Biomedical subjects
Publications and source records attributed to J W Merkus.
We describe our first false negative sentinel node biopsy after ceasing confirmatory axillary lymph node dissection in breast cancer. Palpation of the axilla through the biopsy wound prevented understaging.
To explain an occasionally observed transient swelling of the ipsilateral leg in renal transplant recipients in the absence of deep vein thrombosis, we took serial measurements of venous outflow resistance and duplex examinations of both legs. Fourteen recipients of a living related donor kidney graft were submitted to strain gauge plethysmography and duplex examination before transplantation and 1 and 6 weeks thereafter. Venous outflow resistance and venous flow were measured and the veins were assessed for thrombosis. Strain gauge plethysmography showed a significant increase in venous outflow resistance in the leg on the side of the renal transplant 1 week after transplantation [0.28 +/- 0.13 vs 0.40 +/- 0.15 mmHg.s (ml/100 ml)-1; P < 0.05]. Six weeks later, the venous outflow resistance had returned to preoperative values [0.30 +/- 0.11 mmHg.s (ml/100 ml)-1; P = NS]. On the contralateral side, no significant differences were found. Duplex examinations showed no signs of thrombosis. Venous flow measurements in the common femoral vein showed no significant differences. We conclude that the additional blood supply to the iliac veins results in an increase in venous outflow resistance in the ipsilateral leg, which can explain the observed swelling of this leg and may have implications for the preferred method of diagnosis of venous thrombosis after renal transplantation.
Cyclosporin A (CyA) nephrotoxicity and rejection of a renal allograft each demands a specific therapy. This study was designed to establish the capability of Doppler spectrum analysis to diagnose either one of these causes during renal dysfunction. Between October 1989 and October 1991 we performed echo-Doppler examinations in 209 renal transplant recipients on a routine basis during the first three months after transplantation. Echo-Doppler examinations during periods of renal dysfunction were analyzed. A total of 93 periods of renal dysfunction, retrospectively due to rejection (n = 40) or CyA toxicity (n = 53), occurred in 70 patients during the study period. A control group consisted of 82 patients with normal functioning grafts. When compared to the control group, the Doppler features (in segmental arteries) of the rejection group showed significant lower frequency shifts [Fmax (Hz) 1637 +/- 423 vs. 1436 +/- 465; p < 0.05; Fdia (Hz) 582 +/- 180 vs. 458 +/- 225; p < 0.05], a shorter deceleration time of the Doppler spectrum [Tdown (ms) 340 +/- 100 vs. 276 +/- 102; p < 0.05], and a higher Resistance Index (RI 0.64 +/- 0.08 vs. 0.68 +/- 0.13; p < 0.05). Doppler spectra during CyA toxicity showed only a significantly longer acceleration time [Tmax (ms) 123 +/- 36 vs. 139 +/- 40; p < 0.05]. The capability of differentiation between the two causes was assessed with ROC analysis of single Doppler features, stepwise regression and canonic discriminant analysis on a set of Doppler features and with manual selection of several features with extreme values. ROC analysis yielded maximum sensitivity and specificity for the diagnosis of rejection using Tdown (sensitivity 65%; specificity 68%). Stepwise regression and canonic discriminant analysis of a set of features rendered a sensitivity and specificity of 73% and 64%, respectively. Explorative selection of extreme Doppler feature values showed that 18 of the 40 grafts with rejection had values that were only seen in 2 cases with CyA toxicity (positive predictive value 90%; sensitivity 45%; specificity 96%). In half of these cases Doppler features preceded the clinical diagnosis of rejection by a median of 4 d. In conclusion, Doppler spectra are influenced by rejection and CyA toxicity in specific ways. The Doppler features, however do not enable definite differentiation between rejection and CyA toxicity in all cases. Some changes in Doppler spectra are only seen in cases of rejection and thus enable positive identification of grafts with rejection, often earlier than clinical signs indicate rejection. A normal Doppler spectrum does not exclude rejection as the cause of renal dysfunction.
For the diagnosis of allograft artery stenosis in recipients of a renal transplant with hypertension a noninvasive investigation such as echo-Doppler is preferable to invasive methods such as angiography. Therefore we analyzed our experience with echo-Doppler diagnosis of renal allograft artery stenosis. In 131 renal transplant recipients with hypertension echo-Doppler examinations were performed. During the examinations several features indicative of stenosis were measured, and intrarenal Doppler spectra were quantitatively analyzed with a user-written program. Four patients showed signs of iliac artery stenosis. In 12 patients a renal allograft artery stenosis was suspected on echo-Doppler examination. In 8 of these 12 patients angiography was performed. All these showed a stenosis, 6 of which had more than > 75% stenosis. In 8 patients with normal echo-Doppler findings angiography was performed because of highly suggestive clinical signs of stenosis. In 7 of these no stenosis was found and in one a 50% stenosis was found. Comparison of quantitative Doppler spectrum features from patients with (n = 6) and without severe (> 75%) stenosis on angiography (n = 10) showed significant differences in several Doppler parameters. Subsequently an analysis of the best differentiation between these to groups on the basis of quantitative Doppler criteria was performed. In conclusion, echo-Doppler examinations with quantitative analysis of Doppler spectra enables reliable identification of renal allograft artery stenosis.
During posttransplant acute renal failure (ARF), the diagnosis of allograft rejection constitutes a major problem. We evaluated the value of Doppler ultrasonography in identifying grafts at risk of rejection during ARF. In 184 recipients of a renal allograft, Doppler examinations were performed on the first and fifth postoperative day. Doppler spectra were quantitatively analyzed with a user-written computer program. Doppler findings were not used in clinical decision making. ARF was defined as a diuresis < 400 ml/24 hr and/or the necessity for dialysis. Doppler spectra obtained on the first day after transplantation showed a resistance index (RI) of 0.59 +/- 0.09 in recipients with immediately functioning cadaveric grafts (n = 123), while living related donor grafts (n = 20) showed a lower RI (0.55 +/- 0.07; P < 0.05). Grafts with ARF (n = 41) showed a considerably higher RI (0.67 +/- 0.13; P < 0.05). When grafts with a duration of ARF < or = 4 days (n = 17) were compared with ARF > 4 days (n = 24), RI was not significantly different (0.63 +/- 0.07 vs. 0.68 +/- 0.15; NS). However, the acceleration time of the systolic deflection of the spectrum waveform (Tmax) was shorter in grafts with ARF > 4 days (86 +/- 47 msec vs. 128 +/- 39 msec; P < 0.05). On the fifth day after transplantation, Doppler spectra in grafts with ARF > 4 days (n = 24) showed a Tmax < 90 msec in 9 patients, 8 of whom experienced rejection during ARF (positive predictive value, 8/9 = 89%). In the 15 patients with Tmax > or = 90 msec, only 2 rejections occurred (negative predictive value, 13/15 = 87%). For the RI (> 0.85), positive predictive value was 4/5 = 80% and negative predictive value (RI < or = 0.85) was 13/19 = 68%. In conclusion, a short acceleration time of the Doppler waveform on the first day after transplantation is associated with a longer duration of ARF. Quantitative analysis of Doppler spectra can be helpful in the identification of patients at risk for rejection and in the timing of allograft biopsy during ARF. Persistently short Tmax values on the fifth day after transplantation perform better in identifying grafts at risk of rejection than high RI values.
This paper describes, by case histories and a literature review, the cause, diagnosis and therapy of pseudoaneurysm of the superficial temporal artery. Two patients with a traumatic pseudoaneurysm of the superficial temporal artery were examined by physical examination and histology of the excised lesions. Blunt injury caused a histologically proved pseudoaneurysm in two reported cases. A total of 12 additional reports of pseudoaneurysm of the superficial temporal artery were found in the literature. Pseudoaneurysm of the superficial temporal artery is an uncommon complication of blunt head injury. Symptoms are limited and diagnosis can be made by noninvasive means. A high suspicion level for arterial injury and sufficient follow-up of patients is necessary for the detection of arterial injury.
Arteriovenous fistula (AVF) is a well known but rarely diagnosed complication of percutaneous biopsy of kidney allografts. In the past diagnosis was usually made when clinical signs of an AVF occurred but Doppler ultrasonography has now enabled non-invasive diagnosis. Doppler examination of kidney allografts was performed after 100 biopsies. A total of ten AVFs were diagnosed within 2 weeks of biopsy. On repeated examination 2 months later, no additional fistula was detected. All fistulas were detected by abnormal colour shading of the artery and vein of the fistula caused by high blood velocity. Quantification in the artery supplying the fistula showed a higher systolic velocity compared with that in a normal artery of comparable size and location in the graft (mean (range) 64 (25-150) versus 36 (20-65) cm/s, P < 0.05). Diastolic velocity was also higher in the artery supplying the fistula than in a normal artery (mean (range) 34 (9-72) versus 7 (0-13) cm/s, P < 0.05). In the group with an AVF the proportion with a prolonged bleeding time (> 3 min) was higher (80 versus 47 per cent, P < 0.05), as was the prevalence of a platelet count < 200 x 10(9)/l (60 versus 22 per cent, P < 0.05). After detection of the fistula, four of the grafts were lost because of rejection and two patients died from sepsis during antirejection treatment. During follow-up of the remaining four AVFs, three disappeared spontaneously and one persisted. None of the fistulas has had an impact on renal function requiring intervention. In conclusion, AVF is a complication observed frequently after kidney allograft biopsy that can be detected and monitored by Doppler ultrasonography.
In a retrospective analysis of 1165 renal transplantations in our center, 65 cases of renal allograft artery stenosis were diagnosed angiographically (prevalence 5.5%). Hypertension was present in all cases; a bruit over the allograft and an increase in serum creatinine level were additional reasons for angiography. Shortly after diagnosis of the stenosis, two patients died and two others lost their grafts due to thrombosis. In 24 patients the decision was made not to correct the stenosis. One of these grafts was lost because the stenosis could not be corrected. Medical management of hypertension in these patients resulted in a decrease in diastolic blood pressure from 109 +/- 22 to 96 +/- 12 mm Hg (P < 0.01) 3 months after diagnosis with the use of almost twice as many antihypertensive drugs as at the time of diagnosis (P < 0.01). The stenosis was corrected if the angiography showed it to be so severe that it jeopardized renal allograft function or caused uncontrollable hypertension. Only three of nine percutaneous transluminal angioplasty (PTA) procedures resulted in a definitive correction of the stenosis. Surgical intervention was performed in 30 patients, including two patients whose PTAs had proved unsuccessful. Surgery led to graft loss due to thrombosis in 6 of 30 operations (20%), whereas restenosis occurred twice (7%). In three other cases (10%), the correction was not successful due to local anatomical variations or concomitant rejection.(ABSTRACT TRUNCATED AT 250 WORDS)
Analysis of Doppler spectrum waveforms is increasingly used in the differential diagnosis of human renal allograft dysfunction. The physiologic interpretation of changes in Doppler spectra obtained from renal allografts, however, remains a major problem. Computer simulation models of the renal circulation may provide insight into the physiologic mechanisms responsible for changes in Doppler spectrum characteristics. The results of measurements of renal allograft hemodynamics with both determinations of PAH clearance and Doppler spectrum analysis in 11 kidney allograft recipients were explained physiologically using a computer simulation model of kidney allograft hemodynamics. Using PAH clearance and blood pressure measurements a significant decrease in RVR was found (from 0.32 +/- 0.17 to 0.20 +/- 0.07 mm Hg x min/ml, P < 0.05) after administration of the vasodilatory drug nifedipine. The Doppler spectrum waveform obtained from interlobar renal arteries showed a decrease in the RI (from 0.60 +/- 0.04 to 0.56 +/- 0.06; P < 0.05) and Tmax (from 133 +/- 32 to 98 +/- 32 ms; P < 0.05). The user-designed simulation model of renal hemodynamics showed comparable changes of the waveform when, in the model, the analogs of blood pressure, impedance of the artery, and the impedance of the peripheral vascular bed were altered proportionally.
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Cyclosporin A (CyA) nephrotoxicity is at least partly caused by the vasoconstrictive action of the drug. In this study we set out to assess this hemodynamic effect of CyA on Doppler spectra obtained in arteries of human renal allografts. Doppler spectra of renal arteries were obtained shortly before and after the start of CyA infusion in renal transplant recipients. Doppler spectrum analysis revealed a significant change in several spectrum-derived parameters. Tmax (acceleration time of the systolic frequency peak), in particular, showed a decrease after 4 h of CyA administration (106 +/- 58 ms vs 76 +/- 36 ms in segmental arteries; P less than 0.05). On day 2 the Tmax returned to its original value (117 +/- 57 ms). Thus, Doppler spectrum analysis enables one to detect temporary hemodynamic changes in the transplanted kidney following CyA administration. These observations may be useful in differentiating causes of renal dysfunction by Doppler spectrum analysis in clinical transplantation.
In a retrospective study the incidence and consequences of acute renal failure were evaluated in 324 renal transplantations performed in our centre. The overall incidence of acute renal failure was 31.2%. In recipients with acute renal failure, patient and graft survival were significantly worse than in those without acute renal failure (P less than 0.02 and P less than 0.0001 respectively). Acute renal failure also increased the morbidity during the first 3 months after transplantation. Three months after transplantation renal function as determined by serum creatinine and proteinuria, was less satisfactory. Factors influencing the incidence of acute renal failure appeared to be: match grade on the AB locus, percentage of antibodies, duration of dialysis, number of blood transfusions prior to transplantation, anastomosis time and total ischaemia time. Recipients transplanted for the first time were less likely to develop acute renal failure, but also for this group total ischaemia time was a prognostic factor for the development of acute renal failure. When recipients were allocated to different classes of total ischaemia time it appeared that the incidence of acute renal failure differed, especially between groups with total ischaemia time 32-36 h (27%) and 36-40 h (38%). The difference in acute renal failure between these groups was also reflected in a difference in graft survival for total ischaemia time less than 36 h and greater than 36 h. Thus, it appears that acute renal failure has a detrimental effect on graft survival and postoperative morbidity in renal transplantation. Total ischaemia time is one of the prognostic factors for the development of acute renal failure. To improve renal transplantation results it is worth attempting to shorten total ischaemia time.
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An investigation was carried out of the drug-use of 198 patients in three nursing homes. Almost 80% of the patients used 2 to 7 drugs. The average number of drugs per patient relating to regular medications for internal use was 4,36. It was 5,25 when p.r.n. medications and medications for external use were also included. The most frequently used drugs were psychotropics, analgetics, cardiac drugs, diuretics and laxatives. Combinations of drugs (including alcohol) that can lead to interaction, were often prescribed. The following combinations were found to have the highest frequency: two drugs with anticholinergic action, digoxin with a potassium-loosing diuretic, two or more drugs which can cause hypotension. The number of patients with one or more of these combinations as well as the number of combinations per patient increased in correspondence with drug-use per patient.
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A study in a nursing home in the Netherlands confirmed findings from previous studies that a high percentage of geriatric patients use laxatives. This applies especially to patients taking antidepressants or hypnotics in combination with other psychotherapeutic agents or suffering from a neurological disease or to those who are rather inactive. Our study shows that it is possible for the large majority of geriatric patients using other laxatives to switch to bulk laxatives. This changing-process requires appropriate instructions and demands close attention. Eventually it will result in the normalisation of the patients' defecation, to the daily relief not only of the patient but also of the nursing staff.
There is no reason to assume that in old age defecation is different from younger people. Old people who are sound and active often have normal defecation. Their intestinal transit time has been shown to be normal. Nevertheless about fifty percent of the elderly use laxatives. In the very old and in institutions the use is even more frequent. The main cause of this real or supposed constipation is the lack of dietary fibre in the food. In the aged constipation can have dangerous complications, e.g. acute mental confusion, urinary retention, urinary incontinence and fecal impaction. Treatment may include general measurements, the addition of bulk-laxatives to the diet and the prescription of other laxatives. The use of laxatives other than bulk-laxatives may cause many harmful side-effects in the aged. The daily food must contain sufficient dietary fibre. Failing this one can use bran, preparations of psyllium or lactulose syrup.