module 10: excretory system disorders Flashcards
Define obstructive uropathy. Give examples of what can cause this condition.
- obstructive uropathy = anatomic changes in the urinary system caused by obstruction
- examples:
- kidney stones
- compression from tumour
- inflammation
Describe the two most damaging effects of urinary tract obstruction
- stasis of urine
- increases the possibility of infection and stone formation
- progressive dilation of the renal collecting ducts and tubules
- glomerular filtration continues = pressure build-up in the renal pelvis, then tubules
Describe compensatory hypertrophy and hyperfunction
- if one kidney is obstructed, the body can compensate
- the unobstructed kidney can increase the size of individual glomeruli and tubules is increased.. NOT total number of functioning nephrons
Define “calculi”. What are the most common stones composed of and where can they be located?
- calculi = kidney stones
- most common cause of upper urinary tract construction
- composed of:
- calcium oxalate
- phosphate
- located:
- kidneys
- ureters
- urinary bladder
What 2 conditions can lead to the formation of calcium oxalate or phosphate kidney stones?
- hyperabsorption of calcium
- hyperparathyroidism
Describe the two types of pain that can be experienced as a result of kidney stones and give the probable location of the stone for each type of pain
- renal colic = excrutiating pain in the flank and abdomen
- caused by a 1-5mm stone moving into the ureter
- dull, deep, mild to severe ache = in flank or back
- caused by a stone in the renal pelvis or calyces
How are urinary calculi treated?
- removing stones
- managing pain
- reduction of further formation through increasing fluid flow
- altering diet
To what is lower urinary tract obstruction primarily related?
storage of urine in the bladder or emptying of urine through the bladder outlet
Describe neurogenic bladder – what does the type of dysfunction depend upon?
- bladder dysfunction caused by neurologic disorders
- depends upon where damage has occurred in the nervous system
- CNS vs peripheral nerves
Name two physical obstructions of the lower urinary tract
- scarring of the urethra
- enlarged prostate
Define glomerulonephritis. What is the most common contributing factor?
- inflammation of glomerulus caused by immunologic responses, infection, diabetes Mellitus, etc
- hypertension is most common contributing factor
Identify the two common immune mechanisms that can lead to glomerulonephritis and a common disease that is associated with each.
- type III:
- post-streptococcal = can start to make antibodies/complexes to go in glomeruli and deposit in glomeruli
- type II:
- Goodpasture syndrome = creates antibodies that bind to capillaries/ glomerulus themselves
Describe the series of steps in the development of glomerulonephritis as caused by the immune mechanisms.
- Ab activate complement proteins = rush of macrophages and neutrophils
- compounds are secreted to damage glomerular cells = increased glomerular permeability
- increased glomerular permeability = proteins and RBC escape into the filtrate
- proteinuria and/or hematuria develops
Define glomerular filtration rate. How is it usually estimated?
- the production of filtrate by the glomerulus
- typically 125 ml/min
- estimated using serum creatinine concentration
Describe nephritic syndrome, naming the disorder that is the usual cause.
- sudden excretion of blood cells, protein, diminished GFR, oliguria
- caused by inflammation that blocks the glomerular capillary lumen and damages the capillary wall
Describe nephrotic syndrome, naming a disorder that can be the cause
-
massive proteinuria
- excretion of 3.5 g or more per day
- caused by an increase in glomerular permeability
Define BUN. Identify and explain the two facts that it reveals about the state of the kidney.
- BUN = blood urea mitrogren
- concentrations of urea in the blood
- shows degree of:
- glomerular filtration
- urine-concentrating capacity
Identify and explain the one fact that the level of creatinine in the plasma reveals about the state of the kidney.
- creatinine is produced by the muscles, is filtered at the glomerulus, and never reabsorbed
- the plasma creatinine concentration only indicates the amount of filtration that is occurring at the glomerulus (GFR)
Define AKI (include BUN and plasma creatinine). Is this condition reversible?
- AKI = acute kidney injury
- sudden (less than 2 days) decline in kidney function with a decrease in glomerular filtration and accumulation of nitrogenous waste products in the blood
- potentially reversible
What do the letters in “RIFLE” represent in terms of acute kidney injury?
- R = risk
- I = injury
- F = failure
- L = loss
- E = end stage
What three criteria are used to establish the category of AKI in the RIFLE classification?
- risk
- injury
- failure
List the 3 causes of AKI – identify the most common one.
- prerenal acute kidney injury - most common
- postrenal acute kidney injury
- intrarenal acute kidney injury
What could cause prerenal AKI? What conditions could lead to this?
cause:
- renal hypoperfusion
conditions:
- renal vasocrontriction
- hypotension
- hypovolemia
- hemorrhage
- inadequate cardiac output
Why is the ratio of BUN to creatinine in the serum higher than normal with prerenal AKI?
urea increases disproportionately to creatinine due to enhanced proximal tubular reabsorption that follows the enhanced transport of sodium and water
With what does postrenal AKI usually occur? Give an example of one condition that would lead to this.
- urinary tract obstruction that affects both kidneys
- ex: prostatic hyperplasia
From what does intrarenal AKI usually result? What events/conditions would lead to this?
- tubular necrosis
- events:
- ischemia associated with prerenal failure
- sepsis
- nephrotoxic effects of drugs
Why is the serum BUN to creatinine ratio lower than normal with intrarenal acute kidney injury
Renal damage causes reduced reabsorption of BUN
What is vital in the treatment of AKI? What is the primary goal of therapy for AKI? What 3 areas of concern are addressed? What may finally be necessary?
- vital to determine and correct the cause of the kidney injury
- primary goal = maintain life until renal function had been recovered
- 3 areas of concern to address:
- correct fluid and electrolyte imbalances
- treat infections
- maintain nutrition
- continuous renal replacement therapy or hemodialysis may be required
Define chronic kidney disease. What diseases/conditions are risk factors?
- kidney damage of a GFR less than 60 ml/min for 3 months or longer
- risk factors:
- hypertension
- diabetes mellitus
- chronic glomerulonephritis
- obstructuve uropathies
What criteria is used to assess the stage of CKD?
- decreasing GFR, indicating increasing levels of kidney damage, ending in kidney failure
What does the intact nephron hypothesis propose and what is the significance to the appearance of CKD manifestations?
- proposes that the unaffected nephrons are capable of hypertrophy ad hyperfunction in their rates of filtration, reabsorption, and secretion, in order to make up for the declining GFR
- renal function decline to less than 35% of normal before CKD is apparent
Define azotemia.
increased levels of serum urea and other nitrogenous compounds
- can be asymptomatic
Define uremic syndrome (uremia).
the systemic signs and symptoms associated with the accumulation of nitrogenous wastes and toxins in the plasma brought about through kidney failure
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how sodium is affected
- the kidney loses its ability to regulate sodium and water = both retained = edema
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how potassium is affected
in later stages, potassium is not secreted sufficiently and can increase to life-threatening levels
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how creatinine and urea is affected
levels in the plasma increase as GFR decreases
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how metabolic acidosis is affected
the kidney’s ability to secrete hydrogen ions and reabsorb bicarbonate ions is decreased
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how calcium is affected
- less calcium is absorbed from the GIT
- detected by parathyroid gland = increased levels of PTH
- increased levels of PTH = loss of calcium from the bone = increases the risk of bone fracture
Fluid, electrolyte and acid/base balance are disturbed by CKD. Describe how proteins and fat is affected
- advanced CKD causes decreases in amount of proteins
- also a shift in the ratio of LDL/HDL, with more LDL = increased atherosclerosis
Define anasarca.
a general accumulation of fluid in body cavities and tissues
Describe the effects (and their causes) on each of the following body systems: cardiovascular
- major cause of death in CKD
- excess sodium and water lead to hypertension
- excess LDL leads to increased atherosclerosis
Describe the effects (and their causes) on each of the following body systems: pulmonary
- complications associated with fluid overload
- acidosis results in Kussmaul respirations
Describe the effects (and their causes) on each of the following body systems: hematologic
anemia impaired platelet function
Describe the effects (and their causes) on each of the following body systems: immune
overall suppression by high levels of urea and metabolic wastes
Describe the effects (and their causes) on each of the following body systems: neurologic
- numerous effects of uremic toxins, including both peripheral and central nervous systems
- restless leg syndrome
- muscle atrophy
- headache
- impaired concentration
- seizures
- coma
Describe the effects (and their causes) on each of the following body systems: gastrointestinal
- anorexia, vomiting possibly due to breakdown of urea by intestinal bacteria
Describe the effects (and their causes) on each of the following body systems: endocrine and reproductive
- decrease in levels of sex steroids bring symptoms such as impotence, amenorrhea
- insulin resistance can occur, as well as alterations in thyroid hormone metabolism
How is CKD evaluated? How is it treated?
- evaluated
- elevated serum creatinine and BUN levels
- protein in urine, particularly albumin
- confirmed by renal biopsy
- management
- dietary control to replace/restrict appropriate factors
- drugs to treat hypertension
- dialysis and renal transplantation
Describe the use of sodium in the body and how levels are regulated (with what compound’s levels are they associated? What hormones are involved?)
- important for water balance, conduction of nerve impulses, regulation of acid-base balance, some biochemical reactions, membrane transport
- regulation:
- sodium is coupled with water levels in the body
- sodium levels coupled with blood pressure and volume
- controlled by hormones that control reabsorption of water and sodium in the kidneys
What is the main effect of hypernatremia?
intracellular dehydration
Describe the main causes of hypernatremia.
- retention or therapeutic infusion of sodium
- retention can be caused by oversecretion of aldosterone or ACTH
- not usually caused by increased intake: higher amount of dietary sodium are eliminated by kidneys
- decreased intake or increased loss of water
- increased loss from respiratory tract
- normally would stimulate thirst and drinking
Describe the clinical manifestations of hypernatremia
- if due to sodium retention
- hypervolemia
- weight gain
- bounding pulse
- increased blood pressure
- if due to water loss
- headache
- thirst
- dry skin and mucous membranes
- increased temp
- weight loss
- hypovolemia
- tachycardia
- weak pulse
- for both
- thirst
- alterstions in membrane potential
- shrinking of nerve cells
- confusion, coma, and convulsions
What is the main effect of hyponatremia?
- decreased concentration of sodium ions in the blood
Describe the main causes of hyponatremia
- loss of sodium
- burns
- vomiting
- diarrhea
- excessive renal loss from diuretics
- insufficient aldosterone levels
- inadequate intake of sodium (rare)
- retention of water
- dilutional hyponatremia (most common cause)
What are the clinical manifestations of hyponatremia?
- changes in sodium concentration across the membrane alters the cell’s ability to depolarize and polarize normally
- causes neurological alterations
- lethargy
- apprehension
- confusion
- depressed reflexes
- seizures
- coma
- muscle twitching
- weakness
What is water intoxication?
drinking too much water in too short a period of time leads to neurological symptoms
How is potassium used in the body?
- fluid balance
- nerve impulse conduction
- some biochemical reactions
Describe the two main mechanisms for the regulation of potassium.
- by the kidney (main source of loss from the body)
- negative feedback release of aldosterone occurs in relation to serum potassium levels
- H+/K+ transporter that responds to increased serum potassium levels
- shifts across body cell membranes
- H+/K+ transporter in body cell membranes causes exchange of these ions
- ECF levels rise with acidosis/fall with alkalosis
- insulting also causes the uptake of K+
What are the causes of hyperkalemia?
- usually by renal disease
- increased intake (more likely through too rapid IV)
- a shift from intracellular to extracellular acidosis
- insulin deficits
- under secretion of aldosterone
What is the relationship between insulin and potassium?
insulin promotes the entry of potassium into cells
what is the relationship between aldosterone and potassium?
Aldosterone causes potassium to be excreted into the lumen by principal cells
Describe the manifestations of hyperkalemia
- decrease in neuromuscular excitability has several effects
- paresthesia with mild attacks
- loss of muscle tone
- paralysis with more severe attacks
- most serious effect is on the heart
- the decrease in membrane excitability produces changes in the conduction and repolarization of electrical signals in the heart
- severe hyperkalemia can cause ventricular fibrillation or cardiac arrest
Describe 3 causes of hypokalemia
- excessive loss of potassium
- diuretics
- metabolic acidosis
- increased aldosterone and cortisol (activates aldosterone receptors)
- inadequate intake
- increased entry into cells
What are the manifestations of hypokalemia?
- mild losses usually asymptomatic
- manifestations reflect body’s attempt to regulate ECF potassium levels, as well as potassium’s effect om excitable tissues
- urine output is increased - thirst and polyuria are common
- weakness, fatigue and muscle cramps
- most serious effects involve the heart
What are the uses of calcium in the body?
- major cation of bones and teeth
- many enzyme reactions
- muscle contraction
- release of neurotransmitters
- blood clotting
What is the relationship between calcium and sodium membrane transport?
reduces the sodium permeability
How is calcium regulated in the body?
- through vitamin D and parathyroid hormone
- absorption/secretion by bones
- kidney
- GIT
What is the main cause of hypercalcemia and to what is this due?
- increased bone resorption
- due to neoplasms or hyperparathyroidism
What are the manifestations of hypercalcemia?
- fatigue
- weakness
- lethargy
- hypoactive reflexes
- depression
- bizarre behaviour
- bradycardia/arrythmias
- nausea
- vomiting
- constipation
Name three causes of hypocalcemia
- decreased parathyroid hormone
- kidney disease
- alkalosis
- alkaline pH in plasma causes increased binding of calcium ions to proteins = decrease the amount of free calcium
What are the clinical manifestations of hypocalcemia?
- increased excitability of both muscles and nerves
- spasms
- tetany
- increased gi motility
- cardiovascular dysrhythmias
What are the uses of magnesium in the body?
- cofactor in many intracellular enzymatic reactions
- role in nerve conduction
- role in smooth muscle contraction and relaxation
What is the relationship between magnesium and calcium membrane transport?
high levels of magnesium inhibit calcium transport into the cell and release from SR
What are the clinical manifestations of hypermagnesemia?
- decreased excitability of both muscle and nerves
- hypoactive reflexes
- muscle weakness
- brachycardia
- respiratory distress
- nausea
- vomiting
What are the clinical manifestations of hypomagnesemia?
- increased excitability of both muscles and nerves
- increased reflexes
- muscle cramps and convulsions
- tachycardia
- behavioural changes
- irritability
What are 2 reasons for the necessity of correct pH in the body?
- hydrogen ion concentration is very important for the proper shape and function of proteins
- involved in metabolic reactions
What is the relationship between the excitement of the nervous system and pH?
- decreasing pH depresses the nervous system
- increasing pH overexcites the nervous system
What are the causes of metabolic acidosis?
- increase in H+
- concentrations of acids increase through increased production or ingestion, or kidneys can’t secrete excess H+
- decrease in HCO-3
- excessive bicarbonate is lost through Gi tract or kidney, or can’t be regenerated by the kidney
Describe some conditions that can result in metabolic acidosis?
- nervous system depression
- headache
- lethargy
- Kussmaul respirations
- deep and fast, as with exercise
- anorexia
- nausea
- vomiting
- diarrhea
- abdominal discomfort
Describe the clinical manifestations of metabolic acidosis
- nervous system depression
- kussmaul respirations
- anorexia
- nausea
- vomiting
- diarrhea
- abdominal discomfort
Describe the anion gap and its significance. Be able to calculate and interpret the anion gap.
- anion gap = an expected value that represents miscellaneous anions that are present due to miscellaneous anions that are present due to miscellaneous metabolic acids (H+)
- subtract the concentration of the anions (largest amounts of CI- and HCO-3) from the cations (largest amount of Na+)
- there may be metabolic acidosis, but the anion gap is normal = loss occurring of HCO-3 from the body
What are the causes of metabolic alkalosis?
- excessive loss of metabolic acids
- gain in bicarbonate
What are the clinical manifestations of metabolic alkalosis?
- weakness
- muscle cramps
- hyperactive reflexes
- confusion
- convulsions
- hypopolarized cells
- shallow/slow respirations
What is the relationship between H+ and plasma calcium concentration? Why does this affect the activity of the nervous system?
- decrease in H+ = increased pH - increased binding of Ca2 to c=plasma proteins = decrease Ca2 concentration = more Na allowed to cross membrane = hypopolarized cells
What is hypercapnia?
increase in plasma pCO2
Describe the causes and manifestations of respiratory acidosis.
causes
- depression of respiratory center
- disorders of respiratory muscles or lung tissue, etc
results
- CO2 easily crosses blood brain barrier and decreases pH of brain tissue
- headache
- blurred vision
- restlessness
- lethargy
- tremors
- convusions
- coma
Describe the causes and manifestations of respiratory alkalosis
causes
- pulmonary disease
- congestive heart failure
- high altitudes that increase breathing rate
manifestations:
- nervous system is stimulated
- dizziness
- confusion
- paresthesias
- convulsions
- coma
What are the two compounds that balance to maintain correct pH, and what are the systems that control the amounts of each of these compounds?
- CO2 & HCO3-
- respiratory system controls the levels of CO2 and therefore H+ levels
- excretory system controls the levels of HCO3-
what is compensation?
what is done to maintain the pH in response to disturbances
define partially compensated
one or the systems (respiratory or excretory) is attempting to rectify the disturbance but has not yet been successful, resulting in values for that system that are outside normal ranges
- action, but not fixed yet
define fully compensated
pH levels are within normal limits but values for both systems are outside of normal limits (in opposite directions)
- normal value, but there is still compensation
define corrected state
all values are within normal limits
What is meant by a mixed acid-base imbalance?
occasionally, two imbalances arise in the same person
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Identify the signs that specifically indicate that Ms. Bales is experiencing some degree of renal injury
Higher than normal BUN and creatinine
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Explain why glomerulonephritis can be ruled out as a cause of renal injury in this case.
No protein in the urine
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
If Ms. Bales produces 132 ml of urine over the first 6 hours after her admission, into which category of the RIFLE system does she fall? (Show your calculations: how many ml/h is she producing? How many ml/ h (over a 6 h period) would signify a category of risk for a person of her weight?). What is the medical term for the amount of urine that she is producing?
Information is given only for 6 hours, therefore, can make decision for only in “Risk” category, or not. She should be making at least 0.5 ml of urine for every kg of body weight every hour over the course of 6 hours
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Based on the described signs/symptoms, propose the class of the acute kidney injury that Ms. Bales is experiencing (i.e., pre-, intra-, post- renal (include the definition of each class)). Explain your conclusions with the use of abnormal signs/symptoms exhibited by Ms. Bales.
- Prerenal (a problem in blood delivery to the kidney).
- The diarrhea that she had for four days has left her dehydrated (supported by observation of poor skin turgor and dry mucous membranes). The dehydration resulted in a drop in blood volume, which caused a drop in blood pressure, which resulted in pre-renal AKI.
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Does the BUN:creatinine ratio support this conclusion? Explain the meaning of the BUN:creatinine ratio that you calculated in this case.
- The BUN / creatinine ratio is 40 mg/dl /1.9 mg/dl = 21. This is above the normal value of 20, which means the BUN is elevated more than values seen with other types of kidney injury.
- This is due to a pre-renal cause: lower blood delivery to the kidney = lower production of filtrate = slower flow of filtrate through the nephron = greater opportunity to reabsorb urea = elevated levels of BUN more than with other types of injury.
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
What is the state of Ms. Bales’ sodium balance? Explain the resultant mechanism that could lead to her dizziness.
She has hypernatremia. With more than normal amounts of sodium in the ECF, water moves out of cells, causing shrinking. The results of this is most easily seen in the nervous system.
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Identify the type of pH imbalance from which Ms. Bales is suffering and explain your conclusion
Metabolic acidosis
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
What is Ms. Bales’ anion gap? Does the value agree with her condition? Explain.
- Na+ - (HCO3- + Cl- ) = 12 mEq/L.
- This is within normal anion gap levels, therefore she must be losing bicarbonate from the body.
- This is consistent with her history of 4 days of diarrhea.
Ms. Bales is a 47 yr old female (54 kg) who presents to the emergency ward with a four day history of diarrhea. She is weak and dizzy, with pallor and sweating. She has poor skin turgor, with dry mucous membranes. Her HR is 115 bpm, BP is 95/60 mmHg, respirations 25/min and temperature is 38.7°C. Blood tests reveal a BUN value of 40 mg/dL, creatinine of 1.9 mg/dL, and a specific gravity of 1.040. No protein or glucose was found in the urine. An electrolyte analysis revealed: Na+ - 147 mEq/L, K+ - 4.5 mEq/L, Cl- - 115 mEq/L, while a blood gas assessment revealed an arterial pH of 7.2, pCO2 of 30 mmHg, and HCO3- of 20 mEq/L.
Is her pH balance corrected, compensated, partially compensated, or not compensated? Support your conclusion with facts from her case
The carbon dioxide level is decreased, indicating that the respiratory system is trying to compensate (or by the arrow method, both the bicarb and the CO2 are low). However, the pH is not yet returned to a normal level. The system is only partially compensated.
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
An examination of the laboratory results shows problems with which organ? On which results do you base your answer?
Kidney. The urea and creatinine are elevated and there is protein in the urine (only due to renal cause). The GFR value gives a level of Stage 3 CKD. Reduction in size of both kidneys.
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
is it acute or chronic?
chronic
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
What is a likely cause for injury to the organ affected? Describe a probable specific site of injury within this organ, and support why you have chosen this site.
Hypertension. The glomeruli, not performing job perfectly, as protein is passing through into the filtrate.
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
List all of the health issues from which Peter is suffering and describe how they are brought about from malfunctioning of the organ in question.
- Fatigue - anemia – lack of erythropoietin, so RBC production is decreased.
- Difficulty concentration – could be due to build-up of nitrogenous waste products in blood (azotemia) due to kidney’s inability to rid the blood of these. Also metabolic acidosis and anemia.
- Hyperkalemia – caused by the inability of the kidneys to get rid of potassium.
- Metabolic acidosis – caused by the hyperkalemia and the inability to get rid of hydrogen within the nephron.
- Hypocalcemia – caused by decreased production of calcitriol by kidney, which causes absorption of calcium in the GIT
- Increased respiratory rate – compensation for the acidosis
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
Peter’s kidneys have probably been decreasing in function for years. Why have signs and symptoms only shown up relatively recently?
Intact nephron hypothesis – functions no longer performed by damaged nephrons is taken over by healthy nephrons.
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
Does a calculation of Peter’s anion gap fit with the pathophysiology of his disease? Explain your conclusion.
145 – (107 + 20) = 18, which equals elevated anion gap. This fits with metabolic acidosis caused by excess of H+, and can be caused by inability of kidney to secrete H+
45 yr old Peter G. visits his physician with complaints of ongoing fatigue and difficulty in concentrating. He has an additional concern to discuss: his wife has insisted that he mention the higher than normal blood pressure values that the drugstore machine has given him the last few times they’ve been there (she finally convinced him to start checking his BP). Examination of his retina shows some localized narrowing of the vessels. A measurement of his blood pressure reveals a value of 175/100 mmHg (“Yeah, that’s about what I’ve been getting at the drugstore”, he confirms), and a respiratory rate of 20/min. Subsequent blood analyses are performed, with the following results: pH = 7.3, urea: 11.5 mmol/L, creatinine: 300 µmol/L, Na+ = 145 mmol/L, K+ = 5.2 mmol/L, Cl- = 107 mmol/L, Ca2+ = 2.0 mmol/L, HCO3- = 20 mmol/L, pCO2 = 20 mmHg and Hb 101 g/L. Analysis of a random urine sample revealed a presence of 30 mg/dL of protein. After receiving these results, his doctor orders a renal ultrasound that shows both kidneys to be reduced in size. A GFR was calculated to be 30 ml/min
Calculate the urea:creatinine ratio. Does this agree with the type of renal damage in Peter’s case?
11.5 / 0.300 = 38. This is less than 40, which suggests an intra-renal cause (which fits with damage within the kidney, caused by at least the hypertension). It does not point to a pre-renal cause (decreased perfusion), or post-renal (obstruction).
