Electrolyte Disorders

Dom Colao, DO

November 2011

Review of Electrolyte disorders

• HypoNatremia

• Hypernatremia

• HypoKalemia

• HyperKalemia

• Calcium

• Magnesium

• Phosphorus

Overview of Disorders

• The differential for any lab abnormality:– Lab error

• Lab error– Lab error

– Polypharmacy– Iatrogenic– Real disease

• In that order!

Always consider the potential for a confounding variable

• Was the blood drawn above a running IV?

• Did it sit too long before the test was run?

• Is it your patients blood?

• Is there a pattern of abnormalities in numerous patients on the same day?

Over view of Sodium Disorders

• Pseudo-hyponatremia– Due to high concentrations of other solutes

in the blood - Mannitol in a pt with cerebral edema, Glucose in a diabetic.

• Then look at the patient’s volume status

• Hypervolemic/Euvolemic/Hypovolemic

Hyponatremia

• Hypervolemic:

• HypOvolemic:

• Euvolemic:

Hyponatremia

• Hypervolemic:– CHF, – Cirrhosis, – Pregnancy, – Nephrotic syndrome– In these conditions, total body sodium is up, but

total body WATER is up even more.– Due to reduced Effective Arterial Blood Volume,

(EABV) leading to increased ADH secretion.

Hyponatremia

• Hypervolemic:– CHF, Cirrhosis, Pregnancy, Nephrotic syndrome

• HypOvolemic:– GI losses (diarrhea, Vomiting, NG suction)– Renal Losses (diuretics, Salt wasting nephropathy,

recovery phase from ATN or obstruction).– Due to true depletion of water and sodium, leading

to increased secretion of Aldosterone AND ADH

Hyponatremia

• Hypervolemic:– CHF, Cirrhosis, Pregnancy, Nephrotic syndrome

• HypOvolemic:– GI losses (diarrhea, Vomiting, NG suction)– Renal Losses (diuretics, Salt wasting nephropathy,

recovery phase from ATN or obstruction).

• Euvolemic:– Medication effects, Endocrine syndromes,

Excessive water intake, reset osmostat, SIADH

Hyponatremia

• Euvolemic:– Medication effects

• ACE/ ARB/Tekturna/Spironolactone/HCTZ• Antidepressant and antipsychotic meds• NSAID’s

– Endocrine syndromes• Hyper and Hypo thyroid, • Adrenal insufficiency and excess (addison’s / Cushings)

– Excessive water intake, • Psychogenic polydipsia, beer potomania

– reset osmostat, • Seen in conditions which stimulate tonic ADH secretion from tissues

which have Neuroectoderm (brain and Lung)

– SIADH

Hyponatremia

• Euvolemic:– reset osmostat,

• Seen in conditions which stimulate tonic ADH secretion from tissues which have Neuroectoderm (brain and Lung)

• Pneumonia, COPD, stroke, brain hemorrhage.• These conditions result in a stable low level of sodium, around

which water and sodium regulation are functioning normally, but at a new lower setting.

• Confirmed by water loading test.

– SIADH - Persistant high production of ADH which does not suppress in the face of water load, usually due to a tumor such as small cell lung carcinoma or brain tumor.

Case 1, Hyponatremia

Case 1b Hyponatremia

Case 1c, Hyponatremia

Pieces of metal in abdominal wall

Can you guess what she swallowed?

Case 2a Hypernatremia

Case 2b Hypernatremia

Case 3a Hypokalemia

Case 3a Hypokalemia

Case 3 b, Hypokalemia

Case 3 b, Hypokalemia

Case 4 Hyperkalemia

Case 4 Hyperkalemia

Case 4 Hyperkalemia

Case 5, Hypercalcemia

Case 6 Hypocalcemia

Case 6 Hypocalcemia

Case 7, Hypomagnesemia

Case 7, Hypomagnesemia

Case 8 Hypermagnesemia

• Hypermagnesemia is seen only in patients with renal failure who are supplemented,

• or in cases where large amounts of magnesium are infused.

Case 9, Hypophosphatemia

Case 9 Hyperphosphatemia• Classic presentation of Hypophosphatemic

rhabdomyolysis.• Prolonged NPO status/starvation• Resp failure requiring reintubation after extubation

or surgery. Due to resp muscle weakness.• Phos goes very low, then suddenly climbs without

any supplementation. Associated with high K and Low calcium.

• Creatinine climbs more than 1.0 mg/dl/day, suggesting increased creatinine production

Reference

• Narins. Fluid and Electrolyte Disorders: Am journal of Medicine, 1982