Related Conditions     • Overview
    • Prone to OI
        –  CFS
        –  Prolonged ICU Stays
    •  Associated with OI
    •  Secondary to OI

Secondary Conditions:
Conditions That Develop After OI Conditions

These are conditions that develop after the main condition, which is the orthostatic intolerance, either POTS or orthostatic hypotension (NMH).

Secondary conditions can develop either because of the first condition or they can be "complications" of the first. They might also be related to the treatment or medications used. For our purposes, it is not important which came first, the chicken or the egg. We are interested in knowing that they exist so that we can be alert to them.

These are important things for you and your physician to watch for. They may require testing to see if they exist. This could be done every few months or every year, depending on the condition. Some you may be able to avoid or make them less intense if you take precautions. If they develop, they may need specific treatment.

  • Anemia
  • Bones-Osteopenia
  • GI-Stomach-Intestine
  • High BP at Night (Supine Nocturnal Hypertension)

How anemia affects OI: The red blood cells in the blood pick up oxygen in the lungs and carry it to all the cells of the body. If there are not enough cells, then not enough oxygen gets to the cells. If you have OI AND anemia, it can make the symptoms from orthostatic intolerance worse.

HOW IT RELATES TO OI: There are limited reports investigating the rate of anemia in people with POTS. How POTS relates to the anemia is not addressed. In the literature on prolonged bedrest, the red blood cell mass (number of cells) decreases early. The bone marrow where red blood cells are created is replaced with fat, which is thought to be related to the lower number of red blood cells.Winkelman There is limited information about how or when the body goes back to making more red blood cells and how the bone marrow is corrected.

What is anemia?  Anemia describes the number of red blood cells. There are not are many red blood cells that would be "normal" for a person of this age and size. There are different names for the kinds of anemia.The kind of anemia depends on what is causing it.

"Normochromic, normocytic anemia: This is the type that has been reported with OI and POTS. It is also reported with autonomic failure7 and prolonged bedrest. "Normochromic, normocytic anemia" means the number of red blood cells is lower than normal but there is the right amount of hemoglobin (it carries the oxygen)(normochromic). They are the right size (normocytic).

"Iron-deficient anemia": The body needs iron to create red blood cells. If there is not enough iron in the body, the anemia would be "iron deficiency" anemia. The blood tests would show there is not enough iron in the body. The body "saves" iron - red blood cells are constantly being developed, worn out and destroyed by the body. The body "saves" the iron, stores it and uses it to make new red blood cells. It's often called the "iron store". If there isn't iron stored, the body cannot make normal red blood cells.

The" iron store" runs out for 2 reasons.

  1. if the blood is actually lost from the body by bleeding. If you have had an injury or surgery with blood loss, that would be an obvious reason for low red blood count, until the body has time to make new red blood cells. There are 2 common ways to lose blood and not know about it. Women can be low on iron if they have heavy periods and do not get enough iron in their diet. It is also possible to have something that is causing a "slow" bleed, like an ulcer or condition in the GI tract (intestines). There could be very small amounts of blood in the stool (BM). There are simple tests the doctor can recommend that would test for blood in the stool.

  2. The "iron store" can also be low if there is not enough iron being taken in through the person's diet. We get iron from red meat and specific vegetables. This means, people who are vegetarian need to pay special attention and make sure they eat iron-rich foods and/or take a vitamin with iron in it.

What should be done: When you see your doctor, blood tests are often done, usually a hemoglobin and hematocrit. If they are not normal, additional tests would be done to decide what kind of anemia is present, whether there is enough iron, if other vitamins are involved, and so on.

Why this matters: OI tends to affect adolescent girls more than boy. This is a very important time for bone growth.3 The teen years are the years when bone density increases the most. Bone density doubles between childhood and young adulthood. Also, women have a lower bone density than men. Anything that interferes with increasing bone density during the teen years puts them at high risk for bone problems on into adulthood.

Bones that have lost calcium and minerals are not as strong. It is easier for them to break with very little injury or force. In severe cases, people can collapse a bone in their spine (a vertebrae) just by sneezing or rolling over in bed.

People with Orthostatic intolerance conditions like NMH and POTS as well as Chronic Fatigue Sydrome (CFS), as well as other chronic conditions, have a bigger chance of developing bone problems for a number of reasons.

  1. Prolonged bedrest:

    This causes changes in how bones function.1 Like most parts of the body, they are constantly removing damaged/old cells and replacing them. Normally, the number of cells created matches the number of cells destroyed. When a bone is immobilized or not used, the bone is broken down faster than it is being created. (Called bone resorption.) See the topic "bedrest" to learn more about the effect of bedrest on the bones. It takes astronauts up to 2 years for their bones to recover from a stretch of time in space.

  2. Being homebound- lack of sunshine :

    This often means - in-the-house-bound. People who are homebound or bed bound don't get enough sunlight for their body to convert the Vitamin D to active vitamin that is necessary for bone growth. It only takes about 20 minutes in the daylight. The skin is able to synthesize the Vitamin D to the active form when it is exposed to the sun. Vitamin D is important because it helps the intestines absorb (take in the calcium) from the food you eat. Vitamin D is also important for muscles.

  3. Lactose Intolerance:

    Many people with CFS also have lactose intolerance. (See Associated Conditions for more details). In the US, most people relay on milk products to get enough calcium. Milk products are often fortified with Vitamin D.

  4. Cola drinks.

    Cola drinks affect how the body handle calcium in the kidneys. They can worsen bone loss.

  5. No "weight-bearing" exercise

    Exercise where the body is standing up, putting weight on the bones in the legs and spine stimulates bone growth. (It's related to the problem with prolonged bedrest.)

   What should be done:

Evaluation for bone problems: This is something you should talk over with your doctor. If you have been sick for a while and have been on prolonged bedrest - either continuous bedrest or 2-3 weeks of bedrest on and off over the last few months. To consider: bone density studies and measuring vitamin D levels.


In the meantime, there are a number of things you can do:

Check how much calcium you are getting in your diet including your multivitamin. You need at least 1500 mg/da.

Make sure you are getting enough Vitamin D3 in your diet/food.

Try to get some sun each day - just 20 minutes without sunscreen. If you have not been out in the sun for awhile, you should start with a few minutes with your skin uncovered, like your arms and legs. Watch for sunburn. Skip a day if you are red the next day then cut the time outside in half when you start again.


More about this topic later.

GI Conditions "Digestion - Stomach - Intestines"

There are a number of GI problems with orthostatic intolerance (OI). In a survey of people wthe POTS, A high number of people reported GI.8 GI symptoms seem to be a common and troublesome problem for people with OI. We will be addressing the research on it and related conditions in more detail in the near future.

What's causing the symptoms: It is hard to sort out what is causing the problem. It could be damage to the autonomic nerves that go to the stomach and intestines as part of the Autonomic Nervous System failure.

It could also be caused by the poor blood flow to the stomach and intestines that comes with low blood pressure. When there is low blood flow to the head, the body shifts the blood from the legs/ arms and stomach/intestines area to the chest and head. It makes the blood vessels to the stomach and intestines smaller so there is less blood that gets to them.

OI and other GI conditions: In some GI conditions, like Cyclic Vomiting Syndrome, orthostatic is common and treatment for the OI is recommended.9, 10 We will address Cyclic Vomiting Syndome in the near future. (Sign Up for notices)

Impact of managing OI on GI symptoms:

Sullivan did report that some of the upper GI symptoms got better when the orthostatic intolerance (OI) was better4. [Upper GI symptoms would be heartburn and esophageal reflux (GERD).]

Others have looked at GI symptoms in children, symptoms during Tilt Table Testing, POTS diagnosis and response to fludrocortisone.11

What you can do: We offer suggestions about eating and orthostatic symptoms in Taking Care - Tricks to Avoid Getting Dizzy.

Sign Up for notices.

One of the downsides of taking medication to increase blood pressure and blood flow when you stand up is that it can also increase blood pressure when you lie down.

For more detailed information, go to Supine Nocturnal Hypertension.

  1. Winkelman, Chris RN, PhD, CCRN ACNP. Bed Rest in Health and Critical Illness: A Body Systems Approach. AACN Advanced Critical Care: 2009; 20(3); 254-266. Abstract.
  2. Zuckerman, KS. Chapter 159. .Approach to the Anemias.pp.840-847. From Goldman, Lee and Bennett, J. Claude. Editors. Cecil Textbook of Medicine. 21st Edition. 2000. W.B. Saunders & Co. Philadelphia, PA.
  3. Finkelstein, Joel S. Chapter 257. Osteoporosis. pp. 1366-1372. From Goldman, Lee and Bennett, J. Claude. Editors. Cecil Textbook of Medicine. 21st Edition. 2000. W.B. Saunders & Co. Philadelphia, PA.
  4. Sullivan SD, Hanauer J, Rowe PC, Barron DF, Darbari A, Oliva-Hemker M. Gastrointestinal symptoms associated with orthostatic intolerance. J Pediatr Gastroenterol Nutr. 2005 Apr;40(4):425-8. Abstract.
  5. Medow MS, Stewart JM, Sanyal S, Mumtaz A, Stca D and Frishman WH. Pathophysiology, Diagnosis, and Treatment of Orthostatic Hypotension and Vasovagal Syncope. Cardiology in Review 2008;16(1):4-20. Abstract.
  6. Figueroa JJ, Basford JR, Low PA. Preventing and treating orthostatic hypotension: As easy as A, B, C. Cleve Clin J Med. 2010 May;77(5):298-306.  Abstract.  Article PDF.
  7. Freeman, Roy. Neurogenic orthostatic hypotension.NEJM 2008;358(6):615-624. Abstract
  8. Ojha A, Chelimsky TC, Chelimsky G.   Comorbidities in pediatric patients with postural orthostatic tachycardia syndrome. J Pediatr. 2011 Jan;158(1):20-3. Epub 2010 Aug 17. Abstract.
  9. Chelimsky G, Madan S, Alshekhlee A, Heller E, McNeeley K, Chelimsky T.   A comparison of dysautonomias comorbid with cyclic vomiting syndrome and with migraine.Gastroenterol Res Pract. 2009;2009:701019. Epub 2010 Jan 6.  Abstract. Article PDF.
  10. Chelimsky TC, Chelimsky GG. Autonomic abnormalities in cyclic vomiting syndrome.J Pediatr Gastroenterol Nutr. 2007 Mar;44(3):326-30.
  11. Safder S, Chelimsky TC, O'Riordan MA, Chelimsky G.   Autonomic testing in functional gastrointestinal disorders: implications of reproducible gastrointestinal complaints during tilt table testing. Gastroenterol Res Pract. 2009;2009:868496. Epub 2009 May 5. Abstract  .Article PDF.
  12. Chelimsky G, Chelimsky TC.  Evaluation and treatment of autonomic disorders of the gastrointestinal tract.Semin Neurol. 2003 Dec;23(4):453-8. Abstract.

Author: Kay E. Jewell, MD
Page Last Updated: August 28, 2012