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Glomerular diseases present clinically in several different ways,
depending on the nature and severity of the primary disease and
the extent to which the normal physiological functions of the glomerulus
are perturbed.1,2 Some children with glomerulonephritis
(GN) are found incidentally to have microscopic hematuria or proteinuria
when checked by routine urinalysis but are otherwise asymptomatic.
At the other extreme, children may become critically ill with oligoanuric rapidly
progressive GN in need of urgent dialysis. A few glomerular diseases
are inherited (see Chapter 473), but most forms of GN are acquired
and are generally considered to be immunologically mediated. There
are three classical clinical syndromes that develop from glomerular
injury: acute and chronic glomerulonephritis,
defined by the triad of hematuria, hypertension, and azotemia; nephrotic
syndrome, defined by proteinuria and hypoalbuminemia; and hemolytic
uremic syndrome, defined by microangiopathic hemolytic
anemia, thrombocytopenia, and renal insufficiency.
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The pathophysiological sequence of events that lead to the development
of the nephritic triad (hematuria, azotemia, and hypertension) are shown
in Figure 472-1. In each of the clinical
entities with glomerular proliferation, the inflammation process
leads to decreased glomerular perfusion, resulting in compromised
renal function and retention of salt and water with potential development of
hypertension and edema.
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Approach to
a Patient with Glomerulonephritis
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The patient with glomerular disease presents clinically with
a constellation of features that may include hematuria, proteinuria,
hypertension, edema, and renal insufficiency. The urinary sediment is
characterized as active when dysmorphic erythrocytes and cellular
casts are present. A series of questions guides the initial diagnostic
and management plan.1
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1. Does this patient have acute or chronic
GN? Many patients with chronic GN appear relatively asymptomatic until
the disease is advanced. Clues of chronicity include significant
anemia, evidence of renal osteodystrophy (abnormal bone radiographs
or an elevated PTH level), or small echogenic kidneys on ultrasound
examination. Acute onset of severe hypertension often causes neurological
symptoms such as headaches and seizures, while long-standing hypertension of
insidious onset may be clinically silent, but left ventricular hypertrophy
may be present.
2. Does this patient have isolated renal disease, or
are extrarenal organ systems involved? A careful systems
review and physical examination will help determine whether the
investigation should move in the direction of primary (acquired)
GN or toward multisystem disease associated with GN (Table
472-1). Relevant extrarenal involvement may be clinically silent.
For example, postinfectious serological studies (such as a streptozyme
or anti–hepatitis B or anti–hepatitis C antibodies)
may be indicated if infection-associated GN is a possibility. When
patients present with vasculitis caused by Wegener’s granulomatosis,
involvement of ...