Elderly Abdominal Pain-Know the Ischemia!

Elderly abdominal pain is always a conundrum. Even catastrophic, life threatening diagnoses can present with vague and mild symptoms. One confusing area-that has multiple variants- is the issue of ischemic intestinal disease.  In this realm of diseases, note that the ideal way to remember the presentations is to think about and thoroughly understand the source of the ischemia in the first place. Relating this physiologic origin to the clinical presentation in the clinic will assist your memory and recognition skills. Remember, the eyes cannot see what the mind does not know!

While I will explore the permutations of ischemic intestinal disease (IID) shortly, recall that all IID, regardless of etiology- has risk factors. Keep these in mind.

Risk Factors for Ischemic Intestinal Disease

• Atherosclerosis
• Recent MI
• Atrial fibrillation (be sure to listen to the pulse on your visit, as the a-fib could be new onset!)
• Dilated Cardiomyopathy
• Hypovolemia
• Valvular disease
• Advanced age
• Intra-abdominal malignancy (see thrombosis below)   

Now, let's review the variety of issues with IID.

Chronic Mesenteric Ischemia 

• Note the chronicity.
• Is an issue of low flow, not actual occlusion.
• Resembles intestinal angina, often see post prandial pain. Crampy and poorly localized.
• Phagophobia- actual weight loss because the angina is triggered by intestinal demand.
• "Classic patient"-Female over 60 with CV risk factors, past negative workup for cancer (due to weight loss), with several months of pain, and has been told she has irritable bowel syndrome (recall irritable bowel syndrome is usually a "young person's" disease!).
• 10% are guaiac postive, 60-80% have an abdominal bruit. 

Acute Mesenteric Ischemia

• Is the usual pain out of proportion to exam.
• Usually involves the superior mesenteric artery (SMA)
• Can be embolic (clot forms in heart from a-fib, then breaks off and lodges in the SMA), or can be thrombotic (just like cardiac angina can occlude to the point of a MI, the above chronic mesenteric ischemia can progress to total occlusion and become an acute "intestinal heart attack" via thrombosis).  
• Triggers for the thrombosis can be infection or abdomen trauma. 
• Classic triad is 1.formal "acute abdomen pain", with 2.cardiac disease and 3.acute GI emptying (forceful nausea, vomiting and bowel evacuation).
• Mortality is 70-90%. Translation- if this elderly acute abdomen is missed the lawyers will come calling!
• Recall pain out of proportion to exam---the patient is writhing!

Mesenteric VENOUS Thrombosis

• is 5% of the acute ischemias, but can present in a sub-acute manner
• I predict this is the one most unknown/overlooked.
• Cardinal feature is that the patient has an underlying hypercoaguable state. Remember one of the above risk factors is "abdominal malignancy".
• Involves superior mesenteric vein
• 50% of these cases have a family history of venousthromboembolism!
• Usually mid abdomen, colicky pain and unlike the arterial acute ischemias, patient often waits over 48 hours to present.
• Key risk factors: family history of VTE, female, smoker, birth control pills, recent abdomen trauma/MVA, other risk factors for VTE like malignancy.
• over 50% have heme pos stool.
• IN SUMMARY THIS IS A DVT OF THE INTESTINE. SO RISK FACTOR ASSESSSMENT IS IMPERATIVE.

NON- occlusive Mesenteric Ischemia (NOMI) 

• This is basically secondary intestinal ischemia from a primary inciting insult, such as MI, CHF, sepsis, or shock.
• Insidious onset of hours to days, and 25% lack abdomen pain, and rather have a quiet, distended abdomen without rebound.
• Often can occur post cardiac surgery or dialysis.
• Attacks the aged (over 70) with severe atherosclerosis ( dialysis, legion stents, etc.)
• Physiologically is hypoperfusion to watershed areas of splenic flexure and distal sigmoid.
• Key here is not to ignore the "rotting intestine" as you focus on the primary insult.

 Respect elderly abdomen pain, as it can hurt the patient and the medical provider severely!

( Summary source: "General Surgery, Part II The Acute Abdomen" Lecture by Americo D. Fraboni, MD for AAFP Board Review Manual, 2013 edition. Published by American Academy of Family Physicians)