小儿淋巴管瘤的MRI诊断

目的分析小儿淋巴管瘤的磁共振表现及其病理基础。方法对６例经手术病理证实的、年龄７天至７岁的小儿淋巴管瘤患者的磁共振表现进行回顾性分析。结果淋巴管瘤磁共振表现为Ｔ１ＷＩ上呈与肌肉相似或稍高的信号，Ｔ２ＷＩ上高于脂肪信号。５例瘤内可见低信号分隔，１例瘤内见血管流空影，３例见明显包膜，３例边界不清。２例病理诊断为海绵状淋巴管瘤，４例诊断为囊状淋巴管瘤。结论磁共振成像可较好地显示肿瘤的大小、形态及范围，从而指导手术治疗。     

Antihypertensive drugs, dietary salt, and renal protection: how low should you go and with which therapy?

Although it is clear that hypertension accelerates the rate of progression of most forms of chronic renal disease, many unanswered questions remain concerning how to optimally preserve kidney function in patients with hypertension and renal insufficiency. The mechanisms by which hypertension accelerates progression of renal disease have been extensively studied in experimental models. Glomerular capillary hypertension, consequent to an increase in systemic blood pressure combined with a reduction in preglomerular resistance and/or an increase in postglomerular resistance, results in increased hydraulic stress to the glomerular capillary wall. This and other mechanisms result in the release of growth-promoting cytokines and soluble mediators of fibrosis that stimulate cellular proliferation and matrix accumulation, ultimately leading to glomerular sclerosis and interstitial fibrosis. Almost without exception, studies in animals demonstrate that blood pressure reduction reduces the rate of progression of experimental renal disease. Angiotensin-converting enzyme inhibitors and, possibly, calcium antagonists may have a therapeutic advantage compared with other antihypertensive drugs in preventing kidney damage. This has been linked to both blood pressure-dependent and -independent actions. However, most experimental studies have failed to reduce blood pressure to a level sufficient to establish the clinical relevance of potential blood pressure-independent effects. Experimental studies comparing various types of antihypertensive drugs in which a mean arterial pressure (MAP) of approximately 92 mm Hg is achieved are necessary to determine whether clinically important differences in the effects of these drugs on the rate of progression of renal disease exist. Clinical experience with high blood pressure and kidney disease in humans suggests that the risk of developing hypertension-associated renal disease is a continuous variable across the entire range of systolic and diastolic blood pressures. Logically, optimal protection of kidney function may therefore be a continuous function of declining systemic blood pressure. Consistent with this view, recent clinical trials suggest that reducing MAP to 92 mm Hg, corresponding to a blood pressure reading of 125/75 mm Hg, provides more optimal stabilization of renal function in patients with nondiabetic proteinuric kidney disease (>1 g/d) compared with more conventional therapy with a blood pressure goal of 140/90 mm Hg (MAP 107 mm Hg). Clinical trials in patients with diabetes mellitus and renal insufficiency also demonstrate the benefits of reducing blood pressure to approximately 95 mm Hg MAP. Dietary salt consumption may be another important variable affecting the rate of progression of renal disease due to both direct, salt-dependent effects on renal growth and the action of decreased salt intake to augment the antihypertensive and antiproteinuric properties of many drugs. The precise role of alterations in dietary salt consumption on progression of renal disease directly as well as on the effectiveness of various antihypertensive drugs has yet to be examined in clinical trials.     

Functional outcome in a contemporary series of major lower extremity amputations

PURPOSE: We undertook this study to document the functional natural history of patients undergoing major amputation in an academic vascular surgery and rehabilitation medicine practice. METHODS: A retrospective review was conducted of consecutive patients undergoing major lower extremity amputation and rehabilitation in a university and Department of Veterans Affairs hospital. Main outcome variables included operative mortality, follow-up, survival, median time to incision healing, secondary operative procedures for wound management, and conversion from below-knee amputation (BKA) to above-knee amputation (AKA). For surviving patients, quality of life was determined by degree of ambulation, eg, outdoors, indoors only, or no ambulation; use of a prosthesis; and independence, eg, community housing or nursing facility. RESULTS: From August 1997 through March 2002, 154 patients (130 men; median age, 62 years) underwent 172 major amputations, 78 AKA and 94 BKA, because of either critical limb ischemia (87%) or diabetic neuropathy (13%). Thirty-day operative mortality was 10%. Mean follow-up was 14 months. Healing at 100 and 200 days, as determined with the Kaplan-Meier method, was 55% and 83%, respectively, for BKA, and 76% and 85%, respectively, for AKA. Twenty-three BKA and 16 AKA required additional operative revision, and 18 BKA ultimately were converted to AKA. Survival was 78% at 1 year and 55% at 3 years. Function in surviving patients at 10 and 17 months, respectively, was as follows: 21% and 29% of patients ambulated outdoors, 28% and 25% ambulated indoors only, and 51% and 46% of patients were nonambulatory; 32% and 42% of patients used prosthetic limbs; and 17% and 8% of patients who lived in the community before amputation required care in a nursing facility. CONCLUSIONS: We were surprised to find that vascular patients in a contemporary setting who require major lower extremity amputation and rehabilitation often remain independent despite infrequent prosthesis use and outdoor ambulation. Although any hope for postoperative ambulation in this population requires salvaging the knee joint, because of the morbidity incurred in both wound healing and rehabilitation efforts, aggressive effort should be reserved for selected patients at good risk. Ability to predict ambulation after BKA in the vascular population is poor.