What are the diagnostic criteria for Poststreptococcal Glomerulonephritis (PSGN) in Physical Examination (PE)?

From the Guidelines

When evaluating for Poststreptococcal Glomerulonephritis (PSGN) in the physical exam (PE), look for non-specific signs/symptoms of infection, such as lethargy, fever, and clinical signs of bacteremia, as well as active skin or tonsil infections present in some cases. According to the KDIGO 2021 guideline for the management of glomerular diseases 1, the physical examination may reveal signs of infection, but these are not specific to PSGN.

In terms of diagnostic criteria, the guideline suggests assessing for:

• History of antecedent resolved pharyngitis (1-2 wks) or impetigo (4-6 wks)
• Physical exam findings, such as active skin or tonsil infections present in some cases
• Laboratory kidney tests, including urinalysis to assess for glomerular hematuria and red blood cell casts, albumin-creatinine ratio (ACR), and protein-creatinine ratio (PCR)
• Laboratory infection tests, such as culture of skin or tonsils if infected
• Laboratory immunology tests, including assessment for low complement (C3, C4), rheumatoid factor, cryoglobulins, and factor B antibody levels

Key physical exam findings may include:

• Edema, especially periorbital and in lower extremities
• Hypertension
• Cola-colored or smoky urine
• Recent history of streptococcal infection (usually 1-3 weeks prior)

It is essential to note that the diagnosis of PSGN is often based on a combination of clinical presentation, laboratory tests, and history of recent streptococcal infection, rather than a single physical exam finding 1.

From the Research

Diagnostic Criteria for Poststreptococcal Glomerulonephritis (PSGN) in Physical Examination (PE)

The diagnostic criteria for PSGN in physical examination (PE) include:

• Hypertension: defined as diastolic pressure over 13 kPa (97.5 mmHg) 2
• Edema: often presents with hypertension and hematuria 3, 4
• Gross hematuria: red to brown urine, a hallmark of PSGN 4, 5
• Proteinuria: nephrotic range proteinuria, often accompanied by hematuria and hypertension 3, 4
• Acute kidney injury: may present with impaired renal function 4, 5

Clinical Presentation

The clinical presentation of PSGN can range from asymptomatic, microscopic hematuria to the nephritic syndrome, which is defined by:

• Red to brown urine
• Nephrotic range proteinuria
• Edema
• Hypertension
• Acute kidney injury 4, 5

Urinalysis

Urinalysis may show:

• Red blood cells
• Red blood cell casts
• Proteinuria
• However, a normal urinalysis does not rule out the diagnosis of PSGN, as some patients may have only minimal and transient abnormalities in the urinalysis 6

Laboratory Tests

Laboratory tests that may aid in the diagnosis of PSGN include:

• Low C3 level (hypocomplementemia): found in more than 90% of PSGN cases 4
• Antistreptolysin O titers: may be elevated in PSGN 3, 4
• Measuring C3 and C4: may be helpful in the evaluation of other causes of acute nephritis 4