Physiological Adaptation Q 84
Which of the following conditions most commonly causes acute glomerulonephritis?
A. A congenital condition leading to renal dysfunction.
B. Prior infection with group A Streptococcus within the past 10-14 days.
C. Viral infection of the glomeruli.
D. Nephrotic syndrome.
Correct Answer: B. Prior infection with group A Streptococcus within the past 10-14 days.
Acute glomerulonephritis is most commonly caused by the immune response to a prior upper respiratory infection with group A Streptococcus. Glomerular inflammation occurs about 10-14 days after the infection, resulting in scant, dark urine, and retention of body fluid. Periorbital edema and hypertension are common signs at diagnosis.
Option A: No congenital condition predisposes to glomerulonephritis. Noninfectious causes of acute GN may be divided into primary renal diseases, systemic diseases, and miscellaneous conditions or agents.
Option C: Viruses may cause acute glomerulonephritis but rarely. Cytomegalovirus (CMV), coxsackievirus, Epstein-Barr virus (EBV), hepatitis B virus (HBV), rubella, rickettsiae (as in scrub typhus), parvovirus B19, and mumps virus are accepted as viral causes only if it can be documented that a recent group A beta-hemolytic streptococcal infection did not occur. Acute GN has been documented as a rare complication of hepatitis A.
Option D: Nephrotic syndrome does not cause acute glomerulonephritis. PSGN usually develops 1-3 weeks after acute infection with specific nephritogenic strains of group A beta-hemolytic streptococcus. The incidence of GN is approximately 5-10% in persons with pharyngitis and 25% in those with skin infections.