Chapter 92 Dehydration (Case 49)
Patient Care
Clinical Thinking
• What diagnostic tests, if any, would be useful to help you make an accurate diagnosis or formulate a treatment plan?
History
• A history of recent travel, unusual food intake, or exposure to reptiles, along with bloody diarrhea, may increase concern for bacterial gastroenteritis.
Physical Examination
• Vital signs: Tachycardia can be an early sign of dehydration, or related to fever and anxiety. Hypotension is a late and ominous finding.
• Realize that the normal range for heart rate, blood pressure, and respiratory rate varies with age.
• Clinical assessment includes pulse, blood pressure, skin turgor, decreased tearing, dry mucous membranes, a sunken fontanelle in infants, decreased urine output, and systemic signs such as lethargy.
Tests for Consideration
• Electrolytes: Bicarbonate to assess acidosis, sodium to identify hypernatremia or hyponatremia, hypokalemia secondary to potassium losses in emesis or stool. $29
• Urinalysis: If concern for urinary tract infection; specific gravity can assist in assessing degree of dehydration in older infants and children. $38
• Complete blood count (CBC): If concern for bleeding, infection, hemolytic uremic syndrome (HUS) $53
Clinical Entities: Medical Knowledge
| Gastroenteritis | |
|---|---|
| Pϕ | Viral gastroenteritis: Viruses causing gastroenteritis include rotaviruses, caliciviruses, astroviruses, adenoviruses types 40 and 41, and some picornaviruses. Viruses infect and destroy enterocytes, resulting in transudation of fluid into the intestinal lumen. They are predominantly transmitted via the fecal-oral route, with peak incidence in children 3 to 24 months of age. Cases and hospitalizations typically peak during the winter months, with up to 7% to 10 % of all pediatric hospitalizations resulting from acute gastroenteritis. Bacterial gastroenteritis: Bacterial sources of gastroenteritis include but are not limited to Salmonella, Campylobacter, Shigella, enterohemorrhagic and enterotoxigenic Escherichia coli, Clostridium perfringens and C. botulinum, Staphylococcus aureus, group A streptococcus, Yersinia enterocolitica, and Listeria monocytogenes. Most of these bacteria are the cause of foodborne-disease outbreaks resulting from multiple factors but most commonly improper food storage and poor hygiene practices of food handlers, with direct person-to-person spread being a common cause. Young children and immunocompromised patients are at highest risk for developing serious consequences. |
| TP | Infectious gastroenteritis typically presents with fever, vomiting, diarrhea, abdominal cramping, myalgias, and varying degrees of dehydration. Although no one clinical feature distinguishes viral from bacterial gastroenteritis, watery nonbloody stools without mucus are more likely viral. Symptoms may change as the disease develops and may differ within a family. |
| Dx | Diagnosis is primarily clinical. It is most important to assess for signs of dehydration and evidence for competing diagnoses that would require a different approach. In a straightforward case without severe dehydration, no diagnostic tests are needed unless a bacterial etiology is suspected, in which case stool cultures may be indicated. |
| Tx | Treatment of both viral and bacterial gastroenteritis is supportive and primarily depends on the patient’s degree of dehydration and ability to maintain hydration. |
| Antibiotic therapy should be administered in select cases to those in whom a pathogen has been isolated with ongoing symptoms after identification of the pathogen (such as Shigella and Clostridium difficile) or in patients who develop bacteremia, sepsis, or other extraintestinal infections such as osteomyelitis or meningitis.1,2 See Nelson Essentials 112. | |
| Milk-protein allergy | |
|---|---|
| Pϕ | Cow or milk is a common cause of food allergy, affecting about 2.5% of children in the first 2 years of life. These allergies may be IgE mediated, causing gastrointestinal (GI) anaphylaxis, or non–IgE mediated, which causes dietary protein–induced proctitis/colitis, enteropathy, or enterocolitis. Most infants with milk-protein allergy develop tolerance with resolution of symptoms by 3 years of age. |
| TP | Patients with IgE-mediated allergy causing GI anaphylaxis typically present with acute-onset nausea, vomiting, abdominal pain/cramping, and/or diarrhea within minutes to 6 hours after ingestion. Patients with non–IgE mediated allergies have more subacute or chronic symptoms. Infants with protein-induced enterocolitis are often ill-appearing and present with chronic GI symptoms of vomiting, diarrhea, and malabsorption resulting in failure to thrive (FTT), and/or melena. However, patients with dietary protein–induced proctitis/colitis, present with microscopic gross blood in the stool. Although the blood loss may cause mild anemia, these patients are unlikely to be ill-appearing or have FTT as seen in patients with dietary protein–induced enterocolitis. Symptoms typically resolve with removal of the causative agent.3 |
| Dx | Dietary trials and skin tests are used for diagnosis. |
| Tx | Treatment includes removal of the causative agent and supportive care with intravenous fluid hydration and electrolyte imbalance correction an needed. (See Chapter 34, Diarrhea.) See Nelson Essentials 129. |
| Pyloric Stenosis | |
|---|---|
| Pϕ | In infantile hypertrophic pyloric stenosis the pylorus is elongated and thickened, leading to near-to-complete obstruction of the gastric outlet. The etiology is unclear, but most likely multifactorial, ranging from genetic predisposition to environmental factors. Administration of macrolides (specifically oral erythromycin) is associated with increased risk for developing pyloric stenosis. |
| TP | Patients typically present between 3 and 6 weeks of age with nonbilious projectile emesis immediately after feeds. It occurs in 2 to 3.5 live births, with a male predominance. The so-called “hungry vomiter” is hungry soon after vomiting and demands to be refed quickly. In the past, infants have been described as being emaciated and dehydrated at presentation with electrolyte abnormalities revealing a hypochloremic metabolic alkalosis; now with earlier diagnoses, infants with pyloric stenosis are typically well nourished with no or very minimal electrolyte abnormalities. |
| Dx | The classic teaching is a palpable “olive” on physical examination (unlikely to be palpable unless the patient is completely relaxed). Pyloric ultrasound is the imaging study of choice for diagnosis. Before the advent of ultrasonography, upper gastrointestinal contrast study was used to confirm diagnosis with the “string sign” demonstrated by the slow passage of barium through the narrowed pyloric channel. In addition, electrolyte levels should be obtained for these infants to screen for the electrolyte abnormalities mentioned above. |
| Tx | In the emergency department, ensure adequate hydration for these patients. Patients with normal electrolyte levels and mild dehydration may be managed with maintenance intravenous fluids (IVF). If the patient is moderately to severely dehydrated, IVF resuscitation with isotonic solution should be administered. Patients should not undergo surgical correction, the definitive treatment for this condition, until after any metabolic alkalosis and volume depletion have been corrected have been corrected because metabolic alkalosis has been associated with an increased risk for postoperative apnea in these infants.4 See Nelson Essentials 128. |
| Intussusception |
|---|
| See Chapter 94, Abdominal Pain. |
Only gold members can continue reading. Log In or Register to continue
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
