GI and IV Flashcards
Types of Dehydration
Hyponatremic/Hypotonic = Na less than 130
From excess loss of Na, or most commonly replacement fluid w/ excess of free water (hypotonic solutions)
Isonatremic/Isotonic = Na 130-150
Proportional loss of Na and water
Most common and what we’ll focus on today
Hypernatremic/Hypertonic = Na >150 Implies free water loss or increased insensible losses (DI) Slow rehydration (over two days) to avoid fluid shifts that could cause cerebral edema or intracranial bleeding – drop sodium no faster than 15meq/day ** Maybe be deceiving clinically --> extravascular fluid is maintained for longer while intracellularly the patient may be dehydrated
signs of dehydration
turgor, skin feel dry --> clammy mucosa dry--> parched eyes deep set--> sunken fontanelle--> soft--> sunken CNS irritable --> lethargic/ obtunded pulse rate mild increase --> increased pulse quality weak--> feeble cap refill 2 sec --> over 3 sec urine output decreased --> anuric
ORAL REHYDRATION
Oral rehydration therapy (ORT) is recommended as the preferred treatment of fluid and electrolyte losses caused by diarrhea in children with mild to moderate dehydration, 50-100cc/kg over four hours.
WHO packets: mix one packet with 1L water.
World-wide use has decreased mortality by 50% since 1980s
When to choose intravenous rehydration therapy over Oral rehydration therapy?
- Inability of the child to take ORT (altered mental status, ileus, anatomic anomaly)
- Inability of the caregiver to provide ORT
- Failure of ORT to provide adequate rehydration (eg, persistent vomiting)
- Severe electrolyte problems in clinical setting where ORT cannot be closely monitored or electrolytes frequently assessed
crystalloid fluids
- Based on crystalloid solutions, thus containing water and electrolytes, but have the added component of a colloidal substance that does not freely diffuse across a semipermeable membrane
THE APPROACH TO FLUID REPLACEMENT IN DEHYDRATION
- Restore intravascular volume for hemodynamic stability: the boluses!**
- Calculate 24 hr water requirements
Part 1: Maintenance – given at constant rate over 24 hrs
Part 2: Deficit – divided so that ½ is given over first 8 hrs, then ½ over the next 16 hrs.
- Calculate 24 hr water requirements
Calculate 24 hr electrolyte requirements
Part 1: Maintenance Na+ and K+
Part 2: Deficit Na+ and K+ (especially important in hypo/hypernatremic dehydration)
- Select appropriate fluids
- Replace ongoing losses
- RESTORE INTRAVASCULAR VOLUME in hemodynamically unstable patients
usually for severe dehydration
bolus therapy
- Rapid infusion of relatively isotonic fluid
- 20 ml/kg (consider 10 ml/kg for cardiac pts)
- Normal saline or Lactated ringers
- Calculate 24 hr water requirements- maintenance
Maintenance
Daily water needs based on energy expenditure
1 kcal expended/day = 1 ml water required
You can calculate it by
- Caloric expenditure method (more needed for illness) - Holliday-Segar (based solely on weight), kids only, over 4 wks - BSA
Holliday-segar method (maintenance)
4+2+1
4 ml/kg/hr for the first 10 kg
2 ml/kg/hr for the next 10 kg
remainder 1 ml/kg/hr
- Calculate 24 hr water requirements part 2- deficit
Deficit
“How much is he down?”
Fluid deficit (ml) = %dehydration of pre-illness wt.(kg) X 1000 ml/kg
Example: infant with weak pulses, tenting of skin, irritability, etc, would be estimated at 10% dehydration, so: 10% of 12 kg child = 1.2 kg then 1.2 kg X 1000 ml/kg = 1200 ml fluid deficit
maintenance of Na+ and K+
Na+: 3 Na+ mEq per 100ml of H2O
K+: 2 K+ mEq per 100ml of H2O
electrolytes and compartments
Na+ is essentially all EXTRACELLULAR, while
K+ is essentially all INTRACELLULAR.
selection of fluids
In general, for isonatremic dehydration :
<10 kg use 0.25 NS
10-20 kg use 0.5 NS
add potassium
K+ to be added after the patient has voided
K+ concentrations should not exceed 40 mEq/L or rate of 0.5mEq/kg/hr in peripheral IVs
little kid vs bigger kid maintenance
Little kid maintenance:
D1/4 NS with 20-40 mEq KCl or K acetate added per liter
Bigger kid maintenance:
D ½ NS with 20-40 mEq KCl or K acetate added per liter
bolus calculation
20 ml/kg - now
make sure the subtract the bolus out from the deficit later!
Duodenal atresia
Congenital obstruction of 2nd portion of duodenum
Failure of recanalization of bowel segment
Recanalization occurs during the 4th - 5th week of gestation
Usually occurs below the ampulla of Vater
Associations Polyhydramnios Down syndrome 25% of patients CHD in 20% Presentation: bilious emesis in neonate
double bubble
The double bubble sign on x-ray is pathognomonic for duodenal atresia
3 types of duodenal atresia
Type I – mucosal web with normal muscular wall (most common)
Type II – short fibrous cord connecting two atretic ends of duodenum
Type III – complete separation of the atretic ends
viral gastroenteritis bs bacterial
watery diarrhea- viral
normally self-limiting but can cause severe dehydration
bacterial– often bloody bowel movements
fecal leukocytes
most common causes of bloody stools
Campylobacter Salmonella Shigella Yersinia Enterohemorrhagic E. Coli
causes of viral gastroenteritis
rotavirus caliciviruses astroviruses adenoviruses food borne: NOROVIRUSES
diarrhea workup
** Vast majority of cases do not require work up
Electrolyte disturbances rare in children with moderate dehydration.
Consider baseline BMP if starting IVF
Fecal leukocytes and stool culture with hx of bloody diarrhea
C. difficle toxin in those 12m or older recently treated with Abx
Rarely occurs in children less than 12-24 months
Stool for ova/parasites in those with prolonged watery diarrhea (>14d) and travel in endemic area of parasites
CBC/blood cultures in those suspecting systemic infection
Oral rehydration therapy
ORT with electrolyte solution is the preferred method of rehydration for mild to moderate dehydration
If patient has been vomiting, then small sips of electrolyte solution till emesis stops then slow reintroduction of liquids/bland solids (labor intensive!!): ideally 5 cc every 1-2 minutes, but commonly 5 cc (one teaspoon) every 10 minutes or 30 cc (one ounce) every 15 minutes
Can try Zofran (ondansetron) ODT (oral disintegrating tablet) if vomiting
Intravenous rehydration recommended for severe dehydration (or if not tolerating ORT)
antimotility agents
Do not use antimotility agents in children!
Reflux episodes occur most often during
transient relaxations of the lower esophageal sphincter (LES) unaccompanied by swallowing
important symptoms, signs maybe associated with GE reflux
Recurrent regurgitation with/without vomiting
extra-esophageal, like Cough (which can be mistaken for URI)
esophagitis
recurrent pneumonia
dental erosion
Sandifer syndrome (dystonic neck posturing)
STANDARD MEDICAL CARE of GERD
**First line therapy is nonpharmacologic
Advise on appropriate amounts of formula
Thickening of feedings by adding rice cereal to formula
Prone positioning at 30 degrees while awake
Elevating HOB and placing on back while asleep
Hold upright for 30 min after feeding
H2 receptor blockers
proton pump inhibitors
surgical treatment
Constipation
The most common nonorganic cause is functional fecal retention or voluntary stool withholding.
It can be associated with encopresis (overflow stool) and urinary tract infections.
INTUSUSSCEPTION
intermittent episodes of severe abdominal pain
Telescoping of the intestine, sometimes from a lead point
Between episodes patients are active and asymptomatic.
“currant jelly” stools
air contrast enema can be diagnostic and potentially therapeutic
FUNCTIONAL ABDOMINAL PAIN
Diagnosis of exclusion
Generally presents * between 6 and 14 years of age
Normal physical exam findings without weight loss or blood in stools, normal labs
Symptoms are usually present for * more than three months.
be concerned if the pain awakens child at night
Esophageal foreign bodies- urgent or emergent intervention:
- When the object is sharp, long, or consists of magnets
- When the object is a disc battery in the esophagus
If airway compromise,
ESOPHAGEAL FOREIGN BODY
Coins easily pass
Most esophageal foreign bodies are retained at the thoracic inlet, the level of the aortic arch, or the gastroesophageal junction.
Less than 1% of esophageal foreign body cause significant morbidity. These uncommon complications include esophageal erosion and perforation, esophageal stenosis, or fistula.
Ingested button batteries and sharp objects should be removed immediately!!!
MECKEL DIVERTICULUM
the MOST COMMON cause of SERIOUS lower GI bleeding in children (blood transfusions often needed)
May see currant jelly stool (despite being lower GI bleed) as with intussusception or bright red blood
Pyloric Stenosis
between 3-5 weeks of age, and very rarely occur after 12 weeks of age.
Typical nonbilious vomiting that is forceful immediately after feeding, while the infant remains hungry.
–> “Projectile vomiting”
A firm “olive-like” mass may be palpable in the right upper quadrant of the abdomen
–> hypochloremic metabolic alkalosis
