Reversible suppression of the renin-aldosterone axis after unilateral adrenalectomy for adrenal adenoma.

Reduced adrenocortical (aldosterone and cortisol) and adrenomedullary (adrenaline) secretory mass after unilateral adrenalectomy for aldosterone-producing adenoma has been associated with long-term hypotension (more than 2 years) in some studies. In these patients, cortisol and aldosterone levels are low, whereas plasma renin activity is high. Other studies suggest that normotension and normal plasma renin activity and serum aldosterone and cortisol levels are achieved in 60% to 87% of the patients without evidence of decreased adrenal mass, whereas the remaining patients may continue to have hypertension. We report a unique case in which unilateral adrenalectomy for adrenal adenoma was followed by severe hyperkalemia, marked volume depletion and undetectable plasma renin activity, and serum aldosterone, suggesting marked, chronic suppression of the renin-aldosterone axis. One year later, a gradual return to normokalemia, normotension, and normal plasma renin activity and aldosterone levels was achieved, indicating resolution of the suppression of the renin-aldosterone axis. Patients undergoing unilateral adrenalectomy for aldosteronoma should be followed up closely after unilateral adrenalectomy of adrenal adenoma to avoid life-threatening hyperkalemia and severe intravascular volume depletion.

Role of Fogarty catheter manipulation in management of migrated, nonfunctional peritoneal dialysis catheters.

Peritoneal dialysis (PD) catheter migration to the upper abdomen is not an uncommon cause of catheter failure. We prospectively examined the role of the Fogarty catheter manipulation technique to reposition the PD catheter in the pelvis and regain patency. All patients with PD catheter malfunction caused by migration, confirmed by abdominal radiograph, underwent the same protocol. The patient was placed flat on the back, and the Fogarty was advanced into the PD catheter to a premarked point at which the end of the Fogarty was near the end of the PD catheter. The Fogarty balloon was inflated with 0.5 mL of sterile saline, and manipulation was performed by tugging movements until proper placement of the PD catheter into the pelvis was suspected. Infusion and drainage of dialysate was performed to determine patency. The return of the PD catheter into the pelvis was then confirmed by repeated radiograph. Success rates of Fogarty catheter manipulation, early and late recurrence (remigration < or =90 days or >90 days), and complications were prospectively examined in 232 patients over a 6-year period. Catheter migration occurred in 34 of 232 patients (15% incidence). All patients had curled-end, double-cuffed, non-swan-neck PD catheters. Successful repositioning occurred in 24 of 34 patients (71%). None of the 24 repositioned catheters had early recurrence, and 1 of 24 catheters (4%) had late recurrence. None of the patients had procedure-related peritonitis, bowel perforation, or exit-site trauma. These results show that PD catheter migration is relatively common (15%). The Fogarty manipulation technique is a simple, cost-effective way to prolong PD catheter life and preserve its long-term patency. This eliminates the need for surgical intervention in approximately 70% of patients with PD catheter migration.

Role of preoperative antibiotic prophylaxis in preventing postoperative peritonitis in newly placed peritoneal dialysis catheters.

The role of vancomycin and other antibiotics in the treatment of acute peritonitis in peritoneal dialysis (PD) patients is well established. However, the role of preoperative vancomycin or cephalosporins in preventing early infection in newly placed PD catheters remains controversial. We performed a prospective randomized study to examine the role of vancomycin or cefazolin prophylaxis in decreasing the incidence of postoperative peritonitis. Over a 6-year period, 221 patients undergoing 254 permanent peritoneal catheter placement procedures were randomized into three groups. Group I patients (86 procedures) were administered a single intravenous (IV) dose of vancomycin, 1,000 mg, 12 hours before peritoneal catheter placement procedures, whereas group II patients (85 procedures) were administered a single IV dose of cefazolin, 1,000 mg, 3 hours before the procedure. Group III patients (83 procedures) were not administered antibiotics preoperatively for at least 1 week before the procedure. Patients were monitored for peritonitis in the following 14 days. Peritonitis developed in 1 patient (1%) in group I (vancomycin group) and 6 patients (7%) in group II (cefazolin group) compared with 10 patients (12%) in group III (control group); P = 0.02. We conclude that the use of preoperative single-dose IV vancomycin prophylaxis for permanent PD catheter placement reduces the risk for postoperative peritonitis. Single-dose vancomycin is superior to single-dose cefazolin in reducing the risk for postoperative peritonitis. Absence of prophylaxis is associated with a high risk for developing postoperative peritonitis.

Peritoneoscopic versus surgical placement of peritoneal dialysis catheters: a prospective randomized study on outcome.

The most commonly used technique for insertion of peritoneal dialysis (PD) catheters is open surgical approach by minilaparotomy. Percutaneous implantation via the peritoneoscopic technique is expanding. Studies have suggested that PD catheters placed peritoneoscopically have longer survival rate than surgically placed ones. However, these studies were not randomized, where the surgical group had more patients who were obese or had prior abdominal surgery, and therefore, the selection of patients may have biased the results. We conducted a prospective randomized study in which patients underwent PD catheter placement by either the surgical or the peritoneoscopic technique. In the period from October 1992 through October 1995, 148 double-cuff, curled-end, swan-neck PD catheters were placed in 148 patients. The outcome of the 76 patients in whom the PD catheters were placed peritoneoscopically was compared with that of the 72 patients in whom the catheters were placed surgically. Early peritonitis episodes (within 2 weeks of catheter placement) occurred in 9 of 72 patients (12.5%) in the surgical group, versus 2 of 76 patients (2.6%) in the peritoneoscopy group (P = 0.02). This higher rate of infection was most likely related to a higher exit site leak in the surgical group (11.1%) as compared with the peritoneoscopy group (1.3%). Moreover, peritoneoscopically placed catheters were found to have better survival (77.5% at 12 months, 63% at 24 months, and 51.3% at 36 months) than those placed surgically (62.5% at 12 months, 41.5% at 24 months, and 36% at 36 months) with P = 0.02, 0.01, and 0.04, respectively. We conclude that peritoneoscopically placed PD catheters have a longer survival rate than surgically placed ones. Furthermore, the rate of exit site leak and early infection is lower in the peritoneoscopic method.

Diagnosis of mixed acid-base disorders in diabetic ketoacidosis.

In diabetic ketoacidosis, a mixed acid-base disorder is suggested when the anion gap increase (delta AG) does not equal the bicarbonate decrease (delta HCO3), or when the delta AG/delta HCO3 ratio does not equal 1.0. It is widely assumed that delta AG/delta HCO3 is significantly different from 1.0 when it is less than 0.8 or greater than 1.2. The validity of these ratio limits were examined by analyzing a normal control group of 68 subjects and 27 diabetic ketoacidosis admissions that had no evidence of mixed disorders. In the 27 ketoacidosis admissions, regression analysis showed that delta AG was predicted to equal delta HCO3, as expected in pure anion gap acidosis: delta AG = 1.0 delta HCO3 (r = 0.744, p < 0.001). It was found that delta AG is significantly different from delta HCO3 when they differ by more than 8 mEq/L, and equivalently, delta AG/delta HCO3 is significantly different from 1.0 when it is less than (1.0 - 8/delta HCO3) or greater than (1.0 + 8/delta HCO3). These criteria from regression analysis suggested that 4% of the 27 pure anion gap acidoses, and 3% of the control group, had mixed disorders. In contrast, the ratio limits of 0.8 and 1.2 suggested 56% of the pure anion gap acidoses, and 94% of the control group, had mixed disorders. It was concluded that mixed disorders are overdiagnosed by the ratio limits of 0.8 and 1.2. Mixed disorders are more accurately detected by noting whether delta AG and delta HCO3 differ by more than 8 mEq/L.

Case report: mannitol nephrotoxicity syndrome: role of hemodialysis and postulate of mechanisms.

High-dose intravenous mannitol infusion in various clinical settings may result in acute renal failure (ARF). This form of ARF is characteristically anuric and follows a distinctive clinical course. Most importantly, it occurs only after high doses of mannitol (> 200 g/day or cumulative dose of > 400 g in 48 hours), but not at lower doses. It appears that a low dose of mannitol acts as a renal vasodilator while high-dose mannitol is renal vasoconstrictor. Mannitol-induced ARF responds promptly to hemodialysis with rapid resolution of anuria and recovery of renal failure. This is a report of a case of anuric ARF after high-dose mannitol infusion for treatment of narrow-angle glaucoma that readily responded to acute hemodialysis. The literature is also reviewed for ARF associated with mannitol infusion in patients who received dialysis and those who did not receive dialysis; and the possible mechanism(s) of mannitol nephrotoxicity are discussed. Hemodialysis should be performed for rapid reversal of mannitol-induced ARF. Patients not treated with hemodialysis have increased morbidity and significant prolongation of their hospital course.

The role of peritoneal dialysis catheter configuration in preventing catheter tip migration.

Migration of the peritoneal dialysis (PD) catheter from the pelvis to the upper abdomen frequently results in peritoneal dialysis failure and removal of the catheter. Previous studies compared PD catheter survival in various catheter configurations. These studies included single-cuff and double-cuff, straight-end and curled-end catheters, and showed an incidence of catheter migration ranging from 5%-35% depending on the catheter type. Recent studies demonstrated that the double-cuff, Swan-neck, curled-end configuration is associated with a considerably lower incidence of migration. Most of these studies, however, had a small patient sample or no control group, or they compared nonequivalent catheters (for example, Swan-neck, curled-end versus straight, non-curled-end). Over a six-year period, we examined two similar double-cuff, curled-end catheters: Group I catheters had a straight segment between the two cuffs, and Group II catheters had a 60 degrees Swan-neck bend between the two cuffs (Quinton Instrument Co., Bothell, WA, U.S.A.). The two catheters were identical, except for the presence or absence of the Swan-neck bend. All catheters were placed by the closed laparoscopic technique. In the two groups of patients in whom the catheters were implanted, no statistically significant difference was observed in primary disease, age, sex, race, weight, prior abdominal surgery, or duration of dialysis before catheter migration. In group I, 33 of the 219 patients developed catheter migration (15%); in group II, 2 patients of 243 patients developed catheter migration (less than 1%, p = 0.002). In conclusion, the Swan-neck configuration presents an independent factor in preventing PD catheter migration. Review of previous studies and the data from our study, show that double-cuff, curled-end, Swan-neck PD catheters are superior to other catheters in regard to prevention of catheter migration and should be the catheter of choice in PD patients.

Role of intraperitoneal urokinase in acute peritonitis and prevention of catheter loss in peritoneal dialysis patients.

Some studies have demonstrated the efficacy and safety of intraperitoneal (i.p.) urokinase in the resolution of recurrent or relapsing peritonitis, while others have not. Most studies were small, and they varied in methodology. Furthermore, the role of i.p. urokinase in shortening the duration of peritonitis or in preventing recurrence after initial peritonitis has not been examined. In addition, no previous studies have examined the role of i.p. urokinase in preventing, after first infection, catheter loss due to unresolving (resistant) peritonitis. Over a period of 3 years, we prospectively randomized into two groups all peritoneal dialysis (PD) patients who developed a first episode of peritonitis. Group I (n = 40) received i.p. urokinase on the first day of diagnosis (5000 IU intraluminally in the peritoneal catheter and left for 4 hours before next exchange). Group II (n = 40) received no urokinase. The duration of peritonitis was assessed by daily PD fluid white blood cell (WBC) count. Indications for catheter removal were: persistent peritonitis after four days from initiation of antibiotic therapy, or peritonitis with multiple organisms, suggesting bowel perforation. No statistically significant difference was seen between the two groups in regard to primary cause of end-stage renal disease (ESRD), age, sex, race, weight, type of dialysis [continuous ambulatory peritoneal dialysis (CAPD), automated peritoneal dialysis (APD), continuous cycling peritoneal dialysis (CCPD)], or duration of dialysis prior to first peritonitis. No statistically significant difference was seen between the two groups in the duration of peritonitis or in the severity of symptoms and signs of peritonitis. Neither was any difference seen in the peritonitis recurrence or relapse rate (10% in the urokinase group vs 7.5% in the control group). Nine patients lost their catheters (3 in the urokinase group: 1 Pseudomonas aeruginosa and 2 Candida tropicalis; 6 in the control group: 1 Klebsiella pneumonia, 1 enterococcus, 2 Pseudomonas aeruginosa, and 2 Candida tropicalis). The difference in the rate of catheter loss between the two groups was not statistically significant; it appeared to relate to the type of organism rather than to the response to urokinase. In conclusion, i.p. urokinase plays no significant role in shortening the course of peritonitis or in preventing recurrence or loss of the PD catheter. Loss of PD catheters in patients having their first peritonitis appears to be related primarily to the type of organism causing the infection.

Relationship between intraperitoneal bleeding, adhesions, and peritoneal dialysis catheter failure: a method of prevention.

Intraperitoneal (i.p.) bleeding causes intense inflammatory reactions and extensive adhesions. The relationship between i.p. bleeding and adhesions is well documented in both animal and human studies. Over an 8-year period, we performed 362 permanent peritoneal dialysis (PD) catheter placements in 317 patients, using the laparoscopic technique. In the first 203 procedures (group I), we observed intra-operative bleeding in 12 patients (intra-operative i.p. bleeding seen laparoscopically, and significant blood-tinged dialysate irrigation). Patients were left dry for 3-5 days before dialysate instillation during the break-in period. During the break-in period, 7 of the 12 patients (58%) developed primary catheter failure requiring catheter removal (p = 0.03). All 7 patients underwent repeat laparoscopy for placement of a new catheter. In all 7 patients, laparoscopy showed significant adhesions. In the subsequent 159 procedures (group II), we observed intra-operative bleeding in 10 patients. We irrigated the peritoneal cavity repeatedly, until clear dialysate was obtained, then instilled 500-1000 mL 1.5% Dianeal solution (Baxter Healthcare Corporation, Deerfield, IL, U.S.A.) and capped the catheter. These patients were then placed on low-volume continuous cycling peritoneal dialysis [(CCPD) 700-1200 mL, based on the patient's size, every 2 hours, until the effluent became clear]. Following this, patients underwent daily irrigation and PD fluid cell count, and were left with 700-1200 mL dialysate to dwell. The process was continued until PD fluid drainage showed no red blood cells or until the patient was started on routine peritoneal dialysis. None of these patients were drained dry. Compared with group I, no patient among the 10 in group II developed catheter failure (p = 0.001), and mean catheter survival was 31 +/- 7 months. Of the 10 patients, 2 developed exist-site leaks, both after clearance of red blood cells from the drained dialysate. None developed peritonitis. We conclude that intra-operative i.p. bleeding associated with significant blood-tinged dialysate irrigation may lead to local adhesions if the peritoneum is drained dry. The result may be loss of the PD catheter in about 60% of cases. Continuous irrigation, combined with a moderate amount of Dianeal solution left to dwell, or early initiation of low-volume PD, or both, prevents this complication.

Preoperative vancomycin prophylaxis for newly placed peritoneal dialysis catheters prevents postoperative peritonitis.

The role of vancomycin and other antibiotics in treatment of acute peritonitis in peritoneal dialysis patients is well established. However, the role of preoperative vancomycin or cephalosporins in preventing early infection in newly placed peritoneal dialysis catheters remains controversial. We performed a prospective randomized study to examine the role of vancomycin or cefazolin prophylaxis in decreasing the incidence of postoperative peritonitis. Over 8-year period, 265 patients undergoing 305 permanent peritoneal catheter placement procedures were randomized into three groups. Group I (103 procedures) received a single intravenous (i.v.) dose of 1000 mg vancomycin 12 hours before the peritoneal catheter placement procedure. Group II (102 procedures) received a single i.v. dose of 1000 mg of Ancef (cefazolin) 3 hours before the procedure. Group III (100 procedures) received no antibiotics preoperatively for a least one week before the procedure. Patients were monitored for peritonitis during the following 14 days. Peritonitis developed in 1 patient (1%) in Group I (vancomycin group) compared to 12 patients (12%) in Group III (control group), p = 0.002, and in 9 patients (9%) in Group II (cefazolin group) compared to Group III, p = 0.68. We conclude that the use of preoperative single-dose i.v. vancomycin prophylaxis for permanent peritoneal dialysis catheter placement reduces the risk of postoperative peritonitis. Cefazolin did not achieve a statistically significant difference from the control group and may not provide adequate prophylaxis.

Pulse oral versus pulse intraperitoneal calcitriol: a comparison of efficacy in the treatment of hyperparathyroidism and renal osteodystrophy in peritoneal dialysis patients.

Controversy exists among various studies in regard to the efficacy of oral (p.o.) versus parenteral calcitriol. Some studies suggest that intravenous (i.v.) calcitriol is superior to p.o. calcitriol for treating renal osteodystrophy in hemodialysis patients; others suggest that these routes of administration are equivalent. To our knowledge, no large, prospective, randomized study compares intraperitoneal (i.p.) to p.o. calcitriol in adult peritoneal dialysis patients. We conducted a prospective randomized study in 76 patients (38 on i.p. calcitriol and 38 on p.o. calcitriol), whom we followed for 48 months. Of the 76 patients, 34 (18 in the i.p. group and 16 in the p.o. group) completed the 48-month study period. Calcitriol dosing was similar in both groups (3-6 micrograms per week in three divided doses). Dose adjustments were made depending on levels of parathyroid hormone (PTH), serum calcium, phosphorus, and calcitriol. No significant difference was seen between the groups in regard to age, sex, race, body mass index, dialysis duration, or cause of ESRD. Neither was any difference in the incidence of peritonitis seen between the groups. In the first 3-6 months, PTH decreased equivalently in both groups. The PTH level remained suppressed in the i.p. group throughout the remainder of the study, but, in the p.o. group, PTH returned to its pretreatment level after 3-6 months. Mean serum calcium was not different in the two groups. In the p.o. group, a considerably higher mean follow-up phosphorus level (6.8 +/- 2.3 mg/dL versus 4.7 +/- 1.4 mg/dL, p = 0.008), PTH level (384 +/- 146 pg/mL versus 162 +/- 64 pg/mL; p = 0.005), and alkaline phosphatase level (178 +/- 37 IU/L versus 72 +/- 21 IU/L, p = 0.02) were seen as compared to the i.p. group. In the i.p. group, resolution of osteodystrophy occurred in all patients at the end of the study; in the p.o. group, 5 patients maintained or developed osteodystrophy by the end of the study (p = 0.016). We conclude that i.p. calcitriol is more effective than pulse p.o. calcitriol in lowering PTH and alkaline phosphatase levels and in resolving renal osteodystrophy, and that i.p. calcitriol is associated with a lower incidence of hyperphosphatemia and elevated Ca x PO4 byproduct.

Changing the trend: a prospective study on factors contributing to the growth rate of peritoneal dialysis programs.

Compared with countries worldwide, the United States currently has one of the lowest peritoneal dialysis (PD) populations as compared with its hemodialysis (HD) population. Approximately 12% of the total dialysis population in the United State is on PD. This figure correlates with the take-on rate [percentage of end-stage renal disease (ESRD) patients enrolling in PD programs] of about 12%-15% in the United States. Over a two-year period, we prospectively examined the role that developing a comprehensive infrastructure and support system had on expanding our PD program. The changes made included these: nephrologists placing PD catheters using the laparoscopic method; active identification of, and training for, family members and personnel in nursing homes and daycare centers to perform PD; improvements in home conditions through support by social workers; early ESRD patient education; and provision of in-center intermittent PD (IPD) for selected patients. We then compared the results from the two years after commencement of the changes against the two years before the changes were made. Training of personnel in nursing homes increased enrollment from 3 to 11 patients (p = 0.01); training of personnel in daycare centers increased enrollment from 0 to 5 patients (p = 0.05); training family members and providing family support increased enrollment from 4 to 15 patients (p = 0.03); early patient and family education increased enrollment from 4 to 24 patients (p = 0.008); improving home conditions increased enrollment from 1 to 14 patients (p = 0.01); and providing an IPD program for selected patients added 6 patients (p = 0.05). Introducing a program for nephrologists to place PD catheters by the laparoscopic technique decreased catheter mechanical failure (and subsequent transfer to HD), from 22 to 3 patients (p = 0.005). Our PD take-on rate (percentage of ESRD patients choosing PD modality) increased from 19% to 76% (p = 0.002). The total number of patients in the PD program over the two years after initiation of the changes increased from 33 to 93 (p = 0.01), while the number of HD patients decreased from 168 to 142 (p = 0.05). Developing a comprehensive infrastructure and support system for PD programs permits enrollment of patients who otherwise would have been excluded as PD candidates and eliminates loss of PD patients to HD. Implementation of such programs can contribute considerably to enhancing the PD population growth rate.

Factors modulating cytosolic calcium. Role in lipid metabolism and cardiovascular morbidity and mortality in peritoneal dialysis patients.

Studies in the uremic rat indicate that insulin resistance and glucose intolerance leading to dyslipidemia are associated with a hyperparathyroid-induced increase in cytosolic calcium ([Ca++i]). These alterations are reversed with verapamil, but recur after discontinuation of the drug, suggesting that increased [Ca++i] is responsible for the metabolic derangement. To our knowledge, no similar studies have been conducted in humans. We retrospectively examined, over 12-year period, the effects of factors that lower [Ca++i] on total serum cholesterol and triglycerides in 176 peritoneal dialysis (PD) patients. Because the study was retrospective, detailed lipid profiles were not available. We therefore relied on the morbidity and mortality outcome related to atherosclerotic vascular disease. Diabetic patients were excluded from the study, because their dyslipidemia and vascular disease are mediated via a different mechanism. The patients were classified into four groups. Group I [high parathyroid hormone (PTH) in the absence of calcium channel blockers (CCBs), n = 56] represented the highest [Ca++i]. Group II (high PTH in the presence of CCBs, n = 43) and group III (lower PTH in the absence of CCBs, n = 37) represented intermediate [Ca++i]. Group IV (lower PTH in the presence of CCBs, n = 40) represented the lowest [Ca++i]. High PTH was defined as > or = 3.0 times normal; lower PTH, as < 3.0 times normal. Lower [Ca++i] was achieved through the use of CCBs, or through lower PTH, or both. Lower PTH was achieved by parathyroidectomy or calcitriol administration. The four groups showed no differences in age, sex, race, weight, dialysis duration, or primary disease. Group I showed a mean serum cholesterol of 358 +/- 27 mg/dL and serum triglycerides of 469 +/- 41 mg/dL. Group II showed mean serum cholesterol of 198 +/- 21 mg/dL and serum triglycerides of 147 +/- 17 mg/dL. Group III showed a mean serum cholesterol of 205 +/- 20 mg/dL and serum triglycerides of 174 +/- 16 mg/dL. Group IV showed mean serum cholesterol of 184 +/- 10 mg/dL (p = 0.008) and serum triglycerides of 103 +/- 8 mg/dL (p = 0.005). The cardiovascular morbidity and mortality incidences were: group I, 64%; group II, 27%; group III, 31%; and group IV, 20% (p = 0.002). We conclude that, in non diabetic PD patients, dyslipidemia is related to a hyperparathyroid-induced increase in cytosolic calcium [Ca++i]. Lowering [Ca++i] by decreasing the parathormone level (via parathyroidectomy or calcitriol administration), or by blocking calcium entry into cells (via CCBs), or both, is associated with less dyslipidemia and improved long-term morbidity and mortality related to atherosclerotic vascular disease.

A 38-year-old man with nephrotic syndrome, episodic fever and abdominal pain.

The differential diagnosis for a 38-year-old white man with a chronic fever associated with nephrotic syndrome is discussed in the setting of a clinicopathological conference at Louisiana State University Medical Center in Shreveport, Louisiana. The etiology and pathophysiology of fever-associated nephrotic syndrome are discussed.

Lithium intoxication: clinical course and therapeutic considerations.

Lithium therapy has various neurologic cardiovascular, and renal side effects. Lithium intoxication with a serum lithium level of greater than or equal to 3.5 mEq/l is considered potentially lethal and hemodialysis therapy is recommended. We reviewed the clinical course and therapy of 55 patients with lithium toxicity seen during a 6-year period. Forty-two patients had acute lithium intoxication following the ingestion of an overdose. In 13 patients, toxicity developed during maintenance therapy with the drug. The patients with acute intoxication had significantly milder symptoms than those with chronic intoxication. Ten patients with acute intoxication had a serum lithium concentration of 3.5 mEq/l or higher. None of these 10 patients had severe neurologic or cardiovascular symptoms. Five patients were treated with hemodialysis and 5 patients were not. Serum lithium concentration did not differ between the two groups (4.7 +/- 0.7 and 5.7 +/- 1.0 mEq/l, respectively). No patient in either group died or suffered permanent sequelae of lithium toxicity. In conclusion, patients with acute lithium toxicity frequently have mild symptoms, despite potentially lethal levels and may not require hemodialysis therapy. On the other hand, patients who develop toxicity while receiving chronic maintenance therapy are more likely to have severe symptoms. Patients with severe symptoms and serum lithium levels above the therapeutic range should be treated with hemodialysis.

Liddle's syndrome, an underrecognized entity: a report of four cases, including the first report in black individuals.

Liddle's syndrome, a rare cause of hypokalemic hypertension, is characterized by a renal tubular sodium channel defect resulting in excessive sodium absorption and concomitant potassium wasting. In this disorder, although the clinical manifestations resemble primary aldosteronism, serum and urine aldosterone are suppressed. The syndrome is transmitted in an autosomal dominant pattern. It has been reported previously in white and oriental populations but not in the black individuals. We identified four patients (two of whom are black) in our nephrology clinic, with severe hypokalemic hypertension not correctly diagnosed for several years. All patients underwent an extensive work-up for secondary hypertension because of persistent severe hypertension (average blood pressure, 210/130 mm Hg) despite high-dose multi-drug therapy. Primary aldosteronism was excluded because of low serum aldosterone. Cushing's syndrome, pheochromocytoma, renal artery stenosis, and enzymatic deficiencies of cortisol synthesis (11 beta-hydroxylase, 17 alpha-hydroxylase, 5 beta-reductase, and 11 beta-hydroxysteroid dehydrogenase) were ruled out with extensive endocrine and radiologic studies. Once the diagnosis of Liddle's syndrome was suspected, all patients were treated with either triamterene or ameloride, with resolution of hypokalemia and correction of hypertension occurring within 5 to 7 days. Our findings suggest that Liddle's syndrome can occur in the black population. Although the actual incidence of this syndrome remains unknown, it may be significantly more common than we are led to believe since it is inherited in a Mendelian pattern. Whether there is a subset of low-renin, salt-sensitive black hypertensive patients who have the same or similar sodium channel defect remains to be elucidated.

Peritoneal dialysis-associated peritonitis caused by Alcaligenes xylosoxidans.

Despite significant progress to decrease its incidence, peritonitis remains the main source of morbidity and treatment failure in patients on continuous ambulatory peritoneal dialysis (CAPD). The majority of cases of peritonitis result from infection with aerobic gram-positive (Staphylococcus epidermidis and Staphylococcus aureus), or gram-negative organisms. Less common organisms that are also reported include anaerobic bacteria, fungi, and mycobacteria, which collectively account for less than 10% of isolates cultured. We report a case of peritoneal dialysis-associated peritonitis, and review the literature on peritonitis caused by Alcaligenes species. Alcaligenes xylosoxidans is a nonfermenting gram-negative rod and opportunistic pathogen that is motile with peritrichous flagella. The clinical features and microbiological data of our case, as well as the other previously reported cases of peritonitis caused by Alcaligenes species show no particular pattern of peritoneal dialysate cell count. However, the rate of recurrence of peritonitis is characteristically high. The cause of such a high rate of recurrence of peritonitis is probably a reflection of the predilection of Alcaligenes species to cause infection in the 'sicker' patients, and the almost universal resistance of this species to most antimicrobial agents. We, therefore, recommend that catheter removal be undertaken as early as the identification of the organism is made. Whether patients should be allowed to return to CAPD after recovery is a more difficult question. We suggest that a reevaluation of the patient's overall status be undertaken, including personal hygiene, exchange technique, presence of diabetes mellitus, malnutrition, and/or other factors that may render the patient more prone to infection with opportunistic pathogens.

Tuberculosis of the spine (Pott's disease) in patients with end-stage renal disease.

Extrapulmonary tuberculosis is more common in end-stage renal disease than in normal subjects, and it frequently poses both diagnostic and therapeutic challenges. We describe 2 dialysis patients with tuberculosis of the spine (Pott's disease). The 1st patient presented with back and left hip pain, low-grade fever, left-quadriceps weakness, hypoesthesia of the left thigh, and hypoactive left-knee jerk. X-rays of the spine showed only osteophytes. Magnetic resonance imaging showed increased signal intensity of L3 with focal expansion into the spinal canal. A computerized tomography guided biopsy revealed granulomas, and Ziehl-Neelsen stain was positive. Therapy with rifampin, isoniazid, ethambutol, and pyrazinamide caused peripheral neuropathy and optic neuritis. The 2nd patient developed bilateral proximal thigh pain and weakness that progressed to paraplegia. Magnetic resonance imaging showed destructive lesion of L3-5, involving both psoas muscles, prevertebral space, and neural foramina. Ziehl-Neelsen stain of the biopsy specimen was negative, but culture was positive for Mycobacterium tuberculosis. Paraplegia improved only partially after 1 year of therapy. Pott's disease should be suspected in end-stage renal disease patients with back pain and/or neuromuscular complaints, particularly in those who immigrated from Asian and Latin-American countries. Treatment of tuberculosis in dialysis patients may cause significant morbidity.