UMEM Educational Pearls

Post- streptococcal glomerulonephritis (PSGN) is an inflammatory reaction of the kidneys following infection with group A strep, and can occur sub clinically or have a severe presentation requiring admission, Nephrology consult, and careful management.

This diagnosis should be considered in any child between ages 2-12, or adults over 60, presenting with sudden unexplained hematuria or brown urine.  Patients may also present with generalized edema secondary to urinary protein loss, hypertension, and acute kidney injury.  Since kidney involvement usually trails the throat injection by 2-3 weeks or more, the patient and their family may not relate the two symptoms.  A previous or current diagnosis of strep throat is not necessary to consider a patient for PSGN, since they may test negative by throat culture at the time of urinary and renal symptoms

When considering this diagnosis, the EM physician should order the following lab tests:
- Urinalysis (for casts and protein)
- Creatinine
- ASO Titer (or full streptozyme assay of 5 tests including ASO)
- Complement C3, C4, C50

Treatment is primarily supportive, and many cases will be mild enough to discharge home with pediatrician or Nephrology follow up.  However, some cases may warrant admission for AKI, pulmonary edema, or cerebral edema.  Edema can be managed with sodium restriction and loop diuretics.  Hypertension can be managed with anti hypertension medications.

Renal biopsy can confirm the diagnosis with the presence of epithelial crescents in the glomeruli, but this is only necessary in severe cases where it is important to determine the etiology of the nephritis.
 

References

Eison TM, et al. Post-streptococcal acute glomerulonephritis in children: clinical features and pathogenesis.  Pediatr Nephrol 2011; 26:165-180.