Benign proteinuria

Edema is a relatively frequent finding in normal pregnancy. It appears to be benign and can even be associated with improved obstetric performance (139). Edema, even in the presence of hypertension or proteinuria, is not a useful predictor of obstetric complications (140). These observations are important, in view of the finding that treatment with thiazide diuretics is associated with a reduced birth weight in normotensive pregnant subjects (141). 

Leukocytoclastic vasculitis is a well-described and confirmed adverse effect of G-CSF, as documented in several reports, with recurrence after renewed administration of G-CSF (SEDA-19,343). Most cases were confined to the skin, and renal insufficiency with hematuria and proteinuria was noted in only very few patients. Based on 18 cases reported in the hterature or to the manufacturers, vasculitis was thought to have occurred in 6% of patients with chronic benign neutropenia, but in only six of about 200 000 patients with mahgnant disease (68). Vasculitis usually developed when the neutrophil count rose above 800 X 10 /1, suggesting that an increase in neutrophil count may play a role in necrotic vasculitis. Against this background, the occurrence of vascuhtis is not considered as treatment-hmiting and does not preclude further G-CSF administration if the absolute neutrophil count is lower than 1000 x 10 /1. 

Fig. 15. Benign paraproteinemia. Electrophoresis on cellulose acetate of serum and concentrated urine reveals (i) no Bence Jones proteinuria (ii) no loss of normal y-globulin (iii) a low level of serum paraprotein. In this case the paraprotein is of post-y-mobility, is type GL, and is typically (but not exclusively) found in lichen myxedematosus. Reproduced by courtesy of the Proceedings of the Royal Society of Medicine (H30).

Where Bence Jones proteinuria, 7 S IgM, subnormal IgG, or atypical cold agglutinin (anti-i, type L, etc.) are found, the probability of lymphosarcoma looms large (C2, C14). Some 10% of IgM lymphomata present with atypical cold agglutinins, and conversely disease terminates as lymphosarcoma. Apart from these, the prognosis is fair, for this would be a benign paraprotein in most cases, were it not for its hemolytic potential. 

These are uncommon and cannot be diagnosed with complete assurance until some 10 years of observation have passed. In general in Britain such patients are symptomless and have normal lymph nodes, spleen, and bone marrow. (In Africans the condition may be associated with parasitic infections, see M17.) The serum level is mostly under l.Og/100 ml, and hitherto always under 2.5g/100 ml. It shows no tendency to rise with many years of follow-up indeed it may disappear spontaneously. In our experience there is no Bence Jones proteinuria, and IgA and IgG levels are usually normal. Such apparently benign IgM paraproteins can be found in relatives of patients with malignant IgM paraproteins (S9), emphasizing the need for careful follow-up. 

Orthostatic, or postural, proteinuria is common in teenagers. It is a benign condition in which proteinuria occurs only when the subjects are standing upright, and is a re.sult of an incnaise in the hydrostatic pressure in the renal veins. 

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