Diagnosis of kidney damage with Wegener's granulomatosis

Laboratory diagnosis of Wegener's granulomatosis

In patients with Wegener's granulomatosis, a number of nonspecific laboratory changes are noted: an increase in ESR, neutrophilic leukocytosis, thrombocytosis, normochromic anemia, in a small percentage of cases eosinophilia. Characteristic of disproteinemia with an increase in the level of globulins. In 50% of patients, rheumatoid factor is detected. The main diagnostic marker of Wegener's granulomatosis is the ANCA, whose titer correlates with the degree of vasculitis activity. In most patients, c-ANCA (to proteinase-3) is detected.

Differential diagnosis of Wegener's granulomatosis

Diagnosis of Wegener's granulomatosis does not cause difficulties in the presence of a classical triad of signs: upper respiratory tract, lung and kidney damage, especially when ANCA is detected in the serum. However, on average in 15% of patients, the test for antibodies to the cytoplasm of neutrophils gives a negative result. For this reason, for the diagnosis of Wegener's granulomatosis, morphological examination of organs and tissues is of great importance.

• In patients with respiratory tract infection, a biopsy of the nasal mucosa and paranasal sinuses is very informative, in which necrotizing granulomas are detected, although in some cases only non-specific inflammation is detected. A great help in diagnosing the disease can also be biopsy of the skin, muscles, nerve, if necessary - light.
• A kidney biopsy is indicated to all patients with Wegener's granulomatosis with clinical signs of glomerulonephritis. In addition to establishing a histological diagnosis (low-immunity necrotizing glomerulonephritis), this procedure allows to determine the treatment strategy and prognosis, which is especially important for patients entering the nephrologist with a clinical picture of severe renal failure (creatinine of blood more than 440 μmol / L) from the onset of the disease. In this case, only with the help of kidney biopsy can we distinguish the rapidly progressive glomerulonephritis with a high degree of activity (which requires aggressive immunosuppressive therapy, which should be followed by hemodialysis treatment), from terminal renal failure with diffuse glomerulosclerosis, in which treatment with immunosuppressants is already futile.

Differential diagnosis of Wegener's granulomatosis with kidney damage is performed with other diseases that occur with the development of renal and pulmonary syndrome.

Causes of Renal Pulmonary Syndrome

• Goodpasture Syndrome
• Wegener's granulomatosis
• Nodular polyarteritis
• Microscopic polyangiitis
• Czurdzha Strauss Syndrome
• Purple Shonlein-Genocha
• Cryoglobulinemic vasculitis
• Systemic lupus erythematosus
• Antiphospholipid syndrome
• Pneumonia with:
  • acute poststreptococcal glomerulonephritis;
  • acute interstitial drug nephritis;
  • glomerulonephritis in patients with subacute infective endocarditis;
  • acute tubular necrosis.
• Lymphomatoid granulomatosis
• Primary or metastatic tumors of the kidneys and lungs
• Pulmonary artery thromboembolism with renal vein thrombosis, complicated nephrotic syndrome
• Sarcoidosis
• Uremic lung

One of the differential-diagnostic problems is the delineation of Wegener's granulomatosis and other forms of systemic vasculitis occurring with similar clinical symptoms.

The rapidly progressive glomerulonephritis within Wegener's granulomatosis should be differentiated from the rapidly progressive glomerulonephritis without extrarenal signs of vasculitis, which is also a low-immune ANCA-associated glomerulonephritis and is considered a local renal form of vasculitis. In connection with the morphological identity and the same serological markers, differential diagnosis is difficult in these cases, which, however, is not always important, since the tactics of treatment are the same (immediate, even before the results of histological and serological studies, the appointment of glucocorticoids and cytostatics).

Differential diagnosis of Wegener's granulomatosis also requires the need to distinguish between lung lesions within this form of systemic vasculitis with opportunistic respiratory infection, mainly with tuberculosis and aspergillosis, the development of which is often noted in the treatment of immunosuppressants.

[1], [2], [3], [4], [5], [6], [7], [8], [9]