37 A 20-Year-Old Female With Chronic Fatigue


Case 37

A 20-Year-Old Female With Chronic Fatigue



Monisha Bhanote, Daniel Martinez



A 20-year-old female presents to her primary care doctor over summer break complaining of worsening fatigue for the past 6 months. She is constantly tired and lacks the energy to do her usual summer activities with her friends. She denies associated weight loss, heat/cold intolerance, anhedonia, drug use, menorrhagia, unprotected sexual contacts, shortness of breath, skin rashes, or joint swelling. She does report mild episodes of diarrhea but it is well controlled with loperamide as needed. She states that she is a vegan since she started college to avoid the “freshman 15.” Fruits, vegetables, cereals, and pastas are now the cornerstones of her diet.



What should be reasonably considered in a young female with new fatigue?


Pregnancy should be considered in any female of reproductive age with nonspecific symptoms such as fatigue. Taking a sexual history and ordering a pregnancy test is therefore important in the evaluation. Hypothyroidism is also a reasonable consideration, and a screening thyroid stimulating hormone (TSH) is generally indicated. Many rheumatologic diseases can cause fatigue, and thus a thorough review of systems and a physical exam that includes the skin, joints, and nails are also important; these will help narrow down which of the many rheumatologic tests are indicated if at all. Anemia can cause fatigue in all populations, and a complete blood count (CBC) is generally ordered.



On physical exam, the patient’s temperature is 36.7 °C (98 °F), blood pressure is 110/70 mm Hg, pulse rate is 80/min, respiration rate is 14/min, and oxygen saturation is 100% on room air: body mass index (BMI) is 17 kg/m2. She is a thin-appearing female in no acute distress. She has mild pallor of the conjunctiva but moist mucus membranes. The thyroid is not palpable and there is no lymphadenopathy. She has a 1/6 early systolic murmur and her lungs are clear to auscultation. Her abdomen is soft, nontender, and nondistended with no hepatosplenomegaly. There are no rashes or joint swelling.


Laboratory findings include a normal chemistry panel, normal thyroid panel, and negative urine pregnancy test. The CBC includes a white blood cell count of 8000 cells/µL, hemoglobin of 11 g/dL, mean corpuscular volume (MCV) of 114 fL/cell. You explain that her fatigue is likely due to anemia and that there are more tests that you have to order when she follows up in a week.



What are the pathologic causes of macrocytic anemia and how do you work it up?


Macrocytosis refers to the presence of abnormally large red blood cells. This can be associated without anemia as in cases of newborns or during pregnancy. It can also be associated with anemia due to many other causes (see Table 37.1).



Many of the pathologies listed have other significant clinical or laboratory abnormalities that would make the diagnosis easy to make (such as liver disease or an acute leukemia). However, in a patient with macrocytosis who has an otherwise normal clinical exam and labs, the main differential is between vitamin B12 and folate deficiency. The workup includes a peripheral smear, checking a reticulocyte count to confirm the anemia is due to decreased production, and ordering B12/folate levels. If B12 and folate levels are normal and there remains a high suspicion for deficiency, then homocysteine and methylmalonic acid levels can be ordered as they are more sensitive.




What etiologies should be considered for a patient with vitamin B12 deficiency?


Vitamin B12 deficiency can be seen in decreased intake, poor absorption, and increased need. Therefore, vitamin B12 deficiency can happen in individuals who are vegan as well as vegetarians who do not consume enough milk, eggs, or cheese and do not supplement the vitamin in other ways. However, the average person’s vitamin B12 stores can lasts several years without any signs or symptoms of deficiency. This makes it difficult for decreased vitamin intake to be the sole reason for the significant deficiency seen in this patient. A good clinician would consider other reasons for a vitamin B12 deficiency in a young person who has only been a vegan for a couple years.


Vitamin B12 deficiency can also be seen in certain medical conditions such as atrophic gastritis, Crohn’s disease, celiac disease, bacterial overgrowth, parasitic infections, immune disorders (Grave’s disease or lupus), and weight loss surgery, which can cause loss of part of the gastrointestinal tract that absorbs nutrients.



You inform the patient that her fatigue is cause by an anemia due to a vitamin B12 deficiency. It is possibly due to her diet, though not definitively, and you advise her to take vitamin B12 injections weekly for 8 weeks, then once monthly thereafter. She explains that she is going on a summer trip to Europe and cannot come back to the office that frequently. Instead, you advise her to take 1 milligram (1000 µg) of vitamin B12 daily. She then returns back to school after the summer for the fall semester.



Step 2/3


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During Thanksgiving break the patient returns home and comes to your office. She reports that she is not feeling any better than this past summer. She also confirms that she is compliant with the oral vitamin B12. She now appears pale overall and has cracking around her mouth with some oral ulcers. She also complains that her diarrhea has worsened and is now associated with greasy stools and a rash on her arms. You recheck her CBC and vitamin B12 level. Her hemoglobin is now 9.5 g/dL and her vitamin B12 level is still low. Given that she did not respond to the oral vitamin supplementation, you suspect a malabsorption syndrome and refer her to a gastroenterologist.



What are common causes of malabsorption syndromes?


Malabsorption is characterized by abnormal or suboptimal absorption of nutrients (fats, vitamins, proteins, carbohydrates, electrolytes, and minerals) across the gastrointestinal tract. It can include one or multiple nutrients depending on the abnormality. Malabsorption can be subclassified into three categories: selective, partial, and total. Selective malabsorption is seen with specific nutrients such as lactose intolerance. The causes of malabsorption can be due to infective agents, structural defects, surgical changes, mucosal abnormalities, enzyme deficiencies, digestive failure, and systemic diseases (see Table 37.2).


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Jun 15, 2016 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on 37 A 20-Year-Old Female With Chronic Fatigue

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