If one looks up the word pernicious in the dictionary, it can be seen to be defined as “that will destroy or ruin; causing great harm or damage; injurious”.  Over many years, it was known that the most common form of anemia due to iron deficiency caused weakness and pallor.  However, as long ago as 1855, Thomas Addison recognized that there was an unusual form of anemia that was associated with worsening degenerative changes especially involving the spine.  Patients with this form of anemia developed worsening weakness, numbness and tingling of the extremities, difficulty walking and an eventual fatal outcome.  The anemia didn’t seem to be helped at all by providing iron supplements for the person.

     Over many years research eventually demonstrated that this form of anemia was due to Vitamin B-12 deficiency.  Research eventually showed that special cells in the stomach secrete a protein that binds to Vitamin B-12 in your diet and allows this the complex of vitamin B-12 protein to be absorbed into the body.  Patients with pernicious anemia lacked this protein called “intrinsic factor”  and they could not absorb vitamin B-12 without it.  Note that a “vitamin” is defined as an essential body component that the body is unable to make for itself.

      It turns out that intrinsic factor is produced by the same stomach cells that make acid to help digest our food.  Patients with pernicious anemia lacked these cells because the patients had become allergic to these cells in their own stomach.  Eventually, the acid producing cells in the stomach all died and the person no longer produced intrinsic factor and also had no acid at all in their stomach.  Without intrinsic factor to help them absorb Vitamin B-12, they eventually became Vitamin B-12 deficient and developed pernicious anemia.  Fortunately, acid is not essential for humans to digest their food and there are no ill effects from the absence of stomach acid.

    In 1948, the Merck Pharmaceutical Company in the United States and Glaxo Pharmaceutical Company in England both produced Vitamin B-12 in pure form that could be injected.  At that point, the problem of pernicious anemia was solved.  Even though the person did not have intrinsic factor in their stomach to help them absorb Vitamin B-12, the pure product could be injected on a monthly basis and all the problems of pernicious anemia were stopped.

     Today, pernicious anemia is very easily treated.  The major problem is one of diagnosis.  It tends to be an illness of elderly individuals with non-specific symptoms.  When an elderly person complains of weakness, memory loss and inability to walk normally, sometimes the cause is inappropriately attributed to the person “just getting older”.  Missing the diagnosis of Vitamin B-12 deficiency is a tragedy because the condition can be effectively treated to prevent further damage.  Unfortunately, those central nervous system abnormalities that have already occurred not reversed by starting Vitamin B-12 but progression of the problem is stopped.

     There is a second reason for telling this story and it has to do with modern medications.  There is a family of medicines made up of Prilosec, Nexium, Prevacid, Protonix, and Aciphex.  All of these problems specifically inhibit the acid making capability of the stomach.  A patient recently noted that he had been taking these medications for several years and wondered if they were safe.  He wondered if turning off the stomach acid didn’t have some adverse effect, perhaps causing a cancer.  This person had read several medical books and learned that when a body product such as stomach acid is turned off, the body works very hard to turn the stomach acid back on.  The above person wondered if the system that makes stomach acid wouldn’t get over stimulated and perhaps degenerate into a malignancy.

     Pernicious anemia provides an answer to that question.  Here was a naturally occurring disease in which the person became allergic to their own stomach acid producing cells deleting all the stomach acid production.  Yet over many years time, it’s been noted that there is no increased incidence of stomach cancer in patients with pernicious anemia.  Fortunately, for the last fourteen years since Prilosec was first introduced on the market, there has been no increase in the incidence of stomach cancers in patients using these drugs.  It might be added at this point, that the class of drugs called “proton pump inhibitors” mentioned above appear to be remarkably safe with very few side effects.

     The healthcare professionals at your local clinic are aware of these considerations.  When patients come in with anemia problems or with abnormalities in their gait, or memory/thinking impairment, the potential for Vitamin B-12 deficiency is routinely examined.  In addition, patient safety remains a paramount consideration.  To this time, it appears that the proton pump inhibitor class of drugs is very safe and not associated with the generation of a malignancy.