Clinical presentation
Acute nephritic syndrome manifests as a specific set of signs, primarily based on the so-called "classic triad" combined with additional clinical and laboratory markers of renal damage.
- Edema syndrome. Develops extremely rapidly. It is characterized by typical localization: edema primarily appears on the face, creating a specific picture of pale puffiness.
- Urine output disorder. Manifests as oliguria — a significant decrease in the volume of urine excreted.
- Proteinuria. Urinary protein loss can range from moderate to very high values.
- Hematuria. The presence of blood in the urine is clearly of renal origin. Visually, this is determined by a change in urine color, which becomes resembling "meat slops".
- Arterial hypertension. Is progressive in nature. A specific feature is the predominant increase in diastolic blood pressure, which is often accompanied by marked renal dysfunction.
Syndrome complications
When assessing the severity of a patient's condition with acute nephritic syndrome, primary attention should be paid to the development of life-threatening conditions.
- Cardiovascular complications. Their pathogenesis is based on a combination of progressive arterial hypertension and marked hypervolemia (increased circulating blood volume). The clinical outcome of this overload state is acute left ventricular failure. Objectively, it manifests as the appearance of a pathological "gallop rhythm" on cardiac auscultation and the development of pulmonary edema.
- Neurological manifestations. May include renal eclampsia, which is based on angiospastic encephalopathy, as well as severe muscle cramps.
- Dyspeptic syndrome. Patients are troubled by nausea, vomiting episodes, and persistent hiccups.
- Acute kidney injury (AKI). One of the most formidable consequences of progressive renal damage.
Etiology
The causes of the syndrome are usually divided into classic forms and manifestations of other systemic or chronic diseases.
Classic form Most commonly represented by acute poststreptococcal glomerulonephritis, which is most typical for pediatric and adolescent patients. Triggering factors usually include a previous streptococcal sore throat or severe hypothermia. The disease has a characteristic latent period: clinical symptoms appear suddenly, but after a certain time (from several hours to 7–12 days) following exposure to the negative factor.
Other nosological forms In addition to the classic variant, nephritic syndrome can manifest in the following pathologies:
- Exacerbation of chronic glomerulonephritis.
- Rapidly progressive glomerulonephritis.
- Acute tubulointerstitial nephritis.
- Systemic connective tissue and vascular diseases, such as systemic lupus erythematosus (SLE), polyarteritis nodosa, and hemorrhagic vasculitis.
Briefly: answers to topical questions
What does the classic triad of symptoms of acute nephritic syndrome include?
The classic triad of symptoms of acute nephritic syndrome includes hematuria, arterial hypertension, and edema.
- Edema syndrome — rapid onset, typical facial localization (pale puffiness).
- Hematuria — of renal origin, "meat slops" urine color.
- Arterial hypertension — progressive, with a predominant increase in diastolic pressure.
What is the pathogenesis of edema development in nephritic syndrome?
Hydrodynamic, oncotic, and membranogenic pathogenetic factors take part in the development of nephritic edema. The pathogenesis is realized through decreased glomerular filtration against the background of inflammatory glomerular damage, renal sodium and water retention, and increased hydrostatic pressure in the vascular bed.
How does nephritic syndrome differ from nephrotic syndrome?
| Sign | Nephritic syndrome | Nephrotic syndrome |
|---|---|---|
| Leading components | Hematuria, arterial hypertension, edema; additionally — proteinuria and oliguria | Edema, proteinuria, hypoproteinemia |
| Proteinuria | Moderate, usually not reaching nephrotic levels; also indicated in sources as ranging from moderate to significant | Proteinuria with hypoproteinemia; with the development of full-blown nephrotic syndrome, massive protein loss is possible |
| Edema | Often starts in the face/periorbital region; pale facial puffiness is possible | Hypo-oncotic edema with sodium and water retention |
| Hematuria | Classic component; gross hematuria with "meat slops" urine color and red blood cell casts are possible | For the nephrotic form of chronic glomerulonephritis, the source lists edema, proteinuria, and hypoproteinemia |
| Arterial hypertension | Classic component | The combination of nephrotic syndrome and arterial hypertension is highlighted as a mixed form of chronic glomerulonephritis |
What specific changes are detected by microscopic examination of the urinary sediment in nephritic syndrome?
Microscopic examination of the urinary sediment in nephritic syndrome predominantly reveals red blood cell casts, as well as abacterial leukocyturia (predominantly lymphocytic).
- Red blood cell casts — confirm the glomerular source of bleeding.
- Abacterial leukocyturia — is a marker of acute immune inflammation in the glomeruli.
To memorize the manifestations of nephritic syndrome, use the mnemonic rule: Proteinuria, Edema, Hematuria, Arterial hypertension, Decreased urine output (oliguria).
Class and exam questions
Why does urine turn the color of "meat slops" in nephritic syndrome?
This is due to marked gross hematuria of renal origin, when red blood cells penetrate through the damaged glomerular filtration barrier.
What is the mechanism of pulmonary edema development in this syndrome?
Pulmonary edema occurs as a consequence of acute left ventricular failure, which develops due to a sharp increase in blood pressure combined with hypervolemia (increased circulating blood volume).
What age group is most characteristic of acute poststreptococcal glomerulonephritis?
This classic form of nephritic syndrome is most typical for children and adolescent patients.
What else to study on this topic
- Pathogenesis of renal edema formation
- Mechanisms of development of angiospastic encephalopathy (renal eclampsia)
- Differential diagnosis of nephritic and nephrotic syndromes
- Criteria of acute renal failure (ARF) in glomerulonephritis
- Features of renal involvement in systemic lupus erythematosus (SLE)
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