49 Electrolytes Flashcards
What is the free water deficit? 53F. 60 Kgs. CBG 322. Serum sodium 155 mg/dl
3.2L
A 24F diabetic presents with vomiting and abdominal pain. She is dehydrated and Febrile. CBG shows 420 mg/dl. Na 134 mg/dl. K 4.8 mmol/ml. Creatinine is 1.6 mg/dl. What is her corrected sodium?
Corrected Na is 140
Osmolality of human fluid
280-295 mOsm/kg
Half life of AVP
10-20 minutes
Site of action of AVP/vasopressin
V2 receptor of thick ascending loop of Henle (TALH) and
Principal cells of collecting duct
Site where 2/3 of NaCl is reabsorbed? The remaining 1/3?
2/3 in Proximal tubule
1/3 in TALH
Site sensitive to aldosterone
Distal convoluted tubile
Connecting tubule
Collecting duct
Site sensitive to thiazide
Apical NaCl Co transporter
More reliable signs of hypovolemia
Decreased jugular venous pressure
Ortho static Tachycardia
Orthostatic hypotension
What is Orthostatic tachycardia? Orthostatic hypotension?
Orthostatic tachycardia: increase of 15-20 beats while standing
Orthostatic hypotension: 10-20 mmHg drop in blood pressure while standing
More dependable measure of GFR: Creatinine or BUN?
Creatinine
Decreased TBW. Decreased body sodium. Urine Na more than 20
Renal losses
Diuretic excess
Cerebral Salt wasting syndrome
Ketonuria
Decreased TBW. Decreased body sodium. Urine Na less than 20
Extra renal losses Vomiting Diarrhea Third spacing of fluids Burns Pancreatitis Trauma
Euvolemia. Hyponatremia. Urine sodium more than 20
Hypothyroidism Stress Drugs SIADH Glucocorticoids deficiency
SS HGD
Sige higda
Increased TBW. Decreased body sodium. Urine sodium less than 20
Acute or chronic renal failure
Increased TBW. Decreased body sodium. Urine Na less than 20
Nephrotic syndrome
Cirrhosis
Cardiac failure
Rare cause of hypovolemic Hyponatremia and inappropriate natriuresis in association with Intracranial disease
Cerebral Salt wasting
Management of cerebral Salt wasting
Aggressive NaCl repletion
Most frequent cause of euvolemic hyponatremia
SIADH
Common causes of SIADH
Pulmonary disease: pneumonia, tuberculous, pleural effusion
CNS disease: tumor, Sah, Meningitis
Loss of oligodendrocytes due to rapid reaccumulation of organic osmolytes; brain area classically affected
Osmotic demyelination syndrome;
Lesion affects the pons, cerebellum, lateral geniculate, thalamus, putamen, cerebral cortex or subcortex
Na concentration correction allowed in 24 hours
8-10 mM within first 24 hours
Not more 18 mM within first 48 hours
Cornerstone in the therapy of hyponatremia
Water deprivation
Quick indicator of electrolytre- free water excretion
Urine to plasma electrolyte ratio (urinary Sodium + urinary Potassium/ plasma sodium)
Interpretation of urine to plasma electrolyte ratio
More than 1: water aggressive restricted to less than 500 ml/day
About 1: fluid restricted to 500-700 ml
Less than 1: water restricted to 1 L/day
Causes of Acute Hyponatremia
Thiazides Polydipsia MDMA (ecstasy) Exercise Polydipsia Colonoscopy preparation Glycine irrigation in TURP or uterine surgery
Causes of hypernatremia. ECF volume increased. Minimum volume of maximally concentrated urine, Yes.
Insensible water loss
GI water loss
Remote renal water loss
Causes of hypernatremia. Increased ECF volume. Minimal maximally concentrated urine, No. Urine osmole excretion rate more than 750 mOsm/day
Diuretic use
Osmotic diuresis
Causes of hypernatremia. Increased ECF volume. Minimal maximally concentrated urine, No. Urine osmole excretion rate less than 750 mOsm/day. Desmopressin given. Urine osomolality increased
Central diabetes insipidus
Causes of hypernatremia. Increased ECF volume. Minimal maximally concentrated urine, No. Urine osmole excretion rate less than 750 mOsm/day. Desmopressin given. Urine osomolality unchanged
Nephrologenic diabetes insipidus
Causes of Hypokalemia. Decreased intake
Starvation
Clay ingestion
Causes of Hypokalemia. Redistribution to cells
Metabolic alkalosis Bronchodilators/tocolytics Insulin Downstream regulation of NaKATPase: theophylline, caffeine Thyrotoxic periodic paralysis --- Vit B administration TPN
Hypokalemia. Urine K less than 15. ABG normal
Extra renal cause
Profuse sweating
Hypokalemia. Urine K less than 15. ABG metabolic acidosis
GI K loss
Hypokalemia. Urine K less than 15. ABG metabolic alkalosis
Diuretic use
Vomiting or stomach drainage
Profuse sweating
Hypokalemia. Urine K more than 15. TTKG more than 4. BP high. Aldosterone high. Renin high.
Renal loss Increased Distal K secretion -- Renal artery stenosis Renin secreting tumor Malignant hypertension
Hypokalemia. Urine K more than 15. TTKG less than 2.
Increased tubular flow
Osmotic diuresis
Hypokalemia. Urine K more than 15. TTKG more than 4. BP high. Aldosterone high. Renin low
Primary aldosteronism
Familial hyperaldosteronism type I
Hypokalemia. Urine K more than 15. TTKG more than 4. BP high. Aldosterone low. Renin normal. Cortisol normal
Liddle syndrome
Licorice
Syndrome of apparent mineralocorticoid excess
Hypokalemia. Urine K more than 15. TTKG more than 4. BP high. Aldosterone low. Renin normal. Cortisol high
Cushing syndrome
Hypokalemia. Urine K more than 15. TTKG more than 4. BP low to normal. ABG metabolic acidosis
RTA
DKA
Amphotericin B
Acetazolamide
Hypokalemia. Urine K more than 15. TTKG more than 4. BP low to normal. ABG metabolic alkalosis. Urine Chloride less than 10
Vomiting
Chloride diarrhea
Hypokalemia. Urine K more than 15. TTKG more than 4. BP low to normal. ABG metabolic alkalosis. Urine Chloride more than 20. Urine Ca/CR ratio more than 0.2
Loops diuretic
Barterrs syndrome
Hypokalemia. Urine K more than 15. TTKG more than 4. BP low to normal. ABG metabolic alkalosis. Urine Chloride more than 20. Urine Ca/CR ratio less than 0. 15
Thiazides diuretic
Gitelmans syndrome
Causes of Hyperkalemia. Pseudo hyperkalemia
Cellular efflux: thrombocytosis, erythrocytosis, leukocytosis
