Approach to diarrhea (pediatrics): Clinical sciences

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Introduction 0:00–0:30

Diarrhea refers to stools that are unusually loose or frequent when compared to a patient’s normal stooling pattern. In pediatric patients, acute diarrhea is commonly caused by infection, whereas chronic diarrhea often represents a pathologic condition or a functional gastrointestinal disorder.
The underlying cause of diarrhea can be determined after assessing its chronicity and associated symptoms. Now, if a pediatric patient presents with diarrhea, first perform an ABCDE assessment to determine if they are unstable or stable.

Unstable 0:30–1:02

If unstable, stabilize their airway, breathing, and circulation. Next, obtain IV access, administer IV fluids, and place your patient on continuous vital sign monitoring, including respiratory rate, pulse oximetry, and cardiac monitoring.
Finally, if needed, don’t forget to provide supplemental oxygen. Alright, now let’s go back to the ABCDE assessment and look at stable patients.

Stable 1:02–1:29

First, obtain a focused history and physical examination. Patients or caregivers typically describe loose or frequent stools, while the physical exam might demonstrate abdominal tenderness, hyperactive bowel sounds, or dry mucous membranes.
At this point, diagnose diarrhea and assess the duration of your patient’s symptoms. First, let’s focus on acute diarrhea, or diarrhea that lasts for less than two weeks.

Acute Diarrhea 1:29–1:49

In this case, your next step is to assess for red flag signs and symptoms, including high fever, blood or mucus in the stool, severe abdominal pain, and signs of dehydration.
If your patient reports no red flag signs or symptoms, consider mild viral gastroenteritis, which is the most common cause of acute diarrhea in children.

Viral GE 1:49–2:39

These patients often report a known sick contact, and symptoms including vomiting and watery stool, possibly in combination with a low-grade fever.
Additionally, the exam may reveal mild abdominal tenderness and increased bowel sounds. These findings are highly suggestive of mild viral gastroenteritis, which is a clinical diagnosis that doesn’t require laboratory evaluation.
This self-limited infection is commonly caused by rotavirus in unimmunized patients or by norovirus during outbreaks in closed environments like daycare centers and schools.
However, if your patient has one or more red flag signs or symptoms, consider severe viral gastroenteritis or bacterial gastroenteritis.

Acute, Red Flags Present 2:39–3:00

Then, order a CBC, CMP, and stool studies, including culture, viral antigen testing, and ova and parasites, or O&P. First, let’s focus on severe viral gastroenteritis.

Severe viral GE 3:00–3:45

In addition to vomiting and watery stools, these patients also report symptoms of dehydration, like decreased urine output and weight loss.
Physical exam typically reveals dry mucous membranes and delayed capillary refill; and some patients may have significant abdominal tenderness.
Labs might reveal a normal anion gap hyperchloremic metabolic acidosis from bicarbonate loss in the stool. Stool studies will reveal no ova, parasites, or bacterial pathogens; and the viral antigen test will often be positive, which confirms your diagnosis of severe viral gastroenteritis.
On the flip side, individuals with bacterial gastroenteritis often have bloody stools, severe abdominal pain, and high fever.

Bacterial GE 3:45–4:47

The exam may demonstrate abdominal tenderness and hyperactive bowel sounds; while labs might show an elevated white blood cell count and normal anion gap hyperchloremic metabolic acidosis.
The stool culture will identify a pathogen such as Salmonella, Shigella, Campylobacter, or E. coli; while the O&P and viral antigen tests will be negative.
These findings indicate bacterial gastroenteritis. In this case, historical clues can occasionally suggest the causative pathogen; for example, if a patient became sick after eating poultry, eggs, or dairy, think of Salmonella; while high fever and seizures suggest Shigella.
Finally, recent travel suggests enterotoxigenic E. coli, and animal exposure suggests Campylobacter jejuni.
Now, switching gears and moving on to individuals with chronic diarrhea, which persists for 2 or more weeks. Again, the first step is to assess for red flag signs and symptoms, including blood in the stool, weight loss, or fever.

Chronic 4:47–5:01

If any of these are present, order labs including CBC, CMP, and an ESR or CRP; and obtain stool studies, including a culture and O&P.

Red Flags Present 5:01–5:17

Then, assess for bloody stools. If your patient reports bloody stools, order a fecal calprotectin, which is a sensitive marker of gastrointestinal inflammation.

Bloody Stools Present 5:17–5:26

An elevated fecal calprotectin should make you consider an inflammatory bowel disease like Crohn disease or ulcerative colitis.

IBD 5:26–5:43

To differentiate these conditions, order an upper or lower gastrointestinal endoscopy with biopsies. First, let’s look at findings you’ll see in Crohn disease.

Crohn Disease 5:43–6:12

In this case, labs typically demonstrate a low hemoglobin; elevated platelets; elevated ESR or CRP; and negative stool studies.
Endoscopic findings include cobblestoning and ulcerations with a discontinuous pattern of disease, or skip lesions; along with creeping fat anywhere along the GI tract.
With these findings, diagnose Crohn disease. Next let’s focus on findings you’ll see in ulcerative colitis.

Ulcerative Colitis 6:12–6:58

Labs will also demonstrate a low hemoglobin; elevated platelets; elevated ESR or CRP; and negative stool studies. Endoscopic findings will reveal a continuous pattern of ulcerations in the large intestine and loss of haustra, which are the pouches in the large intestine giving it a segmented appearance.
With these findings, diagnose ulcerative colitis. Here’s a clinical pearl!
In addition to bloody diarrhea, fever, abdominal pain, and weight loss; patients with inflammatory bowel disease may experience extraintestinal manifestations, like polyarthralgia, uveitis, or erythema nodosum.
On the other hand, if the fecal calprotectin level is normal, consider a gastrointestinal food allergy such as eosinophilic gastroenteropathy.

Allergic Enteropathy/Colitis 6:58–7:07

In this condition, patients often have a family or personal history of atopy, and many report sensitivity to cow’s milk, soy, or egg whites.

Eosinophilic Gastroenteropathy 7:07–8:32

Patients also demonstrate poor weight gain and may have recurrent vomiting. In severe cases, the physical exam might reveal generalized edema as a result of protein malabsorption.
As far as labs go, hemoglobin is often low; eosinophils are usually elevated; and stool studies are negative. To evaluate further, you could order a food skin-prick test or upper and lower gastrointestinal endoscopy with biopsies.
The skin-prick test might identify the offending food protein. The endoscopy will show erythema, edema, erosions, or ulcerations of the intestinal mucosa; and the biopsy typically reveals eosinophilic infiltration of the gastrointestinal mucosa, which confirms eosinophilic gastroenteropathy.
This inflammatory condition is caused by an IgE-mediated hypersensitivity reaction to proteins in specific foods such as cow’s milk or soy.
Other non-IgE-mediated allergic reactions to food proteins that can cause diarrhea or bloody stools include food protein-induced allergic proctocolitis, food protein-induced enterocolitis syndrome, and food protein-induced enteropathy.
Okay, let’s switch gears and discuss individuals who don’t report bloody stools. Here, your next step is to assess stool characteristics.

Bloody Stools Absent / Steatorrhea 8:32–8:43

If the stool is greasy, bulky, fatty, and foul smelling, it’s called steatorrhea, and you should consider pancreatic insufficiency.

Pancreatic Insufficiency 8:43–9:20

As a next step, obtain a fecal elastase test. If labs are normal, stool studies are negative, and the fecal elastase is low, diagnose pancreatic insufficiency, Here’s a clinical pearl!
Some conditions that can cause chronic diarrhea and steatorrhea in children include cystic fibrosis and Shwachman-Diamond syndrome.
Now, if the stool consists of constipation or diarrhea, with or without steatorrhea, consider celiac disease. In this case, your patient’s history might include abdominal distension, a pruritic rash, and weight loss; and labs demonstrate a low hemoglobin and negative stool study.

Celiac Disease 9:20–10:05

Next, obtain a tissue transglutaminase immunoglobulin A antibody test, or anti-tTG IgA; as well as a total IgA level. An elevated anti-tTG IgA and normal total IgA are highly suggestive of celiac disease, which you can confirm with endoscopy and duodenal biopsy.
Next, let’s discuss stools that are watery, and accompanied by flatulence. In this case, the history might reveal an exposure to contaminated water, and patients also report bloating with or without fever and abdominal pain.

Parasitic Gastroenteritis 10:05–10:41

Physical exam typically reveals mild abdominal tenderness and distension, with hyperactive bowel sounds. Labs might demonstrate elevated white blood cells with eosinophilia.
Stool O&P typically reveals Giardia or Cryptosporidium, which confirms parasitic gastroenteritis. On the other hand, if the stool is loose and frequent, without steatorrhea, consider hyperthyroidism.

Hyperthyroidism 10:41–11:10

In this case, your patient may report symptoms like heart palpitations, heat intolerance, and weight loss; and the lab results will be normal with negative stool studies.
To confirm, order a serum TSH and free T4; and if the TSH is low and the free T4 is elevated, diagnose hyperthyroidism. Now, let’s go back and take a look at patients who present without red flag signs or symptoms.

Red Flags Absent 11:10–11:27

In this case, you should consider conditions like lactase deficiency, toddler diarrhea, or irritable bowel syndrome. First, let’s focus on lactase deficiency.

Lactase deficiency 11:27–12:16

If your patient has diarrhea after ingesting dairy products, consider lactase deficiency, and ask your patient to avoid lactose-containing foods.
Next, assess their response to dietary modification, and if symptoms improve, diagnose lactase deficiency. Here’s another clinical pearl!
Older children and adults often develop primary lactase deficiency, which involves a gradual decline in lactase activity with increasing age.
On the flip side, secondary lactase deficiency is acquired after a gastrointestinal infection or other illness damages the intestinal mucosa, which interferes with lactase production.
Next up is toddler diarrhea. These patients are under 3 years of age and typically pass four or more large, unformed stools daily.

Toddler Diarrhea 12:16–12:58

Stools may contain undigested food and tend to become more loose as the day goes on. Caregivers will often report a high consumption of fruit juice or other sweetened drinks.
Exam findings are benign, and patients demonstrate normal growth. These findings are highly suggestive of toddler diarrhea, which is also called functional diarrhea or chronic nonspecific diarrhea.
This multifactorial condition is thought to be caused by increased gut motility as well as osmotic diarrhea from increased fructose or sorbitol intake.
Okay, let’s finish with irritable bowel syndrome, which is a diagnosis of exclusion. These patients report recurrent abdominal pain at least 4 days per month during the previous 2 months.

IBS 12:58–13:59

Additionally they have one or more of the following symptoms: abdominal pain related to defecation, a change in stool frequency, or a change in stool appearance.
Patients who fit this description can be diagnosed with irritable bowel syndrome, which commonly occurs in tandem with depression, anxiety, or fibromyalgia.
And here’s one last clinical pearl! Children with chronic constipation occasionally develop encopresis with overflow incontinence.
In this condition, impacted stool accumulates in the rectum, and the child experiences involuntary leakage of liquid stool around an impacted fecal mass.
These children appear to have diarrhea, when in reality they have constipation with overflow fecal incontinence. Alright, as a quick recap… Diarrhea refers to stools that are unusually loose or frequent when compared to a patient’s normal stooling pattern.

Review 13:59–14:16

In pediatric patients, acute diarrhea is commonly caused by infection, whereas chronic diarrhea often represents a pathologic condition or a