**Core Concept:** Nephritic syndrome is a clinical entity characterized by nephrotic range proteinuria (>3.5 g/day), and signs of glomerular inflammation and damage. It is often associated with systemic diseases like systemic lupus erythematosus (SLE), vasculitis, and infections.

**Why the Correct Answer is Right:** September 2009 is not relevant to the question as it is a month and does not pertain to the clinical presentation or pathogenesis of nephritic syndrome. Instead, we should focus on the key features of nephritic syndrome:

1. Nephrotic range proteinuria: Protein excretion in excess of 3.5 g/day, indicating severe glomerular damage and dysfunction.
2. Glomerular inflammation: Evidence of immune complex deposition, vasculitis, or other inflammatory processes within the glomerulus.
3. Clinical manifestations: Edema, hypoalbuminemia, hyperlipidemia, and hypertension.

**Why Each Wrong Option is Incorrect:**

A. Proteinuria (>3.5 g/day): While proteinuria is a feature of nephritic syndrome, the cutoff of 3.5 g/day is not mentioned in the question. Additionally, nephrotic range proteinuria (>10 g/day) is associated with nephrotic syndrome, not nephritic syndrome.

B. Hypoalbuminemia: A common finding in nephritic syndrome due to decreased glomerular filtration rate and increased protein catabolism. However, the correct answer is not directly addressing the question about September 2009.

C. Nephrotic syndrome: Nephrotic syndrome is characterized by proteinuria (>10 g/day), minimal change disease, and edema. Nephritic syndrome, on the other hand, is associated with nephrotic range proteinuria (>3.5 g/day) and inflammation.

D. Systemic diseases: Nephritic syndrome is a clinical entity, not a disease itself. The correct answer should focus on the specific clinical features and pathogenesis of nephritic syndrome rather than listing systemic diseases.

**Clinical Pearls:**

1. A high index of suspicion and appropriate workup are crucial in differentiating nephrotic syndrome and nephritic syndrome, as treatment and prognosis differ significantly.
2. Nephritic syndrome often presents with fever, hematuria, and thrombocytopenia, while nephrotic syndrome is typically asymptomatic or presents with edema and hypoalbuminemia.
3. Consulting a nephrologist is essential in diagnosing and managing these conditions effectively.