Renal parenchymal disease in Obstretic patients.pptx

In depth understanding of renal parenchymal diseases in pregnancy

1. Renal parenchymal disease

2. Introduction Renal parenchymal disease consists of two general groups Glomerulopathies Tubulointerstitial The incidence of kidney disease in pregnancy is approximately 0.12%. In two thirds of these patients, the disorder results from glomerulopathy, and in one third, from tubulointerstitial disease.

3. Introduction Patients with renal parenchymal disorders may remain asymptomatic for years, and they may exhibit only proteinuria and microscopic hematuria, with little if any evidence of reduced renal function. Spontaneous recovery or improvement with treatment occurs with many glomerulopathies. However, other patients exhibit progressive nephropathy, hypertension, and renal insufficiency

4. Glomerulopathies Nephritic syndromes Disorders that involve inflammatory or necrotizing lesions Nephrotic syndromes Disorders that involve abnormal permeability to protein and other macromolecules

5. Tubulointerstitial diseases These are disorders characterized by abnormal tubular function. They result in abnormal urine composition and concentration but are not characterized by decreased GFR until late in the disease course. The disorders in this category include interstitial nephritis, renal cystic disease, renal neoplasia, and functional tubular defects.

6. Diagnosis Serial blood pressure measurements are obtained to define the severity of hypertension and the efficacy of current antihypertensive therapy. Creatinine clearance and the level of proteinuria should be determined. Urinalysis yields information about the presence of renal casts and bacteriuria. The determination of serum creatinine and BUN concentrations defines the extent of renal insufficiency. A serum creatinine concentration greater than 0.8 mg/dL, which may be normal in the nonpregnant woman, may represent significant renal insufficiency during pregnancy

7. Diagnosis Both preeclampsia and renal disease may manifest as hypertension, proteinuria, and edema. The distinction between the two disorders is often unclear, especially after 20 weeks’ gestation. Histologic evidence of preeclampsia(e.g., glomerular endotheliosis without hypercellularity) was present in only 65% of these hypertensive women. Because renal biopsy exposes the pregnant woman to potential complications, many perinatologists recommend biopsy only when sudden deterioration in renal function or symptomatic nephrotic syndrome occurs before 28 weeks’ gestation, at which time definitive diagnosis may guide appropriate treatment

8. Effect of Pregnancy on Preexisting Kidney Disease The extent to which pregnancy affects preexisting renal disease depends on the level of renal insufficiency before pregnancy. Among women with mild antenatal renal insufficiency, pregnancy does not substantially alter the natural course of renal disease. With a serum creatinine concentration greater than 2.0 mg/dL who become pregnant have a one-in-three chance of developing dialysis-dependent end-stage renal disease during or shortly after pregnancy.

9. Effect of Pregnancy on Preexisting Kidney Disease The pathophysiology by which pregnancy exacerbates renal disease is unknown. One hypothesis is that increased glomerular perfusion, which normally accompanies pregnancy, paradoxically causes further injury to the kidneys in patients with preexisting impairment of function. An alternative hypothesis is that preexisting renal disease may induce a cascade of platelet aggregation, microvascular fibrin thrombus formation, and endothelial dysfunction that leads to microvascular injury in the already tenuous kidneys

10. Effect on the Mother and Fetus Pregnant women with chronic kidney disease are at an increased risk for maternal and fetal complications. Maternal complications(5 times greater) include gestational hypertension, preeclampsia/eclampsia, and maternal mortality. Adverse fetal outcomes(2 times greater) included preterm births, fetal growth restriction, small-for-gestational-age infants, neonatal mortality, stillbirths, and low birth weight Preexisting hypertension and a high preconception serum uric acid level predicted worse outcome.

11. Medical and Obstetric Management During pregnancy, the nephrologist and the obstetrician monitor maternal renal function, blood pressure, and fetal development at frequent intervals. Monthly determination of serum creatinine concentration, creatinine clearance, and proteinuria allows the recognition of renal deterioration. Some glomerulopathies respond to corticosteroids, and corticosteroid therapy should be continued during pregnancy. Recombinant human erythropoietin improves maternal anemia during pregnancy.

12. Hemodialysis and Long-Term Ambulatory Peritoneal Dialysis When renal disease has progressed to end-stage renal failure (i.e., GFR < 5 mL/min), fertility is suppressed and conception and pregnancy are rare. Less than 10% of premenopausal patients undergoing dialysis have regular menses. Luteinizing hormone and follicle-stimulating hormone concentrations assume an anovulatory pattern, which causes 40% of affected women to be amenorrheic. Half of all female patients undergoing dialysis exhibit hyperprolactinemia because of reduced clearance and hypothalamic disturbances.

13. Hemodialysis Extracorporeal hemodialysis vascular access and the need for anticoagulation of the extracorporeal circuit and may be complicated by cardiovascular instability, large fluid and electrolyte shifts, and the risk for hepatitis. Hypotension may compromise uteroplacental perfusion and cause fetal compromise. Even when hypotension and major fluid shifts are avoided, Doppler ultrasonographic examination of uterine and umbilical artery flow during hemodialysis suggests the occurrence of a redistribution of arterial flow away from the uteroplacental vascular bed. Fetal heart rate monitoring is recommended during dialysis. Rapid removal of maternal solutes and reduced oncotic pressure with attendant free-water diffusion into the amniotic cavity may lead to polyhydramnios. Hemodynamic consequences are minimized by more frequent but shorter dialysis runs.

14. Peritoneal Dialysis Intracorporeal Long-term ambulatory peritoneal dialysis allows less hemodynamic trespass, a more stable fetal environment, and the freedom to undergo dialysis at home. However, peritoneal dialysis may not be associated with greater fetal survival. Complications of this modality include peritonitis and catheter difficulties. 71% of women undergoing hemodialysis and 64% of women undergoing peritoneal dialysis have a successful delivery

15. Maternal complications These include malnutrition, anemia, and hypertension. Fetal complications include fetal growth restriction, fetal death, and preterm labor. BUN levels should be kept below 50 mg/dL before dialysis and below 30 mg/dL after dialysis. At birth, azotemia in the newborn is similar to that in the mother, but this quickly corrects because the newborn has normal kidney function. Patients undergoing hemodialysis have a high prevalence of viral hepatitis, a greater frequency of active tuberculosis, and a higher rate of infection HIV, HCV and MRSA.

16. Anaesthetic Management Anesthetic management is influenced by the extent of renal dysfunction and hypertension. The parturient with stable renal disease, mild to moderate renal insufficiency, well-controlled hypertension, and euvolemia requires minimal special consideration. In contrast, the dialysis patient with end-stage renal failure presents many anesthetic challenges because renal disease may affect almost every organ system.

17. Cardiovascular Hypertension Fluid overload Ventricular hypertrophy Accelerated atherosclerosis Uremic pericarditis Uremic cardiomyopathy

18. Pulmonary Increased risk of difficult airway Recurrent pulmonary infections Pleural effusion

19. Metabolic and endocrine Hyperkalemia Metabolic acidosis Hyponatremia Hypocalcemia Hypermagnesemia Decreased protein binding of drugs Hypoglycemia

20. Hematologic Anemia Platelet dysfunction Decreased coagulation factors Leukocyte dysfunction

21. Neurologic Autonomic neuropathy Mental status changes Peripheral neuropathy Restless legs syndrome Seizure disorder

22. Gastrointestinal Delayed gastric emptying Increased gastric acidity Hepatic venous congestion Hepatitis (viral or drug-induced) Malnutrition

23. Neurologic Autonomic neuropathy Peripheral neuropathy Cerebrovascular insufficiency

24. Neuraxial Anaesthesia Neuraxial anesthesia is the preferred technique for both labor analgesia and cesarean delivery, but there are some unique considerations in the parturient with renal disease. Uremic patients may be hypervolemic or hypovolemic, depending on the time elapsed since their last dialysis session. Hypovolemia and autonomic neuropathy may lead to profound hypotension during the initiation of sympathetic blockade. Intravascular volume should be assessed before induction of anesthesia. Assessment of clinical signs (e.g., skin turgor, mucous membranes, tachycardia) is generally sufficient.

25. Neuraxial Anaesthesia Frequent monitoring of blood pressure and immediate treatment of hypotension is suggested. Preexisting peripheral neuropathy should be documented before the administration of neuraxial anesthesia Administering spinal anesthesia Maximal segmental anesthesia occurred more rapidly in the patients with renal disease compared to normal parturients , but the duration was reduced. Further, the extent of sensory blockade was two segments higher in the patients with renal disease.

26. General Anaesthesia Patients with chronic uremia exhibit delayed gastric emptying and hyperacidity, which may increase the risk for aspiration pneumonitis. All the standard induction agents are safe in patients with renal failure. Etomidate may have an advantage because it supports the circulation better than other induction agents. Propofol exhibits normal volume of distribution and elimination in patients with renal failure and is also commonly used. Uremia increases blood brain barrier permeability, these changes may warrant a small reduction in the dose of propofol or thiopental for induction.

27. General Anaesthesia The serum potassium concentration should be determined before induction of anesthesia. If the potassium concentration is greater than 5.5 mEq /L, dialysis should be performed before an elective procedure. Succinylcholine will cause a 0.5 to 0.7 mEq /L increase in potassium concentration, which is similar to the increment that occurs in patients without renal disease. If the patient is already hyperkalemic, this mild elevation may be sufficient to precipitate cardiac dysrhythmias

28. General Anaesthesia Plasma cholinesterase concentrations are normal, even after dialysis, and the duration of action of succinylcholine is not prolonged. Neuromuscular blockade should be maintained with an agent that does not rely on renal elimination. Hypermagnesemia, commonly found in patients with kidney disease, may potentiate neuromuscular blockade. Although anticholinesterase agents undergo renal elimination and have a prolonged duration in patients with renal insufficiency, the volume of distribution remains the same and standard doses are used for the reversal of neuromuscular blockade

29. Postoperative Analgesia The principles of postoperative analgesia for the woman with renal disease are the same as for healthy woman, with some important considerations because drug clearance can be altered for opioids and their metabolites. Morphine is generally safe as a single dose, but with longer-term use its metabolite, morphine-6-glucuronide, may accumulate. Meperidine is of particular concern because its active metabolite, normeperidine, is neurotoxic and is renally excreted. Hydromorphone and oxycodone, and their metabolites hydromorphone-3-glucuronide and α- and β- oxycodol , respectively, are also renally excreted and may accumulate with prolonged use.

30. Postoperative Analgesia Methadone does not accumulate in patients with renal disease and may be a useful long-term analgesic. Fentanyl and sufentanil are only minimally excreted in the urine, and because they are short-acting drugs they may be particularly useful. Remifentanil is metabolized by blood and tissue esterases and is not dependent on the kidney for excretion, making it safe as well for use in patients with renal failure. The safest approach may be to use neuraxial opioids because small doses are administered. Alternative techniques that avoid opioids such as transversus abdominis plane (TAP) block may also be considered.

31. Acute renal failure

32. Introduction Acute renal failure (ARF) is an uncommon but serious complication of pregnancy. Rapid deterioration of renal function leads to an accumulation of fluid and nitrogenous waste products with impaired electrolyte regulation. In the mid-20th century, nearly a fourth of all cases of ARF were obstetric. The incidence of ARF from 1 in 3000 to 1 in 18,000 pregnancies from 1958 to 1994. The proportion related to pregnancy decreased from 43% to 0.5%. This progress has resulted from improved obstetric care and fewer septic abortions.

33. Pathophysiology and Diagnosis ARF is suggested by a sharp increase in the plasma creatinine (> 0.8 mg/dL) and BUN (> 13 mg/dL) concentrations. In complete renal failure, the serum creatinine concentration increases at the rate of 0.5 to 1.0 mg/dL/day. Urine output typically decreases to less than 400 mL/ day (oliguria), but some patients may be nonoliguric . In developing countries septic abortion is the leading cause of pregnancy related ARF. In developed countries, severe preeclampsia/eclampsia, acute pyelonephritis of pregnancy, and bilateral renal cortical necrosis are the most common underlying disorders

34. Causes of Acute Renal Failure during Pregnancy PRERENAL Hyperemesis gravidarum Uterine hemorrhage Heart failure POSTRENAL Urolithiasis Ureteral obstruction by the gravid uterus Drug-induced acute INTRARENAL Acute tubular necrosis Septic abortion Amniotic fluid embolism Drug-induced acute interstitial nephritis Acute glomerulonephritis Bilateral renal cortical necrosis Acute pyelonephritis Preeclampsia/eclampsia Hemolysis , elevated liver enzymes, and low platelets (HELLP) syndrome Acute fatty liver of pregnancy Idiopathic postpartum renal failure

35. Prerenal Causes The most common prerenal causes of ARF hyperemesis gravidarum and obstetric hemorrhage—lead to hypovolemia and inadequate renal perfusion. Urinary indices show urinary osmolality greater than 500 mOsm /kg water, urine sodium less than 20 mEq /L. Concealed uterine hemorrhage from placental abruption may remain unrecognized until hypotension and renal failure ensue. Women with preeclampsia may be more likely to develop ARF after hemorrhage because of preexisting intravascular contraction and widespread maternal endothelial dysfunction. Women who developed preeclampsia during pregnancy, with or without renal failure, are more likely to develop renal failure later in life.

36. Intrarenal Causes An intrarenal cause is diagnosed once prerenal and postrenal causes of ARF have been excluded. In general, oliguric intrarenal ARF is not easily reversed and must run its course. A thorough history, review of medications, and urinalysis typically help determine the specific initiating factor.

37. Acute tubular necrosis Results from nephrotoxic drugs, amniotic fluid embolism, rhabdomyolysis, intrauterine fetal death, and prolonged renal ischemia secondary to hemorrhage or septic shock. Urinalysis demonstrates dirty brown epithelial cell casts and coarse granular casts. Urinary indices show urine osmolality less than 350 mOsm /kg water, urine sodium concentration greater than 40 mEq /L, fractional sodium excretion greater than 1%, and a urinary-to-plasma creatinine ratio less than 20.

38. Acute interstitial nephritis Is caused by nonsteroidal anti-inflammatory drugs (NSAIDs) and various antibiotics. Patients typically have fever, rash, eosinophilia, and urine eosinophils.

39. Acute glomerulonephritis Is rare during pregnancy. It is suggested by hematuria, red cell casts, and proteinuria. Urinary indices of acute glomerulonephritis are similar to those of prerenal ARF.

40. Bilateral renal cortical necrosis This is rarely observed in the non obstetric patient, is responsible for 10% to 38% of cases of obstetric ARF. It may occur during early or late pregnancy. Hemorrhage is the most common precipitating event. The pathogenesis of this disorder is unclear but may involve renal hypoperfusion or endothelial damage by endotoxins imposed on the normal hypercoagulable state of pregnancy. Extensive microthrombi are found within the glomeruli and renal arterioles. Diagnosis is made by selective renal arteriography, which reveals absence or patchiness of blood flow in the cortex. Renal biopsy may also be performed in the absence of active coagulopathy

41. Acute pyelonephritis Is one of the most common infectious complications of pregnancy. Although acute pyelonephritis rarely leads to ARF in the nongravid patient, it accounts for 5% of cases of ARF among pregnant women.53 The reason for this greater susceptibility is unclear. It causes a marked reduction of GFR in pregnant women. In contrast, pyelonephritis causes little reduction in GFR in nonpregnant patients. This may be due to increased sensitivity of kidney to bacterial endotoxins during pregnancy.

42. Severe preeclampsia/eclampsia

43. Acute fatty liver of pregnancy

44. Idiopathic postpartum renal failure Initially described in 1968 by Robson et al, this syndrome is characterized by ARF, microangiopathic hemolytic anemia, and thrombocytopenia occurring 2 days to 10 weeks after an uncomplicated delivery. It appears closely related to the hemolytic uremic syndrome. Idiopathic postpartum renal failure is typically preceded by a viral upper respiratory tract or gastrointestinal syndrome that rapidly progresses to ARF. The use of ethinyl estradiol as a contraceptive may also be related to this syndrome

45. Idiopathic postpartum renal failure Spontaneous bleeding, congestive heart failure, hypertension, and seizures have been reported with this syndrome. Some believe that this syndrome represents a clinically to the generalized Shwartzman reaction, a condition induced in laboratory animals by two successive injections of endotoxin, which results in factor XII activation, thrombin generation, and fibrin deposition. Others consider the platelet deposition to be the primary event that leads to microvascular thrombi. Management involves plasma exchange transfusion, dialysis, and antiplatelet therapy. The role of heparin is controversial.

46. Postrenal Causes The postrenal causes of ARF include nephrolithiasis and ureteral obstruction by the gravid uterus. The latter complication is more likely in pregnant women with polyhydramnios or multiple gestation. Preexisting ureteral dilation and impaired peristalsis increase the risk for obstructive uropathy during pregnancy. Flank pain and decreased urine output during late gestation should alert the clinician to this possibility.

47. Effect on the Mother and Fetus Although maternal prognosis has improved significantly in developed countries, mortality ranges between 20% and 30% in developing countries. The prognosis for the fetus is worse than for the mother. Reported fetal mortality is as high as 40% to 50%. Two groups reported much lower mortality rates (0% to 13%) with the use of aggressive hemodialysis (six times per week with the goal of maintaining the blood urea nitrogen level < 50 mg/dL)

48. Medical and Obstetric Management Reversible disorders such as hypovolemia, concealed uterine hemorrhage, urinary tract infection, ureteral obstruction, and drug-induced ARF must be excluded. Intravascular volume should be optimized. Electrolyte and acid-base status should be monitored carefully. Hypertension and preeclampsia must be managed aggressively. Many obstetric causes of ARF also may cause disseminated intravascular coagulation; therefore, coagulation abnormalities should be excluded in pregnant women with ARF.

49. Medical and Obstetric Management Because urea and other metabolic products cross the placenta, hemodialysis or peritoneal dialysis should be directed toward maintaining the post-dialysis BUN concentration at or below 30 mg/dL. Fluid shifts during hemodialysis should be minimized by short but frequent periods of dialysis. If the fetus is mature, delivery should be accomplished when the maternal condition is stabilized. The pediatrician must be alerted to the presence of high fetal BUN levels, which may lead to an osmotic diuresis and neonatal dehydration.

50. Anaesthetic Management A multidisciplinary approach involving anesthesiologists, obstetricians, and nephrologists should be employed to optimize the maternal condition before the induction of labor or performance of cesarean delivery in a woman with ARF. If the BUN level is greater than 80 mg/dL or the serum potassium concentration greater than 5.5 mEq /L, dialysis should be performed before elective vaginal or cesarean delivery. Neuraxial anesthesia may be administered in the absence of coagulopathy, thrombocytopenia, and severe hypovolemia. Intravenous fluid without potassium (e.g., 0.9% saline) should be administered.

51. Anaesthetic Management Occult uterine hemorrhage should be excluded, and hypertension, if present, controlled. Both spinal and epidural analgesia/ anesthesia are safe and preferred to general anesthesia. As the sympathetic blockade dissipates, the mother should be monitored for evidence of volume overload and pulmonary edema. General anesthesia may be required for urgent cesarean delivery or in patients with coagulopathy or hemorrhage.

52. Renal transplantation Although pregnancy is uncommon in women undergoing long-term dialysis, fertility is improved within months of transplantation. United States, a pregnancy rate of 20 per 1000 was estimated in transplanted patients compared with 100 per 1000 in the general population. Although a successful obstetric outcome can be anticipated in more than 95% of kidney transplant recipients, they are at greater risk for both maternal and fetal complications than healthy women. The incidences of preeclampsia (27%), gestational diabetes (8%), cesarean delivery (56.9%), and preterm delivery (45.6%) were greater than in the general population.

53. Effect of Pregnancy on the Renal Allograft When a kidney is removed from a donor and transplanted into an anephric recipient, it undergoes a process of hyperfiltration. This is a maladaptive response that, in the short term, attempts to bring the GFR toward the rate of a bi-nephric system. In the long term, this hyperfiltration may lead to glomerular sclerosis and loss of renal function if it is associated with increased glomerular or capillary pressure. In normal pregnancy, the GFR increases by 30% to 50% during the first and second trimesters and subsequently decreases during the third trimester. Theoretically, this additional hyperfiltration of pregnancy predisposes the patient to a loss of renal function.

54. Effect of Pregnancy on the Renal Allograft Baylis et al. allayed many of these concerns by demonstrating that gestational hyperfiltration is not associated with increased glomerular pressure because of matching afferent and efferent arteriolar vasodilation. There have been a number of studies assessing graft function after pregnancy. Most studies suggest that there is no adverse effect provided renal function is normal before conception and there is no evidence of hypertension.

55. Effect on the Fetus Although pregnancy seems to have minimal effect on maternal health or allograft survival in renal transplant recipients, fetal outcome is less favorable. Spontaneous or elective abortion occurred in 14% in the remaining successful pregnancies were complicated by preterm delivery (45%) and fetal growth restriction (86%). Most post-transplantation protocols consist of a primary immunosuppressant (cyclosporine or tacrolimus) and one or two adjunctive agents (azathioprine, mycophenolate mofetil, sirolimus, and/or corticosteroids). Despite transplacental exposure to immunosuppressant drugs, congenital anomalies and other adverse effects are not greater than in the general population

56. Effect on the Fetus There have been reports of congenital defects with mycophenolate mofetil, including cleft lip and palate, microtia, absence of auditory canals, brachydactyly of the fifth finger, and hypoplastic toenails; therefore, its use has to be weighed against the risk for allograft rejection. Intrauterine exposure to cyclosporine impairs development and function of T, B, and NK lymphocytes in neonates. This effect, persists during the first year of life. These factors place the infant at risk for a suboptimal immunologic response after administration of classic vaccines and for adverse effects after administration of live, attenuated vaccines.

57. Effect on the Fetus Transplant recipients may become infected with cytomegalovirus (CMV) at the time of transplantation, or they may experience reactivation secondary to immunosuppression. Active CMV infection during pregnancy is associated with congenital anomalies (e.g., cerebral cysts, microcephaly, mental retardation). In addition, active neonatal CMV infection may lead to serious illness or death.

58. Medical and Obstetric Management The renal transplant recipient’s immunosuppressant regimen must be continued during pregnancy except mycophenolate mofetil. Cyclosporine requirements increase during pregnancy, most likely because of enhanced metabolism. The pregnant patient must be intensively monitored for any evidence of acute or chronic allograft rejection, infection, ureteral and renal artery obstruction, impaired renal function, hypertension, fluid volume disturbances, anemia, or any combination of these symptoms. Recombinant human erythropoietin is used to treat anemiaduring pregnancy.

59. Medical and Obstetric Management Initial laboratory studies in pregnant renal transplant patients include complete blood cell count Renal function tests serum electrolyte and glucose concentrations, viral serologic testing for CMV, hepatitis B virus, HCV, and HIV. Serial ultrasonographic assessments allow the recognition of fetal anomalies and the evaluation of fetal growth.

60. Medical and Obstetric Management A patient who presents in labor and with evidence of active genital herpes simplex virus infection should undergo cesarean delivery. Vaginal examinations are minimized and always performed in a strict aseptic manner. The renal allograft is typically implanted in the extraperitoneal iliac fossa and does not impair vaginal delivery. Prophylactic antibiotics and stress-dose corticosteroids are indicated in patients who undergo cesarean delivery.

61. Anesthetic Management In the absence of renal dysfunction and hypertension, anesthetic management of the parturient with a renal transplant is similar to that of the healthy parturient. Strict aseptic technique is maintained during the placement of intravascular catheters and the performance of neuraxial anesthetic techniques. In the absence of systemic infection, immunosuppression itself should not be considered a contraindication to administration of epidural or spinal anesthesia.

62. UROLITHIASIS

63. Introduction Urolithiasis is characterized by the abnormal formation of calculi within the renal calyces or pelvis. Calculi may lodge within the ureters or bladder. Most stones are calcium oxalate (70%) or calcium phosphate (10%). Symptomatic urolithiasis occurs during 1 in 240 to 1 in 3300 pregnancies. The pregnancy does not affect the rate of urolithiasis.

64. Pathophysiology The presence of urolithiasis presumes an underlying physiologic abnormality that leads to persistent supersaturation of the particular minerals involved. During pregnancy, an elevated plasma vitamin D level causes greater intestinal absorption of calcium, net mobilization of calcium from bone, and a state of absorptive hypercalciuria. Ultimately, these changes provide calcium for the fetal skeleton. Other physiologic changes during pregnancy offsets this stone-forming factor in pregnant women. Calcium stone inhibitors such as citrate, magnesium, and glycoprotein are excreted in the urine to a greater extent during pregnancy.

65. Diagnosis Urolithiasis most commonly manifests during the second or third trimester. 80% of cases of gestational urolithiasis are diagnosed in parous women, The signs and symptoms of urolithiasis during pregnancy must be differentiated from that of ectopic pregnancy, preterm labor, appendicitis, pyelonephritis, and benign hematuria of pregnancy . A history of previous urolithiasis, recurrent urinary tract infections, or urologic surgery. Symptoms include flank and abdominal pain, urgency, dysuria, nausea, and fever. Examination reveals costovertebral tenderness, abdominal tenderness, pyuria, and hematuria. Urolithiasis must be considered in patients with pyelonephritis who remain febrile or have continued bacteriuria despite 48 hours of parenteral antibiotics.

66. Diagnosis Transabdominal ultrasonography is diagnostic in about 60% of cases and does not expose the mother or fetus to radiation. Color Doppler ultrasonography allows the identification of ureteral jets; the asymmetry or absence of these jets indicates the presence of urinary calculi. Transvaginal ultrasonography may augment suboptimal transabdominal ultrasonographic images. Combining ultrasound evaluation with assessment of the intrarenal artery resistive index increases the accuracy of ultrasonography to greater than 70%.

67. Diagnosis If urinary calculi are not successfully visualized with ultrasonography and clinical suspicion for urolithiasis remains high, magnetic resonance (MR) urography should be considered because it does not use ionizing radiation or iodinated contrast media. If the diagnosis is still unclear and the patient has persistent flank pain after both these tests, some experts recommend low-dose computed tomography whereas others recommend intravenous pyelography

68. Effect of Pregnancy on Urolithiasis In an effort to determine any effect of pregnancy on the natural history of urolithiasis, Coe et al. reviewed the records of 58 pregnancies in women with the preexisting diagnosis of urolithiasis. The stone recurrence rate in this group was 0.49 stone per patient-year, which was not significantly different from the rate of 0.44 stone per patient-year in the general population. The authors concluded that pregnancy does not alter the activity or severity of stone disease.

69. Effect on the Mother and Fetus In a retrospective cohort study, Swartz et al. the investigators found that women with nephrolithiasis had an almost two fold higher rate of preterm delivery. However, these women were not at increased risk for other adverse pregnancy outcomes , including premature rupture of the membranes, low birth weight, and infant death . The etiology of preterm labor may be related to urinary tract infections. Honoré suggested that there is a higher incidence of renal stones among women who have a spontaneous abortion. He hypothesized that abnormalities of calcium hemostasis may lead to myometrial hyperirritability or abnormal hormonal secretion by the corpus luteum, the placenta, or both..

70. Urologic and Obstetric Management Women with a history of urolithiasis should increase their intake of fluids. Calcium supplementation through prenatal vitamins should be avoided in women with recurrent urolithiasis. During pregnancy, 70% of calculi pass spontaneously with conservative management. The decision to move beyond conservative therapy should be taken on a case-by-case basis. Infected hydronephrosis, especially with impaired renal function or urosepsis, is an indication for more aggressive therapy

71. Urologic and Obstetric Management Medical expulsive therapy with alpha-adrenergic receptor blocking agents has been used successfully to increase the rate of stone passage and decrease pain associated with expulsion by relaxing ureteral smooth muscle. However, there are no published reports of its use during pregnancy. Other medical treatments that are used to treat urolithiasis, including thiazide diuretics, xanthine oxidase inhibitors, and d-penicillamine, are contraindicated during pregnancy owing to possible effects on the fetus

72. Urologic and Obstetric Management Urologic intervention is indicated in the patient with persistent pyelonephritis, deterioration of renal function, massive hydronephrosis, persistent pain, or sepsis. Ureteral stent placement with ureteroscopy and ultrasonographic guidance, or percutaneous nephrostomy, should be considered. Holmium:yttrium-aluminum-garnet (YAG) laser lithotripsy, using state-of-the-art ureteroscopes, is an emerging technique for stone management in pregnancy. Extracorporeal lithotripsy should be avoided during pregnancy because the shockwaves may be harmful to the fetus.

73. Urologic and Obstetric Management The following conditions may raise suspicion of the presence of primary hyperparathyroidism in a pregnant woman: Urolithiasis with or without pancreatitis Hyperemesis beyond the first trimester History of recurrent spontaneous abortion or intrauterine fetal Death neonatal hypocalcemia or tetany Total serum calcium concentration greater than 10.1 mg/dl during the second trimester or greater than 8.8 mg/dl during the third trimester.

74. Anaesthetic Management The ureters receive sensory innervation through the renal, ovarian, and hypogastric plexuses (T11 to L1 spinal segments). During conservative management of urolithiasis, epidural analgesia provides the patient with significant pain relief and facilitates the passage of the calculus. Neuraxial analgesia avoids the use of systemic opioids, which impair normal peristalsis in ureteric smooth muscle. Improved maternal pain control may also decrease endogenous catecholamine release and improve uteroplacental blood flow.