سال:1387 | دوره: | شماره: |تعداد مقالات:11

In situations where the cause of hypokalemia is not obvious, measurement of urinary potassium excretion and blood pressure and assessment of acid-base balance are often helpful. A random urine potassium-creatinine ratio (K/C) less than 1.5 suggests poor intake, gastrointestinal losses, or a shift of potassium into cells. If hypokalemia is associated with paralysis, we should consider hyperthyroidism, familial or sporadic periodic paralysis. Metabolic acidosis with a urine K/C ratio less than 1.5 suggests lower gastrointestinal losses due to diarrhea or laxative abuse. Metabolic acidosis with K/C ratio of 1.5 higher is often due to diabetic ketoacidosis or type 1 or type 2 distal renal tubular acidosis. Metabolic alkalosis with a K/C ratio less than 1.5 and a normal blood pressure is often due to surreptitious vomiting. Metabolic alkalosis with a higher K/C ratio and a normal blood pressure suggests diuretic use, Bartter syndrome, or Gitelman syndrome. Metabolic alkalosis with a high urine K/C ratio and hypertension suggests primary hyperaldosteronism, Cushing syndrome, congenital adrenal hyperplasia, renal artery stenosis, apparent mineralocorticoid excess, or Liddle syndrome. Hypomagnesemia can lead to increased urinary potassium losses and hypokalemia. The differential rests upon measurement of blood magnesium, aldosterone and rennin levels, diuretic screen in urine, response to spironolactone and amiloride, measurement of plasma cortisol level and the urinary cortisol-cortisone ratio, and genetic testing.

Although the incidence of hypertension is low in children, its prevalence appears to be increasing.1 This can be related to the increasing prevalence of obesity in children and the growing awareness in detection of hypertension. Essential hypertension has its antecedents during childhood. It has become clear that hypertension begins in childhood and adolescence and can contribute to the early development of cardiovascular diseases. Left ventricular hypertrophy is the most detected evidence of cardiovascular diseases in childhood hypertension. In its severe cases, there is an increasing risk of developing hypertensive encephalopathy, cerebrovascular accidents, and congestive heart failure. Based upon these observations, identifying children at risk of hypertension could have an important impact on the long-term outcomes of cardiovascular diseases.

Introduction: Proteinuria is an important diagnostic component of preeclampsia. We prospectively compared the results of spot urine protein-creatinine (P/C) ratio with 24-hour urine protein excretion in women with preeclampsia. Materials and Methods: A total of 81 pregnant women with preeclampsia were prospectively studied for proteinuria. Urine P/C ratio was determined in a spot mid-stream urine sample, and the amount of protein excretion was measured in 24-hour urine collected on the subsequent day. The correlation between the spot P/C ratio and 24-hour urine protein excretion was assessed. Diagnostic value of P/C ratio was expressed in terms of specificity and sensitivity. The receiver operating characteristic curve analysis was used to determine the best discriminator values of the spot urine P/C ratios for preeclampsia (proteinuria³300 mg/24 h). Results: There was a strong correlation between the spot P/C ratio and 24-hour urine protein excretion (r=0.84; P<.001). The optimal spot P/C ratio cutoff point was 0.20 for 300 mg/24 h of protein excretion (preeclampsia), with a sensitivity, specificity, positive predictive value, and negative predictive value of 91.2%, 87.8%, 94.4%, and 96.8%, respectively. The spot P/C ratios less than 0.19 yielded a sensitivity of 100% for exclusion of preeclampsia. Conclusions: We found that there is a significant correlation between the spot urine P/C ratio and 24-hour urine protein excretion in women with preeclampsia. Urine P/C ratio could be used for exclusion of preeclampsia.

Introduction: The mechanism by which blood transfusion increases blood pressure in a substantial proportion of patients with congenital hemolytic anemia is unknown. Vascular endothelium dysfunction and increased endogenous vasoactive substances have been postulated in the pathogenesis of hypertension following multiple blood transfusions. The present study was undertaken to test the hypothesis whether increased circulating vasoconstrictors following blood transfusions, if documented, is a potent modulator of hypertension in patients with congenital anemia. Materials and Methods: Four children with congenital hemolytic anemia developed severe hypertension and convulsions 2 to 4 days after they received multiple blood transfusions. None had a history of prior hypertension, kidney disease or seizures before the blood transfusion. Baseline blood and urine samples were obtained for routine renal function studies. Blood samples were also drawn during and 2 weeks after the clinical events for determination of epinephrine, norepinephrine, dopamine, and plasma renin activity. Results: Kidney function was normal in all the 4 patients. All had elevated plasma renin activity and increased blood epinephrine, norepinephrine, and dopamine concentrations during hypertensive crises. Hypertension responded to antihypertensive drugs with the patients remaining normotensive 3 to 6 days after commencing therapy. All recovered without further seizures. The elevated plasma renin activity, epinephrine, norepinephrine, and dopamine levels returned to reference levels 2 weeks after completion of the last blood transfusion.Conclusions: These data suggest that increased activity of vasoconstrictors in the recipient plasma may be responsible for the development of hypertension after multiple blood transfusions.

Introduction: The aim of this study was to assess the usefulness of peripheral leukocyte count, differential leukocyte count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in febrile urinary tract infection (UTI) for defining the UTI level. Materials and Methods: A total of 61 children aged between 1 and 10 years with documented febrile UTI (axillary temperature³38oC) were studied. They had a urine culture positive for infection. Laboratory investigations including peripheral total and differential leukocyte counts, ESR, and CRP were assessed in relation to the inflammatory responses. Leukocyte count results were available in all of the patients, ESR in 41, and CRP in 36. Results: Leukocyte count was normal in 6 patients (9.8%). Lymphocytic leukocytosis was seen in 1 patients (1.6%), neutrophilic leukocytosis in 25 (41.0%), and relative neutrophilia in 29 (47.5%). Thirty patients (73.2%) had a high ESR and 23 (63.9%) had a positive CRP. In children with a high ESR, 12 (29.3%) had neutrophilic leukocytosis and 14 (34.1%) had relative neutrophilia. Relative neutrophilia and neutrophilic leukocytosis with positive CRP both were found in 11 patients (30.6%). Negative CRP with absence of neutrophilic leukocytosis was found in a significantly higher proportion of patients. There were no direct correlations between the severity of systemic inflammatory responses and urinary tract inflammatory response. Conclusions: Findings of this study showed that ESR and differential leukocyte count are two valuable tests in febrile UTI and may be useful for localization of UTI level, but the total leukocyte count and CRP level as in qualitative methods are not useful, and many patients with febrile UTI do not have leukocytosis.

Introduction: Little is known about the incidence of temporary kidney dysfunction following major vascular surgeries. We aimed to assess the frequency of temporary decreased kidney function following aortic surgeries. Materials and Methods: In a retrospective study, we assessed 108 hospital records of the patients who had undergone elective open abdominal surgery of aortic aneurysm. Preoperative and postoperative (days 1, 2, and 3) data on estimated glomerular filtration rate (GFR) were collected and evaluated in relation to the patients’ clinical characteristics and outcomes. A decline greater than 10% in GFR on day 1 or 2, and then, an increase of GFR to a level of maximum 10% below the baseline value on the third postoperative day was considered as temporary worsening of kidney function. Postoperative alterations of GFR not greater than 10% in relation to the baseline were considered as improved or unchanged kidney function. Two patients with persistent decrease in GFR were excluded. Results: Temporary worsening of kidney function was seen in 25 patients (23.6%). Short-term mortality rate was 44.0% in this group of patients, while it was 17.3% in those without decreased GFR (P=.006). According to the regression analysis, the only predictor of mortality was temporary worsening of kidney function, with a hazard ratio of 4.03 (95% confidence interval, 1.44 to 11.31; P=.008). Conclusions: Nearly 1 out of 4 aortic surgeries results in kidney dysfunction. Albeit temporary in most cases, it seems to be associated with a higher short-term mortality rate.

Introduction: End-stage renal disease causes impairment of all body organs including the heart and the lung. The main problems in the afflicted patients are pulmonary edema due to increased permeability of the capillaries, intravascular and interstitial volume overload, hypertension, and congestive heart failure. These changes cause altered physiologic and mechanical function of the lungs and subsequently increase in airway resistance. We aimed to study the impact of hemodialysis on spirometry parameters. Materials and Methods: In a cross-sectional study performed on 41 patients on maintenance hemodialysis, spirometry was done before and after the dialysis session. The patients were on either acetate or bicarbonate hemodialysis with the same method, dialysis machine, and duration of dialysis. Alterations in spirometry parameters including forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and maximal midexpiratory flow rate were determined and their relation with serum electrolytes, serum creatinine, blood urea nitrogen, and hemoglobin were analyzed. Results: Twenty-nine patients undergoing dialysis with bicarbonate dialysate and 21 on dialysis with acetate were compared. Improvement in spirometry parameters was only significant in patients undergoing dialysis with bicarbonate dialysate. All spirometry parameters showed significant increases in the bicarbonate group except for the FEV1/FVC ratio. Furthermore, significant increase in these parameters was only prominent in the men. Postdialysis weight reduction and laboratory indexes had no significant correlation with improvement of spirometry parameters. Conclusions: Dialysis with bicarbonate dialysate causes significant improvement in spirometry parameters in men on maintenance dialysis. This effect might be independent of the effect of removing the volume overload by dialysis.

Introduction: We measured bone mineral density (BMD) before and after transplantation to determine the frequency and severity of preoperative and postoperative osteoporosis and compare them with the BMD in healthy individuals.Materials and Methods: We determined the BMD at the lumbar spine and femoral levels in 22 men and 18 women who were on long-term dialysis in Yazd, Iran, and a group of kidney transplant recipients including 43 men and 18 women. They were compared with each other and healthy individuals studied in a recent study in Iran. Factors potentially associated with alterations of the BMD were studied in each group.Results: The frequency of osteoporosis in the vertebrae and femoral neck was higher in the kidney transplant recipients than the healthy population (21.3% versus 4.9%; P=.001; odds ratio, 5 and 9.8% versus 2.4%; P =.02; odds ratio, 5.4, respectively) but not significantly different from those in the patients on dialysis (17.9% and 17.5%, respectively). In transplantation group, multivariate analysis showed that there was a significant negative correlation between the lumbar BMD and the cumulative prednisolone dose (r=-0.36, P=.003). No correlation was found between BMD of lumbar or femoral neck and the body mass index, age, and cumulative cyclosporine level.Conclusions: Osteoporosis is more frequent in patients on dialysis and kidney transplant recipient than in general population. However, there is no difference in osteoporosis frequency between transplanted patients and those on dialysis. In the lumbar spine, a higher cumulative prednisolone dose results in decreased BMD among kidney transplant recipients.

Intrathoracic kidney is a rare congenital anomaly, with only about 50 cases reported in the literature to date. It comprises less than 5% of all ectopic kidney disorders. However, it should be included in the differential diagnosis of posterior mediastinal masses as confirmation of the diagnosis obviates the need for further clinical studies, further treatment, or unnecessary surgical operation. Chest computed tomography is an important and efficient tool in confirming the diagnosis. We report a case of a 72-year-old woman who suffered from nonspecific chest pain for 3 years. Chest radiography revealed a left posterior mediastinal mass which was later confirmed by chest computed tomography to be a congenital intrathoracic kidney.

Fungal infections are rare but represent serious complications following organ transplantation. We present a case of mucormycosis primarily affecting the paranasal sinuses in a 51-year-old man with a kidney allograft. The patient presented with headache, left facial and orbital pain, nasal discharge, and elevation of serum creatinine 18 months after kidney transplantation. Laboratory tests revealed cyclosporine nephrotoxicity, cytomegalovirus infection, and prediabetes. Imaging findings were compatible with left maxillary, ethmoidal, and sphenoidal sinusitis. Diagnosis was made based on pathologic findings and detection of typical fungal hyphea in the infected tissues. The patient was successfully treated by discontinuation of cyclosporine and mycophenolate mofetil, initiation of systemic amphotericin B, and aggressive surgical debridement.

Complications during hemodialysis are frequent and sometimes potentially fatal and peculiar in terms of etiology. We encountered an epidemic among our patients on maintenance hemodialysis in Fatemeh Zahra Hospital in Sari, Iran. In the summer of 2000, after the seasonal floods in the region, 2 patients on maintenance hemodialysis at Fatemeh Zahra Hospital were inflicted with fever of 39oC, chills, increased blood pressure, and generalized pruritus within 30 minutes after the beginning of hemodialysis session