Vignette: Peds GI # 1

1. Of the following findings associated with Crohn disease, the BEST indication for instituting parenteral nutrition is: Choose one answer
i) perianal abscess and fistula
ii) abdominal radiograph demonstrating air fluid levels
iii) active ileitis demonstrated on colonoscopy

Answer is: abdominal radiograph demonstrating air fluid levels.
Explanation: Because air-fluid levels indicate ileus.
The principle for nourishing a chronically ill child is "if the gut works, use it."
Obviously, in ileitis, one can still continue feedings.
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Some questions and themes on H pylori
2. One Board question suggests that a a 4 yrs has a gastric ulcer and asks which is most appropriate diagnostic procedure:
a) esophagogastroduodenoscopy with biopsy OR b) upper GI series OR c) Helicobacter pylori serology.
Answer: Pick up endoscopy (choice a) even though it seems that it is more invasive than upper GI. But PREP justifies it:
-The history in the vignette is most consistent with a bleeding ulcer or severe gastritis, and the best test to identify and treat the suspected lesion is esophago-gastro-duodeno-scopy with biopsy. Endoscopy has a sensitivity for ulcer disease of more than 95%, compared with a yield of less than 50% for an upper gastrointestinal tract radiographic series.
In addition, bleeding ulcers sometimes can be treated endoscopically, either by injection of epinephrine into the ulcer or by cautery.

- Serology for Helicobacter pylori may help identify an underlying cause for an ulcer, but it is not useful in the acute setting. Abdominal ultrasonography and Meckel scans are not useful tests in the evaluation of peptic ulcer.
3. You are treating a 16 yrs old for H pylori infection. After 2 weeks of therapy, parents ask if the bug has been eradicated? What is the least invasive test to assess eradication of H pylori?

Ans: Fecal H pylori antigen testing

i) Helicobacter pylori infection is a known risk factor for gastritis and duodenal ulcers in children and adults. Rarely, and primarily in older adulthood, H pylori also is associated with a gastric lymphoma of the mucosal-associated lymphoid tissue (MALToma).
ii) Diagnosis (Dx): The "gold standard" for the diagnosis of H pylori infection of the stomach is endoscopy with biopsy.
Endoscopy may show: a nodular gastritis of the antrum , and histology of the gastric mucosa demonstrates the characteristic curved organisms in the gastric glands.
Other tests:
Of the options offered, the H pylorfecal antigen is the best test to document eradication in a previously treated host. Patients colonized with H pylori have detectable antigen in their stool that disappears upon eradication of the organism.

H pylori immunoglobulin G serology (serum antibody) is a useful marker for epidemiologic studies of past or current infection, but its sensitivity and positive predictive value in children is suboptimal.
The same is true for salivary antibody. Accordingly, a positive antibody screen should be confirmed by a second test (either fecal antigen, urea breath test, or endoscopy).

The Campylobacter-like organisms (CLO) test is performed on a duodenal biopsy.

In the CLO test, the duodenal biopsy specimen is placed in a test tube containing chemical reagents. The H pylori bacteria convert urea to ammonia and carbon dioxide via their urease enzyme, and the alkalinity of the ammonia can be detected using an indicator dye. The CLO test cannot be performed on feces.
Serum urease concentrations are not helpful in identifying H pylori, which is a mucosal bacterium.

iii) Rx: Patients who have documented ulcers should be tested for H pylori and the organism eradicated if found, but it is unclear if asymptomatic children colonized with H pylori need to be treated.
Therapy is given for 14 days and should include:
a proton pump inhibitor (eg, omeprazole, lansoprazole, pantoprazole) and
two antibiotics (eg, tetracycline + clarithromycin, amoxicillin + metronidazole, amoxicillin + clarithromycin).
Treatment failures are common, either because of resistant bacteria or because of poor compliance with the regimen. Therefore, testing for eradication of the organism (either by fecal antigen, urease breath test, or endoscopy) should be performed more than 1 month after therapy has been completed.

4. Another board question tests you about the histologic appearance of gastritis caused by H pylori.
i) The endoscopic appearance of a nodular antrum and duodenal ulcer: is strongly suggestive as H pylori as the cause.

ii) The nodular antrum is present because of lymphoid hyperplasia that occurs when the mucosal immune system is activated by H pylori.
iii) Upon careful examination of the gastric biopsy, spiral-shaped microorganisms can be seen in the mucus layer overlying the epithelium in the gastric glands.
iv) Although H pylori is a common commensal organism in adults, it can cause ulcer disease. Strains that cause ulcers are more likely to possess a virulence protein called CagA (cytotoxin-associated gene A).
The prevalence is lower in children, presumably because of improvements in hygiene and socioeconomic status over time.
v) Dx: The gold standard: endoscopy and biopsy. The organism usually can be identified on histology, especially if silver stain is used; culture typically is not necessary.

Noninvasive tests (including serum serology, fecal antigen, and urea breath testing) are useful in patients in whom the index of suspicion for H pylori infection is high.
If the prevalence or likelihood of H pylori is low, serologic testing is likely to give a false-positive result.
vi) Rx: 14-day course of therapy with a proton pump inhibitor plus two antibiotics (amoxicillin and clarithromycin, amoxicillin and metronidazole, tetracycline and metronidazole).
If repeated courses of antibiotics do not eradicate the organism, culture and testing for antimicrobial resistance and the CagA virulence factor can be performed at research laboratories.
NOTE: Other risk factors for ulcers in childhood include:

- use of nonsteroidal anti-inflammatory drugs (NSAIDs),

- Crohn disease,

- viral infections, and physical stress (eg, intensive care hospitalization).

- Ulcers also may occur without any obvious predisposing cause.

- Celiac disease and eosinophilic gastroenteritis may cause ulcers, but not nodular gastritis.

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5. A 18-year-old girl presents with a 6-day history of jaundice. She has a 3-year h/o anxiety and depression and has seen a neurologist because of tremor and slurred speech. On physical examination, the girl is responsive but withdrawn and has scleral icterus. Her liver is slightly enlarged, but there is no splenomegaly. Her total serum bilirubin is 12.0 mg/dL , direct bilirubin is 1.0 mg/dL , and hematocrit is 25% . Serum albumin is 3.0 g/dL , and total protein is 6.5 g/dL . The peripheral blood smear demonstrates schistocytes and burr cells, PT is 23 seconds, APTT is 60 seconds, and serum NH3 is 80 mcg/dL.

What blood test to do?

Ans: ceruloplasmin levels

This is Wilson disease (WD)

i) Suspect WD: if signs of neurologic disease, liver failure, and hemolysis .

ii) Basic defect: is caused by a defect in ATP7b, an ATPase that transports copper out of hepatocytes.

Impaired cu excretion leads to the accumulation of copper within the liver.

In fulminant Wilson disease, a massive release of copper from the liver causes both hepatocellular necrosis and hemolysis.

iii) Tests for Wilson Disease:

a] Serum ceruloplasmin concentrations typically are low in Wilson disease, although they occasionally can be in the normal range.

b] slitlamp examination of the eyes for Kayser-Fleischer ring,

c] 24-hour urinary copper measurement,

d] and liver biopsy for copper content


6. A 12-month-old boy comes to ER with a 3-day history of intractable AGE. Decreased urine output for the past 24 hours. HR 180 beats/min, and his BP is 85/40 mm Hg. He is lethargic but responds to stimulation. His mucous membranes are very dry, his skin turgor is decreased, and his capillary refill is 3 seconds.

If you do a BMP, what kind of electrolyte status you will get?


ans: Serum Sodium:Low; Serum Osmolality:Low;

Urine Sodium:Low; Urine Osm:High

i) Diarrhea due to acute gastroenteritis usually causes a proportional water and sodium loss, resulting in isonatremic dehydration. Hyponatremic dehydration also may be seen in acute gastroenteritis, especially if the only fluids tolerated are low-sodium fluids, such as water or juice.

ii) The clinical signs of both hyponatremic and isonatremic dehydration are due to decreased extracellular fluid, primarily from the intravascular compartment. The signs include decreased skin turgor, delayed capillary refill, decreased tear production and urine output, sunken eyes and anterior fontanelle, and tachycardia. Hypotension is a late finding, indicating decompensated shock.
Because the child described in the vignette displays these clinical signs, isonatremia or hyponatremia is likely.

iii) With hypernatremic dehydration, intravascular volume is relatively preserved, despite an overall body water loss, so the degree of dehydration may be underestimated.
Points to remember:

A] Never correct hyponatremia rapidly. Rapid correction may result in CPM (Central Pontine Myelinosis).

B] In Hyper-natremia: Patient is at risk of brain hemorrhage (because, fluid will tend to shift from intra-cellular compartment to ECF).

C] Rapid correction of hyper-natremia: patient can develop Brain edema. Hence correct hyper-natremia slowly (Correct in a way so that the serum sodium levels come down by 12 mEq/L per day).

7. Next q is also on AGE.

A 2-year-old boy presents with a history of vomiting and diarrhea for several days. P/E: lethargy, poor oral intake, tachycardia, dry mucous membranes, and poor skin turgor. He refuses to take oral fluids, so you decide to begin intravenous fluid administration.

Of the following, the BEST next step in fluid management is to:
TRUE answer: administer a bolus of isotonic fluid at 20 mL/kg
Wrong answers: administer 5% dextrose and 0.25 normal saline with 20 mEq potassium chloride at maintenance rate OR await laboratory results before starting fluid therapy

i) The child described in the vignette appears to be : moderately to severely dehydrated, and his refusal to drink is somewhat ominous and implies depleted intravascular volume.

Initial therapy of a severely dehydrated child includes intravenous administration of isotonic fluids (generally normal saline) at 20 mL/kg, with prompt re-evaluation after 30 minutes to 1 hour.
NB: Initial therapy for mild-to-moderate dehydration may be accomplished at least as effectively, if not more so, with oral rehydration, but it is labor-intensive, requiring one-to-one parent or nursing presence with the patient. So Prep does not like it!
8. A 2-year-old girl: fussiness, low-grade fever, and what her parents describe as "growing pains." P/E: you palpate a nontender mass deep in the right periumbilical area and note mild purple discoloration of the eyelids.

Of the following, the MOST likely diagnosis is:
Neuroblastoma
Neuroblastoma is the most common extracranial solid tumor of childhood.
Most frequently in children <> F
It may arise anywhere in the sympathetic nervous system, but most commonly presents in the abdomen.
Although it may present as an abdominal mass, as for the child in the vignette, it is diagnosed most commonly as widely disseminated disease.
The "heliotrope" discoloration of the periorbital tissues reported for the child in the vignette results from mass effects of involved lymphoid tissue in the periorbital area.

Paraneoplastic manifestations: such as opsoclonus or "dancing eyes," may result from a postulated immune mechanism and may persist despite surgical or chemotherapeutic cure of the underlying malignancy.

NB: Neuroblastoma tumors with amplification of the N-myc protooncogene or with multidrug resistance protein expression have a poorer prognosis.

9. Intussusception:

The diagnosis: Do Barium- or air- enema. The diagnosis is suggested by the typical findings on history and physical examination and confirmed by either barium enema or "air" enema.

Note that the above diagnostic modalities are also usually therapeutic.