Pressure/Fullness Under Left Rib Cage

What Causes Pressure Under Left Rib Cage?

Pressure under left rib cage can have various causes, ranging in severity from 'troubling' to 'generally fatal'.  Finding the true cause means ruling out or confirming each possibility – in other words, diagnosis.

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Diagnosis is usually a complex process due to the sheer number of possible causes and related symptoms.  In order to diagnose pressure under left rib cage, 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 "pressure under left rib cage" as a symptom.  Here are eight possibilities (more below):
  • Hypersplenism
  • Sarcoidosis
  • Leukemia
  • Valley Fever (Coccidioidomycosis)
  • Enlarged Spleen
  • Congestive Heart Failure
  • Malaria
  • Infectious Mononucleosis

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:
multiple painful cervical nodes
much reduced sense of smell
blue/bluish fingernails
loss of appetite
frequent unexplained nausea
frequent painful inguinal nodes
long-term hoarse voice
painful cervical nodes
easy bruising
edema of the ankles/lower legs
minor joint pain/swelling/stiffness
regular unexplained nausea
... and more than 70 others

Step 3: Rule Out or Confirm each Possible Cause

A differential diagnosis of your symptoms and risk factors finds the likely cause of pressure under left rib cage:
Cause Probability Status
Hypersplenism 93% Confirm
Infectious Mononucleosis 13% Unlikely
Malaria 24% Unlikely
Valley Fever (Coccidioidomycosis) 5% Ruled out
Sarcoidosis 0% Ruled out
Leukemia 0% Ruled out
Congestive Heart Failure 0% Ruled out
Enlarged Spleen 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.

If you indicate abdominal discomfort, The Analyst™ will ask further questions including this one:
MIDDLE-LEFT abdomen: Do you experience pressure or 'fullness' below your lower left rib which is painless or slightly tender? (Do not answer this question if there is significant pain.)
Possible responses:
→ There is significant pain / don't know
→ No
→ Yes, slight pressure with no/slight pain
→ Yes, significant pressure with no/slight pain
Based on your response to this question, which may indicate no left lumbar pressure, slight left lumbar pressure or significant left lumbar pressure, The Analyst™ will consider possibilities such as:
Enlarged Spleen

Enlarged Spleen also suggests the following possibilities:

Congestive Heart Failure

In severe failure of the right ventricle, elevated venous pressures are transmitted to the portal system, leading to congestion of the spleen and splenomegaly.


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.

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.


ALL, CML, or hairy cell leukemia can cause enlargement of the spleen.

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