Biomedical subjects

Michael F Michelis

Publications and source records attributed to Michael F Michelis.

5 recordsLinked to original sources

PubMed2006

Iron deficiency in patients with chronic kidney disease: potential role for intravenous iron therapy independent of erythropoietin.

UNLABELLED: The prevalence of iron deficiency and its contribution to the anemia of end stage renal disease has been extensively studied, but much less is known about the role of iron deficiency in the pathogenesis of the anemia of chronic kidney disease in predialysis patients. All new hemodialysis patients entering a single hemodialysis unit between July 1999 and April 2002 were included in the study. The admission laboratory tests and the Health Care Financing Administration (HCFA) 2728 form were examined to determine the prevalence of erythropoietin use, anemia (Hb<11 g/dl), and iron deficiency (ferritin<100 ng/ml and transferrin saturation %<20%). In a second part of the study, the effect of intravenous iron gluconate replacement in patients with stage III & IV chronic kidney disease was examined. Anemia was present in 68% of all patients starting hemodialysis. Iron deficiency was a common feature occurring in 29% of patients taking erythropoietin (49% of all patients) and 26% of patients without erythropoietin (51% of all patients). Following the administration of intravenous iron gluconate to four patients, there was a significant rise in hemoglobin levels from 10.6+/-0.19 to 11.7+/-g/dl (p=0.02). CONCLUSION: Iron deficiency is common in predialysis patients. Replenishing iron stores in anemic patients with chronic kidney disease significantly increases hemoglobin levels and should be considered as an integral part of the therapy for treating anemia in the predialysis population.

Anemia, Iron-Deficiency↗

PubMed2004

Refractory hypotension and edema caused by right atrial compression in a woman with polycystic kidney disease.

We present the case of a 60-year-old woman with a history of autosomal dominant polycystic kidney disease and long-standing hypertension who developed persistent hypotension. While in the hospital for the treatment of bacteriemia, the patient had low systolic blood pressures (90 to 100 mm Hg), which was thought to be the consequence of infection. After the infection was adequately controlled and the blood pressure did not improve, an echocardiogram was done to further elucidate her hypotension. It was nondiagnostic and revealed an ejection fraction of 70% with left ventricular hypertrophy. Shortly after discharge, she developed significant lower extremity edema and her blood pressure remained low. Due to the low blood pressure it was not possible to mobilize the fluid with her dialysis treatments. A repeat transthoracic echocardiogram at that time revealed that the right atrium was partially compressed throughout the cardiac cycle by polycystic hepatic tissue. This tissue invaginated up through the right hemidiaphragm. A partial liver resection was considered for the patient. Instead, right nephrectomy was performed and the blood pressure improved.

Cysts↗

PubMed2003

Effectiveness of furosemide in uncontrolled hypertension in the elderly: role of renin profiling.

BACKGROUND: Despite many advances in the treatment of hypertension, adequate blood pressure (BP) control in elderly patients continues to be a challenge. Optimal control of BP remains elusive because of issues relating to drug dosage and proper choice of therapeutic agents, including questions regarding the role of diuretics. METHODS: We examined the effect of diuretic treatment on BP in 12 elderly hypertensive patients whose hypertension was poorly controlled on previous drug regimens. We also evaluated the relationship of systolic, diastolic, and mean arterial BP (SBP, DBP, MAP, respectively) to changes in plasma renin activity (PRA), serum aldosterone (SA), atrial natriuretic peptide (ANP), and serum chemistries both before and after adding furosemide to the prior antihypertensive agents. RESULTS: At baseline, 83% of patients had low PRA (< 1 ng/mL/h). After furosemide, in 67% of patients, decreases in SBP (166 +/- 5 to 134 +/- 5 mm Hg; P <.001), DBP (82 +/- 4 to 71 +/- 4 mm Hg; P =.004), and MAP (111 +/- 3 to 92 +/- 3 mm Hg; P <.001), were associated with increases in PRA (2.1 +/- 1.2 to 5.1 +/- 1.8 ng/mL/h; P =.01) and SA (4.8 +/- 1.0 to 9.4 +/- 1.4 ng/dL; P =.01) and with decreases in ANP (101 +/- 28 to 58 +/- 11 pg/mL; P =.01) and body weight (77.5 +/- 3.6 to 76.4 +/- 3.3 kg; P =.02), findings consistent with volume mediated/salt sensitive hypertension. In the remaining 33% of patients, BP also decreased significantly, but there was no increase in PRA (0.15 +/- 0.05 to 0.10 +/- 0 ng/mL/h) or SA (9.2 +/- 2.2 to 7.0 +/- 0.8 ng/dL) and no decrease in ANP (66 +/- 5 to 75 +/- 18 pg/mL) (P = ns for all), suggesting alternate mechanisms for their responses. CONCLUSIONS: Many of the elderly hypertensive patients in our study had decreased PRA levels and showed significant reductions in BP after furosemide administration. Despite the associated increases in PRA and SA and decreases in ANP in 67% of patients, diuretic use remains important in the control of hypertension in this population.

Aged↗

PubMed2002

Failure of intravenous fluid therapies to decrease serum sodium levels in elderly hospitalized patients.

Elderly patients may have a tendency to develop hyponatremia due to sensitivity to stimuli that release ADH as well as an impaired ability to excrete a water load. We evaluated changes in serum sodium in elderly hospitalized patients who received various forms of intravenous fluid therapies. All patients were required to have a baseline serum sodium of 136-145 meq/L. Fourteen patients were enrolled in the study. The mean age was 82.9 +/- 6.8 years (mean +/- SEM). Thirty-six % were nursing home residents. Seventy-nine % were females. Seventy-two % received half normal saline and the remainder received normal saline as intravenous fluid therapy. The patients received a mean of 1098 +/- 145 mL of intravenous fluid per day, in addition to oral fluids. Mean follow up period was 5.9 days (3-10 days). Mean baseline serum sodium was 140.2 +/- 0.7 meq/L andmean follow up serum sodium was 141.4 +/- 0.9 meq/L. The m ean baseline BUN was 25 +/- 3.6 mg/dL and mean follow u BUN was 19.6 +/- 3.4 mg/dL. The mean baseline serum creatinine was 0.9 +/- 0.1 mg/dL and mean follow up creatinine was 0.9 +/- 0.1 mg/dL. The postintravenous fluid therapy serum sodium in the group receiving half normal saline was 141.7 +/- 0.7 meq/L and 140.8 +/- 3 meq/L in the normal saline group. No significant difference was observed between the pre and post fluid therapy for any of these paramenters (p > 0.05). Mean baseline plasma renin activity was 1.6 +/- 0.7 ng/ml/hour and fifty-seven % had PRA of less than 1 ng/ml/hour. Mean plasma aldosterone was 8.5 +/- 1.8 ng/mL and forty-two % were less than 5.5 ng/mL. Plasma ADH and ANP was 5.7 +/- 3.4 pg/mL and 83.6 +/- 26.9 pg/mL, respectively. Mean serum and urine osmolalities were 290 +/- 3.1 mOsm/kg and 471 +/- 57.7 mOsm/kg, respectively. No patient developed hyponatremia and 7 of the 14 patients experienced an increase in serum sodium during the follow up period. We conclude that many elderly patients hospitalized for acute medical illnesses either maintain a stable serum sodium or experience an increase in serum sodium. This occurs because total fluids administered to these patients are generally insufficient.

Aged↗

PubMed2002

Changes in serum sodium, sodium balance, water balance, and plasma hormone levels as the result of pelvic surgery in women.

Postoperative hyponatremia in women has been associated with the development of serious neurological disorders and even death, with a predisposition for menstruant women. The objective of this study was to evaluate the immediate hormonal, water and electrolyte responses to pelvic surgery in both pre and postmenopausal women. Of the twenty-five consecutive women studied, twenty were premenopausal while five were postmenopausal. Mean age was 45.4 +/- 1.6 years. Measurements of plasma renin activity, follicular stimulating hormone and luteinizing hormone showed no significant change pre to postoperatively. There was a significant decrease in pre to postoperative values of estrogen, 97.4 +/- 20.3 to 36.3 +/- 7.5 pg/mL (p < 0.05). There was also a significant decline in postoperative values for plasma aldosterone and plasma progesterone. Data were similar in pre and postmenopausal patients. Serum sodium levels decreased from 141.5 +/- 0.5 to 137.2 +/- 0.5 mEq/L (p < 0.01). During the twenty-four hours following surgery, mean net sodium balance was positive 122 mEq and mean measured fluid balance was positive 1108 mL. Ringers lactate or normal saline were used. On the first postoperative day, plasma arginine vasopressin levels were elevated at 4.0 +/- 0.8 pg/mL, with a mean urine osmolality of 504 +/- 29 mOsm/kg H2O. The data illustrate that women undergoing pelvic surgery decrease their serum sodium in the immediate postoperative period. Despite both positive sodium and water balance, there is a stronger tendency to conserve water. Decreased estrogen levels occur and this decrease may facilitate brain cell adaptation to plasma hypotonicity. Since the administration of isotonic fluid will not protect against the decrease in serum sodium, postoperative sodium concentration should be carefully monitored.

Aldosterone↗