Pernicious anemia twists Downton Abbey finale

photo from Wikimedia Commons

photo from Wikimedia Commons

Downton Abbey brought us history, drama and a peek at bygone lifestyles.  It also used diseases in plot development: eclampsia, the Spanish flu, stomach ulcers, shell shock, war wounds, cataracts, palsy and many others found their way into the story lines.  The final episodes featured Pernicious Anemia, diagnosed in Lord Merton.  21st Century viewers might have been left wondering why this was such a big deal in the plot.  Why didn’t Lord Merton’s doctor just give him a B12 injection so life can go on?  What viewers might not understand is that while pernicious anemia is now easily treated, in the early 20th Century there were no injections.  Survival after diagnosis with pernicious anemia was 1-3 years, with rapidly deteriorating quality of life.  A perfect plot twist to put Lord Merton in danger.

Pernicious Anemia is caused by a defect in vitamin B12 absorption, which is controlled by intrinsic factor (IF), a specialized carrier molecule made in the stomach.  Without IF, B12 is not absorbed and all the metabolic systems that depend on B12 deteriorate.  B12 is involved in red blood cell production, and a unique type of anemia develops.  Enlarged red blood cells are a key sign, accompanied by the usual symptoms of anemia: fatigue, shortness of breath, cold extremities, irregular heart beats and pale or yellowish skin tone.

In addition to the anemia, B12 deficiency can cause nerve damage leading to tingling or numbness in hands and feet, and GI effects like nausea, heartburn and diarrhea.  One classic sign of B12 deficiency is a sore tongue that is smooth and red.

Pernicious anemia, which affects 1-2% of older adults, has been recognized for centuries, but the link to a vitamin absorption problem was not understood.  In the late 1920’s and 30’s, doctors experimented with treatments that involved consuming raw liver (1/2 lb a day!), raw liver juice or liver extract.  B12 is stored in the liver, so in fact the patients were consuming large doses of B12 on this regimen, and enough was absorbed passively to subdue deficiency symptoms.  Eventually injections of B12 were developed, eliminating the need for all that daily liver.  But in Lord Merton’s time there were no injections, no knowledge of the curative powers of liver and no understanding of vitamin B12.

Now we have more accurate ways to diagnose B12 deficiency and sort out simple deficiency from pernicious anemia.  IF production gradually decreases with age, and older people are more prone to deficiency from malabsorption.  B12 deficiency in the elderly affects cognition, and sometimes deficiency symptoms are misdiagnosed as dementia.  Use of antacids or other medications that interfere with stomach acid can also adversely impact B12 absorption.  Stomach surgery is another risk factor, as are malabsorption syndromes such as celiac disease or intestinal bacterial or parasitic infections.

Another risk factor: a vegan diet.  B12 is only found in animal-sourced foods.  It is not found in plant foods.  A vegan who does not pay attention to this issue is at risk for deficiency.  Worst case scenario: an elderly person who eats little meat/dairy/eggs and takes one or more drugs that impact stomach acidity.

It’s not clear what tests Lord Merton had that resulted in his diagnosis.  Current tests may include a B12 blood level, measurement of by-products of B12 metabolism, measurement of red blood cell volume and hemoglobin levels, and B12 absorption tests.  Luckily for Lord Merton, he was eventually found to have a simple anemia, presumably iron-deficiency.  Which didn’t exactly make sense, since iron deficiency anemia has distinctly different effects on red blood cells.  But it did allow for a happier ending, and after all the other tragedies — medical and otherwise — the happiness was welcome.

You can find more detailed information on vitamin B12 and pernicious anemia from:

National Library of Medicine

National Institute of Health

Linus Pauling Institute

National Heart Lung and Blood Institute

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