In severe and prolonged cases, the entire kidney may become These disorders include the following:. Autosomal dominant polycystic kidney disease Autosomal Dominant Polycystic Kidney Disease ADPKD Polycystic kidney disease PKD is a hereditary disorder of renal cyst formation causing gradual enlargement of both kidneys, sometimes with progression to renal failure. Almost all forms are Medullary sponge kidney Medullary Sponge Kidney Medullary sponge kidney is formation of diffuse, bilateral medullary cysts caused by abnormalities in pericalyceal terminal collecting ducts.
See also Overview of Cystic Kidney Disease. Pyelonephritis Chronic Pyelonephritis Chronic pyelonephritis is continuing pyogenic infection of the kidney that occurs almost exclusively in patients with major anatomic abnormalities. Symptoms may be absent or may include fever Principal causes include hyperparathyroidism, vitamin Amyloidosis Amyloidosis Amyloidosis is any of a group of disparate conditions characterized by extracellular deposition of insoluble fibrils composed of misaggregated proteins.
These proteins may accumulate locally It is characterized by dryness of the mouth, eyes, and other mucous membranes due Certain cancers eg, myeloma Myeloma-Related Kidney Disease Patients with multiple myeloma overproduce monoclonal Ig light chains Bence Jones proteins ; these light chains are filtered by glomeruli, are nephrotoxic, and, in their various forms free Many drugs, especially lithium , but also others eg, demeclocycline , amphotericin B, dexamethasone , dopamine , ifosfamide , ofloxacin , orlistat.
Acquired NDI can also be idiopathic. A mild form of acquired NDI can occur in any patient who is elderly or sick or who has acute or chronic renal insufficiency. The placenta can secrete vasopressinase during the 2nd half of pregnancy a syndrome called gestational diabetes insipidus. After pituitary surgery, some patients secrete an ineffective ADH precursor rather than vasopressin. Patients typically have a good thirst response, and serum sodium remains near normal.
It implies a deficit of total body water relative to total body sodium caused by water intake being less than water Hypernatremia may cause neurologic symptoms, such as neuromuscular excitability, confusion, seizures, or coma.
In infants, polyuria may be noticed by the caregivers; if not, the first manifestation may be dehydration. Initial testing includes h urine collection without fluid restriction for volume and osmolality, and serum electrolytes. Glucosuria and other causes of solute diuresis must be excluded. The diagnosis is confirmed by a water deprivation test, which assesses the maximum urine concentrating ability and response to exogenous vasopressin. A family history of polyuria and excessive water drinking should be noted.
Drug history should note use of any drugs associated with nephrogenic diabetes insipidus Nephrogenic Diabetes Insipidus Nephrogenic diabetes insipidus NDI is an inability to concentrate urine due to impaired renal tubule response to vasopressin ADH , which leads to excretion of large amounts of dilute urine The general examination should note signs of obesity as a risk factor for type 2 diabetes mellitus Diabetes Mellitus DM Diabetes mellitus is impaired insulin secretion and variable degrees of peripheral insulin resistance leading to hyperglycemia.
Skin examination should note the presence of any hyperpigmented or hypopigmented lesions, ulcers, or subcutaneous nodules that may suggest sarcoidosis. Comprehensive neurologic examination should note any focal deficits that suggest an underlying neurologic insult and assess mental status for indications of a thought disorder. Volume status should be assessed. Extremities should be examined for edema.
History can often distinguish polyuria from frequency, but rarely a hour urine collection may be needed. Diabetes insipidus Central Diabetes Insipidus Diabetes insipidus results from a deficiency of vasopressin antidiuretic hormone [ADH] due to a hypothalamic-pituitary disorder central diabetes insipidus or from resistance of the kidneys Abrupt onset of polyuria at a precise time suggests central diabetes insipidus, as does preference for extremely cold or iced water.
Onset during the first few years of life is typically related to inherited central or nephrogenic diabetes insipidus Nephrogenic Diabetes Insipidus Nephrogenic diabetes insipidus NDI is an inability to concentrate urine due to impaired renal tubule response to vasopressin ADH , which leads to excretion of large amounts of dilute urine Polyuria caused by solute diuresis is suggested by a history of diabetes mellitus.
Psychogenic polydipsia is more common in patients with a history of a psychiatric disorder primarily bipolar disorder Bipolar Disorders Bipolar disorders are characterized by episodes of mania and depression, which may alternate, although many patients have a predominance of one or the other.
Exact cause is unknown, but heredity Once excess urine output has been verified by history or measurements, serum or fingerstick glucose determination should be done to rule out uncontrolled diabetes. The most common cause is It implies a deficit of total body water relative to total body sodium caused by water intake being less than water Common causes include diuretic use, diarrhea, heart failure, liver If the diagnosis remains unclear, then measurement of serum and urine sodium and osmolality in response to a water deprivation test and exogenous ADH administration should be done.
Because serious dehydration may result from this testing, the test should be done only while patients are under constant supervision; hospitalization is usually required. Additionally, patients in whom psychogenic polydipsia is suspected must be observed to prevent surreptitious drinking.
Various protocols can be used in water deprivation tests. Each protocol has some limitations. Typically, the test is started in the morning by weighing the patient, obtaining venous blood to determine serum electrolyte concentrations and osmolality, and measuring urine osmolality. Voided urine is collected hourly, and its osmolality is measured. Dehydration is continued until orthostatic hypotension Orthostatic Hypotension Orthostatic postural hypotension is an excessive fall in blood pressure BP when an upright position is assumed.
Serum electrolytes and osmolality are again determined, and 5 units of aqueous vasopressin are injected subcutaneously.
Urine for osmolality measurement is collected one final time 60 minutes postinjection, and the test is terminated. In central diabetes insipidus Central Diabetes Insipidus Diabetes insipidus results from a deficiency of vasopressin antidiuretic hormone [ADH] due to a hypothalamic-pituitary disorder central diabetes insipidus or from resistance of the kidneys In nephrogenic diabetes insipidus Nephrogenic Diabetes Insipidus Nephrogenic diabetes insipidus NDI is an inability to concentrate urine due to impaired renal tubule response to vasopressin ADH , which leads to excretion of large amounts of dilute urine The water deprivation test Water deprivation test Nephrogenic diabetes insipidus NDI is an inability to concentrate urine due to impaired renal tubule response to vasopressin ADH , which leads to excretion of large amounts of dilute urine Serious dehydration may result.
Additionally, if psychogenic polydipsia is suspected, the patient must be observed to prevent surreptitious drinking. The test is started in the morning by weighing the patient, obtaining venous blood to determine electrolyte concentrations and osmolality, and measuring urinary osmolality. Voided urine is collected hourly, and its specific gravity or, preferably, osmolality is measured. Serum electrolytes and osmolality are again determined.
Urine for specific gravity or osmolality measurement is collected one final time 60 minutes postinjection, and the test is terminated.
Patients with nephrogenic diabetes insipidus are unable to concentrate urine to greater than the plasma osmolality and show no additional response to vasopressin administration see table Water Deprivation Test Results Water Deprivation Test Results Diabetes insipidus results from a deficiency of vasopressin antidiuretic hormone [ADH] due to a hypothalamic-pituitary disorder central diabetes insipidus or from resistance of the kidneys Measurement of circulating vasopressin is the most direct method of diagnosing central diabetes insipidus; levels at the end of the water deprivation test before the vasopressin injection are low in central diabetes insipidus and appropriately elevated in nephrogenic diabetes insipidus.
However, vasopressin levels are difficult to measure, and the test is not routinely available. In addition, water deprivation is so accurate that direct measurement of vasopressin is unnecessary. Plasma vasopressin levels are diagnostic after either dehydration or infusion of hypertonic saline. The water deprivation test should be done while the patient is under constant supervision because serious dehydration may occur.
Psychogenic polydipsia may present a difficult problem in differential diagnosis. Unlike patients with central diabetes insipidus and nephrogenic diabetes insipidus, they usually do not have nocturia, nor does their thirst wake them at night. Common causes include diuretic use, diarrhea, heart failure, liver Patients with acute psychogenic water drinking are able to concentrate their urine during water deprivation. However, because chronic water intake diminishes medullary tonicity in the kidneys, patients with long-standing polydipsia are not able to concentrate their urine to maximal levels during water deprivation, a response similar to that of patients with partial central diabetes insipidus.
However, unlike central diabetes insipidus, patients with psychogenic polydipsia show no response to exogenous vasopressin after water deprivation. This response resembles nephrogenic diabetes insipidus, except that basal vasopressin levels are low compared with the elevated levels present in nephrogenic diabetes insipidus. Central diabetes insipidus can be treated with hormone replacement and treatment of any correctable cause.
In the absence of appropriate management, permanent renal damage can result. Desmopressin , a synthetic analog of vasopressin with minimal vasoconstrictive properties, has prolonged antidiuretic activity, lasting for 12 to 24 hours in most patients, and may be administered intranasally, subcutaneously, IV, or orally. Desmopressin is the preparation of choice for both adults and children and is available as an intranasal solution in 2 forms. A dropper bottle with a calibrated nasal catheter has the advantage of delivering incremental doses from 5 to 20 mcg but is awkward to use.
A spray bottle that delivers 10 mcg of desmopressin in 0. For each patient, the duration of action of a given dose must be established, because variation among individuals is great. The duration of action can be established by following timed urine volumes and osmolality. The nightly dose is the lowest dose required to prevent nocturia. The morning and evening doses should be adjusted separately. For children age 3 months to 12 years, the usual dosage range is 2. Overdosage can lead to fluid retention and decreased plasma osmolality, possibly resulting in seizures in small children.
In such instances, furosemide can be given to induce diuresis. Headache may be a troublesome adverse effect but generally disappears if the dosage is reduced. Infrequently, desmopressin causes a slight increase in blood pressure. Absorption from the nasal mucosa may be erratic, especially when an upper respiratory infection or allergic rhinitis occurs. When intranasal delivery of desmopressin is inappropriate, it may be administered subcutaneously using about one tenth of the intranasal dose.
Desmopressin may be used IV if a rapid effect is necessary eg, for hypovolemia. With oral desmopressin , dose equivalence with the intranasal formulation is unpredictable, so individual dose titration is needed. The initial dose is 0. The duration of action of a given dose of desmopressin varies greatly among individuals and must be established for each patient.
Lypressin, a synthetic form of vasopressin given as a nasal spray, is no longer available. Thus, this drug has little use in long-term treatment but can be used in the initial therapy of unconscious patients and in patients with central diabetes insipidus who are undergoing surgery.
Synthetic vasopressin can also be administered twice a day to 4 times a day as a nasal spray, with the dosage and interval tailored to each patient. Vasopressin tannate in oil 0. Vasopressin -releasing drugs eg, chlorpropamide , carbamazepine , clofibrate. These drugs have been particularly useful in partial central diabetes insipidus and do not cause the adverse effects of exogenous vasopressin. Thiazide diuretics paradoxically reduce urine volume in partial and complete central diabetes insipidus and nephrogenic diabetes insipidus , primarily as a consequence of reducing extracellular fluid ECF volume and increasing proximal tubular resorption.
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