Nausea is the unpleasant sensation of being about to throw up. Nausea may be secondary to a disorder of the GI tract, however, other causes are not uncommon.
Nausea may or may not be followed by vomiting. Vomiting is the actual throwing out of gastric contents. Vomiting is a protective reflex in animals and humans to get rid of ingested toxic particles.
What Causes Nausea and vomiting?
Since nausea is a very non-specific symptom, the causes are multiple. Nauseous feelings can be due to a disorder of the gastrointestinal tract, however, often it is caused by disorders other than the gastrointestinal tract. Nausea treatment and classes of medicines used to treat vomiting are not discussed here.
Abdominal/ gastrointestinal causes:
- Acute gastroenteritis: Acute gastroenteritis may be caused by toxins, viruses, bacteria or parasitic infections of the gastrointestinal tract. It may present as vomiting, diarrhea, abdominal pain and fever.
- Acid peptic disease: Gastroesophageal reflux disease, gastric and duodenal ulcers can all cause heartburn, nausea, vomiting and epigastric pain.
- Gastric outlet and intestinal obstruction: These conditions are of serious nature and usually present with vomiting that lasts for more than one month. Weight loss and features of malnutrition are obvious in patients with longstanding disease.
- Hepatitis and cholecystitis: Both these conditions can present with fever, upper right abdominal pain, nauseating feelings, vomiting, and anorexia. Liver function test and ultrasound abdomen may help in the diagnosis.
Neurological causes of nausea and vomiting:
- Migraine: Recurrent episodes of a headache, blurred vision, nauseous feelings, and vomiting are the classical manifestations of a migraine attack that may last for hours to days.
- Raised intracranial pressure: Raised intracranial pressure is usually associated with a headache, hypertension, altered mental state. Causes of raised intracranial pressure include a brain tumor, brain infection and certain other metabolic causes like hyponatremia.
- Vestibular neuritis: Vestibular neuritis presents with vertigo, ringing in the ears and nauseous feelings. It may be caused by a viral infection of the vestibular system or Meniere disease.
Metabolic causes of nausea and vomiting:
- Vomiting during pregnancy: Pregnant females in their first trimester may develop severe vomiting especially after waking up early in the morning. Females with multiple pregnancies and those with a molar pregnancy, especially have intractable nausea that does not respond to conventional therapy.
- Kidney and liver diseases: Patients who have advanced liver and kidney diseases may make a person nauseous and cause vomiting. Renal function tests, liver function test, and abdominal scans may help in the diagnosis.
- Endocrine disorders: These include Diabetes ( diabetic gastroparesis), adrenal insufficiency, hyperparathyroidism, and thyrotoxicosis.
- Hypertension: Uncontrolled hypertension especially hypertensive encephalopathy (Blood pressure of greater than 180/120 mmHg) is associated with a nauseating feeling, vomiting, headache, and altered mental state.
Miscellaneous causes of vomiting:
- Drugs and medications: Multiple drugs including painkillers, oral contraceptive pills, diabetic medicines, opioids, steroids, antiparkinson medicines, iron supplements, and alcohol can cause nauseating feelings and vomiting. Chemotherapy can be highly emetogenic and causes severe vomiting.
- Psychiatric causes: Bulimia and anorexia nervosa, depression and psychogenic vomiting may be very difficult to treat and do not respond to antiemetic medications.
- Postoperative vomiting: Postoperative vomiting may be secondary to drugs or transient ileus.
- Infections: Infections like pelvic inflammatory diseases, sepsis, liver, and perinephric abscesses can all be associated with a nauseating feeling and vomiting.
Your symptoms might be leading you to a diagnosis …
- Vomiting in the early morning: Conditions causing early morning nausea and vomiting include Pregnancy (first trimester), alcohol abuse, depression and Uremia (renal disease)
- Nauseated after eating: Nausea after eating is usually caused by a stomach ulcer, gastritis, stomach cancer, and psychiatric causes.
- Nausea that occurs in waves: Intracranial hypertension and gastric outlet obstruction may be associated with nausea occurring in waves.
- Nauseated for years is usually psychogenic
- Nausea that is associated with bilious vomiting occurs in patients who have had gastrectomy (stomach removed surgically) and postoperative patients.
- Vomiting with foul-smelling vomitus occurs in distal gut obstruction.