Glomerulonephritis: Complications

Complications and outcomes of acute glomerulonephritis

Acute glomerulonephritis most often has a favorable prognosis, but in the active phase it can be accompanied by severe conditions that threaten the patient's life. Specific renal complications include acute renal failure (up to anuria). In addition, the pathology actively affects other systems, provoking:

• hypertensive encephalopathy;
• pulmonary edema and pulmonary embolism (PE);
• stroke and myocardial infarction;
• acute heart failure;
• acute psychoses and secondary infectious complications.

The outcome of the acute process largely depends on the patient's age, timing of therapy initiation, presence of concomitant renal failure, as well as the severity of arterial hypertension and edema. Several disease resolution scenarios are distinguished:

1. Complete recovery. Clinical recovery occurs in 3–8 months, but complete morphological restoration of renal tissue takes up to 3 years.
2. Recovery with a defect. Clinical symptoms disappear, but erythrocytes and protein are sporadically detected in the urine.
3. Transition to chronic glomerulonephritis.
4. Fatal outcome. Accounts for no more than 1% of cases.

Chronic form and systemic changes

Chronic glomerulonephritis inevitably leads to systemic vascular and metabolic disorders. The key link in pathogenesis is renal tissue ischemia, which triggers hyperactivation of the renin-angiotensin-aldosterone system (RAAS). This forms persistent nephrogenic (vasorenal) arterial hypertension, entailing a cascade of extranephric changes:

• Heart: pronounced myocardial hypertrophy develops (predominantly of the left ventricle).
• Vessels: arteries undergo elastofibrosis and atherosclerosis, and arterioles undergo arteriolosclerosis. These destructive processes affect the vascular beds of the brain, heart, retina, and the kidneys themselves.

High levels of renin, angiotensin, and aldosterone can provoke an accelerated phase of hypertension. In this case, generalized vascular spasm leads to a sharp spike in blood pressure and vascular necrosis, forming malignant nephrosclerosis.

In addition to hypertension, the chronic course is accompanied by nephrotic syndrome. Ultimately, chronic renal failure (CRF) develops. At this stage, conservative medicine exhausts its capabilities: the only ways to prolong life become chronic hemodialysis and kidney transplantation.

Nephrosclerosis and causes of death

The terminal stage and outcome of most glomerulopathies is nephrosclerosis—the formation of a secondary shrunken kidney. The rate of sclerosis progression is directly dictated by the morphological variant of the disease:

• In rapidly progressive glomerulonephritis (if the patient survived the acute episode) and focal segmental sclerosis, the terminal stage occurs rapidly.
• Membranous, IgA nephropathy, and mesangiocapillary glomerulonephritis progress to CRF slowly.
• Asymptomatic (latent) forms can proceed covertly for decades, but their ultimate outcome is also uremia.

At the stage of secondary shrinkage, differential diagnosis between the outcome of glomerulonephritis and the renal form of essential hypertension is extremely difficult due to the similarity of the picture (vascular sclerosis, cardiac hypertrophy, hypertension).

The direct causes of death in the chronic course are:

1. Chronic renal failure (uremia). Azotemic intoxication affects all systems: uremic encephalopathy, fibrinous-hemorrhagic gastroenterocolitis, uremic pericarditis, and pneumonitis develop.
2. Cardiovascular decompensation. Caused by nephrogenic hypertension. Patients die from heart failure or massive cerebral hemorrhages.
3. Intercurrent infections. Occur against the background of pronounced secondary immunodeficiency characteristic of the uremic state.

Class and exam questions

What else to study on this topic

• Pathogenesis of nephrotic syndrome and accompanying metabolic disorders
• Uremic intoxication: mechanism of development of pericarditis, pneumonitis, and gastroenterocolitis
• Differential diagnosis of secondary shrunken kidney and essential hypertension
• Criteria and morphological picture of malignant nephrosclerosis

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.