Diabetes Insipidus Flashcards
The posterior pituitary is derived from the ______brain during development and is composed predominantly of _____________.
It lies below the ____________, with which it forms a structural and functional unit→ the _______________.
forebrain ; neural tissue.
hypothalamus
neurohypophysis.
The neurohypophysis consists of
three parts:
the __________ and _____________ nuclei of the hypothalamus
the ________________ tract
the _____________ pituitary
supraoptic
paraventricular
supraoptico-hypophyseal
posterior pituitary
the supraoptic and
paraventricular nuclei of the
hypothalamus contains the cell bodies of the magnocellular,neurosecretory neurons that synthesize and secrete ____________ (also called _________) and __________)
antidiuretic hormone[ADH]
vasopressin; Oxytocin
The principle physiological effect of ADH is in the regulation of ____________ in the (proximal or distal?) nephron.
water resorption
Distal
ADH stimulates the expression of a specific water channel protein (__________) on the __________ surface of the interstitial cells lining the collecting duct.
The presence of this in the wall of the distal nephron allows ______________________ from the duct lumen along an osmotic gradient, and excretion of concentrated
urine.
aquaporin
luminal
resorption of water
Diabetes insipidus (DI) is characterized by:
production of ________________ urine in excess of _____litres/24 hours
(>40 ml/kg/24 hours in adults,
>____ ml/kg/24 hours in infants
or >4ml/kg/hour)
excessive ______
severely dilute
3litres
100 ; thirst
DI arises through one of three mechanisms :
____________ of _______: ________ (Central) DI (HDI)
___________ to the ________________ : __________ DI (NDI)
Inappropriate, ____________________: ___________ DI (DDI).
Deficiency of ADH
Hypothalamic
Renal resistance to the antidiuretic action of ADH
Nephrogenic DI (NDI)
excessive water drinking
Dipsogenic DI (DDI).
Central DI
Primary Causes:
Genetic
DIDMOAD (________) syndrome
•Autosomal dominant
•Autosomal recessive
Developmental syndromes : _________ dysplasia
Idiopathic
Wolfram
Septo-optic
Central DI
Secondary/Acquired causes:
Trauma- Head injury
- Post surgery (transcranial,
transphenoidal)
Tumour:
Craniopharyngioma
Germ cell tumours
Metastases
Pituitary macroadenoma
Secondary/Acquired causes:
Trauma- Head injury
- Post surgery (transcranial,
transphenoidal)
Tumour:
Craniopharyngioma
Germ cell tumours
Metastases
Pituitary macroadenoma
Central DI
Secondary/Acquired causes:
Vascular
Aneurysm
Infarction
Sheehan’s syndrome
Sickle cell disease
Drugs-
Meperidine, MgSO4, phenytoin, barbiturates,
glucocorticoids
Secondary/Acquired causes:
Vascular
Aneurysm
Infarction
Sheehan’s syndrome
Sickle cell disease
Drugs-
Meperidine, MgSO4, phenytoin, barbiturates,
glucocorticoids
Nephrogenic DI
Genetic
______________ (V2-R defect)
______________ (AQP2 defect)
______________(AQP2 defect)
Idiopathic
Genetic
X-linked recessive (V2-R defect)
Autosomal recessive (AQP2 defect)
Autosomal dominant (AQP2 defect)
Idiopathic
Nephrogenic DI
Secondary/Acquired causes:
Chronic renal disease: Polycystic kidneys, Obstructive uropathy
Metabolic disease: Hypercalcaemia, Hypokalaemia
Drug induced : Lithium, Demeclocycline
Osmotic diuretics : Glucose, Mannitol
Systemic disorders: Amyloidosis, Myelomatosis
Pregnancy
Secondary/Acquired causes:
Chronic renal disease: Polycystic kidneys, Obstructive uropathy
Metabolic disease: Hypercalcaemia, Hypokalaemia
Drug induced : Lithium, Demeclocycline
Osmotic diuretics : Glucose, Mannitol
Systemic disorders: Amyloidosis, Myelomatosis
Pregnancy
Dispogenic DI
Compulsive water drinking
Associated with _________ disorders
Structural/organic hypothalamic disease:
____________
________ involving hypothalamus
Head injury
___________ __________
affective
Sarcoidosis
Tumours
Tuberculous meningitis
DI: signs and symptoms
_________
____________, may not be readily apparent ( b/c of _______-osmolarity, fluid shifts from ______ to __________ and maintains blood pressure, CVP)
_________ is a better measure of fluid status
Polyuria
Dehydration, ; hyper-osmolarity
cells ; intravascular spaces
Weight loss
DI: investigation
________ _________
______ ____________
_______ __________
________ ________
Serum osmolality
Urine osmolality
Serum sodium
Urine sodium
Central DI: Lab values
Hypernatremia, Na >_____-____meq/L
(low or high?) serum osmolality (normal value is 270mOsm/kg)
Urine Na < _____ mmol/L
(low or high ?) urine osmolality (very dilute urine)
150-160meq/L
High
20 mmol/L
Low
The water deprivation test- assessing the capacity to ____________ during the
osmotic stress of _________________
concentrate urine
controlled water deprivation
Central DI treatment
•_________ease oral free water consumption, IV can use _____tonic saline
Volume _____________
Those with significant symptoms require
______________ :
intranasal spray (5-100 mcg daily);
parenteral injection (0.1-2.0 mcg daily)
or oral (100-1000 mcg daily),
in divided doses
Treat underlying cause
Increase
hypotonic
replacement
Desmopressin
Nephrogenic DI
•No specific therapy exists.
High dose _________ (4 mcg im. bd) can produce a response in __________ NDI, especially if the lesion is ____________.
Reducing GFR and reducing diluting capacity
of the distal nephron by using:
_____________ : hydrochlorothiazide 25
mg/24 hours.
________ : Ibuprofen 200 mg/24 hours.
__________ diets.
Desmopressin ; partial
acquired.
Thiazide ; NSAIDs
Low salt
Dispogenic DI
Address the underlying disorder.
Switching to _________ may reduce polydipsia in those patients with refractory ___________ and a history of _____________ on other dopamine antagonists.
Reduced fluid intake
Clozapine
schizophrenia
hyponatraemia
SIADH
Definition: When levels of _______ are
__________________ compared to the
body’s (low or high?) osmolality, and ADH levels are not suppressed by further _______eases in blood
osmolality.
ADH
inappropriately elevated
low ; decreases
Why we worry about SIADH
The resulting hyponatraemia (a plasma
sodium concentration less than _______ meq/l)
is a common source of __________ and increased __________ in clinical practice.
130
morbidity
mortality
SIADH: causes
•Irritation of CNS: _________ , _________,
brain _________, brain _________, hypoxic
insult, trauma, brain abscess, _________ syndrome, hydrocephalus
•Pulmonary disorders: _________ , _________, positive end expiratory pressure ventilation, _________ failure, TB, pneumothorax
meningitis, encephalitis,
brain tumors, brain hemorrhage,
Guillain Barre
pneumonia, asthma,
cardiac failure
SIADH: causes
Drugs:
__________
____________
opiates
carbamazepine
cyclophosphamide
NSAIDs
TCAs
Haloperidol
vincristine
vinblastine
