Algorithm for patients with hypokalemia on the basis of the potassium-to-creatinine ratio in the urine
Urine K+ <13 mEq K+/g creatinine (<2.5 mEq K+/mmol creatinine)
• Cell shift: Hypokalemic periodic paralysis, Administration of inulin, B2-adrenergic stimulation
• Gastrointestinal loss: Diarrhea
Urine K+ >13 mEq K+/g creatinine (>2.5 mEq K+/mmol creatinine)
High effective arterial blood volume
• ↑ Renin, ↑ Aldosterone: Kidney artery stenosis, Renin secreting tumor
• ↓ Renin, ↑ Aldosterone: Adrenal adenoma, Bilateral cortical hyperplasia, Glucocorticoid suppressible hyperaldosteronism
• ↓ Renin, ↓ Aldosterone: Cushing syndrome, 11beta-hydroxylase deficiency, 17alpha-hydroxylase deficiency, Syndrome of apparent mineralocorticoid excess, Liddle syndrome
Low-normal EABV, Low Plasma HCO3-:
• Proximal RTA
• Distal RTA
Low-normal EABV, High Plasma HCO3-
• Low Urine Cl - Non-reabsorbable anion effect: Vomiting, Ticarcillin, carbenicillin, piperacillin
• High Urine Cl - Loop diuretics, Thiazide diuretics, Mg2+ deficiency, Bartter syndrome, Gitelman syndrome
#hypokalemia #urine #potassium #differential #algorithm #diagnosis #nephrology
Hypokalemia - Differential Diagnosis Algorithm
Extra-renal Losses:
• Normal Acid-Base: Low intake
• Metabolic acidosis: Gl tract loss (Diarrhea)
Renal Losses:
• Metabolic acidosis: Proximal and distal RTA, Ureterosigmoidoscopy
• HTN, Low Aldosterone: Liddle's Syndrome, Licorice, Carbenoxolone, SAME, Cushing Syndrome
• HTN, High Aldosterone: Malignant HTN, Renovascular HTN, Renin secreting tumor, Primary hyperaldosteronism
• HTN Absent: Loop and thiazide diuretics, Bartter syndrome, Gitelman syndrom, Vomiting, Non-reabsorbable anions
Dr Priti Meena @priti899
#Hypokalemia #Differential #Diagnosis #Algorithm #causes #potassium #low #nephrology
Hypokalemia Differential Diagnosis Algorithm
Hypertensive:
• High Al, Low R - Primary aldosteronism
• High Al, High R - Secondary Hyperaldosteronism: malignant HT, renovascular HT, Renin-secreting tumor
• Low Al, Low R - Pseudo-hyperaldosteronism: exogenous mineralocorticoids, glycyrrhizic acid, Liddle's Syndrome, Congenital Adrenal Hyperplasia
• Normal Al, Normal R - Cushing's syndrome
Normotensive:
• UCl- <20 mEq/24 h - Vomiting, Nasogastric drainage, Post-hypercapnia
• UCl- >20 mEq/24 h - Diuretics, Bartter's syndrome, Gitelman's syndrome
#Hypokalemia #Differential #Diagnosis #Algorithm #nephrology #causes #low #potassium
Hypokalemia - Differential Diagnosis Algorithm
Transcellular Shift:
• Alkalosis
• ↑ beta-2 adrenergic simulation
• Erythropoiesis (B12 injections in pernicious anemia)
• G-CSF
• Hypokalemic periodic paralysis
• Refeeding syndrome
• Thyrotoxicosis
Medications
Renal Losses
Non-renal losses:
• GI losses (NG suction, diarrhea, vomiting)
• Low K intake (anorexia, dementia, starvation, TPN)
• Transcellular shifts
• Discontinued diuretic
Matthew Ho, MD PhD @MatthewHoMD
#Hypokalemia #Differential #Diagnosis #Algorithm #nephrology #low #potassium
Causes of Hypokalemia - Differential Diagnosis Algorithm
Defining the cause of hypokalemia starts by measuring urinary K level. If inappropriately increased, the existence of hypertension suggests either secondary or primary hyperaldosteronism. Clinicians should also look for excess glucocorticoids.
• Skin and/or gastrointestinal K loss
• Renal K loss
• Hypomagnesemia-induced hypokalemia
• Renal tubular acidosis (type 1 of 2), Ureterosigmoidostomy, Diabetic ketoacidosis
• Vomiting, Nasogastric drainage, Post-hypercapnia
• Diuretics, Bartter's syndrome, Gitelman's syndrome
• Primary Hyperaldosteronism
• Secondary Hyperaldosteronism: malignant HT, renovascular HT, Renin-secreting tumor
• Pseudo-hyperaldosteronism: exogenous mineralocorticoids, glycyrrhizic acid, Liddle's syndrome, Congenital adrenal hyperplasia
• Cushing's syndrome
#hypokalemia #differential #diagnosis #algorithm #causes #nephrology #potassium
Pragmatic diagnostic algorithm for hypokalemia.
***Typical presentations:
• Vomiting: urine Na/Cl > 1.6, low urine Cl;
• Laxative: urine Na/Cl < 0.7, high urine Cl;
• Active diuretic use: similar to tubulopathy;
• Tubulopathy: urine K/creatinine (Cr) > 2.5 mmol/mmol, with urine Na/Cl ~1. Tubulopathy may be confirmed via genetic testing
*If hypokalemia seems disproportionately severe to the dose of diuretic,
one may still consider aldosterone excess.
**Ideally, after correcting serum potassium levels, with the patient not taking mineralocorticoid
receptor antagonists. Other medications, including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers, may be continued in most cases; interpretation is dependent upon local laboratory methods and reporting.137,138
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