutes (urine osmolality >300 mOsm/L) or due to an inability to increase solute concentration (urine osmolality <150 mOsm/L). Sometimes both mechanisms can coexist (urine osmolality 150-300 mOsm/L). Polyuria is a diagnostic challenge and its proper treatment requires an evaluation of the medical record, determination of urine osmolality, estimation of free water clearance, use of water deprivation tests in aqueous polyuria, and measurement of electrolytes in blood and urine in the case of osmotic polyuria.

Nutrition Therapy, Glucose Control, and Brain Metabolism in Traumatic Brain Injury: A Multimodal Monitoring Approach

The goal of neurocritical care in patients with traumatic brain injury (TBI) is to prevent secondary brain damage. Pathophysiological mechanisms lead to loss of body mass, negative nitrogen balance, dysglycemia, and cerebral metabolic dysfunction. All of these complications have been shown to impact outcomes. Therapeutic options are available that prevent or mitigate their negative impact. Nutrition therapy, glucose control, and multimodality monitoring with cerebral microdialysis (CMD) can be applied as an integrated approach to optimize systemic immune and organ function as well as adequate substrate delivery to the brain. CMD allows real-time bedside monitoring of aspects of brain energy metabolism, by measuring specific metabolites in the extracellular fluid of brain tissue. Sequential monitoring of brain glucose and lactate/pyruvate ratio may reveal pathologic processes that lead to imbalances in supply and demand. Early recognition of these patterns may help individualize cerebral perfusion targets and systemic glucose control following TBI. In this direction, recent consensus statements have provided guidelines and recommendations for CMD applications in neurocritical care. In this review, we summarize data from clinical research on patients with severe TBI focused on a multimodal approach to evaluate aspects of nutrition therapy, such as timing and route; aspects of systemic glucose management, such as intensive vs. moderate control; and finally, aspects of cerebral metabolism. Research and clinical applications of CMD to better understand the interplay between substrate supply, glycemic variations, insulin therapy, and their effects on the brain metabolic profile were also reviewed. Novel mechanistic hypotheses in the interpretation of brain biomarkers were also discussed. Finally, we offer an integrated approach that includes nutritional and brain metabolic monitoring to manage severe TBI patients.

Hypernatremia due to Urea-Induced Osmotic Diuresis: Physiology at the Bedside

Hypernatremia secondary to urea-induced solute diuresis is due to the renal excretion of electrolyte-free water. This concept is explained here step-wise physiologically with the help of a clinical vignette.

Disease-specific, versus standard, nutritional support for the treatment of pressure ulcers in institutionalized older adults: a randomized controlled trial

OBJECTIVES

To investigate whether a disease-specific nutritional approach is more beneficial than a standard dietary approach to the healing of pressure ulcers (PUs) in institutionalized elderly patients.

DESIGN

Twelve-week follow-up randomized controlled trial (RCT).

SETTING

Four long-term care facilities in the province of Como, Italy.

PARTICIPANTS

Twenty-eight elderly subjects with Stage II, III, and IV PUs of recent onset (<1-month history).

INTERVENTION

All 28 patients received 30 kcal/kg per day nutritional support; of these, 15 received standard nutrition (hospital diet or standard enteral formula; 16% calories from protein), whereas 13 were administered a disease-specific nutrition treatment consisting of the standard diet plus a 400-mL oral supplement or specific enteral formula enriched with protein (20% of the total calories), arginine, zinc, and vitamin C (P<.001 for all nutrients vs control).

MEASUREMENTS

Ulcer healing was evaluated using the Pressure Ulcer Scale for Healing (PUSH; 0=complete healing, 17=greatest severity) tool and area measurement (mm(2) and %).

RESULTS

The sampled groups were well matched for age, sex, nutritional status, oral intake, type of feeding, and ulcer severity. After 12 weeks, both groups showed significant improvement (P<.001). The treatment produced a higher rate of healing, the PUSH score revealing a significant difference at Week 12 (-6.1+/-2.7 vs -3.3+/-2.4; P<.05) and the reduction in ulcer surface area significantly higher in the treated patients already by Week 8 (-1,140.9+/-669.2 mm(2) vs -571.7+/-391.3 mm(2); P<.05 and approximately 57% vs approximately 33%; P<.02).

CONCLUSION

The rate of PU healing appears to accelerate when a nutrition formula enriched with protein, arginine, zinc, and vitamin C is administered, making such a formula preferable to a standardized one, but the present data require further confirmation by high-quality RCTs conducted on a larger scale.

Alterations in fluid, electrolytes and other serum chemistry values and their relations with enteral tube feeding in acute brain infarction patients

AIMS AND OBJECTIVES

This study was performed to examine whether fluid and electrolyte levels are significantly altered after enteral tube feeding in acute brain infarction patients.

BACKGROUND

Results on the water and electrolyte complications associated with enteral tube feeding are inconsistent and this is partly because of uncontrolled disease-related variables.

DESIGN

Non-experimental design (retrospective study).

METHODS

This study was conducted by retrospectively reviewing the medical records of 85 tube-fed patients.

RESULTS

Mean values of major serum electrolytes (sodium, potassium and chloride) were not significantly altered by tube feeding. However, differences between fluid input and output were significantly increased after tube feeding. The incidence of dehydration reduced overall, while over-hydration increased.

CONCLUSION

The enteral tube feeding of iso-osmolar formulae appeared to be tolerated by most subjects in the present study in terms of electrolyte balance. However, fluid imbalance and over-hydration incidences were significantly increased after tube feeding.

RELEVANCE TO CLINICAL PRACTICE

Due to significant alterations in fluid balance after tube feeding, close attention to the recording of fluid balance, such as intake/output measurements, body weights and simple bedside assessments is needed to detect fluid imbalances and other serious complications at an early stage in enteral tube-feeding patients.

Hyperglycemic crises in diabetes mellitus type 2

Hyperglycemic crises in type 2 diabetes are not rare and are becoming increasingly recognized as part of the spectrum of the presentation of previously undiagnosed diabetes mellitus and the decompensation of established diabetes mellitus. Contributing factors and associations are being elucidated but remain far from clear, particularly in DKA states. Medications commonly used in the treatment of many comorbid illnesses in patients with diabetes can themselves predispose to HHS. Endocrinopathies can contribute to insulin resistance and directly increase the glycemic load, leading to hyperglycemia. Medications such as the protease inhibitors may in the future lead to a better understanding of the pathophysiology of the metabolic derangements seen in the development of type 2 diabetes mellitus.

The importance of the refeeding syndrome

In this review we discuss the refeeding syndrome. This potentially lethal condition can be defined as severe electrolyte and fluid shifts associated with metabolic abnormalities in malnourished patients undergoing refeeding, whether orally, enterally, or parenterally. It can be associated with significant morbidity and mortality. Clinical features are fluid-balance abnormalities, abnormal glucose metabolism, hypophosphatemia, hypomagnesemia, and hypokalemia. In addition, thiamine deficiency can occur. We describe which patient groups are more at risk for this syndrome and the clinical management of the condition.

Overfeeding macronutrients to critically ill adults: metabolic complications

Metabolic complications from overfeeding critically ill patients are serious and sometimes fatal. Nutrition care is best provided through repeated evaluation of patients' responses to feeding. Nutrition support may need to be modified over time to maintain metabolic stability and promote recovery. This article describes the etiology of 10 metabolic complications of overfeeding. Guidelines for recommending macronutrients are discussed, as are factors that could increase the risk of overfeeding. Patients who are very small, very large, or very old are particularly vulnerable to overfeeding. Overfeeding protein has led to azotemia, hypertonic dehydration, and metabolic acidosis. Excessive carbohydrate infusion has resulted in hyperglycemia, hypertriglyceridemia, and hepatic steatosis. High-fat infusions have caused hypertriglyceridemia and fat-overload syndrome. Hypercapnia and refeeding syndrome have also been caused by aggressive overfeeding. Dietitians can prevent or curtail the metabolic complications of overfeeding by identifying patients at risk, providing adequate assessment, coordinating interdisciplinary care plans, and delivering timely and appropriate monitoring and intervention. Dietitians need to document complications, interventions, and the outcomes of their clinical care to evaluate the appropriateness of existing nutrition guidelines.

Nonketotic hypertonicity in diabetes mellitus

Nonketotic hypertonicity (NKH) is one of the most common endocrine emergencies. It is more common in the elderly patient with noninsulin-dependent diabetes mellitus but may occur in insulin-dependent diabetes as well. Although there are many possible precipitating causes, the final common pathway is usually decreased access to water. Treatment consists of vigorous hydration, electrolyte replacement, and small amounts of insulin. Most deaths from NKH occur in the first 2 days of hospitalization; therefore, a significant decrease in morbidity and mortality can be expected by education of patients and their caregivers in the prevention of NKH.

The burden and outcomes associated with dehydration among US elderly, 1991

OBJECTIVES

Dehydration has been underappreciated as a cause of hospitalization and increased hospital-associated mortality in older people. This study used national data to analyze the burden and outcomes following hospitalizations with dehydration in the elderly.

METHODS

Data from 1991 Medicare files were used to calculate rates of hospitalization with dehydration, to examine demographic characteristics and concomitant diagnoses associated with dehydration, and to analyze the contribution of dehydration to mortality.

RESULTS

In 1991, 6.7% (731,695) of Medicare hospitalizations had dehydration listed as one of the five reported diagnoses, a rate of 236.2/10,000 elderly Medicare beneficiaries. In 1991, Medicare reimbursed over $446 million for hospitalizations with dehydration as the principal diagnosis. Older people, men, and Blacks had elevated risks for hospitalization with dehydration. Acute infections, such as pneumonia and urinary tract infections, were frequent concomitant diagnoses. About 50% of elderly Medicare beneficiaries hospitalized with dehydration died within a year of admission.

CONCLUSIONS

Hospitalization of elderly people with dehydration is a serious and costly medical problem. Attention should be focused on understanding predisposing factors and devising strategies for prevention.

Protein-induced hyperthermia for liver cancer treatment

It is suggested that the thermic effect of protein be exploited as a means of hyperthermia therapy in the treatment of liver cancer. Oral ingestion of high amounts of protein or intravenous amino acid therapy could generate heat directly within the hepatocytes primarily through urea synthesis. This approach could enhance the effects of conventional hyperthermia or radiation therapy.

New approach to disturbances in the plasma sodium concentration

Hyponatremia and hypernatremia are among the most common electrolyte disorders. Since the plasma sodium level is determined by the ratio between the total quantity of effective solutes (primarily sodium and potassium salts) and the total body water, abnormalities in the plasma sodium level must be produced by a change in one or more of these parameters. In most patients, alterations in body water are of primary importance because the plasma sodium level is normally regulated by changing water intake and water excretion. Measurement of free water excretion has traditionally been calculated by using a formula that includes the urine osmolality. However, urea is a major urinary solute but does not contribute to regulation of the plasma sodium level, since it is an ineffective osmole. As a result, urinary solute excretion is best expressed as 2 X UNa+K. Making this important correction allows solute and water intake and excretion to be compared, thereby leading to a better understanding of both the development and correction of disturbances in the plasma sodium level.

Adverse metabolic consequences of nutritional support: macronutrients

The administration of a complete and well-balanced diet commensurate with the requirements and limitations of individual patients is essential to obtain maximal benefit of nutritional therapy. Complications related to the provision of nutritional therapy must be considered when providing nutrition support to patients with malignant diseases. Some of these complications are not exclusive of the form of therapy, whereas others are inherent in the different components of nutrient solutions used. A sound knowledge of clinical nutrition as well as the establishment of nutrition support teams will help to reduce the incidence of adverse reactions related to the nutritional treatment. Further research is necessary to understand better the mechanisms of malnutrition in cancer patients and the mechanisms by which several organs and systems are adversely affected during nutrition support. New methods and devices will lead to a more efficacious administration of nutritional requirements.

Diagnostic strategies in disorders of fluid, electrolyte and acid-base homeostasis

Our understanding of the physiology and biochemistry of acid-base and fluid-electrolyte regulations has greatly expanded in recent years. Key physiologic principles have emerged that now permit rational diagnosis and therapy of clinical disorders of serum electrolyte concentration. This paper describes diagnostic strategies based upon these principles. The etiology of the myriad factors in hyponatremia is best derived by first measuring serum tonicity and then assessing extracellular fluid volume. The hyper-, iso- and hypotonic hyponatremia are defined, and the hypotonic group is subclassified into hypo-, iso- and hyper volemic forms. The hypernatremias are best categorized by their state of volume expansion. Classification into the hypo-, hyper- and isovolemic hypernatremias simplifies their diagnosis. Metabolic acidoses are classified in terms of the anion gap. Clinical and chemical aspects of increased and normal anion gap acidoses are described. Metabolic alkaloses require a source of new bicarbonate and its retention by the kidney. The means by which new alkali is synthesized and urinary loss prevented serve to effectively classify the alkaloses. Hypokalemic syndromes are defined in terms of associated changes in body potassium. The potassium-depleted states are further subclassified by whether normotension or hypertension is associated. Hyperkalemia is produced by redistribution of cellular and extracellular potassium or by increased body potassium. Defects in the renin-angiotensin-aldosterone-distal renal tubule effector arm usually underlie hyperkalemic states, which are than classified in terms of this regulatory hormonal cascade. Classifications for disordered serum concentrations of calcium, magnesium, phosphorus and uric acid are presented. Hormonal, metabolic and renal regulatory factors form the basis for an organized approach to these disorders.

Hyperosmolar nonketotic coma in the elderly diabetic

The gravity of this syndrome of severe diabetic stupor without ketosis may not be recognized because patients are usually middle-aged or elderly with mild diabetes. A lack of urgency in treating these patients is probably the cause of the widely reported mortality of 40 to 70 per cent.

Osmolality measurements in heart disease

A study of the variations of plasma and urinary osmolality in patients with acute myocardial infarction and heart failure of different origin was made. It was shown that the plasma osmolality may be related to the clinical evolution of heart disease. The effectiveness of monitoring the osmolality in establishing the alterations of water-electrolyte balance is also reported.

Nonketotic hyperglycemic hyperosmolar coma. Report of neurosurgical cases with a review of mechanisms and treatment

Seventy-eight critically ill patients who died while on the neurosurgical service were studied retrospectively to establish the prevalence of nonketotic hyperglycemic hyperosmolar coma (NHHC). All the patients had been comatose before death, and all underwent necropsy. Criteria for the diagnosis of NHHC included moderate-to-severe hyperglycemia with glucosuria, absence of significant acetonuria, hyperosmolarity with dehydration, and neurological dysfunction. This study revealed seven cases of unequivocal NHHC (9%), and six of hyperosmolarity but with incomplete records. Five of the seven confirmed cases of NHHC demonstrated no evidence of cerebral edema transtentorial herniation, or brain-stem damage, and showed central nervous system (CNS) lesions compatible with survival. Fatal complications of this syndrome, such as acute renal failure, terminal arrhythmias, and vascular accidents, both cerebral and systemic, were common in this series. The mechanism of coma in NHHC is believed related to shifts of free water from the cerebral extravascular space to the hypertonic intravascular space, with subsequent intracellular dehydration, accumulation of metabolic products of glucose, and brain shrinkage. It is uncertain whether injury to specific areas in the CNS is a predisposing factor to the development of NHHC. Factors documented to be significant in its development include nonspecific stress to primary illnesses, hyperosmolar tube feedings, dehydration, diabetes and mannitol, Dilantin, or steroid administration.

Hypernatremia following gastrointestinal bleeding in cirrhosis with ascites

3 patients with hepatic cirrhosis and ascites underwent increased diuresis on six occasions, closely related to episodes of gastrointestinal bleeding. In each instance the increased urine volume was preceded by a sharp increase in blood urea nitrogen, presumably due to absorption of nitrogenous compounds from the gastrointestinal tract, suggesting a mechanism of osmotic diuresis. In each case there was a signigicant increase in serum sodium and osmolality, related to the greater-water-than-sodium diuresis induced by urea, which was promptly reversed by the administration of water or isotonic solution. Clinically this syndrome may be defined as the association of hypernatremia and hyperosmolality due to osmotic diuresis from urea appearing in a cirrhotic patient with ascites and gastrointestinal bleeding.