Differential Diagnosis for Vomiting

When a patient presents with vomiting, it's crucial to take a comprehensive history to guide the differential diagnosis. Key points in the history include the onset and duration of vomiting, the nature of the vomit (e.g., bile, blood, food), associated symptoms (e.g., abdominal pain, fever, diarrhea), and any recent travel or food intake.

Single Most Likely Diagnosis

• Gastroenteritis: This is often the most common cause of vomiting, especially if the patient has other symptoms like diarrhea, fever, and abdominal cramps. The history of recent travel, food poisoning, or exposure to someone with similar symptoms supports this diagnosis.

Other Likely Diagnoses

• Food Poisoning: Similar to gastroenteritis but typically related to the consumption of contaminated food. The history of eating undercooked meat, seafood, or dairy products can point towards this diagnosis.
• Viral Gastroenteritis (Stomach Flu): Presents with vomiting, diarrhea, and sometimes fever. It's highly contagious and can spread quickly in households or communities.
• Pregnancy-related Morning Sickness: In female patients of childbearing age, morning sickness can be a cause of vomiting, especially if there's a missed period or a positive pregnancy test.
• Medication-induced Nausea and Vomiting: Certain medications can cause vomiting as a side effect. A thorough medication history is essential.

Do Not Miss (Deadly if Missed) Diagnoses

• Appendicitis: Although abdominal pain is the hallmark, vomiting can be a presenting symptom, especially in children. A history of migrating abdominal pain and fever is critical.
• Intestinal Obstruction: Severe abdominal pain and vomiting, especially if the vomit is bile-stained, can indicate an obstruction. This is a surgical emergency.
• Pancreatitis: Severe abdominal pain radiating to the back and vomiting can be symptoms of pancreatitis. A history of gallstones or alcohol abuse is relevant.
• Meningitis: In severe cases, especially in children, vomiting can accompany headache, fever, and stiff neck, indicating meningitis.

Rare Diagnoses

• Increased Intracranial Pressure (ICP): Vomiting can be a sign of increased ICP, especially if accompanied by headache and visual disturbances.
• Diabetic Ketoacidosis (DKA): In diabetic patients, DKA can present with vomiting, abdominal pain, and altered mental status.
• Addisonian Crisis: Rarely, vomiting can be part of an Addisonian crisis, characterized by hypotension, abdominal pain, and electrolyte imbalances in patients with adrenal insufficiency.
• Porphyrias: A group of rare genetic disorders that can cause acute episodes of vomiting, abdominal pain, and neurological symptoms.

Treatment and Referral

Treatment depends on the underlying cause. For most cases of gastroenteritis and food poisoning, supportive care with hydration and rest is sufficient. However, if there are signs of dehydration, severe abdominal pain, fever above 101.5°F, or if the patient is unable to keep fluids down, referral to the ER is necessary. Additionally, any suspicion of the "Do Not Miss" diagnoses warrants immediate medical attention.