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[Asymptomatic microhematuria: follow-up in 39 patients]
S Rüttimann1, M Dreifuss, A Di Gallo
1Medizinische Universitätspoliklinik, Kantonsspital Basel.
Abstract:
We have studied 39 patients with asymptomatic microhematuria (AM) over a mean period of 3.7 years (2.6 to 5.3). In 28 patients, the etiology of the AM had remained unknown despite extensive work-up at the time of AM diagnosis. During follow-up, the urine was examined by the dipstick method and a urine sediment was prepared by standard techniques. Erythrocyturia was judged as grade I or grade II (3-9 or less than 9 erythrocytes/hpf) and classified by phase-contrast microscopy as glomerular or non-glomerular (greater than 30% or less than 30% of erythrocytes with glomerular characteristics). The results were as follows. All patients were in good health during the whole follow-up. None developed significant proteinuria or gross hematuria. AM persisted in 28 of the 39 patients (72%) and in 22 of the 28 with AM of unknown etiology (79%). Persistence of AM was independent of grade and morphology of AM. Among the patients with AM of unknown cause, the fifteen who initially showed grade I AM had grade I AM in 92% and grade II AM in 8% of follow-up urinalyses, and the seven with grade II AM at the first examination had grade II AM in 65% and grade I AM in 35% of follow-up urinalyses (p = 0.007). The last morphologic classification of AM corresponded to the first in all patients with grade II AM, but only in 74% of patients with grade I AM. The following conclusions were drawn. (1) Most AM of unknown etiology persists over several years irrespective of grade and morphology of erythrocyturia.(ABSTRACT TRUNCATED AT 250 WORDS)
Insights
Asymptomatic microhematuria (AM) often persists for years, even when its cause is unknown. This study found that the persistence of AM is generally independent of its initial grade or red blood cell characteristics.
Area of Science:
- Nephrology
- Urology
Context:
- Asymptomatic microhematuria (AM) is a common finding.
- The etiology of AM remains unknown in a significant number of cases despite thorough investigation.
Purpose:
- To investigate the long-term persistence and characteristics of asymptomatic microhematuria of unknown etiology.
- To determine if the grade or morphology of AM influences its persistence.
Summary:
- A study followed 39 patients with AM for a mean of 3.7 years.
- Of 28 patients with initially unknown AM etiology, 79% showed persistent AM.
- Persistence was independent of AM grade (I or II) or morphology (glomerular vs. non-glomerular).
Impact:
- Most cases of asymptomatic microhematuria with unknown etiology persist over several years.
- Findings suggest that extensive work-up may not be necessary for all AM cases of unknown origin.
- Further research may clarify the long-term implications and management of persistent AM.