Metformin induced severe hypophosphatemia in a patient on hemodialysis.

A 67-year-old diabetic and hypertensive woman presented to us with very low serum phosphate levels (PO4⁻ =1.1 mg/dL) about 40 days after initiation of hemodialysis (HD). The phosphate binders were discontinued, because they were thought to be the cause of hypophosphatemia. However, the serum phosphate levels continued to remain low during subsequent follow-up visits over one month (PO4⁻⁻⁻ = 0.7 and 0.6 mg/dL respectively). The patient had been started on metformin hydrochloride (850 mg thrice a day) about 18 days after the beginning of HD. The drug was stopped immediately (approximately 50 days after it was started) and the serum phosphate levels increased progressively, reaching 4.3 mg/dL. During the period with hypophosphatemia, the patient suffered from very intense fatigue and weakness (she was unable to walk), anorexia, diarrhea and tenesmus. There were no features suggestive of rhabdomyolysis, hemolysis, low blood pressure or hypoglycemia; she had low white blood cell and platelet counts. The patient was in good clinical condition 2-3 days after the discontinuation of metformin and she recovered totally 15 days later. This case is presented due to its rarity as well as the observation that despite the patient having severe hypophosphatemia, she showed only side effects of metformin. Hypophosphatemia caused only intense fatigue and no other symptoms.

The red blood cell deformability in patients suffering from end stage renal failure on hemodialysis or continuous ambulatory peritoneal dialysis.

Anemia is the main problem for patients suffering from end stage renal disease (ESRD). This study aimed to determine whether the index of rigidity (IR), that shows red blood cells (RBCs) deformability and the possible IR disturbances can provide an explanation about the cause of anemia, in patients undergoing maintenance hemodialysis (HD) or on peritoneal dialysis. The IR was determined in 39 hemodialyzed patients, who were already in dialysis for a period of time ranging from 16 to 120 months (mean+/-SD=41.8 +/-24.1) (Group A). Furthermore, the IR was measured in 32 patients on continuous ambulatory peritoneal dialysis (CAPD), who were in CAPD for a period of time ranging from 6 to 60 months (mean+/-SD = 10.7+/-9.9) (Group B). Finally, the IR was determined in 17 normal individuals (group C). The RBCs IR was measured twice in group A (before and after the end of a hemodialysis session) and once in groups B and C. The IR was determined by hemorrheometry (method of filtration), using special equipment. In group A the IR was increased in comparison to the control group (C) (17.9+/-6.2 vs. 10.2+/-1.8, p<0.0001). This increase was even higher in the measurement at the end of the hemodialysis session (paired t-test, p < 0.0001). The RBCs IR in CAPD patients was significantly lower than that of HD patients (12+/-3.8 vs. 17.9+/-6.2, p<0.0001) and was not statistically different from the control group (12+/-3.8 vs. 10.2+/-1.8, p=0.068). It is concluded from the study that: 1) in HD patients occur disturbances in the deformability of the RBCs, that are worsened by the hemodialysis session; 2) the index of rigidity of RBCs is significantly higher in the HD patients than in CAPD patients; 3) in patients on CAPD, the disturbance of deformability of the RBCs was less in comparison to the control group, which however does not reach the statistically significant levels.

The effect of intense passive apnea in the acid-base balance and electrolytes.

The aim of this study was to investigate the disturbances of the acid-base balance and electrolyte disorders in healthy individuals in the greatest passive apnea (prior to apnea and prior to first inhalation). The changes of the acid-base balance, the serum potassium and calcium levels as well as the disturbances of the cardiac rhythm were studied in a group of 15 healthy males aged 18 to 41 years old. Seven individuals part of the original group participated in a second trial. Following the initial apnea trial the individuals were allowed to 2-3 free inhalations and a second passive apnea effort was performed. The same parameters were measured in the second effort. In the primary effort the apnea duration was 170 +/- 53 s (mean +/- SD). The results received prior to the effort and immediately before the end of the apnea (paired t-test), showed no significant changes in the blood pH. The PaCO2 increased significantly, the PaO2 decreased significantly, blood bicarbonate increased significantly, the hemoglobin oxygen saturation decreased significantly. In addition the serum potassium and calcium levels decreased significantly. In the subgroup (7 individuals) the second effort of apnea lasted 50-70 s and showed no significant changes in the blood pH. The same changes concerning PaCO2 and blood bicarbonate were observed in the first and second effort of passive apnea. The serum potassium and calcium levels as well as the hemoglobin oxygen saturation showed no significant changes. During the initial effort of apnea all men presented bradycardia, which was followed by tachycardia immediately after the end of the effort. One individual, whose effort lasted 290s suffered intense tachycardia, cyanosis, convulsions, and loss of consciousness. It is concluded that during an intense effort of passive apnea: (a) the blood PaCO2 is significantly increased, as well as the blood bicarbonates, (b) the PaO2, the hemoglobin oxygen saturation and the serum potassium and calcium levels are significantly decreased, (c) the cardiac rate is significantly decreased, and (d) the second effort of apnea, following immediately the initial one, is sorter in duration and produces similar or milder changes of the above parameters.