Diagnosis of Diabetes
Diagnostic Test list for Diabetes:
The list of medical tests
mentioned in various sources as
used in the diagnosis of Diabetes
includes:
Diabetes Diagnosis: Book Excerpts
Tests and diagnosis discussion for Diabetes:
Diabetes Overview: NIDDK (Excerpt)
The fasting plasma glucose test is the preferred test for diagnosing
type 1 or type 2 diabetes. However, a diagnosis of diabetes is made for
any one of three positive tests, with a second positive test on a
different day:
- A random plasma glucose value (taken any time of day) of 200 mg/dL
or more, along with the presence of diabetes symptoms.
- A plasma glucose value of 126 mg/dL or more, after a person has
fasted for 8 hours.
- An oral glucose tolerance test (OGTT) plasma glucose value of 200
mg/dL or more in the blood sample, taken 2 hours after a person has
consumed a drink containing 75 grams of glucose dissolved in water. This
test, taken in a laboratory or the doctor's office, measures plasma
glucose at timed intervals over a 3-hour period.
Gestational diabetes is diagnosed based on plasma glucose values
measured during the OGTT. Glucose levels are normally lower during
pregnancy, so the threshold values for diagnosis of diabetes in pregnancy
are lower. If a woman has two plasma glucose values meeting or exceeding
any of the following numbers, she has gestational diabetes: a fasting
plasma glucose level of 95 mg/dL, a 1-hour level of 180 mg/dL, a 2-hour
level of 155 mg/dL, or a 3-hour level of 140 mg/dL.
(Source: excerpt from Diabetes Overview: NIDDK)
Am I at Risk for Type 2 Diabetes: NIDDK (Excerpt)
If you are 45 years old or older, you need to get tested for diabetes,
even if you do not have any of the risk
factors listed below. If you are younger than 45 and have one or more
risk factors, you should also get tested. Ask your doctor for a fasting
blood glucose test. The results of this blood test will tell your doctor
how much glucose is in your blood. Your doctor may ask you to have the
test twice.
Even if your blood glucose level is normal and you have no risk
factors, if you are over 45, you may need to remind your doctor to check
your blood glucose again in 3 years. If you have at least one of the risk
factors below, have your blood checked more frequently. (Source: excerpt from Am I at Risk for Type 2 Diabetes: NIDDK)
Diabetes Diagnosis: NIDDK (Excerpt)
A Lower Number To Diagnose Diabetes The expert committee also
recommended a lower fasting plasma glucose (FPG) value to diagnose
diabetes. The new FPG value is 126 milligrams per deciliter (mg/dL) or
greater, rather than 140 mg/dL or greater. This recommendation was based
on a review of the results of more than 15 years of research. This
research showed that a fasting blood glucose of 126 mg/dL or greater is
associated with an increased risk of diabetes complications affecting the
eyes, nerves, and kidneys. When diagnosis was based on a blood glucose
value of 140 mg/dL or greater, these complications often developed before
the diagnosis of diabetes. The experts believe that earlier diagnosis and
treatment can prevent or delay the costly and burdensome complications of
diabetes.
The prior criteria for diagnosing diabetes relied heavily on performing
an oral glucose tolerance test (OGTT). In this test, the person must come
in fasting, drink a glucose syrup, and have a blood sample taken 2 hours
later. This complicated procedure made detection and diagnosis of diabetes
a difficult and cumbersome process, and the expert committee recommended
that it be eliminated from clinical use. The change to using fasting
plasma glucose for determining the presence of diabetes will make
detection and diagnosis of diabetes more routine. The fasting value can be
easily obtained during routine physician visits, in clinics at the place
of employment, and other situations. Currently, about 5 to 6 million
adults in the United States have diabetes but do not know it. The simpler
testing method of measuring fasting glucose should help identify these
people so they can benefit from treatment sooner. (Source: excerpt from Diabetes Diagnosis: NIDDK)
Diabetes Diagnosis: NIDDK (Excerpt)
The committee states that diabetes can be detected
by any of three positive tests. To confirm the diagnosis, there must be a
second positive test on a different day.
-
A casual plasma glucose level (taken at any time of day) of 200 mg/dL
or greater when the symptoms of diabetes are present.
-
A fasting plasma glucose value of 126 mg/dL or greater.
-
An OGTT value in the blood of 200 mg/dL or greater measured at the
2-hour interval.
As mentioned above, the committee
recommended that the OGTT not be used. (Source: excerpt from
Diabetes Diagnosis: NIDDK)
Diabetes Statistics in the United States: NIDDK (Excerpt)
The new diagnostic criteria for diabetes include
the following changes:
- The routine diagnostic test for diabetes is now a fasting plasma
glucose test rather than the previously recommended oral glucose
tolerance test. (However, in certain clinical circumstances, physicians
may still choose to perform the oral glucose tolerance test.)
- A confirmed** fasting plasma glucose value of greater than or equal
to 126 milligrams/deciliter (mg/dL) indicates a diagnosis of diabetes.
Previously, a value of greater than or equal to 140 mg/dL had been
required for diagnosis.
- In the presence of symptoms of diabetes, a confirmed** nonfasting
plasma glucose value of greater than or equal to 200 mg/dL indicates a
diagnosis of diabetes.
- When a doctor chooses to perform an oral glucose tolerance test (by
administering 75 grams of anhydrous glucose dissolved in water, in
accordance with World Health Organization standards, and then measuring
the plasma glucose concentration 2 hours later), a confirmed** glucose
value of greater than or equal to 200 mg/dL indicates a diagnosis of
diabetes.
In pregnant women, different requirements are used to
identify the presence of gestational diabetes.
*For further information about the new diagnostic
criteria for diabetes, please see the "Report of the Expert Committee on
the Diagnosis and Classification of Diabetes Mellitus," in the References.
**Except in certain specified circumstances, abnormal tests must be
confirmed by repeat testing on another day.
(Source: excerpt from Diabetes Statistics in the United States: NIDDK)
Medicines for People With Diabetes: NIDDK (Excerpt)
One other number to know is the result of a blood test your doctor does
called hemoglobin A-1-c (HE-muh-glow-bin A-1-C) or glycated
hemoglobin (GLY-kay-ted HE-muh-glow-bin). It shows your blood
glucose control during the past 2 to 3 months. For most people, a good
hemoglobin A-1-c is 7 percent. (Source: excerpt from Medicines for People With Diabetes: NIDDK)
Keep your kidneys healthy: NIDDK (Excerpt)
Each year make sure your doctor tests a sample of your urine to see if
your kidneys are leaking albumin. If your kidneys are not leaking a lot of
albumin, ask your doctor to check your urine for even smaller amounts of
albumin. This is called microalbumin (MY-kro-al-BYOO-min).
(Source: excerpt from Keep your kidneys healthy: NIDDK)
Keep your kidneys healthy: NIDDK (Excerpt)
Your doctor might test your blood to measure the amounts of
creatinine (kree-AT-ih-nin) and urea (yoo-REE-uh). These are waste
products your body makes. If your kidneys are not cleaning them out of
your blood, they can build up and make you sick.
Your doctor might also ask you to collect your urine in a large
container for a whole day or just overnight.
(Source: excerpt from Keep your kidneys healthy: NIDDK)
Diabetes: NWHIC (Excerpt)
A diagnosis of diabetes can be confirmed by a series of tests that
might include:
-
A blood test that measures the glucose in your blood. A
blood glucose level of 200 milligrams per deciliter (mg/dL) or greater,
with symptoms, means that you have diabetes.
-
A blood test for glucose after you have fasted, called
fasting plasma glucose (FPG) value. An FPG value of 126 mg/dL or greater
means that you have diabetes.
-
A measurement of glucose in your blood through an oral
glucose tolerance test (OGTT). Although this test is no longer
recommended because it is cumbersome, some health care providers may
still use it. After fasting, you have to drink a glucose syrup and have
a blood sample taken 2 hours later. An OGTT value of 200 mg/dL or
greater means that you have diabetes.
(Source: excerpt from
Diabetes: NWHIC)
Diagnosis of Diabetes: medical news summaries:
The following medical news items
are relevant to diagnosis and misdiagnosis issues for Diabetes:
Diagnostic Tests for Diabetes: Online Medical Books
16 MEDICAL BOOKS ONLINE!
Review excerpts from medical books online, free, without registration,
for more information about diagnostis of Diabetes.
GLYCOSURIA:
Ask the Following Questions:
(Algorithmic Diagnosis of Symptoms and Signs)
- Was the test used specific for glucose? Glucose oxidase tests (Clinistix, etc.) are specific for glucose, whereas other tests (Benedict's, etc.) are not. Thus, the latter will give false positives for lactose, fructose, galactose, and salicylates.
- What is the blood sugar? If the blood sugar is elevated or a glucose tolerance test is positive, one should suspect diabetes mellitus. If these tests are normal, one should suspect renal glycosuria, pregnancy, or renal tubular acidosis.
DIAGNOSTIC WORKUP
The investigation of glycosuria should include a glucose tolerance test, chemistry panel, and electrolyte panel. If there are clinical features of an endocrine disorder, the various tests for these disorders should be ordered.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
HYPERGLYCEMIA:
Ask the Following Questions:
(Algorithmic Diagnosis of Symptoms and Signs)
- What is the free T
4
? If this is elevated, think of hyperthyroidism.
- What is the plasma cortisol? If this is elevated, think of Cushing's syndrome.
- What is the plasma growth hormone? If this is elevated, think of acromegaly or gigantism.
- What is the 24-hr urine catecholamine level? If this is high, think of a pheochromocytoma.
If all of the above tests are normal, diabetes mellitus is usually the diagnosis, although some of these patients could have a glucagonoma or pancreatic disease. Certain drugs can cause a spurious hyperglycemia also.
DIAGNOSTIC WORKUP
Further workup may include a CBC, urinalysis, chemistry panel, glucose tolerance test, plasma cortisol, free T
4
, TSH, plasma and urine catecholamines, skull x-ray,
vanillylmandelic acid (VMA)
, and endocrinology consult.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
POLYDIPSIA:
Ask the Following Questions:
(Algorithmic Diagnosis of Symptoms and Signs)
- Is there a history of drug ingestion? Diuretics and arsenic poisoning are among the many causes of excessive thirst.
- Is there associated polyphagia and weight loss? The presence of these symptoms would suggest diabetes mellitus and hyperthyroidism.
- Is there massive polyuria? The presence of massive polyuria suggests diabetes insipidus or psychogenic polydipsia.
- Is there mild polyuria? The presence of mild polyuria should suggest chronic renal failure, renal tubular acidosis, hyperparathyroidism, and febrile illnesses.
DIAGNOSTIC WORKUP
The basic workup includes a CBC, sedimentation rate, urinalysis, 24-hr urine volume, a serum and urine osmolality, a thyroid profile, and x-rays of the skull and long bones.
The diagnosis of hyperparathyroidism may be assisted by ordering a serum parathyroid hormone level. Also, a 24-hr urine collection for calcium may be done to help diagnose this condition. Microscopic examination of the urinary sediment will help diagnose renal disease, as will renal biopsies. If pituitary diabetes insipidus is suspected, a CT scan of the brain and blood tests for serum growth hormone, FSH, LH, ACTH, and TSH may be done. The Hickey-Hare test and monitoring intake and output before and after vasopressin (Pitressin®) will be useful in differentiating pituitary diabetes insipidus from nephrogenic diabetes insipidus. The concentrations of circulating vasopressin may be measured by immunoassay.
An endocrinologist should be consulted before ordering these expensive diagnostic tests.
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Source: Algorithmic Diagnosis of Symptoms and Signs, 2003
Hyperglycemia:
Differential Diagnosis
(In a Page: Signs and Symptoms)
-
Medications
–Corticosteroids are a common cause
–Common medications include growth
hormone, estrogen (including oral contraceptives), nicotinic acid, salicylates and NSAIDs, thiazide and loop diuretics, phenytoin, and epinephrine - Diabetes mellitus type I
–Diabetic ketoacidosis -
Diabetes mellitus type II
-
Pancreatic disease
–Acute or chronic pancreatitis
–Pancreatectomy
–Pancreatic carcinoma
–Hemochromatosis
–Cystic fibrosis
-
Increased counter-regulatory hormones associated with acute disease
–Myocardial infarction
–Stroke or other neurologic disease
–Renal insufficiency
–Hepatic insufficiency
-
Acromegaly
-
Cushing's syndrome
-
Pheochromocytoma
-
Hyperthyroidism (thyroid storm)
-
Glucagonoma
-
Gestational diabetes
-
Amyloidosis
Workup and Diagnosis
- History and physical examination
–Symptoms of hyperglycemia include fatigue, polyuria, polyphagia, polydipsia, and stomach discomfort
–Complete medication history is essential
–Examination is most commonly normal, but patients occasionally present with acanthosis nigricans (hyperpigmented, velvety lesions commonly on the back of the neck and/or axilla), or necrobiosis lipoidica diabeticorum (atrophic, shiny, erythematous or pale macules on anterior shins).
–Complicating problems of diabetes (end-organ dysfunction) involve many systems (e.g., diabetic retinopathy, peripheral neuropathy, diabetic nephropathy, hypertension, coronary artery disease)
-
Initial presentation may be dramatic, with greatly elevated glucose and significant electrolyte abnormalities
-
Both type I and type II result in elevated levels of insulin
–In type I disease, exogenous insulin is often abnormally elevated
–In type II disease, endogenous insulin is often abnormally elevated
-
C-peptide is increased in type II and decreased in type I
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Source: In a Page: Signs and Symptoms, 2004
Hyperglycemia:
Differential Diagnosis
(In A Page: Pediatric Signs and Symptoms)
- Type I diabetes mellitus
–Most common form of diabetes in children
–Prevalence: 1.9/1,000
–Autoimmune-mediated destruction of
pancreatic islets (β-cells)
–Absolute insulin deficiency
–Often presents with ketosis and DKA
- Type II diabetes mellitus
–Increasing prevalence in children, especially
among obese
–In children, onset usually in mid-puberty
–More frequent in blacks, Hispanics, Pacific
Islanders, Asians, and Native Americans (Pima Indians)
–Strong association with family history of type II diabetes
–Insulin resistance and inadequate insulin secretion results in relative insulin deficiency
-
Maturity-onset diabetes of the young (MODY)
–Infrequent
–Autosomal dominant disease
–Onset usually between 9 and 25 years old
–Genetic defects in enzymes or nuclear
transcription factors involved in islet cell development or the regulation of insulin secretion
-
Drug- or chemical-induced diabetes
–Glucocorticoids, β-adrenergic agonists, phenytoin, asparaginase, cyclosporine, tacrolimus, vacor, pentamidine, diazoxide, nicotinic acid, thyroid hormone, thiazides
-
Other endocrinopathies: Cushing disease, acromegaly, pheochromocytoma
-
Exocrine pancreatic diseases
–Cystic fibrosis
–Hemochromatosis
-
Pancreatectomy
-
Physiological stress (trauma, infection)
-
Infections
–CMV
–Congenital rubella
-
Genetic syndromes: Prader-Willi syndrome, Down syndrome, Turner syndrome, Klinefelter syndrome, Wolfram syndrome
Workup and Diagnosis
- History
–Classic symptoms: Polyuria, polydipsia, weight loss
–Also polyphagia, nocturia, secondary enuresis, intermittent blurry vision
–Nausea, vomiting, abdominal pain with ketoacidosis
–Mental status changes with severe acidosis and
dehydration
–Family history of DM, autoimmune, endocrinopathy
- Physical exam
–Vital signs, weight, body mass index
–Ketoacidosis: Funduscopic exam (blurred optic discs with cerebral edema), Kussmaul respirations, fruity odor to breath, tachycardia/hypotension/poor perfusion, severe dehydration, mental status changes
–Type II diabetes: Obesity and acanthosis nigricans
- Diagnostic criteria for diabetes
–Random plasma glucose >200 mg/dL
–Fasting plasma glucose >126 mg/dL
–Or 2-hour plasma glucose during the oral glucose tolerance test >200 mg/dL
–Lab abnormalities must be present on two different days or in the presence of symptoms of diabetes (polyuria, polydipsia, weight loss)
- Other tests
–HbA1c, urinalysis for glucose and ketones
–If suspect DKA, check electrolytes and blood gas
–To help distinguish type I from type II diabetes, check
fasting insulin, C-peptide, and β-cell autoantibodies
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Source: In A Page: Pediatric Signs and Symptoms, 2007
Polydipsia:
Differential Diagnosis
(In A Page: Pediatric Signs and Symptoms)
-
Diabetes mellitus (type I and type II)
–Hyperglycemia drives an osmotic diuresis that causes polyuria, which then leads to dehydration, increased thirst, and polydipsia
-
Diabetes insipidus
–Abnormal water balance due to vasopressin (ADH) deficiency or resistance, causing excretion of large amounts of dilute urine
-
Central or neurogenic diabetes insipidus
(vasopressin deficiency)
–Congenital
–Familial (autosomal dominant)
–Acquired: Neurosurgery, tumor (e.g.,
craniopharyngioma), head trauma, infiltrative/inflammatory, infectious
-
Nephrogenic diabetes insipidus (decreased responsiveness of the kidneys to vasopressin)
–Familial (X-linked dominant and recessive forms)
–Acquired: Renal disease, obstructive uropathy, hypercalcemia/hypercalciuria
–Hypokalemia, drug-induced (e.g., lithium, diuretics, ethanol, cisplatin)
–Gestational DI: Increased clearance of ADH by placental vasopressinase, lower osmolar threshold for thirst and ADH release
-
Primary polydipsia
–Compulsive water drinking
–Dipsogenic DI
-
Primary hyperaldosteronism
-
Diabetes insipidus, diabetes mellitus, optic atrophy, and deafness (DIDMOAD) syndrome
-
Bartter syndrome
-
Hypertension (e.g., pheochomocytoma)
-
Neuroblastoma
-
Cystinosis
-
Congestive heart failure
Workup and Diagnosis
-
History: Quantification of fluid intake and urine output, drinking overnight, polyphagia, polyuria, nocturia, enuresis, psychosocial factors, interference with normal activities, growth progression, weight loss, weakness, fatigue, leg cramps/muscle aches, neurologic symptoms (headaches, visual changes)
-
Physical exam: Vital signs (HR, BP), weight, height, hydration assessment (mucous membranes, capillary refill, extremities’ temperature, skin turgor), neurologic exam (optic discs, EOM), energy level, muscle pain
-
Initial labs
–Serum electrolytes, BUN, creatinine, glucose, calcium
–Urinalysis with specific gravity, glucose and ketones
–Simultaneous serum and urine osmolality (mOsm/kg)
–Serum osm >300 and urine osm <300 =DI
–If serum osm <270 and urine osm >600 DI unlikely
- Further diagnostic workup
–Water deprivation test in case of ambiguous history and labs (patient deprived of water, then ability to concentrate urine is assessed)
–Differentiates between DI and water intoxication, and between central DI and nephrogenic DI (by response to a dose of vasopressin administered at the end of the study)
-
MRI of brain with special attention to the pituitary
-
Imaging of adrenal glands if hyperaldoterone suspected
>>
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Source: In A Page: Pediatric Signs and Symptoms, 2007
GLYCOSURIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
The investigation of glycosuria should include a glucose tolerance test, chemistry panel, and electrolyte panel. A clinical history of polyuria, polyphagia, weakness, and weight loss will be helpful. If there are clinical features of one of the endocrine diseases listed above, various tests for these disorders and an endocrinology consult should be ordered.
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Source: Differential Diagnosis in Primary Care, 2007
HYPERGLYCEMIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
Obviously, the first thing to do is repeat the blood sugar after fasting. If the result is borderline, a glucose tolerance test should be done. Clinical evaluation for a history of diabetes, hypertension (Cushing disease and pheochromocytoma), protruding jaw and increasing hat size (acromegaly), polyuria, polydypsia, and weight loss (diabetes mellitus and hyperthyroidism) is important. Further workup depends on which endocrine disorder is being considered.
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Source: Differential Diagnosis in Primary Care, 2007
POLYDIPSIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
The approach to the diagnosis of polydipsia involves establishing the presence or absence of other symptoms such a polyuria, polyphagia, weakness, and weight loss. Polydipsia with polyuria and excessive appetite (polyphagia) should suggest diabetes mellitus or hyperthyroidism, whereas polydipsia with polyuria alone should suggest a form of diabetes insipidus (pituitary, renal, or psychogenic). The laboratory workup involves checking intake and output, blood sugars, electrolytes, and a thyroid profile.
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Source: Differential Diagnosis in Primary Care, 2007
Polydipsia:
History and physical examination
(Handbook of Signs & Symptoms (Third Edition))
Obtain a history. Find out how much fluid the patient drinks each day. How often and how much does he typically urinate? Does the need to urinate awaken him at night? Determine if he or anyone in his family has diabetes or kidney disease. What medications does he use? Has his lifestyle changed recently? If so, have these changes upset him?
If the patient has polydipsia, take his blood pressure and pulse when he’s in supine and standing positions. A decrease of 10 mm Hg in systolic pressure and a pulse rate increase of 10 beats/
minute from the supine to the sitting or standing position may indicate hypovolemia. If you detect these changes, ask the patient about recent weight loss. Check for signs of dehydration, such as dry mucous membranes and decreased skin turgor. Infuse I.V. replacement fluids, as needed.
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Source: Handbook of Signs & Symptoms (Third Edition), 2006
Diabetic complications during pregnancy:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
The prevalence of gestational diabetes makes careful screening for hyperglycemia appropriate in all pregnancies. A screening 50-gram 1-hour glucose tolerance test is normally performed at 24 to 28 weeks. In addition, women with a history of fetal macrosomia or who may have nongestational diabetes should be formally tested for diabetes with a 3-hour glucose tolerance test.
Confirming diagnosis A 100-gram 3-hour glucose tolerance test confirms diabetes mellitus when two or more values are above normal.
Procedures to assess fetal status include stress and nonstress tests; ultrasonography to determine fetal age and growth; measurement of phosphatidyl-glycerol; and determination of the lecithin-sphingomyelin (L/S) ratio from amniotic fluid to predict pulmonary maturity. The L/S ratio is less useful in diabetic pregnancies and generally requires a ratio of 3.5:1 to confirm fetal lung maturity.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Hereditary fructose intolerance:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
A dietary history often suggests hereditary fructose intolerance.
Confirming diagnosis A fructose tolerance test (using glucose oxidase or paper chromatography to measure glucose levels) usually confirms the diagnosis. However, liver biopsy showing a deficiency in fructose-1-phosphate aldolase may be necessary for a definitive diagnosis.
Supportive values may include decreased serum inorganic phosphorus levels. Urine studies may show fructosuria and albuminuria.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Diabetes mellitus:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
According to the American Diabetes Association (ADA), DM can be diagnosed if any of the following exist:
❑ symptoms of diabetes (polyuria, polydipsia, and unexplained weight loss) plus a random (non-fasting) blood glucose level greater than or equal to 200 mg/dl accompanied by symptoms of diabetes.
❑ a fasting blood glucose level (no caloric intake for at least 8 hours) greater than or equal to 126 mg/dl.
❑ a plasma glucose value in the 2-hour sample of the oral glucose tolerance test greater than or equal to 200 mg/dl. This test should be performed after a glucose load dose of 75 g of anhydrous glucose.
If results are questionable, the diagnosis should be confirmed by a repeat test on a different day. The ADA also recommends the following testing guidelines:
❑ Test every 3 years: people age 45 or older without symptoms
❑ Test immediately: people with the classic symptoms
❑ High-risk groups should be tested frequently: Individuals with impaired glucose tolerance usually have normal blood levels unless challenged by a glucose load, such as a piece of pie or glass of orange juice. Two hours after a glucose load, the glucose level ranges from 140 to 199 mg/dl. These individuals have an abnormal fasting glucose level between 110 and 125 mg/dl. Because the fasting plasma glucose test is sufficient to make the diagnosis of diabetes, it replaces the oral glucose tolerance test. (See Classifying blood glucose levels.)
An ophthalmologic examination may show diabetic retinopathy. Other diagnostic and monitoring tests include urinalysis for acetone and blood testing for glycosylated hemoglobin (Hb A1C), which reflects recent glucose cortisol.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Diabetes insipidus:
Diagnosis
(Professional Guide to Diseases (Eighth Edition))
Urinalysis reveals almost colorless urine of low osmolality (50 to 200 mOsm/kg, less than that of plasma) and low specific gravity (less than 1.005).
CONFIRMING DIAGNOSIS Diagnosis requires evidence of vasopressin deficiency, resulting in the kidneys’ inability to concentrate urine during a water deprivation test.
In this test, after baseline vital signs, weight, and urine and plasma osmolalities are obtained, the patient is deprived of fluids and observed to make sure he doesn’t drink anything surreptitiously. Hourly measurements then record the total volume of urine output, body weight, urine osmolality or specific gravity, and plasma osmolality. Throughout the test, blood pressure and pulse rate must be monitored for signs of orthostatic hypotension. Fluid deprivation continues until the patient loses 3% of his body weight (indicating severe dehydration). When urine osmolality stops increasing in three consecutive hourly specimens, patients receive 5 units of aqueous vasopressin subcutaneously (S.C.).
Hourly measurements of urine volume and specific gravity continue after S.C. injection of aqueous vasopressin. Patients with pituitary diabetes insipidus respond to exogenous vasopressin with decreased urine output and increased specific gravity. Patients with nephrogenic diabetes insipidus show no response to vasopressin.
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Source: Professional Guide to Diseases (Eighth Edition), 2005
Polydipsia:
History and physical examination
(Professional Guide to Signs & Symptoms (Fifth Edition))
Obtain a history. Find out how much fluid the patient drinks each day. How often and how much does he typically urinate? Does the need to urinate awaken him at night? Determine if he or anyone in his family has diabetes or kidney disease. What medications does he use? Has his lifestyle changed recently? If so, have these changes upset him?
If the patient has polydipsia, take his blood pressure and pulse when he’s in supine and standing positions. A decrease of 10 mm Hg in systolic pressure and a pulse rate increase of 10 beats/minute from the supine position to the sitting or standing position may indicate hypovolemia. If you detect these changes, ask the patient about recent weight loss. Check for signs of dehydration, such as dry mucous membranes and decreased skin turgor. Infuse I.V. replacement fluids as needed.
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Source: Professional Guide to Signs & Symptoms (Fifth Edition), 2006
Polydipsia:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
Thirst, which is the chief complaint of patients with DM, DI, and psychogenic polydipsia, is associated with polyuria. Nocturia occurs more frequently with DM and DI than with psychogenic polydipsia. Polydipsia usually starts abruptly in central DI and patients often have a preference for ice cold water (3). In eliciting the history, take note of neurologic symptoms (problems with visual fields, headaches, numbness), a prior history of cancer (particularly metastatic brain cancer), a history of trauma, neurosurgery, and infections (e.g., encephalitis). The patient’s psychiatric history may also be relevant.
Physical examination
A thorough general physical examination, including vital signs, is helpful in making the diagnosis, but the emphasis is on the neurologic examination (i.e., visual fields, cranial nerve deficits, oculomotor palsies, and reflexes). Signs of recent weight loss or presence of peripheral neuropathy is helpful in making the diagnosis of DM (Chapters 2.13 and 4.6).
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Diabetes Mellitus:
History
(The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter)
The initial presentation of DM can vary. Either type may present with the insidious onset of the symptoms associated with hyperglycemia (polyuria, polydipsia, and polyphagia) or with the abrupt onset of an acute complication [diabetic ketoacidosis (in type 1 DM) or nonketotic hyperglycemic-hyperosmolar coma (in type 2 DM)].
A. Type 1 diabetes. Patients with type 1 DM typically present before the age of 18 years. The symptoms heralding the disease emerge gradually as hyperglycemia appears and becomes more frequent and profound. Physiologic stress (e.g., an acute illness or trauma), which increases the requirement for insulin, can unmask the insulinopenia and give the impression that the problem is acute. Enuresis may be a clue for polyuria in a child who was previously toilet-trained. Lethargy, weakness, and weight loss are other common features.
B. Type 2 diabetes. Patients with type 2 DM usually present after the age of 40 years. The diagnosis is often made in an asymptomatic patient as a result of routine blood tests that reveal an elevation of plasma glucose. Other patients may present with the symptoms of hyperglycemia. The patient may have a history of recurrent skin infections or persistent vulvovaginitis. Other common symptoms include altered sensations in the extremities, nocturia, erectile dysfunction, and visual disturbances (Chapters 4.6, 5.1, 10.3, and 10.4). The use of glucocorticoids, β-adrenergic agonists, or thiazides can precipitate the symptoms of type 2 DM.
Physical examination
Patients often present with similar physical findings in both type 1 and type 2 DM, owing to hyperglycemia. In the young child, failure to grow and gain weight can occur with type 1 DM. The child may be ill appearing, lethargic, and often have signs of dehydration (tachypnea, tachycardia, and low blood pressure). Ketone production will produce a fruity odor on the patient’s breath. The patient with type 2 DM tends to be obese (especially upper body obesity) and may appear fatigued and have muscle weakness or decreased vision. The neurologic examination may reveal painful feet and numbness. Monilial infections may be found in the vagina and pubic areas.
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Source: The 10-Minute Diagnosis Manual: Symptoms and Signs in the Time-Limited Encounter, 2000
Diabetic complications during pregnancy:
Diagnosis
(Handbook of Diseases)
The prevalence of gestational diabetes makes careful screening for hyperglycemia appropriate in all pregnancies in each trimester. Abnormal fasting or postprandial blood glucose levels and clinical signs and history suggest diabetes in patients not previously diabetic. A 3-hour glucose tolerance test confirms diabetes mellitus when two or more values are above normal.
Diagnosis of fetal status
Procedures to assess fetal status include stress and nonstress tests, ultrasonography to determine fetal age and growth, measurement of urinary or serum estriols and of phosphatidylglycerol and determination of the lecithin-sphingomyelin ratio from amniotic fluid to predict pulmonary maturity.
Clinical tip Nonstress tests must be done from 30 to 38 weeks’ gestation because the placenta tends to degenerate faster in gestational diabetes.
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Source: Handbook of Diseases, 2003
Diabetes mellitus:
Diagnosis
(Handbook of Diseases)
In nonpregnant adults, diabetes mellitus is diagnosed with:
❑ at least two occasions of a fasting plasma glucose level greater than or equal to 126 mg/dl
❑ typical symptoms of uncontrolled diabetes and a random blood glucose level greater than or equal to 200 mg/dl
❑ a blood glucose level greater than or equal to 200 mg/dl at 2 hours after ingestion of 75 grams of oral dextrose.
Two tests are required for diagnosis; they can be the same two tests or any combination and may be separated by more than 24 hours.
An ophthalmologic examination may show diabetic retinopathy. Other diagnostic and monitoring tests include urinalysis for acetone and blood testing for glycosylated hemoglobin, which reflects glucose control over the past 2 to 3 months.
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Source: Handbook of Diseases, 2003
Diabetes insipidus:
Diagnosis
(Handbook of Diseases)
Urinalysis reveals almost colorless urine of low osmolality (50 to 200 mOsm/kg, less than that of plasma) and low specific gravity (less than 1.005). However, a diagnosis requires the water deprivation test to provide evidence of vasopressin deficiency, resulting in the kidneys’inability to concentrate urine.
Water deprivation test
In this test, after baseline vital signs, weight, and urine and plasma osmolalities are obtained, the patient is deprived of fluids and observed to make sure he doesn’t drink anything surreptitiously. Hourly measurements then record the total volume of urine output, body weight, urine osmolality or specific gravity, and plasma osmolality. Throughout the test, blood pressure and pulse rate must be monitored for signs of orthostatic hypotension.
Fluid deprivation continues until the patient loses 3% of his body weight (indicating severe dehydration). When urine osmolality stops increasing in three consecutive hourly specimens, the patient receives 5 units of aqueous vasopressin subcutaneously (S.C.).
Hourly measurements of urine volume and specific gravity continue after S.C. injection of aqueous vasopressin. Patients with pituitary diabetes insipidus respond to exogenous vasopressin with decreased urine output and increased specific gravity. Patients with nephrogenic diabetes insipidus show no response to vasopressin.
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Source: Handbook of Diseases, 2003
Polydipsia:
History
(Signs & Symptoms: A 2-in-1 Reference for Nurses)
Obtain a history. Find out how much fluid the patient drinks each day. How often and how much does he typically urinate? Does the need to urinate awaken him at night? Determine if he or anyone in his family has diabetes or kidney disease. What medications does he use? Has his lifestyle changed recently? If so, have these changes upset him?
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Source: Signs & Symptoms: A 2-in-1 Reference for Nurses, 2007
Polyuria and Polydipsia:
Clinical Features and Diagnosis
(The Diagnostic Approach to Symptoms and Signs in Pediatrics)
Diabetes Mellitus
By far,most common cause of polyuria and polydipsia in pediatric populationis diabetes mellitus.Most common form is insulin-dependentdiabetes mellitus (type 1), in which autoimmune destruction of betacells of pancreas causes diminished insulin secretion and hyperglycemia.Subsequent glucosuria produces osmotic diuresis with polyuria, polydipsia,and polyphagia.Second form is non–insulin-dependentdiabetes mellitus (type 2), which is characterized by insulin resistanceand usually relative insulin deficiency.Criteria for diagnosis of diabetesmellitus have been established by American Diabetes Association(1999) and include symptoms of diabetes mellitus plus plasma glucoseconcentration ≥200 mg/dL at any time of day regardlessof time of last meal or fasting plasma glucose concentration ≥126 mg/dL(fasting is defined as no caloric intake for ≥8 hrs). Diabetes Insipidus
2 formsof diabetes insipidus are antidiuretic hormone (ADH) deficiencyand ADH resistance.Primary clinical manifestations arepolyuria and polydipsia. Episodes of hypernatremic dehydration withhypotonic urine also may occur. Antidiuretic Hormone Deficiency (Central Diabetes Insipidus)
Kidney isunable to conserve water with ADH deficiency because of absenceor lack of release of ADH (arginine vasopressin).Genetic transmission of primary formis autosomal-dominant, and gene locus has been mapped to chromosome20p13.Secondary form includes lesions thatdamage neurohypophyseal system: head trauma, infection (meningitis,encephalitis), tumors (most commonly craniopharyngioma), Langerhanscell histiocytosis, and metastatic neoplasia (leukemia).Specific gravity of morning urine specimenshould be ≥1.018 in normal children without any overnight fluidintake. Presence of inappropriately dilute urine with hyperosmolarserum suggests ADH deficiency, and water deprivation test shouldbe performed under controlled supervised conditions.Inability to concentrate urine by waterdeprivation and resolution with administration of exogenous argininevasopressin confirm diagnosis. Antidiuretic Hormone Resistance (Nephrogenic Diabetes Insipidus)
The defectin this form of diabetes insipidus is inability of renal tubuleto respond to ADH.Primary form is usually due to X-linkeddisorder with defect in vasopressin receptor; however, autosomal-dominantand -recessive forms also occur.Secondary form is due to several disorders(renal dysplasia, medullary cystic disease, cystinosis, sickle celldisease, chronic renal failure, Fanconi syndrome, Bartter syndrome,hypercalcemia) and drugs (lithium, demeclocycline, methoxyflurane,amphotericin B, phenytoin) that produce renal concentrating defects. Primary Polydipsia
Is the excessiveingestion of water, when it is not needed to maintain fluid balance.Causes include compulsive water drinkingfor psychological reasons and frequent presentation of fluids toinfants. Another cause of primary polydipsia is hypothalamic damagethat affects thirst center but not ADH release.When overnight fluids are withheld,concentrated urine can be produced in the morning. Serum vasopressinlevels are low but increase to normal with fluid deprivation. Diagnostic Approach
Polyuriamust be distinguished from small volume urinary frequency, whichis common in pediatric practice. Children with polyuria often havenocturia and are unable to sleep through the night without wakingup to urinate. Most children with urinary frequency do not havepolyuria or a defect in urinary concentrating ability. Common causesof isolated urinary frequency are habit, attention-seeking behavior,and urinary tract infection.Random sample of urine with specificgravity of >1.028 and absence of polyuria rules out a concentrationdefect. Even urinary specific gravity of >1.020 on randomor early morning sample indicates sufficient urinary concentrationsuch that symptomatic diabetes insipidus is unlikely. Children whohave urine with a somewhat lower than normal specific gravity butwho can sleep through the night without passing urine do not needfurther evaluation.Presence of polyuria, dehydration,and high urinary specific gravity is evidence for osmotic diuresis,which is most commonly caused by diabetes mellitus. Dilute urineassociated with polyuria suggests diabetes insipidus or psychogenicpolydipsia. If blood glucose and urea nitrogen are normal, high serumosmolality with hyposmolar urine suggests ADH deficiency or resistance.Low serum osmolality with hyposmolar urine suggests primary polydipsia.With either ADH deficiency or resistance,urine specific gravity rarely exceeds 1.005 and urinary osmolalityrarely exceeds 200 mOsm/kg. Water deprivation test thatdemonstrates inability to concentrate urine indicates diabetes insipidusand distinguishes it from primary polydipsia. If urine remains hypotonicwith dehydration, next step is to determine response to exogenousvasopressin, which distinguishes ADH deficiency from resistance.With ADH deficiency, administration of vasopressin causes diminishingof symptoms and increase in urine specific gravity, whereas no responseoccurs with ADH resistance.With suspected renal disease, certaintests should be performed: CBC and differential; UA; urine culture;serum electrolytes, calcium, phosphorus, and creatinine; blood ureanitrogen; hemoglobin electrophoresis; and renal U/S. Othertests (e.g., determination of serum and urinary amino acids, voiding cystourethrography,and renal biopsy) may be necessary to define specific renal abnormality.Psychosocial history of emotional disturbance,including episodes of compulsive water drinking and formation ofconcentrated urine with fluid deprivation, are evidence for psychogenicpolydipsia. This disorder may sometimes be difficult to distinguishfrom hypothalamic thirst defect, and consultation with a pediatricendocrinologist is recommended.
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Source: The Diagnostic Approach to Symptoms and Signs in Pediatrics, 2006
Polydipsia:
History and physical examination
(Nursing: Interpreting Signs and Symptoms)
Obtain a medical history. Find out how much fluid the patient drinks each day. How often and how much does he typically urinate? Does the need to urinate awaken him at night? Determine if he or anyone in his family has diabetes or kidney disease. What medications does he use? Has his lifestyle changed recently?
If the patient has polydipsia, take his blood pressure and pulse when he's in supine and standing positions. A decrease of 10 mm Hg in systolic pressure and a pulse rate increase of 10 beats/minute from the supine to the sitting or standing position may indicate hypovolemia. Ask the patient about recent weight loss. Check for signs of dehydration, such as dry mucous membranes and decreased skin turgor.
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Source: Nursing: Interpreting Signs and Symptoms, 2007
GLYCOSURIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
The investigation of glycosuria should include a glucose tolerance
test, chemistry panel, and electrolyte panel. A clinical history of
polyuria, polyphagia, weakness, and weight loss will be helpful. If there
are clinical features of one of the endocrine diseases listed above, various
tests for these disorders and an endocrinology consult should be ordered.
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Source: Differential Diagnosis in Primary Care, 2007
HYPERGLYCEMIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
Obviously, the first thing to do is repeat the blood sugar test after
fasting. If the result is borderline, a glucose tolerance test should be
done. Clinical evaluation for a history of diabetes, hypertension (Cushing
disease and pheochromocytoma), protruding jaw and increasing hat size
(acromegaly), polyuria, polydipsia, and weight loss (diabetes mellitus and
hyperthyroidism) is important. Further workup depends on which endocrine
disorder is being considered.
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Source: Differential Diagnosis in Primary Care, 2007
POLYDIPSIA:
Approach to the Diagnosis
(Differential Diagnosis in Primary Care)
The approach to the diagnosis of polydipsia involves establishing the
presence or absence of other symptoms such a polyuria, polyphagia, weakness,
and weight loss. Polydipsia with polyuria and excessive appetite
(polyphagia) should suggest diabetes mellitus or hyperthyroidism, whereas
polydipsia with polyuria alone should suggest a form of diabetes insipidus
(pituitary, renal, or psychogenic). The laboratory workup involves checking
intake and output, blood sugars, electrolytes, and a thyroid profile.
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Source: Differential Diagnosis in Primary Care, 2007
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