What is Nephritic Syndrome?
Nephritic syndrome is a disease of kidney structure element- glomeruli. Nephritic syndrome is also known as glomerulonephritis and it is characterized by edema, increased blood pressure and haematuria (red blood cells in urine). Nephritic syndrome can develop rapidly- acute glomerulonephritis or progress slowly- chronic glomerulonephritis. In rare cases acute glomerulonephritis can cause serious complications- if acute nephritic syndrome evolves into rapidly progressive glomerulonephritis which can cause kidney failure [1, 5].
- Streptococcus- after throat or skin infection, most likely in children between 2 and 10 years of age
- Staphylococcus (can also cause toxic-shock syndrome)
- Pneumococcus 
- Hepatitis virus B or C
- Epstein-Barr virus
- Coccidioides immitis
- Churg-Strauss syndrome- eosinophilic granulomatosis with polyangiitis
- Wegener granulomatosis
- Microscopic polyangiitis
- Henoch-Schonlein purpura
- Systemic lupus
- Goodpasture syndrome
- Hereditary nephritic syndrome
- IgA nephropathy
- Membranoproliferative glomerulonephritis
- Gullain-Barre syndrome
- Serum sickness 
Chronic glomerulonephritis causes
Chronic glomerulonephritis can be caused by the same conditions as acute glomerulonephritis. Also, acute glomerulonephritis can become chronic. In most cases the exact cause of chronic glomerulonephritis remains unknown. It can also be caused by hereditary nephritis- a genetic disorder .
In some cases the underlying cause is not known. When patient presents with symptoms of nephritic syndrome, it is worth checking for other symptoms or diseases that are quite rare and patient might not know about them:
- Sinusitis, lung infiltrates and symptoms of nephritis is a classic presentation of Wegener granulomatosis
- Vomiting, nausea, abdominal pain in young patients can suggest Henoch-Schonlein purpura- symptoms similar to Peutz-Jaegers syndrome
- Lupus eritematosus can present with pain in the joints
- Coughing of blood- Goodpasture syndrome
- Skin rashes can be a symptom of vasculitis, lupus, cryoglobulinemia and Henoch-Schonlein purpura .
The diagnosis of nephritic syndrome consists of physical examination, as well as laboratory and imaging studies.
When examining the patient, there are a variety of possible symptoms that are connected with nephritic syndrome and possible underlying cause:
- Symptoms of fluid overload
- Edema around eyes and/or feet
- Edema of the lungs- can present as crackles on auscultation
- Elevated pressure in jugular veins
- High blood pressure
- Swelling of the joints
- Pain in the kidney area
- Microscopic- red blood cells only found when examining urine with microscope
- Macroscopic- visible blood in the urine
- Neural examination
- State of consciousness can be altered due to high blood pressure
- Abdominal pain
- Weight gain
- Loss of appetite
- Ulcers in the mouth
- Respiratory tract infection
In many cases patients have normal physical examination and blood pressure .
To diagnose nephritic syndrome, knowing the underlying cause can be helpful. It is important to ask patient the following:
- What are the symptoms and their severity
- Onset of symptoms
- Post-infectious nephritic syndrome usually occurs 1-4 weeks after infection
- Onset of nephritis after 1-4 days of being infected with streptococcus suggests existing kidney disease
- Recent infections prior to onset of symptoms
- Are there any other systemic diseases the patient knows about
- Has the patient traveled recently 
- Hematuria- presence of red blood cells in the urine
- Oliguria- small amount of urine
- Edema- edema can appear on the face, around the eyes or throughout the body. Edema is usually present in the morning
- Shortness of breath
- Pain sensation around the kidney area
Urine analysis is one of the most important examinations to diagnose nephritic syndrome. In urine analysis there can be abnormalities in the following:
- Protein- mildly increased
- Red blood cells- either some cells seen in the microscope or visible blood
- White blood cells
- Cellular casts- red cell casts is a definitive feature that suggests glomerular damage
- Fat bodies
- Urine sodium
24-hour urine study can be helpful in making the diagnosis. The urine sample is dark brown. There is increased level of protein. Creatinine clearance can be helpful in detecting level of renal dysfunction.
In blood samples the following features can be observed:
- Dilution anemia- hematocrit levels are decreased due to high fluid volume in blood (also see myelodysplastic syndrome)
- Increased serum creatinine
- Increased urea
- Serum electrolytes-
- Low levels of albumin (serum protein)
- Glomerular filtration rate is determined and it shows the level of kidney function
- Complement levels- usually decreased, but in some cases levels can be normal[1,3]
- Antibody to nephritis-associated protease are present in case of streptococcal infection
- Antinuclear antibodies can be present in case of lupus and polyarteritis nodosa
- Triglyceride levels
- Hepatitis B and C virus tests
- c-ANCA can be positive in case of Wegener granulomatosis [1,3]
- X-Ray imaging is suggested for patients who present with cough. Chest X-ray can show signs of edema, as well as signs for syndromes like Goodpasture syndrome and Wegener granulomatosis
- CT imaging can be helpful if abscess is suspected. CT with contrast is used for patients with hypertension and altered consciousness (for other conditions that can alter consciousness read Stevens-Johnsons syndrome).
- Ultrasonography is used to assess the size of the kidney and exclude obstruction
In most cases renal biopsy is not performed. When the exact cause of the disease is unknown and the symptoms are severe, biopsy can help in determining the exact cause of nephritic syndrome.
There is no specific treatment for nephritic syndrome. The treatment consists of managing symptoms and underlying cause. In severe cases of lung edema (when acute respiratory distress syndrome can occur) and altered mental status patient should be placed in intensive care unit.
- Antibiotics to prevent the spread of underlying infection
- Loop diuretics can be used for patients with severe hypertension
- Vasodilators are used for patients with hypertension and hypertensive encephalopathy
- Glucorticoids are used in severe cases of post-streptococcal glomerulonephritis[5,6]
Nephritic syndrome patients have to restrict intake of fluids and sodium in their diet. That can help in reducing and preventing edema. In case the patient presents with abnormally high levels of nitrogen containing compounds in the blood, proteins have to be restricted .
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- Treatment and other relative information about nephritic syndrome for patients and specialists: http://emedicine.medscape.com/article/239278-treatment#d10
- Patient information about nephritic syndrome (glomerulonephritis): https://www.kidney.org/atoz/content/glomerul
- Causes and other features of nephritic syndrome: https://www.msdmanuals.com/home/kidney-and-urinary-tract-disorders/kidney-filtering-disorders/glomerulonephritis-nephritic-syndrome
- Diseases associated with nephritic syndrome http://geekymedics.com/nephrotic-vs-nephritic-syndrome/
- Overview of Nephritic syndrome: http://www.healthline.com/health/acute-nephritic-syndrome#Overview1
- Patient information: http://patient.info/doctor/acute-nephritis