Interstitial nephritis
Encyclopedia
Interstitial nephritis (or Tubulo-interstitial nephritis) is a form of nephritis
affecting the interstitium of the kidney
s surrounding the tubules. This disease can be either acute, meaning it occurs suddenly, or chronic, meaning it is ongoing and eventually ends in kidney failure.
or antibiotic
s such as methicillin). Reaction to medications causes 71% to 92% of cases.
This disease is also caused by other diseases and toxins that do damage to the kidney. Both acute and chronic tubulointerstitial nephritis can be caused by a bacterial infection in the kidneys, known as pyelonephritis
. The most common cause is by an allergic reaction to a drug. The drugs that are known to cause this sort of reaction are antibiotics such as penicillin
and cephalexin, and nonsteroidal anti-inflammatory drugs, such as aspirin, as well as rifampin, sulfa drugs, quinolones, diuretics, allopurinol, and phenytoin. The time between exposure to the drug and the development of acute tubulointerstitial nephritis can be anywhere from 5 days to 5 months (fenoprofen induced).
, and lower back pain. In chronic tubulointerstitial nephritis the patient can experience symptoms such as nausea, vomiting, fatigue, and weight loss. Other conditions that may develop include hyperkalemia
, metabolic acidosis
, and kidney failure.
has been reported to range from 60% to 100%.
Nutrition therapy consists of adequate fluid intake, which can require several liters of extra fluid.
In chronic tubulointerstitial nephritis, the most serious long-term effect is kidney failure. When the proximal tube is injured, sodium, potassium, bicarbonate, uric acid, and phosphate reabsorption may be reduced or changed, resulting in low bicarbonate, known as metabolic acidosis
, low potassium, low uric acid known as hypouricemia, and low phosphate known as hypophosphatemia. Damage to the distal tubule may cause loss of urine-concentrating ability and polyuria
.
In most cases of acute tubulointerstitial nephritis, the function of the kidneys will return after the harmful drug is not taken anymore, or when the underlying disease is cured by treatment. If the illness is caused by an allergic reaction, a corticosteroid may speed the recovery kidney function; however, this is often not the case.
Chronic tubulointerstitial nephritis has no cure. Some patients may require dialysis
. Eventually, a kidney transplant may be needed.
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Nephritis
Nephritis is inflammation of the nephrons in the kidneys. The word "nephritis" was imported from Latin, which took it from Greek: νεφρίτιδα. The word comes from the Greek νεφρός - nephro- meaning "of the kidney" and -itis meaning "inflammation"....
affecting the interstitium of the kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
s surrounding the tubules. This disease can be either acute, meaning it occurs suddenly, or chronic, meaning it is ongoing and eventually ends in kidney failure.
Etiologies
Common causes include infection, or reaction to medication (such as an analgesicAnalgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
or antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s such as methicillin). Reaction to medications causes 71% to 92% of cases.
This disease is also caused by other diseases and toxins that do damage to the kidney. Both acute and chronic tubulointerstitial nephritis can be caused by a bacterial infection in the kidneys, known as pyelonephritis
Pyelonephritis
Pyelonephritis is an ascending urinary tract infection that has reached the pyelum or pelvis of the kidney. It is a form of nephritis that is also referred to as pyelitis...
. The most common cause is by an allergic reaction to a drug. The drugs that are known to cause this sort of reaction are antibiotics such as penicillin
Penicillin
Penicillin is a group of antibiotics derived from Penicillium fungi. They include penicillin G, procaine penicillin, benzathine penicillin, and penicillin V....
and cephalexin, and nonsteroidal anti-inflammatory drugs, such as aspirin, as well as rifampin, sulfa drugs, quinolones, diuretics, allopurinol, and phenytoin. The time between exposure to the drug and the development of acute tubulointerstitial nephritis can be anywhere from 5 days to 5 months (fenoprofen induced).
Diagnosis
At times there are no symptoms of this disease, but when they do occur they are widely varied and can occur rapidly or gradually. When caused by an allergic reaction, the symptoms of acute tubulointerstitial nephritis are fever (27% of patients), rash (15% of patients), and enlarged kidneys. Some people experience dysuriaDysuria
In medicine, specifically urology, dysuria refers to painful urination.Difficult urination is also sometimes described as dysuria.It is one of a constellation of irritative bladder symptoms, which includes urinary frequency and haematuria....
, and lower back pain. In chronic tubulointerstitial nephritis the patient can experience symptoms such as nausea, vomiting, fatigue, and weight loss. Other conditions that may develop include hyperkalemia
Hyperkalemia
Hyperkalemia refers to the condition in which the concentration of the electrolyte potassium in the blood is elevated...
, metabolic acidosis
Metabolic acidosis
In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...
, and kidney failure.
Urinary findings
Urinary findings include:- EosinophiluriaEosinophiluriaEosinophiluria is the abnormal presence of eosinophils in the urine.It can be measured by detecting levels of eosinophil cationic protein.-Associated conditions:It can be associated with a wide variety of conditions, including:* urinary tract infection...
: sensitivity is 67% and specificity is 83%. The sensitivity is higher in patients with interstitial nephritis induced by methicillinMethicillinMeticillin or methicillin is a narrow-spectrum beta-lactam antibiotic of the penicillin class. It should not be confused with the antibiotic metacycline.-History:Methicillin was developed by Beecham in 1959...
or when the Hansel's stain is used. - IsosthenuriaIsosthenuriaIsosthenuria refers to the excretion of urine whose specific gravity is neither greater nor less than that of protein-free plasma, typically 1.008-1.012....
. - HematuriaHematuriaIn medicine, hematuria, or haematuria, is the presence of red blood cells in the urine. It may be idiopathic and/or benign, or it can be a sign that there is a kidney stone or a tumor in the urinary tract , ranging from trivial to lethal...
- Sterile pyuriaPyuriaIn medicine, Pyuria refers to urine which contains pus. Defined as the presence of 4 or more neutrophils per high power field of unspun, voided mid-stream urine. It can be sign of a bacterial urinary tract infection...
: white blood cells and no bacteria
Gallium scan
The sensitivity of an abnormal gallium scanGallium scan
A gallium scan or gallium 67 scan is a type of nuclear medicine study that uses a radioactive tracer to obtain images of a specific type of tissue, or disease state of tissue. Gallium salts like gallium citrate and gallium nitrate are used. The form of salt is not important, since it is the freely...
has been reported to range from 60% to 100%.
Treatment
Remove the etiology such as an offending drug. Corticosteroids do not clearly help.Nutrition therapy consists of adequate fluid intake, which can require several liters of extra fluid.
Prognosis
The kidneys are the only body system that are directly affected by tubulointerstitial nephritis. Kidney function is usually reduced; the kidneys can be just slightly dysfunctional, or fail completely.In chronic tubulointerstitial nephritis, the most serious long-term effect is kidney failure. When the proximal tube is injured, sodium, potassium, bicarbonate, uric acid, and phosphate reabsorption may be reduced or changed, resulting in low bicarbonate, known as metabolic acidosis
Metabolic acidosis
In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...
, low potassium, low uric acid known as hypouricemia, and low phosphate known as hypophosphatemia. Damage to the distal tubule may cause loss of urine-concentrating ability and polyuria
Polyuria
Polyuria is a condition usually defined as excessive or abnormally large production or passage of urine . Frequent urination is sometimes included by definition, but is nonetheless usually an accompanying symptom...
.
In most cases of acute tubulointerstitial nephritis, the function of the kidneys will return after the harmful drug is not taken anymore, or when the underlying disease is cured by treatment. If the illness is caused by an allergic reaction, a corticosteroid may speed the recovery kidney function; however, this is often not the case.
Chronic tubulointerstitial nephritis has no cure. Some patients may require dialysis
Dialysis
In medicine, dialysis is a process for removing waste and excess water from the blood, and is primarily used to provide an artificial replacement for lost kidney function in people with renal failure...
. Eventually, a kidney transplant may be needed.
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