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  #1  
Old 06-25-2012
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GIT Fluid Replacement in Pyloric Stenosis!

As the surgical intern on call, you are summoned to the emergency room (ER) to evaluate a 4-week-old girl who has been evaluated and given a provisional diagnosis of pyloric stenosis. On arrival you find the child sleeping comfortably with a nasogastric tube in place. The child is easily arousable. Your physical exam shows depressed fontanelles, reduced tearing and poor skin turgor. Review of the medical record shows the child weighs 5 kg. Urine output is 10 mL over the last 4 hours. A laboratory blood chemistry panel from samples drawn 2 hours ago shows sodium (Na+) 145 mEq/L, potassium (K+) 3 mEq/L, Cl- 85 mEq/L, HCO3- 18 mEq/L, glucose 60 mg/dL, blood urea nitrogen (BUN) 30 mg/dL, and creatinine (CR) 1.3 mg/dL. What is the most appropriate fluid to administer to the child at this time?

A. {1/2} Normal saline with 40 mEq KCl/L
B. D5 {1/2} NS
C. D5 NS with 10 to 20 mEq KCl/L
D. Lactated Ringer's
E. NS
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  #2  
Old 06-25-2012
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will go for c....
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  #3  
Old 06-25-2012
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Ans E........

the child is simply dehydrated and should be given just NS , ringer lactate is preferred in burns . the electrolyte abnormality will correct itself as the kid is rehydrated

D5 never add to intravascular volume , it is easily absorbed so it doesnot increase the fluid in the vessel nor the urine output .

1/2 NS with 40 meq KCl to much for a small kid ,dangerous to be given IV .
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Old 06-25-2012
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Quote:
Originally Posted by Hitman View Post
Ans E........

the child is simply dehydrated and should be given just NS , ringer lactate is preferred in burns . the electrolyte abnormality will correct itself as the kid is rehydrated

D5 never add to intravascular volume , it is easily absorbed so it doesnot increase the fluid in the vessel nor the urine output .

1/2 NS with 40 meq KCl to much for a small kid ,dangerous to be given IV .

Not sure what you said,

why can't you give B) D51/2NS?

It should correct hypoglycemia, and hypoglycemia.
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Old 06-25-2012
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well i read in some kaplan notes , dont remember which that d5 doesnot correct intravascular volume loss , as glucose gets absorbed by the tissues and water follows it . so the fluid is not retained in the blood vessels . while NS is isotonic so will remain in the vessels and add to intravascular fluid and correct BP and urine output , so even in burns we correct it with ns or ringer lactate first then give D5 not D5 first as it is of no help . so simple NS should be given first
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Old 06-25-2012
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Correct Answer D. RL

dehydration + acidosis: RL
Dehydration + alkalosis: NS
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  #7  
Old 06-26-2012
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Quote:
Originally Posted by tanujasalim View Post
dehydration + acidosis: RL
Dehydration + alkalosis: NS
but by vomiting then the kid has hypochloremic metabolic alkalosis so answer would be NS which would be answer E not D
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Old 06-26-2012
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Originally Posted by XpaezX View Post
but by vomiting then the kid has hypochloremic metabolic alkalosis so answer would be NS which would be answer E not D
I agree but the question shows HCO3 as 18 - acidosis
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  #9  
Old 06-28-2012
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D. Lactated Ringer's


in this patient :
ph is decreasing due losing acid so lr will converted in blood to lactic acid correcting this patient ph
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  #10  
Old 06-29-2012
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E. Normal saline...........once you correct the hypovolumia everything else will correct itself.
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  #11  
Old 06-30-2012
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Should be

C. D5 NS with 10 to 20 mEq KCl/L

Pt has hypochloremic metabolic alkalosis, hypoglycemia & hypokalemia.
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Old 07-01-2012
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Blood tests will reveal hypokalemic, hypochloremic metabolic alkalosis due to loss of gastric acid (which contain hydrochloric acid and potassium) via persistent vomiting; these findings can be seen with severe vomiting from any cause. The potassium is decreased further by the body's release of aldosterone, in an attempt to compensate for the hypovolaemia due to the severe vomiting.

Pathophysiology

The chloride loss results in hypochloremia which impairs the kidney's ability to excrete bicarbonate. This is the significant factor that prevents correction of the alkalosis.
A secondary hyperaldosteronism develops due to the hypovolemia. The high aldosterone levels causes the kidneys to:
avidly retain Na+ (to correct the intravascular volume depletion)
excrete increased amounts of K+ into the urine (resulting in hypokalaemia).
The body's compensatory response to the metabolic alkalosis is hypoventilation resulting in an elevated arterial pCO2.

If you correct the main causes--hypochloremia & hypovolemia by giving Na Cl then it will correct the secondary electrolyte abnormalities by replacing Cl and Na as well as the volume. There is no need to give anything else since Cl replacement will allow the kidney to excrete bicarbonate thereby correcting metabolic alkalosis and volume replenishment (with Na) will get rid of secondary hyperaldosteronism correcting hypokalemia by negative feedback.
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Old 07-01-2012
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The answer is A
Kaplan peds notes say... In pyloric stenosis give Either 0.5 NS or 0.9NS PLUS 20meq/l of KCl

Have to give "rehydrational" and "electrolyte correctional" fluid.

Dr. Cvetnic covered this question during live lectures.
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Old 07-01-2012
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Acute emergency management (0-6 h) of hypochloremic alkalosis

Quote:
Assess dehydration status to determine if it is chronic or superimposed by acute dehydration. If the patient is in shock, treatment should be directed toward aggressive resuscitation with isotonic fluid, preferably normal saline.

Initial management includes assessment of dehydration status and severity of hypochloremia, hypokalemia, hyponatremia, and metabolic alkalosis.
Always remember not to treat chronic acid-base disturbances rapidly because more serious complications may be prevented by meticulous and slow correction. For example, initial blood work shows the following results: 120 mmol/L sodium, 2 mmol/L potassium, 80 mmol/L chloride, 40 mmol/L bicarbonate, and pH 7.5. In this child, assess cardiac function; if dysrhythmia is absent, rapid correction of this severe hypokalemia is not needed. In this case, 5% dextrose in 0.9 isotonic sodium chloride solution plus potassium chloride 20 mEq/L administered at a maintenance rate per 24 hours can be a safe measure.
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Old 07-01-2012
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Pyloric stenosis: Fluid therapy

According to this the only fluid this child needs is NS since any K is contraindicated because child weighs 5 kg & Urine output is 10 mL over the last 4 hours as well as rising BUN/Serum creatinine. There is a reason why they have given this information in the question stem.

Quote:
Pyloric stenosis is a medical emergency, not a surgical emergency. The patient should not be operated on until there has been adequate fluid and electrolyte resuscitation. According to Barash, the infant should have normal skin turgor, and the correction of the electrolyte imbalance should produce a sodium level that is >130 mEq/L, a potassium level that is at least 3 mEq/L, a chloride level that is >85 mEq/L and increasing, and a urine output of at least 1 to 2 mL/kg/hr. These patients need a resuscitation fluid of full-strength, balanced salt solution and, after the infant begins to urinate, the addition of potassium.
The cardinal findings in pyloric stenosis are dehydration, metabolic alkalosis, hypochloremia, and hypokalaemia. Loss of gastric fluid leads to volume depletion and loss of sodium, chloride, acid (H+) and potassium. This results in a hypokalemic, hypochloremic metabolic alkalosis. The kidneys attempt to maintain normal pH by excreting excess HCO3.The kidneys attempt to conserve sodium at the expense of hydrogen ions, which can lead to paradoxical aciduria. In more severe dehydration, renal potassium losses are also accelerated owing to an attempt to retain fluid and sodium.
According to Smith, "The initial therapeutic approach is aimed at repletion of intravascular volume and correction of electrolyte and acid-base abnormalities (e.g., 5% dextrose in 0.45% NaCl with 40 mmol/L of potassium infused at 3 L/m2 per 24 hours). Most children respond to therapy within 12 to 48 hours, after which surgical correction can proceed in a nonemergent manner. The use of cimetidine has also been shown to rapidly normalize the metabolic alkalosis in patients with hypertrophic pyloric stenosis "
In particular, semi-normalization of chloride may be important (and most relevant), as data suggest that 72% of patients with a chloride of 106 mEq/L have achieve resolution of their metabolic alkalosis [Goh DW et al. Br J Surg 77: 922, 1990]
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Old 07-01-2012
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Quote:
Originally Posted by Novobiocin View Post
Pyloric stenosis: Fluid therapy

According to this the only fluid this child needs is NS since any K is contraindicated because child weighs 5 kg & Urine output is 10 mL over the last 4 hours as well as rising BUN/Serum creatinine. There is a reason why they have given this information in the question stem.

i agree with what you are getting at--- the idea of only giving NS and not correcting with KCL cos one acutely treats only dehydratio, electrolyte abnormalities are dealt with later.

but im still a little confused cos of what we were told in the kaplan live lectures. cos they said you treat both simultaneously.


here is the paragraph from the "updated' handouts we were given for peds.
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  #17  
Old 07-01-2012
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  • Immediate treatment requires correction of fluid loss, electrolytes, and acid-base imbalance. Once intravenous access is obtained, an initial fluid bolus (20 mL/kg) of crystalloids (0.9% NS) should be infused immediately if the infant is dehydrated.


  • More than 60% of infants present to the ED with normal electrolyte values or are not in clinical shock. These infants should receive 1.5-2 times maintenance intravenous fluid: 5% dextrose in 0.25% or 0.33% sodium chloride with 2-4 mEq KCl per 100 mL replacement. The infant's fluid status should be continuously reassessed with special attention to acid-base status and urine output.
Reference: http://emedicine.medscape.com/articl...reatment#a1126


The sequence is : Correct IV loss (dehydration) ---> correct electrolyte imbalance---> surgery
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Old 07-02-2012
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so whats the correct answer??
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Old 07-02-2012
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Originally Posted by mbbs2010 View Post
so whats the correct answer??
tyagee is torturing us............
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Acid-Base-, Electrolytes-, Gastroenterology-, Pediatrics-, Step-2-Questions

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