T3 - Renal Assessment Flashcards
~_____% TBW is water (varies w/ _____, ______, _____ %)
- 60%
- gender, age, body fat
Slide 3
ECF- fluid outside of cells ( _____ + _______) = < 1/2 volume of TBW
ISF +Plasma
Slide 3
How is osmolar homeostasis primarily mediated?
Osmolality sensors in the anterior hypothalamus
Slide 3
What is the path created by the hypothalamus to regulate osmolar homeostasis?
- Stimulate thirst
- Cause pituitary release of vasopressin (ADH) (To retain fluid)
- Cardiac atria release ANP (will act on kidney to decrease Na/H2O reasbsorption) (to get rid of fluid)
Slide 3
How is volume homeostasis mediated?
Mediated by juxtaglomerular apparatus
Slide 3
What are the changes caused by the JGA?
- JGA senses a decrease in volume
- JGA triggers Renin-Angiotensinogen-Aldosterone system
- RAAS causes Na+/H2O reabsorption
Slide 3
What would be concerning when it comes to Na levels and surgery?
Acute changes
≤125 or ≥155
Correct prior to elective cases
Slide 4 notes
In hypovolemia, what fluid and Na abnormality would you expect?
What could be some causes?
- Na and H2O loss
- Diuretics, GI loss, burns, trauma
Slide 4 notes
What could cause sodium decrease in a euvolemic state?
- Salt restriction
- Endocrine-related: hypothyroid, SIADH (retaining H2O more than Na)
Slide 4
What disease processes could cause hyponatremia in a hypervolemic state with a urine Na >20?
- ARF/CKD
- Heart failure
Slide 4 notes
What percentage of hospitalized patients are considered hyponatremic?
What could be a cause?
- 15%
- Over fluid-resuscitation
- ↑ endogenous vasopressin
Slide 4 notes
Clinical neurological presentation of hyponatremia: 130-135 mEq/L
- Asymptomatic
- Headache
- Nausea
- Vomiting
- Fatigue
- Confusion
- Muscle cramps
- Depressed reflexes
*Bold are individual to this category and are not repeated in the next category
Slide 5
Clinical neurological presentation of hyponatremia: 120-130 mEq/L:
- Malaise
- Unsteadiness
- Headache
- Nausea
- Vomiting
- Fatigue
- Confusion
- Muscle cramps
*Bold are individual to this category and are not repeated in the other categories
Slide 5
Clinical neurological presentation of hyponatremia: <120 mEq/L
- Headache
- Restlessness
- Lethargy
- Seizures
- Brain-stem herniation
- Respiratory arrest
- Death
*Bold are individual to this category and are not repeated in the other categories
Slide 5
Which are the most severe consequences of hyponatremia:
- Seizures
- Comma
- Death
Slide 5
What is the single most important for the treatment of hyponatremia?
What are some treatment options?
- Treat underlying cause (look at volume status)
- Electrolyte drinks
- Normal saline
- Diuretics
- Hypertonic saline/3% NaCl
Slide 6
What should the infusion rate be when treating hyponatremia with 3% NaCl hypertonic solution?
What should the Na correction not exceed?
- 80 ml/hr over 15h
- Correction should not exceed 1.5 mEq/L/hr
Slide 6
What could happen with rapid correction of hyponatremia?
How fast would you have to correct in order to achieve this adverse effect?
Is this a serious or reversible adverse effect?
- Osmotic Demyelination Syndrome
- You’d have to correct >6 mEq/L in 24h
- Serious - often permanent neuro damage
Slide 6
Are hyponatremic seizures a medical emergency?
How would you treat this?
- Yes! neurological damage could occur
- 3-5 ml/kg of 3% over 20 min until seizures resolve
Slide 6
What are some causes of HYPERnatremia?
- Diabetes insipidus
- Excessive evaporation
- Poor oral intake (very young, very old, altered mental status)
- Overcorrection of hyponatremia
- GI losses
- Excessive sodium bicarb (treating acidosis)
Slide 7
HYPERnatremia diagnostic algorithm
Hypovolemia
S/S:
- Urine Na >20:
- Urina Na <20:
Treatment:
PPT notes: Renal or GI loss
S/S: Decreased skin turgor, flat neck veins, dry mucous membranes, orthostatic hypotension, tachycardia, oliguria
Urine Na >20: Renal salt and water loss
- Osmotic diuretic
- Loop diuretic
- Postrenal obstruciton
- Intrinsic recall disease
- Profound glycosuria
Urine Na <20: Extrarenal salt and water loss
- Diarrhea
- GI fistulas
- Sweating
Treatment: Normal saline
Slide 8/9
HYPERnatremia diagnostic algorithm
Euvolemia
- Urine Na ______?
Treatment:
Urine Na variable
Renal water loss:
- Diabetes insipidus: Central, nephrogenic, gestational
Extrarenal water loss:
- Insensible losses: Respiratory tract; Skin
Treatment: water replacement (po or D5W)
Slide 8
HYPERnatremia diagnostic algorithm
Hypervolemia
S/S
Urine Na >20:
Treatment:
S/S: Peripheral edema, rales, ascites
Urine Na >20: Sodium gains
- Hyperaldosteronism
- Cushing’s syndrome
- Hypertonic dialysis
- IV NaHCO3
- NaCl tablets
- Hyperalimentation
- Salt water drowning
Treatment: diuretics
Slide 8/9
What are common symptoms of HYPERnatremia?
LORDTS (Madea’s voice)
- Lethargy
- Orthostasis
- Restlessness
- Death
- Tremor/muscle twitching
- Seizures
How would you treat HYPERnatremia in hypovolemic, euvolemic, or hypervolmeic states?
Root cause, Assess volume status (VS, UOP, Turgor, CVP)
- Hypovolemic: normal saline
- Euvolemic: water replacement (po or D5W)
- Hypervolemic: diuretics
Slide 9
How fast do you want to reduce Na levels for correction?
Why would you want to correct at this rate?
≤ 0.5 mmol/L/hr and ≤ 10 mmol/L/day
- To avoid cerebral edema, seizures, and neurological damage
What is the percentage of the major intracellular fluid (ICF) cation (K+) that is present in the extracellular fluid (ECF)?
Less than 1.5% of the major intracellular fluid cation is present in the extracellular fluid.
Does serum potassium (K+) reflect transmembrane K+ regulation or total body K+ more accurately?
Serum potassium (K+) reflects transmembrane K+ regulation more than total body K+.
What is the effect of aldosterone on potassium and sodium in the distal nephron?
Aldosterone causes the distal nephron to secrete potassium (K+) and reabsorb sodium (Na+).
How does renal failure affect potassium excretion?
In renal failure, potassium excretion declines and excretion shifts towards GI system.
When renal potassium excretion declines, where does the excretion shift towards?
When renal potassium excretion declines, excretion shifts towards the gastrointestinal (GI) system.
What dietary issue can cause low serum potassium?
Low PO intake
By which 2 ways mentioned in the PPT can we lose K+ through the kidneys?
Diuretics use and hyperaldosteronism can cause renal loss of potassium.
How can gastrointestinal issues lead to low potassium?
Nausea, vomiting, diarrhea, and malabsorption can cause gastrointestinal loss of potassium.
Which conditions lead to an intracellular shift of potassium?
Alkalosis, the use of β-agonists, and insulin administration can cause an intracellular shift of potassium.
Which medical condition related to diabetes can cause low serum potassium? How?
Diabetic ketoacidosis (DKA) can lead to low serum potassium due to osmotic diuresis.
Which type of blood pressure medication can lead to a decrease in potassium?
Hydrochlorothiazide (HCTZ) found in some blood pressure medications.
What unusual dietary source can lead to low potassium levels?
Excessive consumption of licorice.
What are general types of symptoms seen in hypokalemia?
Generally cardiac and neuromuscular symptoms.
What muscular symptoms can hypokalemia cause?
Muscle weakness and cramps.
What is ‘Ileus’ in the context of hypokalemia?
A disruption of the normal propulsive gastrointestinal motor activity due to hypokalemia.
How does hypokalemia affect the heart?
It can cause dysrhythmias and U waves on an EKG.
What is the typical rate for IV potassium replacement?
Generally 10-20 mEq/L per hour IV.
What is the preferred route of potassium administration for treating hypokalemia?
Potassium orally is preferred over intravenous; central venous catheter (CVC) may be used; treatment may require several days.
What is the effect of 10 mEq IV potassium on serum levels?
Each 10 mEq of IV potassium can raise the serum potassium by approximately 0.1 mmol/L.
What treatments or actions should be avoided in hypokalemia?
Avoid excessive insulin, β-agonists, bicarbonate, hyperventilation, and diuretics.
What are renal-related causes of hyperkalemia?
Renal failure and hypoaldosteronism (causes K+ secretion and excretion)
Which type of drugs affecting the renin-angiotensin-aldosterone system (RAAS) can cause hyperkalemia?
Drugs that inhibit RAAS and drugs that inhibit K+ excretion
How can neuromuscular blocking agents affect potassium levels?
Depolarizing NMBs like Succinylcholine (Succs) can cause hyperkalemia by increasing serum K+ by 0.5 to 1 mEq/L
*mEq is used interchangibly in monovalent ions just fyi
ChatGPT:
For monovalent ions (those with a charge of +1 or -1), like potassium (K+), sodium (Na+), chloride (Cl-), and bicarbonate (HCO3-), 1 mmol/L is equivalent to 1 mEq/L because their valence is 1.
However, for divalent ions (those with a charge of +2 or -2), like calcium (Ca2+), magnesium (Mg2+), and sulfate (SO4^2-), the situation is different. For these ions, 1 mmol/L is equivalent to 2 mEq/L because their valence is 2. Therefore, when converting concentrations for divalent ions, the concentration in millimoles is multiplied by 2 to get the concentration in milliequivalents.
What role does acidosis play in potassium balance?
Both respiratory and metabolic acidosis can lead to hyperkalemia.
Which conditions associated with cell damage can lead to hyperkalemia?
Cell death from trauma, use of tourniquets, and massive blood transfusion.
What neuromuscular symptoms can occur with hyperkalemia?
Skeletal muscle paralysis and decreased fine motor skills.
How does hyperkalemia affect the heart?
It can cause cardiac dysrhythmias.
What are the EKG progression signs of hyperkalemia?
- Peaked T waves
- P wave disappearance
- Prolonged QRS complex
- Sine wave formation
- Asystole
When should you dialyze a hyperkalemic patient before surgery?
Dialyze within 24 hours prior to surgery.
What is the first initial treatment for hyperkalemia and why?
Calcium is given to quickly stabilize the cell membrane.
How does hyperventilation affect serum potassium levels?
Increasing the pH by 0.1 can decrease K+ by 0.4-1.5 mmol/L.
What is the role of insulin and glucose in treating hyperkalemia?
Insulin 10 units IV + glucose 25g D50 —> lower K+ levels in 10-20 minutes.
What is the role of bicarbonate in managing hyperkalemia?
Bicarbonate can help shift potassium into cells by increasing blood pH, reducing serum levels.
How does Kayexalate work in treating hyperkalemia?
Kayexalate binds to K in digestive tract and removes potassium from the body, working over hours to days.
What should be avoided in the management of hyperkalemia?
- Avoid using Succinylcholine (0.5-1 mEq/L increase)
- Hypoventilation (decreased pH=increased K)
- Lactated Ringer’s solution (will also decrease pH=increased K)
- Potassium-containing IV fluids.
What is the distribution of calcium in the body?
Only 1% of the body’s calcium is in the extracellular fluid (ECF); 99% is stored in bones.
Which form of plasma calcium is physiologically active?
Only ionized plasma calcium (Ca++) is physiologically active, not protein-bound calcium.
What are the normal levels of ionized calcium (iCa++) in the blood?
Normal iCa++ levels range from 1.2 to 1.38 mmol/L.
How are ionized calcium levels affected by albumin and pH?
- 60% plasma Ca++ is protein bound (mainly to albumin)
- pH changes influence the binding of Ca++ to albumin
Increase in pH/alkalosis=Increased Ca++ binding to albumin, therefore a decrease in plasma Ca++
Which hormone increases gastrointestinal absorption, renal reabsorption of calcium, and pulls calcium from bone?
Parathyroid hormone (PTH) increases GI absorption, renal reabsorption, and mobilizes calcium from bone.
What role does vitamin D play in calcium regulation?
Vitamin D augments intestinal calcium absorption.
How does calcitonin affect calcium levels?
Calcitonin promotes bone resorption, which decreases plasma calcium levels.
Aldosterone _________ effects K+
inversely
3 major categories of cause of hypokalemia?
Renal loss
GI loss
Transcellular shift
Aldosterone causes K+ ________ & ________
secretion & excretion
Succinylcholine increases serum K+ by __________
0.5-1 mEq/L
Dialysis ALSO initially causes ___________
Hypovolemia
pH Δ’s influence the ____________ of Ca++ to albumin
binding
___% plasma Ca++ is protein bound (mainly to _________)
- 60
- Albumiin
↑pH/Alkalosis leads to ↑Ca++ binding to albumin
Therefore, there will be a ________ in plasma iCa++
decrease
What can cause a decrease in parathyroid hormone (PTH) secretion leading to hypocalcemia?
complication of thyroid or parathyroid surgery.
How does magnesium deficiency affect calcium levels?
Magnesium deficiency can lead to hypocalcemia as magnesium is required for PTH production
What role does vitamin D play in calcium levels?
Low vitamin D or disorders of vitamin D metabolism can lead to hypocalcemia due to reduced calcium absorption from the gut.
How does renal failure contribute to hypocalcemia?
Renal failure can cause hypocalcemia due to the kidneys not responding to PTH effectively.
The citrate preservative in blood products can bind calcium, leading to hypocalcemia.
What are the target sites of PTH action to increase calcium absorption?
PTH acts on:
- The bones to mobilize calcium
- The kidneys to increase calcium reabsorption
- The gastrointestinal system to enhance calcium absorption
Why is magnesium important for PTH function?
Magnesium is essential for the production and secretion of PTH.
What is the role of Vitamin D in calcium homeostasis?
Vitamin D facilitates gastrointestinal absorption of calcium.
When should ionized calcium (iCa++) levels be checked in the context of blood transfusions?
Check iCa++ after transfusing 4 or more units of packed red blood cells (PRBCs), as you may need to administer calcium to counteract the binding effects of citrate in transfused blood.
What are neurological symptoms of hypercalcemia?
Confusion and lethargy.
How does hypercalcemia affect muscle tone and reflexes?
Causes hypotonia and decreased deep tendon reflexes (↓DTR).
What are gastrointestinal symptoms of hypercalcemia?
Abdominal pain and nausea/vomiting (N/V).
What is a characteristic EKG change in hypercalcemia?
Short QT interval (QT-I).
What chronic condition can result from elevated calcium levels?
hypercalciuria and nephrolithiasis.
What sensations are typical in hypocalcemia?
Paresthesias.
What behavioral changes might indicate hypocalcemia?
Irritability.
How can hypocalcemia affect blood pressure?
Hypocalcemia can cause hypotension (HoTN).
What are severe neurological symptoms of hypocalcemia?
Seizures and myocardial depression.
What is a characteristic EKG change in hypocalcemia?
Prolonged QT interval (QT-I).
What is a life-threatening complication of hypocalcemia post-parathyroidectomy?
Hypocalcemia-induced laryngospasm
Extra caution when extubating parathyroidectomy, always have ____________ plan
Larangospasm
What dietary issues can lead to hypomagnesemia?
Low dietary intake or poor absorption can cause hypomagnesemia.
How can renal function affect magnesium levels?
Renal wasting can lead to hypomagnesemia.
What are muscular symptoms of hypomagnesemia?
Muscle weakness or excitation can occur.
What are the neurological effects of hypomagnesemia?
Seizures may be a symptom of hypomagnesemia.
What cardiac dysrhythmia is associated with hypomagnesemia?
Polymorphic V-tach or
Torsades De Pointes
Where are the kidneys located?
Retroperitoneal T12-L4
Right is slightly caudal to the left to accommodate liver
How common is hypermagnesemia and what are its usual causes?
Hypermagnesemia is very uncommon and is generally due to:
Overtreatment
- Pre-eclampsia/eclampsia
- Pheochromocytoma
What symptoms are associated with magnesium levels of 4-5 mEq/L?
Lethargy, nausea/vomiting (N/V), and flushing.
What symptoms appear when magnesium levels exceed 6 mEq/L?
Hypotension (HoTN) and decreased deep tendon reflexes (↓DTR).
What are the severe symptoms of magnesium levels over 10 mEq/L?
Paralysis, apnea, heart blocks, and cardiac arrest.
What are the treatment options for hypermagnesemia?
diuresis
intravenous calcium (to stabilize cell membranes)
dialysis.
What is the nephron?
The nephron is the primary structural and functional unit of the kidney. Each kidney contains approximately 1 million nephrons.
What are the main components of a nephron?
A nephron consists of the:
* glomerulus, tubular system
* Bowman’s capsule
* proximal tubule (PCT)
* loop of Henle
* distal tubule (DCT)
* collecting duct.
What percentage of cardiac output does the kidney receive?
The kidneys receive 20% of the cardiac output (COP).
The kidneys filter 1 to 1.25 liters of blood per minute (L/min).
What is the outer layer of the kidney called and what percentage of renal blood flow (RBF) does it receive?
The outer layer is called the cortex, and it receives the majority of renal blood flow, about 85-90%.