Electrolytes Flashcards
Describe the normal range for sodium levels in the body.
135-145.
What is the main organ affected by changes in sodium levels?
CNS.
What are the main CNS manifestations of abnormal sodium levels?
Confusion, convulsion, coma.
What is the most common cause of hypernatremia?
Diabetes Insipidus.
What is the most common cause of hyponatremia?
SIADH.
What is the recommended fluid for treating hyponatremia?
Normal saline (0.9%).
What should be used for hyponatremia with confusion or seizure?
Hypertonic saline (3%).
What is the treatment for hyponatremia with severe neurological manifestations?
Hypertonic saline (3%).
What neurological condition can result from rapid correction of hyponatremia?
Central pontine myelinolysis leading to quadriplegia.
Describe the normal range for potassium levels in the body.
3.5-5.
What EKG changes are seen in hyperkalemia?
Hyper-acute T-wave (tall T-wave), wide QRS, prolonged PR.
What is the first-line treatment for hyperkalemia with EKG changes?
Calcium gluconate.
What should be administered first for hyperkalemia with severe chest pain, dyspnea, or palpitations?
Calcium gluconate.
What is the initial treatment for hyperkalemia with potassium levels above 7?
Calcium gluconate.
What is the treatment for hyperkalemia below 7 without EKG changes or manifestations?
Insulin and glucose.
How can potassium levels be rapidly decreased?
With insulin and glucose.
What is the only drug that removes potassium from the body?
Kayexalate (resonium).
What is the recommended treatment for hyperkalemia in end-stage renal disease patients?
Dialysis.
What action should be taken if potassium levels are less than 6?
Stop the offending drug only.
Describe the treatment for emergency hypercalcemia.
IV fluids and diuretics.
What is the first presentation of hypocalcemia?
Peri-oral numbness.
What is the cause of hypocalcemia following total thyroidectomy?
Hypoparathyroidism due to removal of all 4 parathyroid glands.
If a patient develops perioral numbness after surgery but total calcium levels are normal, what could be the cause?
Hypocalcemia.
Describe the treatment for hypocalcemia requiring rapid correction before surgery.
IV calcium is administered.
What is the long-term treatment for hypocalcemia?
Calcium plus vitamin D.
What is the initial step in managing tetany caused by hyperventilation?
Breathing into a bag.
How is hypocalcemia tetany managed if it persists after breathing into a bag?
With calcium gluconate.
Define the cause of decreased total calcium but not ionized calcium due to hypoalbuminemia.
No tetany.
Hypocalcemia: Practice Essentials, Pathophysiology …
Medscape
https://emedicine.medscape.com › Nephrology
10 Nov 2022 — Patients with a decrease in total serum calcium may not have “true” hypocalcemia, which is defined as a decrease in ionized calcium. A reduction …
What is the diagnosis for a post-operative patient on TPN who develops a skin problem?
Zinc deficiency.
What is the most common cause of zinc deficiency?
TPN.
Describe the diagnosis for a patient with hyponatremia, increased urine Na, and osmolarity.
SIADH.
What is the most common drug causing SIADH?
Carbamazepine.
What is the most common cancer causing SIADH?
Small cell lung cancer.
How can any neurological insult lead to SIADH?
By causing a disruption in the body’s fluid balance.
In SIADH, how do the serum osmolarity, urine osmolality, and urine sodium concentration change?
Serum osmolarity decreases, urine osmolality increases, urine sodium concentration increases.
In Diabetes insipidus, how do the serum osmolarity, urine osmolarity, and urine sodium concentration change?
Serum osmolarity increases, urine osmolarity decreases, urine sodium concentration decreases.
What are the treatment options for hyponatremia in SIADH based on severity?
Mild: fluid restriction, Moderate: normal saline plus diuretics, Severe or with CNS manifestations: hypertonic saline (3%).
What is the initial step in managing a child with meningitis who develops a seizure and hyponatremia?
Administer hypertonic saline (3%).
What is the diagnosis for a patient with hypernatremia, decreased urine Na, and osmolarity?
DI (Diabetes insipidus).
What is the most common drug causing Diabetes insipidus?
Lithium.
What is the diagnosis for a patient with hyponatremia, decreased urine Na, and osmolarity?
Psychogenic polydipsia.m
Psychogenic polydipsia, also known as primary polydipsia, involves excessive water intake driven by psychological factors. Key factors to know include:
- Symptoms: Excessive thirst and fluid intake, leading to polyuria (excessive urination).
- Risks: Can cause water intoxication, hyponatremia (low sodium levels), and associated symptoms like confusion, seizures, or coma.
- Diagnosis: Differentiation from diabetes insipidus and other causes of polyuria; involves water deprivation tests and psychiatric evaluation.
- Management: Fluid restriction, addressing underlying psychiatric conditions, and monitoring electrolytes.
For more details, refer to the RACGP guidelines.
Describe how to differentiate between diabetes insipidus (DI) and psychogenic polydipsia using the H2O deprivation test.
Normalization of lab values after the test indicates psychogenic polydipsia, while no normalization and low urine osmolality indicate DI.
Do you determine the diagnosis of syndrome of inappropriate antidiuretic hormone secretion (SIADH) in a patient with hyponatremia, increased urine sodium, and osmolarity?
Yes, those criteria suggest SIADH.
Define the diagnosis of diabetes insipidus (DI) in a patient with hypernatremia, decreased urine sodium, and osmolarity.
DI is the likely diagnosis.
How do you assess acid-base balance in a patient?
The first step is to assess pH levels, followed by evaluating CO2 and HCO3 levels for respiratory or metabolic changes.
When does a patient require IV calcium administration?
IV calcium is needed when the patient is symptomatic, has serum calcium below 1.9 mmol/L, or rapid correction is necessary before an operation.
What is the normal range for urine osmolarity?
The normal range for urine osmolarity is 500-800 mOsm/kg.
