Unexplained Nausea

What Causes Unexplained Nausea?

Unexplained nausea can have various causes, ranging in severity from 'minor' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose unexplained nausea, we could:
  • Research the topic
  • Find a doctor with the time
  • Use a diagnostic computer system.
The process is the same, whichever method is used.

Step 1: List all Possible Causes

We begin by identifying the disease conditions which have "unexplained nausea" as a symptom.  Here are eight of many possibilities (more below):
  • Stomach Ulcers
  • Pyroluria
  • Valley Fever (Coccidioidomycosis)
  • Irritable Bowel Syndrome
  • Hypersplenism
  • Ovarian Cancer
  • Hyperparathyroidism
  • Copper Toxicity

Step 2: Build a Symptom Checklist

We then identify all possible symptoms and risk factors of each possible cause, and check the ones that apply:
being a recovered alcoholic
minor joint pain/swelling/stiffness
orange stool color
green stool color
sensitivity to bright light
being prone to 'stitches'
history of broken bones
chronic dry cough
general flatulence
frequent aspirin use
right lower abdominal ache
significant red blood in stools
... and more than 80 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of unexplained nausea:
Cause Probability Status
Pyroluria 93% Confirm
Copper Toxicity 13% Unlikely
Ovarian Cancer 26% Unlikely
Stomach Ulcers 1% Ruled out
Hypersplenism 0% Ruled out
Irritable Bowel Syndrome 0% Ruled out
Hyperparathyroidism 0% Ruled out
Valley Fever (Coccidioidomycosis) 0% Ruled out
* This is a simple example to illustrate the process

Arriving at a Correct Diagnosis

The Analyst™ is our online diagnosis tool that learns all about you through a straightforward process of multi-level questioning, providing diagnosis at the end.

In the Gastro-Intestinal Symptoms section of the questionnaire, The Analyst™ will ask the following question about unexplained nausea:
How often do you suffer from nausea that is not due to a known cause such as pregnancy or hunger?
Possible responses:
→ Don't know
→ Never / very rarely
→ Occasionally - a few times per year
→ Regularly - a few times per month
→ Often - several times per week
Based on your response to this question, which may indicate no unexplained nausea, occasional unexplained nausea, regular unexplained nausea or frequent unexplained nausea, The Analyst™ will consider possibilities such as:
Congestive Heart Failure
Accumulation of fluid (due to congestive heart failure) in the liver and intestines may cause nausea, abdominal pain, and decreased appetite.
Delayed Gastric Emptying (Gastroparesis)
Approximately 50% of patients with chronic idiopathic nausea and vomiting evaluated in referral centers have gastroparesis.  A viral etiology was suggested in these patients and in other series when there was an acute onset of nausea and vomiting with other features of a viral illness (fever, myalgia, diarrhea, fatigue, or abdominal cramping).
Hypersplenism
Hypersplenism is sometimes referred to as enlarged spleen (splenomegaly), but in fact an enlarged spleen is one of the symptoms of hypersplenism.  What differentiates hypersplenism is its premature destruction of blood cells.
Leukemia
ALL, CML, or hairy cell leukemia can cause enlargement of the spleen.
Infectious Mononucleosis - Mono
About 50-75% of people with mononucleosis have some spleen enlargement, usually seen two to three weeks after they first become sick.  Whether or not the spleen is enlarged, people who have mono should not lift heavy objects or exercise vigorously – especially participating in contact sports – for two months after they get sick, because these activities increase the risk of rupturing the spleen, which can be life-threatening.  If you have mono and get a severe sharp, sudden pain on the left side of your upper abdomen, go to an emergency room immediately.
Fluoride Toxicity
Nausea is an early sign of fluoride toxicity.
Gastroenteritis
Acute gastroenteritis is a common cause of acute care-seeking and is second only to the common cold as a cause of lost work time.  Bacterial, viral, and parasitic pathogens cause this illness which is characterized by diarrhea and/or vomiting.  Vomiting is especially common with infections caused by rotaviruses, enteric adenovirus, Norwalk agent, and calicivirus.
Zinc Toxicity
Symptoms of zinc toxicity include nausea, vomiting and fever.

Related Questions

Gastro-Intestinal Symptoms