Posterior Pituitary: Function and Disease Flashcards
thyroid
pituitary
hypothalamus
primary
secondary
tertiary
Diabetes insipidus-
1. Hypothalamus
Central “Neurogenic”
- Lithium patients (#cause)
- Renal insufficiency
Diabetes insipitus
2. kidney
“Nephrogenic” /Hypothalamic
- deficiency in secretion of ADH from the posterior pituitary.
- Nephrogenic diabetes insipidus occurs when the kidney is unable to respond to ADH
*Transient (Bad for a month, then better)
Diabetes Insipidus - Neurogenic:
Risk factors:
Associated conditions:
Lesion is central: root cause problem
Risk factors
Majority idiopathic (autoimmune?)
Trauma, infectious (TB, Sarcoidosis), vascular, TBI
Cancer - Craniopharyngioma
Associated conditions
Dehydration
Diabetes Insipidus - Neurogenic:
Six (presentation):
Diagnosis ( PE/labs/imaging):
Lesion is central: root cause problem
SSx (presentation)
3 Ps, nocturia, neurological disruption, attraction to cold drinks
Diagnosis ( PE/labs/imaging) #1-> Water Deprivation Test #2-> Copeptin levels – fragment of AVP precursor (Copeptin/ADH released together)
Antibodies against arginine vasopressin-secreting cells (AVPc-Abs)
Neurogenic Diabetes Insipidus - Labs
*Polyuria and polydipsia due to diminished ability of the patient to concentrate urine Urine osmolality < 200mmol/L Urine Na < 20 mEq/L Plasma osmolality: > 290mOsmol/kg Plasma Na 150-160 mEq/L
*Water deprivation test
Urine abnormally dilute
Urine osmolality < plasma osmolality
*Exogenous AVP (aqueous vasopressin)
Urine osmolality increases by > 50%
*Copeptin – part of the AVP prohormone
Neurogenic Diabetes Insipidus most concerns in plasma & urine test.
- Osmolality
- Sodium
Def. in ADH->urine dilute low osmolality, low sodium (peeing water)
Plasma->High osmolality, high sodium (Dehydrated in plasma)
Neurogenic Diabetes Insipidus Diagnose with these numbers:
Urine: Urine osmolality < 200mmol/L
Urine Na < 20 mEq/L
Plasma osmolality: > 290mOsmol/kg
Plasma Na 150-160 mEq/L
Neurogenic Diabetes Insipidus next step after diagnosis..
Water deprivation test: (make sure he is not dehydrated)
Osmolality (with water deprivation)
(Norm pp: osmolality->up/neuro & nephrogenic-> low.
***give Desmopressin= neuro->50%/nephrogenic 10-15%
Sodium (Norm Pp->up/neuro & nephrogenic-> low.
***give Desmopressin= central.->norm/nephrogenic norm
Diabetes Insipidus: Neurogenic
Naturopathic Treatment Plan:
Lesion is central: root cause problem
Problem with water regulation (dehydration)
Match water intake to diuresis
Fiber to decrease constipation
Omega-3 FA for skin dryness
Counsel on adequate electrolyte intake
Nephrogenic Diabetes Insipidus, what is happening?
Kidney can’t respond to ADH, can’t concentrate urine
Nephrogenic Diabetes Insipidus:
Urine osmolality?
Serum electrolytes?
Due to?
Urine osmolality can be <200mmol/L
After water deprivation, urine remains dilute
After exogenous AVP, minimal rise in urine osmolality
High levels of vasopressin in plasma at end of dehydration
Serum electrolytes
Normal or even elevated Na
Due to: chronic renal insufficiency, Li toxicity, hypercalcemia, and sometimes genetic
Diabetes Insipidus - Nephrogenic: Risk factors? Associated conditions? SSx (presentation) Diagnosis ( PE/labs/imaging):?
Risk factors
Occurs in >50% of patients on chronic lithium therapy
Congenital defects
Chronic disease: sickle cell anemia, renal sarcoidosis, renal amyloidosis
Associated conditions
Dehydration and hypernatremia
Bladder dysfunction
Insomnia
SSx (presentation)
Polyuria
Nocturia
Obtundation (less responsive) - hypernatremia
Diagnosis ( PE/labs/imaging):
24 hour urine
Water Deprivation Test
Diabetes Insipidus: Nephrogenic
Management Strategies:
Pharmaceutical:
Follow up/ Referrals:
Management Strategies:
Monitor patient symptoms
Low sodium diet < 500mg daily
http://www.ndif.org/pages/5-Low_Sodium_Diet_Basics (Great Resource)
Lower protein diet, switch to plant based proteins
Adequate hydration
Pharmaceutical
Thiazide-like diuretics to excrete sodium (HCTZ 12.5-50mg oral daily)
Potassium sparing diuretic Amiloride if lithium etiology
Follow up/ Referrals
Urology consult
Endocrinology consult
Serum electrolytes and visit every 6 months
Diabetes Insipidus: Nephrogenic
Sample Naturopathic Treatment Protocol:
Role for nephroprotective herbal therapies?
Do not combine with lithium
Possible anti-inflammatory diet and supplements
May have elevated Prostaglandin E2
Curcumin inhibits cyclooxygenases 1 and 2 thereby reducing PGE2 production
PMID: 21372035
Fish oil shows greater reduction in PGE2 compared to olive oil or safflower oil
PMID: 8694022
If dietary restrictions for sodium and protein
Diet counseling
Multivitamin prescription
Remove offending agents
In patients with bipolar consider alternatives to lithium therapy
Screen supplements for “lithium”
Colchicine, amphotericin B, loop diuretics can all contribute to acquired NDI
Support for other diseases leading to NDI
Chronic kidney failure
Abnormal high Ca++ or low K+
Protein restriction (excessive)