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Aplastic Anaemia - case discussion
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10.25.06 (1 year ago)
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In May 2005 I met Mr. H, a 30-year-old white male, who presented to the ED with febrile symptoms (fever of 102.7°F) and with a chief complaint of falling and hitting his head. I was in the first week of my ED clerkship and was just finishing up my third year. (Of course, by this time I could recognize fairly quickly when I was in over my head). Mr. H seemed very intimidating (with large lightning bolts tattooed on his balding head), even though he was slumping in his wheel chair, covered in 3 or 4 blankets. While taking the history and physical, I realized that this patient may be one of the most interesting and unique cases I will ever see.
The patient stated that while he was taking a shower, the room "started spinning," his legs got very weak, and he fell backward and hit his head on the shower. He did not remember losing consciousness and did not become disoriented. His history is significant in that he was diagnosed one year prior by the National Institutes of Health (NIH) as having severe aplastic anemia.
Which of the following is most concerning in this patient?
A) Possible skull trauma
B) Dizziness
C) Febrile symptoms
The answer is C. Fever of 102.7° is quite concerning in a patient with aplastic anemia. The major cause of morbidity and mortality in these patients is from infection and bleeding [1].
What is aplastic anemia?
Aplastic anemia (AA) is hematopoietic failure and pancytopenia due to improper functioning of the bone marrow or defects/damage to the stem cells [1]. An extremely rare condition, aplastic anemia affects only 2 to 3 people per million in Europe and Israel, with higher frequency (6 to 7 per million) in Eastern nations such as Thailand and China [3]. (According to the NIH Web site, about 500 to 1,000 people in the United States develop AA each year.)
What are the signs and symptoms?
AA may be insidious or rapid in onset. The most common early symptoms are those from increased bleeding: heavy menstrual flow, easy bruising, nosebleeds, oozing from the gums, and so forth [1][2][3]. Other symptoms, common to most types of anemia, include the following: fatigue, lassitude, shortness of breath, pounding sensation in the ears, dizziness, and unsteady gait [5].
Mr. H first saw his primary care physician one year prior with a complaint of frequent nose bleeds. Complete blood count at that time showed marked pancytopenia and led the physician to refer him to a hematologist.
What causes aplastic anemia?
The most common cause of AA (bone marrow failure) is iatrogenic. Drugs such as chloramphenicol, when introduced in the 1960s, caused anemia of almost epidemic proportions. Today, cytotoxic chemotherapy drugs, NSAIDS, antiprotozoals, anticonvulsants, heavy metals, antibiotics, antihistamines, estrogens, and many others have been linked to marrow failure. [1][2][3][4][5][6]
Other frequent non-iatrogenic causes include the following: radiation, chemicals such as benzene, infections such as hepatitis and Epstein-Barr virus, immunological diseases such as transfusion-associated graft-versus-host disease, pregnancy (transient), congenital disorders such as Fanconi's anemia and dyskeratosis congenital, and unexplained or idiopathic causes [3][6]. Inherited diseases account for only 20% of aplastic anemia cases [1].
Our patient had been evaluated for any and all of the above causes, and none were found to be the culprit. As a result, the NIH had assigned Mr. H as having idiopathic severe aplastic anemia.
What would Mr. H's laboratory tests reveal?
The hallmark pathophysiological sign is empty bone marrow; the architecture is replaced by fat on microscopic examination and on magnetic resonance imaging (MRI). Other diagnostic studies include a complete blood count, which will usually show the following: low red blood cell (RBC) count, leukopenia, and thrombocytopenia. Blood smears may appear normochromic (hypochromic if the patient also has concomitant iron deficiency) and normocytic/macrocytic, have low reticulocyte counts, and the mean corpuscular volume (MCV) is commonly increased [1][3].
Review of Mr. H's chart found that initial bone marrow samples indeed showed "near complete" fatty architecture. Initial comprehensive serum laboratory examination showed marked pancytopenia: white blood cells (WBC) = 0.9 (x109/L), platelets = 23 (x109/L), hemoglobin = 7.8 (g/dL), prothrombin time (PT) = 14.1 (s), partial thromboplastin time (PTT) = 36, MCV = 82.8. In addition, the red blood cells were noted to be hypochromic and microcytic. Urine analysis showed the following: amber color, large amount of glucose, large amount of blood, pH 8.0, 100+ protein, nitrate positive, leukocyte esterase negative, 2-5 WBCs, 65-80 RBCs, 2+ bacteria, 3+ mucous, and 5-10 casts.
Based on the above findings, what is the most likely source of Mr. H's febrile symptoms?
The most likely location of the offending source for both the febrile symptoms and the abnormal urine sample would be in the urinary tract/kidney. Further inspection of Mr. H's chart (15 volumes) revealed that he had had many bouts of nephrolithiasis that had required surgical intervention. Computer tomography (CT) scan confirmed this suspicion, yielding a 3 mm calculus located in the right uteropelvic junction. The patient went to surgery immediately and a stent was placed in the right ureter. He was then started on an appropriate antibiotic regimen.
Is there a definitive cure available for Mr. H?
The simple answer is yes. Treatment options are often curative and include bone marrow transplant (gold standard), immunosuppression to allow for the patient's immune system to recover, and discontinuance of drugs that may have been the causative agents (spontaneous recovery here is rare) [4]. In addition, androgens have shown to be effective in a small number of patients [1]. Splenectomy may also increase blood counts in refractory cases.
Outcomes vary with age and treatment modalities, but the usual course with only supportive care is rapid onset, deterioration, and death. Life can be prolonged with RBC and platelet transfusions. In patients with severe aplastic anemia, the one-year survival after diagnosis is only 20% with supportive treatment. This number has been greatly improved with the aforementioned treatment modalities. Bone marrow transplants from fully histocompatible siblings yield a recovery rate of 80% or better, while immunosuppression alone has an approximately 70% rate of recovery [3].
Mr. H has been going to the NIH for treatment while waiting for an allogenic bone marrow match through the national registry. Treatment has included antithymocyte globulin (ATG) (horse & rabbit), prednisone, cyclosporin, and tacrolimus. Mr. H occasionally needs whole blood or blood product transfusions. In the past, as a result of the above transfusions, the patient had developed secondary hematochromatosis and was treated with desferroximine.
During his hospital course Mr. H received 3 units of packed red blood cells and 4 units of irradiated platelets. Upon discharge he had the following lab values: WBC = 0.9, RBC = 2.83, platelet = 53, hemoglobin = 8.5. His next appointment with the NIH was in two months. He was still active on the bone marrow transplant list.
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