W2L4 DI &SIADH

Question 1

Def Diabetes insipidus?

Answer 1

Disorder of post lobe pitui gla char by deficiency ADH

Question 2

Types of Diabetes Insipidus

Answer 2

1. Central
   - ADH deficit
   - Neurosurgery, TBI, tumor, Inc ICP, brain death, inf
2. Nephrogenic
   - Kidney ignore ADH
   - Kidney dis, drug(lithium)
3. Psychogenis
   - Rare form of DI
   - Drink water up to 5 l/d

Question 3

Pathophysiology DI

Answer 3

ADH deficit- Excessive diuresis- Inc serum osmolarity- Hypernatremia- Hypovolemic shock

Question 4

SS DI

Answer 4

• Polyuria w uo 5-15l daily
• Polydipsia
• Marked dehy
• Anorexia & epigastric fullness
• Nocturia & fatigue

Question 5

Investigations DI

Answer 5

1. Measure 24H uo & urine osmolarity
2. Fluid deprivation test
3. Imaging: ddx DI(MRI pitui & hypothalamus)
4. DI+lab
   - Sodium(>145 mEq/L)
   - Serum osmolarity(>320 mOsm/l)
   - Urine osmolarity(<300 mOsm/l)

Question 6

Treatment DI

Answer 6

A. Central DI:

• Treat primary disease
• Correct a fluid deficit
• DDAVP: inc urine conc & dec urine flow (iv/ subcutaneous, nasal inhalation, tablet

B. Nephrogenic DI
• Underlying disorder/ stop offend medication
• Thiazide diuretics
• Low-sodium diet
• Inhibitors prostaglandin synthesis (indomethacin)

Question 7

Def Syndrome of Inappropriate ADH Secretion?

Answer 7

Disorder of impair water excretion coz by inability suppress secretion/ excessive secretion & action of ADH

Question 8

Causes SIADH

Answer 8

1. 1ry brain injury(meningitis)
2. Inf(pneumonia)
3. Hypothyroidism
4. Kidney(dec S osmo, inc urine osmo)
5. Malig(lung)
6. Drug(carbamazepine, morphine)

Question 9

Assessment and Diagnosis SIADH

Answer 9

– Cp relate h2o & Na imbalance
– Lethargy
– Anorexia
– Mental confusion
– Seizures, coma, death
– S Lab Value 
• Serum ADH
• Urine Osmo(300-1400 mosm/l)
• Urine Specific Gravity

Question 10

Inv SIADH

Answer 10

Chest radiograph:underlying coz (pulmonary disease)

Brain CT: cerebral edema, brain tumor

Question 11

Clinical Management SIADH

Answer 11

1. Ttt underlying medical condition
2. Normalize serum sodium (130 meq/l & >) 24 -48H (Max correction=15meq/d)
3. Elevate S Na fast(pontine myelinolysis)
4. Normalize s osmo
5. Correct excess extravascular fluid volume
   
   • Restrict fluids
   • 3% NaCl
   • Loop diuretics

Question 12

Drug therapy in SIADH

Answer 12

• Demeclocycline & lithium
• Demeclocycline >eff & use- lithium
• Both drugs are nephrotoxic
• Demeclocycline(nausea, vomiting,
 photosensitivity)
• Lithium(neuropsychiatric se)