Acute glomerulonephritis (AGN)

AGN is the inflammation in kidney characterized by hematuria, hypertension, edema (periorbital, leg or sacral) and oliguria. Urine shows proteinuria and red cell cast.

*Long Cases in Clinical Medicine, ABM Abdullah

Glomerulopathies present as nephritic syndrome are:
– Poststreptococcal glomerulonephritis
– Goodpasture’s disease (anti-GBM disease)
– IgA nephropathy
– Henoch-Schönlein purpura.

*Pre-exam preparation for medicine, HN Sarker

About 50%.

Causes are:

1. Infection—post-streptococcal commonest. Other infections include infective endocarditis, infectious mononucleosis, HBV, HCV, etc.
2. Non-infectious—SLE, Henoch-Schönlein purpura, cryoglobulinemia, etc.
3. Primary glomerular disease—diffuse proliferative GN, IgA nephropathy, membranous GN, focal segmental GN.
4. Shunt nephritis.

*Long Cases in Clinical Medicine, ABM Abdullah

Mechanisms of nephritic syndrome are:
– Inflammation
– Reactive cell proliferation
– Breaks in GBM
– Crescent formation.

*Pre-exam preparation for medicine, HN Sarker

No, antibody formed against streptococcal antigen cross react with glomerular protein due to molecular mimicry.

Immune-mediated.

Causes are:
– Focal segmental (necrotizing) glomerulonephritis
– SLE
– Goodpasture’s (anti-GBM ) disease
– IgA nephropathy.

*Pre-exam preparation for medicine, HN Sarker

As follows:

• Post-streptococcal glomerulonephritis (PSGN)
• Subacute bacterial infection: Especially infective endocarditis
• Mesangiocapillary glomerulonephritis, usually type II (90% in type II and 70% in type I)
• Cryoglobulinemia
• Lupus nephritis

*Long Cases in Clinical Medicine, ABM Abdul; Pre-exam preparation for medicine, HN Sarker

The latency is usually about 10 days after a throat infection or longer (2–3 weeks) after skin infection.

*Pre-exam preparation for medicine, HN Sarker

IgA nephropathy.

*Pre-exam preparation for medicine, HN Sarker

Features of nephritic syndrome are:
– Hematuria (red or brown urine)
– Edema and generalized fluid retention
– Hypertension
– Oliguria.

*Pre-exam preparation for medicine, HN Sarker

Symptoms—
– Swelling of the face followed by generalized swelling
– Scanty high colored urine (smoky)
– Sometimes history of sore throat/skin infections 2–3 weeks back.
Signs—
– Puffy face
– Pitting edema
– Hypertension
– Evidence of skin infection
– Signs of complications.

*Pre-exam preparation for medicine, HN Sarker

The mechanisms of hypertension in AGN are:

• Hypervolemia due to salt and water retention secondary to oliguria.
• Secondary hyperaldosteronism due to stimulation of renin angiotensin aldosterone axis.

*Long Cases in Clinical Medicine, ABM Abdullah;  Short and Long Cases in Clinical Medicine, HN Sarker

The mechanisms of edema formation in AGN are due to:

• Retension of salt and water
• Hypoproteinemia

*Short and Long Cases in Clinical Medicine, HN Sarker

• Presence of oligouria, hematuria and proteinuria (as in child)
• Edema is not marked.
• Hypertension may or may not be present
• There is no history of preceding infection

*Short and Long Cases in Clinical Medicine, HN Sarker

As follows:

1. Urine R/M/E:
   • Urine looks smoky.
   • It shows mild to moderate proteinuria, RBC, RBC cast and granular cast (RBC cast is suggestive of AGN)
2. 24 hours urinary total protein (increases, but less than 3 g/L) and volume is less
3. Renal function test
   • Blood urea, serum creatinine – may be raised
   • serum electrolytes – K⁺ may be raised
4. CBC (leukocytosis may be present)
5. Serum C3 and C4 level: Decreased
6. ASO titer (may be high in post-streptococcal glomerulonephritis)
7. Bacteriological
   • Throat swab for C/S to find streptococcal infection
   • Pus from skin lesion for C/S
8. USG of the whole abdomen (to look for renal pathology)
9. CXR (cardiomegaly or pulmonary edema if LVF)
10. Other investigation according to suspicion of causes:
    • ANA, Anti-dsDNA, C3, C4 (if the history is suggestive of SLE)
    • P-ANCA, c-ANCA (if the history is suggestive of vasculitis)
    • HbsAg, Anti-HCV
    • Renal biopsy may be done in some cases

*Long Cases in Clinical Medicine, ABM Abdullah;  Short and Long Cases in Clinical Medicine, HN Sarker

Urine— R/M/E

• RBC ++
• Cast— RBC and granular cast
• Albumin +/++
• Dysmorphic RBC in phase contrast microscopy.

*Pre-exam preparation for medicine, HN Sarker

Presence of dysmorphic RBC under phase contrast microscopy and/or RBC cast in urine.

Casts are cylindrical structures (shape of renal tubule) composed mainly of mucoprotein (the Tamm-Horsefall mucoprotein) which is secreted by epithelial cells lining the loops of Henle, the distal tubules and the collecting ducts.
Common casts include—
Hyaline cast—Nephrotic syndrome
Granular cast—Urinary tract infection
RBC cast—Glomerulonephritis.

*Pre-exam preparation for medicine, HN Sarker

As follows:

• RBC cast—AGN
• WBC cast—Pyelonephritis
• Granular cast—GN
• Hyaline cast—Normal finding.

*Long Cases in Clinical Medicine, ABM Abdullah

Diagnosis is acute glomerulonephritis.

Poststreptococcal glomerulonephritis is the probable cause.

History of:
– Skin infection (infected scabies)
– Sore throat

• Nephrotic syndrome
• Angioneurotic edema

Because in nephrotic syndrome, there will be generalized edema, massive proteinuria which are absent in this case. (Serum protein will show hypoalbuminemia).

In this case, there is history of infected scabies, acute onset of facial puffiness followed by scanty smoky urine (oligouria and hematuria), absence of generalized edema, presence of hypertension. These are against NS.

*Long Cases in Clinical Medicine, ABM Abdullah;  Short and Long Cases in Clinical Medicine, HN Sarker

IgA nephropaty usually follows respiratory tract infection and latent period is about 3 days.

Presence of hypertension, oligouria and hematuria, and absence of itchy swelling of eyelids, lips and tongue; no history of atopy – all these exclude angioneurotic edema.

*Short and Long Cases in Clinical Medicine, HN Sarker

Because there is no anorexia, nausea or vomiting. Also, previous history of sore throat followed by scanty micturition is in favor of AGN.

*Long Cases in Clinical Medicine, ABM Abdullah

*Short and Long Cases in Clinical Medicine, HN Sarker; **Step on to Paediatrics, Md Abid Hossain Mollah

1. General measures
   1. Bed rest—Increases GFR, so helps in reducing hypertension
   2. Diet
      • Salt restricted diet. No added salt in the diet.
      • Protein restricted diet (0.5 gm/kg/day**)
      • Fluid (previous day urine output + 300 mL) / (400 mL/m² + previous day’s output **)
      • K⁺ containing food and fruits restriction.
2. Supportive measures
   1. Edema—Diuretic, e.g. frusemide (1-2 mg/kg/day **) (If renal function impairment, dose of diuretics is single and high. but if renal function is normal, then divided and low dose. ***)
   2. Antihypertensive drug—Calcium channel blocker, ACE inhibitor
      • For rapid reduction of BP: Nifedipine (0.3–0.5 mg/kg) sublingual **
      • For maintenance:
        • Captopril (0.25–6 mg/kg/day) in 2–4 doses **
        • Nifedipine (0.25–0.5 mg/kg/day) in 2–4 doses **
   3. Antibiotic—Phenoxymethylpenicillin/erythromycin for 10 days.
      • Oral Phenoxymethylpenicillin (50 mg/kg/day) in 4 divided doses for 10 days. Penicillin does not alter the course of the disease but prevents spreading of remaining nephritogenic strain of streptococcus to the contacts.**
3. Treatment of complications if any.
4. Follow up: Daily to assess the clinical response and to search for any complications.
   1. Pulse
   2. BP
   3. Edema
   4. Weight
   5. Maintain fluid intake output chart
   6. Albumin chart.

* Short and Long Cases in Clinical Medicine, HN Sarker; ** Step on to Paediatrics, Md Abid Hossain Mollah; ***Long Cases in Clinical Medicine, ABM Abdullah.

Preferred antihypertensives are:
– Calcium channel blocker, e.g. amlodipine
– ACE inhibitor if S.creatinine is less than 5 mg.

*Short and Long Cases in Clinical Medicine, HN Sarker

Follow up: Daily to assess the clinical response and to search for any complications.

1. Pulse
2. BP
3. Edema
4. Weight
5. Maintain fluid intake output chart
6. Albumin chart.

*Short and Long Cases in Clinical Medicine, HN Sarker

1. Complete recovery – 80% of childern and 50% of adults (usually within 2 weeks)
2. Apparent recovery – 10-15% cases live with persistent proteinuria and hematuria for long periods.
3. Complications – 5% cases develop complications e.g. Rapidly Progressive Glomerulonephritis (RPGN)

Recurrence are extremely rare.

*Short and Long Cases in Clinical Medicine, HN Sarker.

As follows:

• Acute renal failure
• Hypertension and its complications, such as
  • acute left ventricular failure,
  • hypertensive encephalopathy
• Fluid and electrolyte imbalance (↑K⁺, ↓Na)
• Nephrotic syndrome**
• May lead to chronic glomerulonephritis.**

*Short and Long Cases in Clinical Medicine, HN Sarker; Step on to Paediatrics, Md Abid Hossain Mollah; **Long Cases in Clinical Medicine, ABM Abdullah

Acute pulmonary edema due to hypertensive LVF.

Hypertensive encephalopathy.