Approach to vomiting (acute): Clinical sciences

Vomiting refers to the forceful expulsion of the stomach contents, which usually occurs after mechanical or chemical stimulation of emetic receptors in the brain. Life-threatening causes of acute vomiting lasting less than 4 weeks include surgical emergencies and medical conditions associated with an acute abdomen, severe gastrointestinal hemorrhage, or increased intracranial pressure, or ICP. Less critical causes include gastrointestinal and non-gastrointestinal intra-abdominal conditions as well as various extra-abdominal systemic and physiological conditions.

Alright, if a patient presents with acute vomiting, first perform an ABCDE assessment to determine if they are stable or unstable. If unstable, stabilize the airway, breathing, and circulation. Then, obtain IV access, start IV fluid resuscitation, and continuously monitor vital signs. If your patient is actively vomiting, keep them NPO, and consider NG tube placement to decompress the bowel and prevent aspiration. Finally, consider elevating the head of the bed. After initiating acute management, obtain a focused history and physical exam, and order labs, including a CBC, CMP, and serum lactate level.

Let’s start by discussing surgical emergencies. Here, patients typically present with severe abdominal pain, and some may have bilious emesis or evidence of gastrointestinal bleeding, such as coffee-ground emesis, hematemesis, melena, or hematochezia. Physical exam might reveal altered mental status and signs of shock, such as tachycardia and hypotension. Patients with an acute surgical abdomen typically have severe generalized abdominal tenderness with distension, rebound, and guarding. Labs often show leukocytosis, electrolyte abnormalities, and elevated serum lactate levels.

These findings should immediately make you consider an acute abdomen, abdominal sepsis, or gastrointestinal hemorrhage. These are surgical emergencies requiring urgent operative intervention, so promptly get an abdominal X-ray. You can also consider a CT scan of the abdomen and pelvis, if X-ray findings are nonspecific, and if your patient is not actively decompensating.

X-ray may demonstrate red-flag findings like pneumoperitoneum, indicating perforation; or a severely dilated bowel with air-fluid levels; indicating obstruction. If you get a CT scan, it may reveal additional red flag findings, like bowel dilation with a transition point; a whirl sign, which represents twisting of the mesentery or volvulus; pneumatosis intestinalis or pneumoperitoneum, a sign of perforation; bowel thickening with fat stranding, which suggests inflammation; or mesenteric ischemia. Any one of these imaging findings indicates a surgical emergency.

Now let’s talk about increased intracranial pressure, another life-threatening cause of vomiting. In this case, the patient might present after a severe headache, head trauma, or a seizure. On physical exam, you’ll often see altered mental status and the Cushing triad, which consists of bradycardia, systolic hypertension with a widened pulse pressure, and irregular respirations.

Depending on the underlying cause, you might also observe nuchal rigidity, anisocoria, paralysis or paresthesia, or a cranial nerve deficit. In this case, immediately consider increased intracranial pressure, and get a head CT scan to find the underlying cause. Findings typically demonstrate evidence of intracranial pathology, such as hemorrhage, hydrocephalus, cerebral edema, brain herniation, or a mass. If you see any of these, that’s a medical emergency.

Now that we have discussed unstable patients, let’s take a look at stable ones. First, perform a focused history and physical exam. History typically reveals abdominal pain, nausea, and vomiting; occasionally with fever, malaise, or changes in bowel habits. On exam, you'll often notice abdominal tenderness and distention. With these findings, consider intra-abdominal causes of vomiting.

Let’s start by assessing for an underlying gastrointestinal condition. First up is infectious gastroenteritis. Your patient will likely report sick contacts or exposure to raw, undercooked, or spoiled food; and they'll often develop diarrhea later in the illness. On exam, you might notice signs of dehydration, like decreased skin turgor and dry mucous membranes, along with mild abdominal tenderness. Here, consider infectious gastroenteritis, which you can usually diagnose from clinical findings alone. However, if you need to determine disease severity, consider ordering labs, including CBC and CMP, which might show mild leukocytosis and electrolyte abnormalities such as hyper- or hyponatremia. These findings further support the diagnosis of infectious gastroenteritis.

Let’s move on to acute appendicitis. Affected patients typically report periumbilical pain that localizes to the right lower quadrant, in combination with anorexia, nausea, and vomiting. On exam, you'll usually find tenderness at McBurney point, or even a positive Rovsing, psoas, or obturator sign. With this clinical presentation, consider acute appendicitis.

Next, order labs, including a CBC, CMP and serum lactate level. Additionally, obtain an abdominal ultrasound, or consider a CT scan of the abdomen and pelvis. Keep in mind that ultrasound is preferred over CT scan, since it can avoid excessive radiation exposure. The CBC classically demonstrates leukocytosis; and on ultrasound, you'll usually see a dilated appendix with wall thickening. If you order a CT scan, it will reveal an inflamed appendix with periappendiceal inflammatory changes, like fat stranding. These findings confirm acute appendicitis.

Now let’s switch gears and discuss gastritis. Patients often report upper abdominal pain, early satiety, and occasionally, frequent NSAID use; while the exam typically reveals epigastric tenderness. With these findings, consider gastritis, and order a CBC and an EGD. In most cases, labs are unremarkable, but EGD will reveal gastric mucosal inflammation, erythema, and erosions; confirming the diagnosis of gastritis.