Which are common clinical manifestations of acute Poststreptococcal glomerulonephritis?

Postinfectious glomerulonephritis occurs after infection, usually with a nephritogenic strain of group A beta-hemolytic streptococcus. Diagnosis is suggested by history and urinalysis and confirmed by finding a low complement level and sometimes by antibody testing. Prognosis is excellent. Treatment is supportive.

Most cases are caused by nephritogenic strains of group A beta-hemolytic streptococci, most notably type 12 [which causes pharyngitis Tonsillopharyngitis Tonsillopharyngitis is acute infection of the pharynx, palatine tonsils, or both. Symptoms may include sore throat, odynophagia, cervical lymphadenopathy, and fever. Diagnosis is clinical, supplemented... read more

] and type 49 [which causes impetigo Impetigo and Ecthyma Impetigo is a superficial skin infection with crusting or bullae caused by streptococci, staphylococci, or both. Ecthyma is an ulcerative form of impetigo. Diagnosis is clinical. Treatment is... read more

]; an estimated 5 to 10% of patients with streptococcal pharyngitis and about 25% of those with impetigo develop PIGN. A latency period of 6 to 21 days between infection and glomerulonephritis onset is typical, but latency may extend up to 6 weeks.

Less common pathogens are nonstreptococcal bacteria, viruses, parasites, rickettsiae, and fungi [see table Causes of Glomerulonephritis Causes of Glomerulonephritis

]. Bacterial endocarditis Infective Endocarditis Infective endocarditis is infection of the endocardium, usually with bacteria [commonly, streptococci or staphylococci] or fungi. It may cause fever, heart murmurs, petechiae, anemia, embolic... read more

and ventriculoatrial shunt Treatment Hydrocephalus is accumulation of excessive amounts of CSF, causing cerebral ventricular enlargement and/or increased intracranial pressure. Manifestations can include enlarged head, bulging... read more

infections are additional important conditions in which PIGN develops; ventriculoperitoneal shunts are more resistant to infection.

The mechanism is unknown, but microbial antigens are thought to bind to the glomerular basement membrane and activate primarily the alternate complement pathway both directly and via interaction with circulating antibodies, causing glomerular damage, which may be focal or diffuse. Alternatively, circulating immune complexes could precipitate on the glomerular basement membrane.

Symptoms and Signs

Symptoms and signs range from asymptomatic hematuria [in about 50%] and mild proteinuria to full-blown nephritis with microscopic or gross hematuria [cola-colored, brown, smoky, or frankly bloody urine], proteinuria [sometimes nephrotic-range], oliguria, edema, hypertension, and renal insufficiency. Fever is unusual and suggests persistent infection.

Renal failure that causes fluid overload with heart failure and severe hypertension requiring dialysis affects 1 to 2% of patients.

Uncommonly, nephrotic syndrome may persist after resolution of severe disease.

Clinical manifestations of nonstreptococcal PIGN may mimic other disorders [eg, polyarteritis nodosa, renal emboli, antimicrobial drug–induced acute interstitial nephritis].

• Clinical evidence of recent infection

• Urinalysis typically showing dysmorphic red blood cells [RBCs], RBC casts, proteinuria, white blood cells [WBCs], and renal tubular cells

• Often hypocomplementemia

Tests done to confirm the diagnosis depend on clinical findings. Antistreptolysin O, antihyaluronidase, and antideoxyribonuclease [anti-DNAase] antibodies are commonly measured. Serum creatinine and complement levels [C3 and total hemolytic complement activity] are also usually measured; however, in patients with typical clinical findings, some tests can be omitted. Sometimes other tests are done. Biopsy confirms the diagnosis but is rarely necessary.

Antistreptolysin O level, the most common laboratory evidence of recent streptococcal infection, increases and remains elevated for several months in about 75% of patients with pharyngitis and in about 50% of patients with impetigo, but it is not specific. The streptozyme test, which additionally measures antihyaluronidase, antideoxyribonuclease, and other titers detects 95% of recent streptococcal pharyngitis and 80% of skin infections.

Urinalysis typically shows proteinuria [0.5 to 2 g/m2/day]; dysmorphic RBCs; WBCs; renal tubular cells; and possibly RBC, WBC, and granular casts. Random [spot] urinary protein/creatinine ratio is usually between 0.2 and 2 [normal,