10 Kidney Disease and Hypertension in Pregnancy K idney disease and hypertensive disorders in pregnancy are disc ussed. Pregnancy in women with kidney disease is associated … The renal physiologic adjustments to pregnancy are reviewed, including hemodynamic and metabolic alterations. The common primary and secondary renal diseases that may occur in pregnant women also are discussed. Some considerations for the management of end-stage renal disease in pregnancy are given. Hypertensive disorders in pregnancy are far more common than is renal disease. Almost 10% of all pregnancies are complicated by either preeclampsia, chronic hypertension, or transient hypertension. Preeclampsia is of particular interest because it is associated with life-threatening manifestations, including seizures (eclampsia), renal failure, coagulopathy, and rarely, stroke. Significant progress has been made in our understanding of some of the pathophysiologic manifestations of preeclampsia; however, the cause of this disease remains unknown. The diagnostic categories of hypertension in pregnancy, pathophysiology of preeclampsia….
Changes in Renal Function During Pregnancy ? Uric acid reabsorption ? Urinary calcium ? Renin ? Urinary protein ? Aldosterone ? Sodium reabsorption ? Water reabsorption ? Glucosuria ? Aminoaciduria ? Renal blood flow Renal vasodilation ? Glomerular filtration rate ? Serum creatinine FIGURE 10-2 Changes in renal function during pregnancy. Marked renal hemodynamic changes are apparent by the end of the first trimester. Both the glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) increase by 50%. ERPF probably increases to a greater extent, and thus, the filtration fraction is decreased during early and mid pregnancy. Micropuncture studies performed in animals suggest the basis for the increase in GFR is primarily the increase in glomerular plasma flow . The average creatinine level and urea nitrogen concentration are slightly lower than in pregnant women than in those who are not pregnant (0.5 mg/d and 9 mg/dL, respectively). The increased filtered load also results in increased urinary protein excretion, glucosuria, and aminoaciduria. The uric acid clearance rates increase to a greater extent than does the GFR. Hypercalciuria is a result of increased GFR and of increases in circulating 1,25-dihydroxy-vitamin D 3 in pregnancy ( absorptive hypercalciuria ). The renin-angiotensin system is stimulated during gestation, and cumulative retention of approximately 950 mEq of sodium occurs. This sodium retention results from a complex interplay between natriuretic and antinatriuretic stimuli present during gestation … 10.3 Kidney Disease and Hypertension in Pregnancy A Altered osmoregulation: ? Serum sodium and ? Posm with ? Osmotic Threshold for the argenine vasopressin release and thirst C Mild hypokalemia may be observed due to ? glomerular filtration rate, ? urine flow, and ? aldosterone B Serum chloride levels are unchanged compared with women who are not pregnant D Mild respiratory alkalosis is associated with small decreases in plasma bicarbonate Na+ 136 mEq/L Cl- 104 mEq/L 3.7 mEq/L K+ 20 mEq/L HCO 3 50 120 60 70 80 90 100 110 4 8 12 16 20 24 28 32 36 40 PP Sitting Standing Gestation, wk Blood pressure, mmHg A * * * * * * * * * (7) (16) (18) (18) (18) (19) (18) (18)(15) (19) 4 8 12 16 20 24 28 32 3638 PP 0 2 4 6 8 10 12 14 PRA Postpartum angiotensinogen values ( N ) Gestation, wk PRA, ng/mL/h B Serum Electrolytes in Pregnancy FIGURE 10-3 Serum electrolytes in pregnancy. A, During normal gestation, serum osmolality decreases by 10 mosm/L and serum sodium (Na+) decreases by 5 mEq/L. A resetting of the osmoreceptor system occurs, with decreased osmotic thresholds for both thirst and vasopressin release . B, Serum chloride (Cl-) levels essentially are unchanged during pregnancy. C, Despite significant increases in aldosterone levels during pregnancy, in most women serum potassium (K+) levels are either normal or, on average, 0.3 mEq/L lower than are values in women who are not pregnant . The ability to conserve potassium may be a result of the elevated progesterone in pregnancy . D, Arterial pH is slightly increased in pregnancy owing to mild respiratory alkalosis. The hyperventilation is believed to be an effect of progesterone. Plasma bicarbonate (HCO- 3 ) concentrations decrease by about 4 mEq/L . Blood Pressure and the Renin-Aldosterone System in Pregnancy….
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