Approach to vomiting (newborn and infant): Clinical sciences

Vomiting, also known as emesis, is defined as the forceful expulsion of gastrointestinal contents, and is a common symptom caused by a wide variety of underlying conditions. Based on the vomitus characteristics, vomiting can be described as bilious or non-bilious.

Now, if a newborn or infant presents with vomiting, perform an ABCDE assessment to determine if the patient is unstable or stable. If unstable, stabilize their airway, breathing, and circulation; obtain IV access, and if needed, provide IV fluids. Next, put your patient on continuous vital sign monitoring, including heart rate, blood pressure, and pulse oximetry, and if needed, provide supplemental oxygen.

You may also need to make your patient NPO and insert a nasogastric tube to decompress the stomach and prevent further vomiting. Finally, if you suspect an underlying infection, don’t forget to start broad-spectrum antibiotics.

Now, here’s a clinical pearl! Infants who are unstable and present with vomiting may have peritonitis, intestinal perforation, or shock, especially if there’s also abdominal distension or tenderness. In addition to acute management, consult your surgical team for consideration of an emergent laparotomy, and consider starting broad spectrum IV antibiotics.

Now, let’s go back to the ABCDE assessment and take a look at stable patients presenting with vomiting. Start by obtaining a focused history and physical examination. Next, assess for bilious emesis, which caregivers may describe as green or bright yellow. It’s critical to identify bilious emesis quickly, as it suggests an intestinal obstruction that requires emergency surgical intervention!

Okay, first, let’s focus on nonbilious emesis. In this case, your next step is to assess for projectile vomiting. If your patient has non-projectile vomiting, assess the onset of vomiting, which could be either sudden or gradual. In this context, a sudden onset means that vomiting developed quickly over the course of 24 to 48 hours.

Let’s start by focusing on infectious gastroenteritis. In this case, caregivers will typically report a known sick contact, diarrhea, and possibly fever. The physical examination will reveal a soft abdomen, without rebound or guarding. Additionally, you will notice reduced skin turgor, suggesting dehydration. Here, you can make a clinical diagnosis of infectious gastroenteritis, which can result from viral or bacterial infections.

Next up are urinary tract infections, or UTIs for short. These patients are usually biologically females or uncircumcised males, and their caregivers typically report fever and irritability, as well as strong-smelling urine. In this case, you should consider a UTI and order a urine dipstick and urine culture. Additionally, order a blood culture if your patient is less than eight weeks old or if they are ill-appearing. If the urine dipstick reveals positive leukocyte esterase with or without nitrites, blood, or protein; and the urine culture is positive with or without a positive blood culture, diagnose a UTI.

Next up is increased intracranial pressure! In this case, caregivers might report altered mental status, irritability, or even seizures. They may also report vomiting after waking from sleep. Additionally, the physical exam could reveal a bulging fontanelle, papilledema, abnormal reflexes, or cranial nerve palsy. You may even detect the Cushing triad of bradycardia, irregular respirations, and widened pulse pressure. With these findings, you should suspect increased intracranial pressure and order a head CT or MRI. If the imaging reveals findings suggestive of increased pressure within the cranium, you can confirm the diagnosis.

Finally, let’s discuss food protein-induced enterocolitis syndrome or FPIES for short. This is usually associated with episodes of delayed vomiting and diarrhea after food exposure that improves once the offending food is removed from the diet. For this patient, diagnose FPIES, which is a non-IgE-mediated allergic reaction often caused by proteins found in cow’s milk, soy, rice cereal, or oatmeal.

Alright, let’s switch gears and talk about patients with nonbilious, non-projectile vomiting that has a gradual onset of several days or weeks.

Let’s start with an inborn error of metabolism. Your patient will usually present with episodic vomiting, poor feeding, and lethargy, with or without an abnormal newborn screen. Additionally, the physical exam may reveal slow growth, a developmental delay, organomegaly, or unusual body odor. In this case, you should consider an inborn error of metabolism, and order labs to evaluate for metabolic disorders, such as amino acid and urea cycle defects.

These labs should include serum amino acids, urine organic acids, urine ketones, carnitine profile, ammonia, lactate, and pyruvate. The presence of any abnormal findings consistent with an inborn error of metabolism will confirm the diagnosis.