Medex Objectives Winter 2003

Medex Objectives Winter 2003

MEDEX Northwest Physician Assistant Objectives Home:

MCHPediatric Gastroenteritis

1. Gastroenteritis (Acute Diarrhea)- Discuss incidence, pathophysiology, clinical presentation, work-up, laboratory tests, and treatment.

incidence:in US, acute diarrhea strikes each child under 3 y.o. 1.3-2.3X/yr. An avg. of 220,000 kids under 5 are hospitalized yearly, with 900,000+ hospital days. 9% of all hospitalizations of kids under 5 secondary to diarrhea. 300 kids under 5 die each yr from diarrhea and dehydration.

pathophysiology: 5 mechanisms exist: A. Osmotic diarrhea occurs with osmotically active particles in intestine. B. Secretory d. results from inhibition of ion absorption or stimulation of ion secretion. C. Deletion or inhibition of a normal active ion absorptive process (congenital or acquired). D. Inflammation usu. results from decrease in functional areas of bowel. E. Abnormal intestinal motility.

clinical presentation: Usually last few days to a week. Diarrhea lasting more than 2 weeks is something else (malabsorption, malnutrition or both). Mostly caused by intestinal infections or food intolerance; other poss. causes include food poisoning, inflammatory disorders, iatrogenic agents (antibiotics, laxatives).

work-up:

Hx: including dietary record, & changes in diet must be correlated with stool frequency and form. Family health, travel to place with contaminated water system, endemic infections, day care, foods recently ingested are all important factors. Thorough fam. hx, GI ROS important to elicit. Short incubation, short duration (<24 hrs.) illnesses are usu. due to ingestion of a preformed toxin. Duration of several days indicates infection w/ agent producing enterotoxin or invasion more likely. Dampness of recent diapers (6-8 hrs.) useful to assess hydration.

PE: assess airway/ventilation. Then focus on hydration status. Vitals, esp. BP & HR, are monitored. Skin turgor, moistness of mucosal membranes and tearing are useful signs. Check also for extraintestinal infection or systemic disease, determine if there is systemic toxicity.

laboratory tests: For uncomplicated diarrhea without evidence of dehydration or toxicity, no extensive eval. is needed. More aggressive for toxic, dehydrated pt. Examine stool: most important. Check color, consistency, odor, presence/absence of blood or mucus. Check pH. Culture if results will alter Tx. Culture also in kids <3 mos., <1 yr if toxic, also those with hemoglobinopathies or immunocompromised states. Proctosigmoidoscopy is indicated for pts. w/ negative cultures and persistent symptoms, esp. bloody diarrhea.

treatment: focuses on oral rehydration therapy (ORT), w/ an objective of restoring or maintaining adequate hydration and electrolyte balance, and ensuring pt.’s nutritional status.

Dershewitz 582-589

• Incidence- diarrheal disease continues to be one of the primary causes of morbidity and mortality in the world, where its incidence is estimated at 2.6 episodes per child per year in children younger than 5 years, and is associated with 3 to 5 million deaths per year. Its incidence in the United States with children under the age of 3 is 1.3 to 2.3 episodes per child per year. An average of 220,000 children younger than 5 years are hospitalized each year with gastroenteritis. Up to 20% of acute care visits to metropolitan hospitals are related to diarrheal illness. Approximately 300 children under the age of 5 die each year of diarrhea and dehydration.

• Pathophsiology- there is five mechanisms of diarrheal production:
• Osmotic Diarrhea- occurs when osmoticlly active particles are present in the intestinal lumen. Examples include the dumping syndrome, lactase deficiency, and overfeeding.
• Secretory Diarrhea- results from inhibition of ion absorption or stimulation of ion secretion. Examples include diarrheas secondary to bacterial exotoxins and diarrheas secondary to substances produced by the body that activate secretion, such as gastrin in Zollinger-Ellison syndrome.
• Deletion or inhibition of a normal active ion absorption process- can be congenital as in congenital chloridorrhea, or acquired, such as in bile salt deficiency and pancreatic enzyme deficiencies.
• Inflammation- usually is secondary to the decrease in the anatomical or functional areas, such as occurs in mucosal disease like celiac sprue, after bacterial invasion, or after bowel resection.
• Abnormal intestinal motility- abnormally reduced peristalsis may allow bacterial overgrowth; rapid motility may reduce contact time between the small bowel mucosa and its contents.

• Clinical Presentation- acute diarrhea is usually self-limited illness lasting a few days to a week, whereas persistent diarrhea typically persists longer than 2 weeks and may be associated with mal-absorption, malnutrition, or both. Almost all acute diarrhea is caused by intestinal infections or food intolerance. Bacterial organisms that invade the mucosa often cause fever, and if the colon is primarily involved, abdominal pain, tenesmus, fecal urgency, and stools with blood and mucus are common. Patients with secretory diarrhea have abdominal cramps with the passage of low to moderate number of large volume stools.

• Work-up- a thorough dietary record with changes in the diet should be correlated with stool frequency and form. Information about other family members with gastrointestinal complaints, endemic infections, recent travel, time spent in day care, or food recently ingested are also important to elicit during the history. A family history of chronic diarrhea, cystic fibrosis, celiac sprue, inflammatory bowel disease, and other chronic conditions should be noted. Other symptoms like fever, vomiting or abdominal cramps should be described. The number of wet diapers in a 6-8 hour period may also be useful.

• Laboratory Tests- examination of the stool is the single most important step in defining the diarrheal illness. Stoll should be observed fore color, consistency, odor, and the presence or absence of blood or mucus. The stool PH should be attained and a clinitest should be preformed. A culture of the stool should be reserved for those patients in whom the results will alter the therapeutic plan. Proctosigmoidoscope with biopsy is limited, but should be preformed when pseudomembranous colitis is suspected.

• Treatment- supportive therapy for acute diarrhea is oral rehydration therapy (ORT). The object of ORT should be the restoration or maintenance of adequate hydration and electrolyte balance. The traditional procedure for rehydration of ill children with acute diarrhea is hospitalizing them and administering intravenous fluid therapy while fasting the patients for variable periods. After rehydration, variable types of clear fluids or oral rehydration solutions are administered and intravenous fluids are slowly weaned. Antibiotics may be given but should be reserved for septic children.

L.H. Emer.Med. pgs.838-843

I am going to post a lot about this, however, you should really look at these pages because there is a LOT of info on this.

Infectious diarrhea may be either inflammatory (dysentery) or noninflammatory.

Inflammatory diarrhea is commonly due to bacterial or parasitic infections/infestations. These organisms tend to localize in the colon or distal small bowel and result in dysentery, which is characterized by frequent bowel movements containing blood, mucous, or pus. Noninflammatory diarrhea is caused by viruses and parasites that localize to the small bowel, or by toxin producing bacteria. In these cases, the diarrhea is profuse, watery, and commonly assoc. with nausea and vomiting. Fever is less likely. The term gastroenteritis is applied to this group of infections, although the stomach is rarely involved.

Epidemiology:

In the U.S. children younger than age 3 have 1.3-2.3 episodes of diarrhea/yr. More in kids attending daycare. Up to 1/5 of all acute care outpatient visits to hospitals are due to infants or children with gastroenteritis. 9% of all hospitalizations of children younger than 5 are for diarrhea. In 10 % of cases, clinical dehydration may occur, and is life threatening in 1%.

Pathogenic viruses, bacteria, or parasites may be isolated from nearly 50% of children with diarrhea. Viral infection is the most common. Bacterial infections may be isolated in 1-4% of cases.

Pathophysiology:

Viral pathogens cause acute GE by tissue invasion and a directly cytopathic effect to small intestinal villous cells which causes villous damage and decreased intestinal absorption of nutrients, electrolytes, and water, resulting in watery diarrhea. Villous injury also results in reduced disaccharidase levels and diminished total mucosal glucose-coupled sodium transport. End result is a decrease in intestinal water absorption. The volume of fluid delivered from the lumen of the damaged small intestine exceeds the colons limited ability for fluid absorption, and the net result is watery diarrhea.

Bacteria cause diarrhea by a variety of mechanisms, including production of enterotoxins and cytotoxins and invasion of the mucosal absorptive surface. Bacterial toxins may also be ingested directly in food. Most common are heat stable toxins produced by staph aureus products. Bacillus cereus produces a heat soluble toxin typically ingested with boiled or fried rice.

Parasitic infestations may cause diarrhea by a variety of mechanisms similar to those discussed for viral GE.

Clinicalpresentation:

Depends on type of infectious agent causing the problem. Most common presenting symptoms include watery diarrhea, fever, vomiting, abdominal pain, and dehydration.

Evaluation, workup:

Obtain a medical history carefully, and selectively choose lab tests according to your suspicion of the causative organism.

Viralinfections—no diagnostic tests indicated. Evaluate for dehydration and treat accordingly.

Suspected bacterial etiology with presence of fever, abrupt onset, more than 4 stools/day, guiac positive: consider fecal WBC, stool culture, or serologic testing. Assess for dehydration and treat according to level of dehydration.

Treatment:

Viral cause—treat the dehydration.

Bacterial—obtain appropriate cultures and treat dehydration while waiting for culture results. Consider empirical antibiotic therapy while awaiting culture results if :

1. fecal leukocyte positive

2. bloody diarrhea, fever, abdominal pain

3. dehydration or more than 8 stools/24 hrs

4. immunocompromised

5. hospitalization required

The majority of children with diarrhea and vomiting can be treated with ORS (oral rehydration solution). It successfully rehydrates 90% of children in whom it is used. Pedialyte and popsicles are used for this. IV rehydration with Ringers Lactate or normal saline may also be used. (see question 2 for specifics)

Reinstatement of food should begin after the 4 hour rehydration phase is completed and never delayed more than 24 hours. Breast feeding should be routinely continued for infants with acute GE. BRAT diet (bananas, rice, applesauce, toast) can be recommended, however, it does not provide adequate energy, fat, or protein. Encourage lean meats, yogurt, fruits, vegetables, and complex carbohydrates.

Indications for hospital admission:

All infants who appear toxic should be admitted. Patients with 10% dehydration, intractable vomiting, and altered consciousness should be given an infusion of normal saline or Ringers Lactate, regardless of serum osmolality, and admitted. Infants who are malnourished should be admitted. Children in high-risk social situations should also be admitted for treatment. These include the single, often teenage parent without an intact support system, or parents who are homeless or unable to provide appropriate fluids to the child.

D. Higbee, Tintinalli pg. 839

In the U.S. children younger than 3 years of age have 1.3 to 2.3 episodes of diarrhea each year.Pathophysiology: Viral pathogens cause acute gastroenteritis by tissue invasion and a directly cytopathic effect to small intestinal villous cells. As a consequence, there is villous damage and decreased intestinal absorption of nutrients, electrolytes, and water, resulting in a watery diarrhea. Bacteria cause diarrhea by a variety of mechanisms, including production of enterotoxins and cytotoxins and invasion of the mucosal absorptive surface.Clinical Presentation: Evaluation of a childs state of hydration is most important. Child may have an ill appearance, capillary refill longer than 3 seconds, dry mucous membranes, and absent tears. Bacteria that invade the mucosa of the terminal ileum and colon can cause dysentery, which is characterized by frequent bowel movements that contain blood, mucus, or pus. The diarrhea is often accompanied by fever, tenesmus, and painful defecation.Work-up: A careful medical Hx, PE, and selective lab testing, assess dehydration.Labs: Cultures and immunoassays of stool for the presence of the enteric pathogens.Treatment: Oral Rehydration Solution (ORS), IVfluids, if bacterial, antibiotics. Avoid fatty or high carb foods.

p. 630, Current Pediatrics; p. 838-848, Tintinalli

Incidence:

Mainly in infants between 3 & 15 months and is seen in the largest amounts during the winter months. In children <3 years of age average 1.3 to 2.3 episodes per year.

Pathophysiology:

Viral pathogens invade the tissues and cause a cytopathic effect on small intestinal villous cells. This results electrolytes, and water. Villous injury also results in ↓ disaccharide levels and diminished total mucosal glucose-coupled sodium transport. This leads to ↓ intestinal H2O absorption.

Bacterial pathogens can cause GE by a variety of mechanisms including enterotoxins and cytotoxins and invasion of the mucosal absorption surface.

Clinical Presentation:

Ill general appearance, cap refill > than 3 sec., dry mucous membranes, and absent tears are good indicators. The presence of 2 or more signs predicts 5% dehydration and 3 or more predicts a 10% dehydration.

Bacteria may cause dysentery characterized by frequent bowl movements that contain blood, mucus, or pus. The diarrhea is often accompanied by fever, tenesmus (spasm of the anus or bladder) and painful defecation.

Work-up:

Careful medical history and selective lab testing.

Lab tests:

Routine stool culture for bacterial pathogens. Enzyme immunoassays to test stool for rotavirus, enteric adenovirus, and astrovirus. Fecal WBC serologic testing as well.

Treatment:

Use oral rehydration fluid (Pedialyte). For IV rehydration between 20 ml/kg and 40 ml/kg of ringers lactate solution or normal saline may be given over 1-3 hours. Antibiotic therapy does not affect the clinical course in most cases. However, if dealing with persistent symptoms and other signs of infection they may be treated with antibiotics as indicated by stool sample. Also infants < 6 months are generally treated with antibiotics because of overall risk of bacteremia and suppurative disease.

2. Describe the physical exam findings associated with dehydration. Discuss re-hydration.

In mild dehydration, there is some increased thirst with no abnormal findings on PE. When fluid deficits reach 50 ml/kg in moderate dehydration, 5% to 10% loss in body wt, there is moderate thirst, dry mucous membranes, irritability, lethargy, decreased urine output, tenting of the skin, and tachycardia. Tachycardia may also be a manifestation of fever or infection. Skin turgor may be poor as well—where the skin remains “tented” rather than rapidly retract to its normal position. As dehydration continues, acidosis and tachypnea contribute to poor peripheral perfusion. In severe dehydration, c greater than 10% loss in body wt, signs of shock may appear with a rapid thready pulse, hypotension, and cool extremities. There is intense thirst; irritability or lethargy with altered mental status, ad sunken eyes. Most physical finding result from decreased extracellular fluid, PE findings are greatest in hyponatremic dehydration. These pts may also have CNS symptoms with lethargy and seizures if the serum Na falls below 120 mEq/liter. In contrast, hypernatremic dehydration is primarily a loss of intracellular fluid; therefore, PE finding may not be as marked b/c of the relative maintenance of circulating blood volume. Shock is a late finding, and these infants may be lethargic but when stimulated become irritable with a shrill cry, hyperreflexive with increased muscle tone and may have seizures.

Dershewitz 909-910

• Physical exam- infants and children who are dehydrated will often appear ill. Children should be weighed and vital signs obtained in all children. Hyperpnea and tachypnea suggests decreased tissue perfusion resulting in metabolic acidosis. Decreased circulating blood volume causes tachycardia, which can result in heart rates over 200 beats per minute in infants. The extent of dehydration can be evaluated by examining the child's mental status, mucous membranes, skin turgor, peripheral perfusion, and peripheral pulses. A careful examination of the abdomen should be performed to exclude signs of surgical diseases, such as bowel obstruction, appendicitis, and pyloric stenosis.
• Oral rehydration therapy (ORT) with oral rehydration solutions is the treatment of choice for dehydration. Patients with mild to moderate dehydration may take ORS over 4hrs or until stable. Severe dehydration with evidence of shock or hemodynamic instability should receive IV or interosseous fluids immediately.

Emer. Med. Pg.840,874-76 and current peds pg 1284.

Physical exam findings are related to the degree of dehydration, moderate, mild, or severe.

Findingmild moderate severe

Decrease body wt 3-5% 6-10% 11-15%

BP normal normalnormal-reduced

Tears decreaseddecreased absent

HR normal increased tachycardia

Skin turgor normal decreased decreased

Fontanelle normal sunken sunken

Mucous membrane slightly dry dry mottled or gray; parched

Eyes normalsunken orbits deeply sunken orbits

Cap refill 2-3 sec 3-4 sec more than 4 sec

Mental status normal normal to listless normal to lethargic

or comatose

Urine output mild oligouria oligouria anuria

Management of dehydrated children depends on the degree of fluid loss, as well as their ability to tolerate oral liquids. Mildly dehydrated patients who can tolerate pedialyte can usually be discharged home on clear liquids, with close follow up. Moderately dehydrated patients generally require iv therapy, but oral rehydration is an option. Oral rehydration for mild dehydration is 50 mL/kg over 4 hours. For moderate dehydration, 100mL/kg over 4 hours. Severely dehydrated patients require aggressive resuscitation. Boluses of 20 mL/kg of normal saline are given until improved mental status, vital signs, and peripheral perfusion indicate stable intravascular volume. In extreme situations, intraosseous line may be necessary. Fluid replacement then consists of replacing 50% of the estimated volume defecit in the first 8 hrs and the remainder of the defecit in the next 16 hrs. If diarrhea continues, maintenance fluids are added to the defecit replacement.

D. Higbee, Tintinalli pg. 841

Ill appearance, capillary refill longer than 3 seconds, dry mucus membranes, absent tears.

Rehydrate with Oral Rehydration Solution (ORS), IV fluids.

3. Given a case scenario, provide a differential diagnosis, identify most likely diagnosis, and form a treatment plan for a child presenting with gastroenteritis or dehydration.

This is a fairly broad area. I’ve listed the most common things that go wrong which are associated w/ abd. pain, N/V + diarrhea. Just remember to consider any associated s/s, + hx of course.