Ontogeny of renal sodium transport

Urinalysis in patients with neuromyelitis optica spectrum disorder

BACKGROUND AND PURPOSE

Increasing evidence has demonstrated that aquaporin-4 (AQP4) immunoglobulin G causes damage to the kidney in neuromyelitis optica spectrum disorder (NMOSD). However, changes in urinalysis in NMOSD have not been investigated thus far. Our objective was to evaluate the changes in urinalysis in NMOSD patients.

METHODS

Case data were collected from 44 patients with AQP4 antibody-positive NMOSD, 53 patients with multiple sclerosis (MS) and 79 age- and sex-matched healthy controls. Analyses of early morning urine and 24-h urine samples comparing NMOSD with MS patients were conducted.

RESULTS

In the acute phase, urine pH levels (P < 0.001) and urine specific gravity levels (P < 0.001) from NMOSD patients were significantly higher and lower, respectively, than for MS patients. 24-h urine sodium and 24-h urine volume from NMOSD patients were significantly higher than for MS patients (both P = 0.001). A 24-h urine volume higher than 2500 ml (odds ratio 11.7, 95% confidence interval 1.863-73.066) and a 24-h urine sodium higher than 200 mmol (odds ratio 16.0, 95% confidence interval 2.122-120.648) are more likely to occur in NMOSD patients in the acute phase than in MS patients.

CONCLUSIONS

The urinalysis results were significantly different between NMOSD patients and MS patients. The pathophysiological changes in AQP4 antibody-positive NMOSD patients were not limited to the central nervous system.

Assessment Considerations in Pediatric Patients

Pharmacy assessment of pediatric patients is similar in many ways to that of adults; however there are many specific nuances that need to be considered in addition to the typical aspects included in an adult assessment. There is a lack of pediatric-specific medication research and a much higher rate of “off label” medication use, so children are at higher risk of medication errors and related harm. Pharmacokinetic differences and other age-related differences result in highly variable responses to medications throughout childhood. Pharmacists need to be aware of this variability and use every patient encounter as an opportunity for assessment of many aspects of medication including dose, formulation, administration, and indication. Infants and children also have physiological differences that need to be considered especially when assessing efficacy, toxicity, and the patient’s overall response to medications through physical exam or use of laboratory values. Lastly, a lack of appropriate medication formulations for children creates a requirement for pharmacists to specifically assess the formulations, measurement, and administration of pediatric medications. This chapter provides an approach to pediatric assessment, highlights common sources of error, and provides strategies for managing pediatric medications.

Role of the kidney in the fetal programming of adult cardiovascular disease: an update

It is well established that an adverse in utero environment can impinge upon fetal development and place the offspring on a track leading to future cardiovascular disease. Significantly, this may occur in the absence of any outward manifestations at birth. In this brief review, we focus on potential renal mechanisms that lead to adaptations in glomerular and tubular function that initiate hypertension of developmental origin and examine potential therapeutic interventions. This report updates recent data in this field.

Renal programming: cause for concern?

Development of the kidney can be altered in utero in response to a suboptimal environment. The intrarenal factors that have been most well characterized as being sensitive to programming events are kidney mass/nephron endowment, the renin-angiotensin system, tubular sodium handling, and the renal sympathetic nerves. Newborns that have been subjected to an adverse intrauterine environment may thus begin life at a distinct disadvantage, in terms of renal function, at a time when the kidney must take over the primary role for extracellular fluid homeostasis from the placenta. A poor beginning, causing renal programming, has been linked to increased risk of hypertension and renal disease in adulthood. However, although a cause for concern, increasingly, evidence demonstrates that renal programming is not a fait accompli in terms of future cardiovascular and renal disease. A greater understanding of postnatal renal maturation and the impact of secondary factors (genes, sex, diet, stress, and disease) on this process is required to predict which babies are at risk of increased cardiovascular and renal disease as adults and to be able to devise preventative measures.

Physiological partial aldosterone resistance in human newborns

In the neonatal period, the human kidney is characterized by an impaired ability to regulate water and sodium homeostasis, resembling partial aldosterone resistance. The aim of our study was to assess this hormonal insensitivity in newborn infants and to determine its relationship with neonatal sodium handling. We conducted a prospective study in 48 healthy newborns and their mothers. Aldosterone, renin, and electrolyte concentrations were measured in umbilical cords and in maternal plasma. Urinary aldosterone concentrations and sodium excretion were determined at urination within 24 h after birth. A significant difference was observed between aldosterone and renin levels in newborn infants compared with their mothers (817 +/- 73 versus 575 +/- 55 pg/mL and 79 +/- 10 versus 15 +/- 2 pg/mL, respectively, p < 0.001). This hyperactivation of the renin-angiotensin-aldosterone system was associated with hyponatremia and hyperkalemia in the newborn infants, and high urinary sodium loss, consistent with a partial aldosterone resistance at birth. Unlike plasma aldosterone, urinary aldosterone concentration was found highly correlated with plasma potassium concentrations, thus representing the best index for accurate evaluation of mineralocorticoid sensitivity. Our study represents a comprehensive characterization of the renin-aldosterone axis in newborn infants and provides evidence for physiologic partial aldosterone resistance in the neonatal period.