interstitial nephritis

What is Interstitial Nephritis?

Interstitial nephritis is a kidney condition characterized by inflammation in the spaces between the kidney tubules, where waste and excess fluids are filtered out of the blood. This condition can be acute or chronic, with symptoms ranging from mild to severe.

Causes and Symptoms

The causes of interstitial nephritis include:

• Allergic reactions to certain medications
• Infections such as streptococcal infections
• Nonsteroidal anti-inflammatory drugs (NSAIDs)
• Other medications that can cause kidney damage

Symptoms of interstitial nephritis may include: * Fever * Nausea and vomiting * Fatigue * Lack of appetite * Weight loss * Swelling in the face, hands, or feet

Types of Interstitial Nephritis

There are two main types of interstitial nephritis:

• Acute Interstitial Nephritis: This is a sudden onset condition that can be caused by an allergic reaction to certain medications.
• Chronic Interstitial Nephritis: This is a long-term condition that can be caused by repeated exposure to toxins or other kidney-damaging substances.

Treatment and Prognosis

The treatment for interstitial nephritis depends on the underlying cause of the condition. In some cases, stopping the offending medication may be sufficient to resolve the symptoms. In more severe cases, hospitalization and dialysis may be necessary. The prognosis for interstitial nephritis varies depending on the severity of the condition and the effectiveness of treatment.

References

• [1] Interstitial nephritis is a kidney condition characterized by inflammation in the spaces between the kidney tubules (2).
• [3] It can be mild and short-term or more severe and longer-term (3).
• [5] The acute form of interstitial nephritis is most often a side effect of certain drugs (5).
• [13] Fever is the most common symptom, occurring in 30-50% of patients, particularly those with drug-induced interstitial nephritis (13).

Interstitial nephritis can manifest in various ways, depending on its severity and duration. Here are some common signs and symptoms associated with this condition:

• Decreased urine output: The most common symptom of interstitial nephritis is a decrease in the amount of urine produced by the kidneys [1].
• Sudden weight gain: Extra fluid in the body can cause sudden weight gain, which may be accompanied by swelling in the feet and ankles [5][12].
• Nausea and vomiting: Some people with interstitial nephritis may experience nausea and vomiting, especially if kidney failure develops [6][9].
• Fatigue and weakness: Symptoms like fatigue and weakness can occur due to a buildup of fluid or body waste in the body [10][12].
• Sleep issues: Difficulty sleeping or experiencing sleep disturbances is another symptom that may be present in some cases [10][12].
• Itchiness: Itching sensations, particularly on the skin, can also be a sign of interstitial nephritis [6][12].
• Urinary changes: Changes in urine output, such as excessive urination or nocturia (urinating at night), may occur [7][8].
• Fever: Fever is a common symptom, especially in cases where the condition is caused by an allergic reaction to medication [13].

It's essential to note that not everyone with interstitial nephritis will experience all of these symptoms. The severity and duration of the condition can vary greatly from person to person.

References: [1] - Context result 1 [5] - Context result 5 [6] - Context result 6 [7] - Context result 7 [8] - Context result 8 [9] - Context result 9 [10] - Context result 10 [12] - Context result 12 [13] - Context result 13

Diagnostic Tests for Interstitial Nephritis

Interstitial nephritis, also known as acute interstitial nephritis (AIN), can be challenging to diagnose due to its nonspecific symptoms and laboratory findings. However, various diagnostic tests can help confirm the condition.

• Kidney Function Tests: Blood tests that detect signs of kidney failure, such as elevated serum creatinine and blood urea nitrogen (BUN) levels [6].
• Complete Blood Count (CBC): A test that measures the number of white blood cells, including eosinophils, which can be elevated in cases of interstitial nephritis [5].
• Kidney Biopsy: The gold standard diagnostic test for interstitial nephritis, particularly in severe or refractory cases [4][7][8]. However, it may not be required in mild cases or when clinical improvement is rapid after removal of the offending agent.
• Gallium 67 Scan: A nuclear medicine test that can help diagnose interstitial nephritis by detecting inflammation in the kidneys [10].
• Urinalysis: A test that examines urine for signs of kidney damage, such as proteinuria and hematuria [15].

Other Diagnostic Tests

In addition to these tests, healthcare providers may also perform a physical examination, ask about medical history and symptoms, and take blood and urine lab samples for testing [11]. It is essential to inform your healthcare provider about all medications you're taking, including over-the-counter (OTC) medications.

Emerging Biomarkers

Researchers are exploring cell-based tests that can identify the exact drug involved in hypersensitivity reactions manifesting as AIN. For example, urinary CXCL9 has been identified and validated as a biomarker for diagnosing acute interstitial nephritis [13].

It is essential to note that a diagnosis of interstitial nephritis should be made by a healthcare professional based on a combination of clinical findings, laboratory tests, and imaging studies.

References:

[4] - A renal biopsy is the gold standard diagnostic test for TIN. [5] - Diagnostic tests. 1st tests to order. serum creatinine and blood urea nitrogen (BUN) CBC with WBC differential ... [6] - Kidney function tests. These are blood tests that can detect signs of failure in your kidneys. [7] - Mar 28, 2024 — Kidney biopsy is the definitive test for diagnosing acute allergic interstitial nephritis, particularly in cases in which the clinical diagnosis ... [8] - by CM Kodner · 2003 · Cited by 275 — Renal biopsy remains the gold standard for diagnosis, but it may not be required in mild cases or when clinical improvement is rapid after removal of the offending agent. [10] - term acute interstitial nephritis is more com-monly used, acute tubulointerstitial nephritis ... test to diagnose AIN. In one small series,26 nine patients with AIN had positive gallium 67 scans ... [11] - Healthcare providers begin the diagnostic process for interstitial nephritis with a physical examination, asking about your medical history, and taking blood and urine lab samples for testing. [13] - Smith RN et al. Identification and validation of urinary CXCL9 as a biomarker for diagnosis of acute interstitial nephritis. J Clin Invest 2023;133. 10.1172/JCI168950. ... [15] - Urine microscopy often reveals white cells (70%), red cells (50%), and white cell casts (15%). Proteinuria is often present, particularly in NSAID-induced interstitial nephritis, but is usually modest (less than 2 g/day).

Treatment Options for Interstitial Nephritis

Interstitial nephritis, a condition where the kidney tubules get inflamed, can be caused by drugs, infections, or immune disorders. The treatment options for interstitial nephritis depend on the underlying cause and the severity of the condition.

• Corticosteroids: Corticosteroids have been a mainstay of therapy for tubulointerstitial nephritis. Early treatment with corticosteroids

Differential Diagnosis of Interstitial Nephritis

Interstitial nephritis, also known as acute interstitial nephritis (AIN), can be caused by a variety of factors, making its differential diagnosis quite broad. Here are some possible causes:

• Drug-induced (allergic) causes: Certain medications, such as antibiotics, NSAIDs, and diuretics, can cause AIN.
• Infectious diseases: Bacterial, viral, and fungal pyelonephritis can lead to interstitial nephritis.
• Autoimmune diseases: Conditions like systemic lupus erythematosus (SLE), sarcoidosis, and Sjögren's disease can cause interstitial nephritis.
• Obstructive nephropathy: Blockage of the urinary tract can lead to chronic TIN.
• Chronic pyelonephritis: Recurrent or persistent bacterial infections in the kidneys can cause interstitial nephritis.
• Papillary necrosis: A condition where the renal papillae become damaged, leading to interstitial nephritis.
• Tubulopathies: Conditions like Fanconi syndrome and progressive interstitial fibrosis can mimic interstitial nephritis.
• Balkan endemic nephropathy (BEN): A rare genetic disorder that affects the kidneys.
• Chinese herb nephropathy: A condition caused by the use of certain herbal remedies.
• Radiation nephritis: Damage to the kidneys due to radiation therapy.

These conditions can be challenging to diagnose, and a renal biopsy may be necessary to confirm the presence of interstitial nephritis. The differential diagnosis is large, and a thorough evaluation is required to determine the underlying cause of the condition.

References:

• [4] Acute interstitial nephritis (AIN) is estimated to be the cause of AKI in 10-27% of hospitalized patients.
• [6] Differential Diagnosis · Acute Tubular Necrosis: · Atheroembolism: · Glomerulonephritis: · Obstructive Uropathy: · Vascular Injury:
• [11] The differential diagnosis of both acute and chronic TIN is broad. Chronic TIN may manifest similarly to obstructive nephropathy, chronic pyelonephritis, papillary necrosis, tubulopathies including Fanconi syndrome, progressive interstitial fibrosis or Balkan endemic nephropathy (BEN), Chinese herb nephropathy, and radiation nephritis [ 41 , 48 ...
• [14] tis, differential diagnosis is large and includes drug-induced (allergic) causes, infectious dis- ... interstitial nephritis and uveitis (TINU) syndrome, and idiopathic conditions.