Questions and Answers
What is the most common cause of nephrogenic Diabetes Insipidus (DI) in childhood?
Which condition is NOT typically associated with nephrogenic DI?
What unusual effect can hydrochlorothiazide have on individuals with nephrogenic DI?
Why does desmopressin not relieve symptoms in nephrogenic DI?
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A plasma sodium concentration greater than 142 mEq/L suggests what condition when paired with low urine osmolality?
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What is the primary treatment strategy for Diabetes Insipidus?
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Which of the following statements about DI is true?
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Which of the following conditions can cause DI as a result of pituitary injury?
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In cases of nephrogenic DI, what is the expected relationship between urine osmolality and plasma osmolality?
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What condition might exhibit urine output of 10-20 mL/kg per hour along with polydipsia?
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What plasma sodium concentration suggests water overload due to primary polydipsia?
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Which urine osmolality value would help exclude a diagnosis of diabetes insipidus?
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What is a common cause of diabetes insipidus?
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What is the primary treatment for diabetes insipidus?
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Which factor distinguishes desmopressin from vasopressin in terms of potency and duration?
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What urine specific gravity is typically found in diabetes insipidus?
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What characterizes nephrogenic diabetes insipidus?
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Study Notes
Diabetes Insipidus Overview
- Diabetes insipidus (DI) results from inadequate production or response to antidiuretic hormone (ADH).
- Symptoms include hypotonic polyuria and polydipsia, similar to mannitol use and diabetes mellitus.
Urine Output and Causes
- Urine output in DI can reach 10-20 mL/kg per hour.
- Major causes of polyuria: primary polydipsia, central DI, and nephrogenic DI.
- Conditions are characterized by increased water output and excretion of hypotonic urine.
Diagnostic Indicators
- Low plasma sodium concentration (<137 mEq/L) with low urine osmolality (<50% of plasma osmolality) indicates water overload due to primary polydipsia.
- High-normal plasma sodium concentration (>142 mEq/L) indicates DI, especially if urine osmolality is less than plasma osmolality.
- Normal plasma sodium concentration with urine osmolality >600 mOsmol/L excludes DI.
- Urine specific gravity in DI is less than 1.005.
Common Causes and Treatment
- DI often occurs due to destruction of the pituitary gland from trauma, infiltrative lesions, or surgery (especially from craniopharyngioma resections); this can be transient.
- Treatment for DI includes water replacement and exogenous vasopressin.
Role of Desmopressin
- Desmopressin is the preferred treatment for most forms of DI; it is less potent than vasopressin and has a longer half-life of 10-20 hours.
- The dosage for treating DI is significantly lower (up to 1/40 of the dose) compared to that for von Willebrand disease.
Nephrogenic DI Characteristics
- Nephrogenic DI features normal ADH secretion but renal resistance to its effects.
- Childhood nephrogenic DI is typically caused by inherited defects.
- Common causes include kidney or systemic disorders such as amyloidosis, polycystic kidney disease, and lithium toxicity.
- Hydrochlorothiazide can alleviate symptoms, reducing urine output despite being a diuretic.
- Desmopressin is ineffective in nephrogenic DI due to non-responsive ADH receptors in the kidneys.
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Description
This quiz explores the causes, symptoms, and management of Diabetes Insipidus (DI), including its presentation and different types such as central and nephrogenic DI. You'll learn about the role of ADH, the implications of polyuria, and measurement techniques to assess the condition. Test your understanding of this important endocrine disorder.
