Chloramphenicol is a broad spectrum antibiotic introduced into clinical practice in 1948, but which was subsequently shown to cause serious and fatal aplastic anemia and is now used rarely and reserved for severe, life-threatening infections for which other antibiotics are not available. Chloramphenicol has also been linked to cases of acute, clinically apparent liver injury with jaundice, largely in association with aplastic anemia. Show
BackgroundChloramphenicol (klor" am fen' i kol) is an antibiotic initially isolated from Streptomyces venezuelae and later characterized biochemically and synthesized. Chloramphenicol was introduced into clinical practice in 1948 under the brand name Chloromycetin and became a widely used antibiotic because of its oral availability, excellent tolerability and wide spectrum of activity. Chloramphenicol has bacteriostatic activity against many gram positive and gram negative organisms, both aerobic and anaerobic including H. influenza, N meningitides, S. pneumoniae, N gonorrhoeae, Brucella species and Bordetella pertussis. It also has activity against many spirochaetes, rickettsiae, chlamydiae and mycoplasmas. Chloramphenicol is thought to act by binding to the 50S ribosomal subunit in bacteria, thus inhibiting bacterial protein synthesis. A similar inhibition of protein synthesis may occur in mitochondria. Within a few years of its introduction, chloramphenicol was linked to rare cases of aplastic anemia and later to other fatal blood dyscrasias including thrombocytopenia, neutropenia and pure red cell aplasia. In addition, cases of leukemia were identified in children who had recovered from blood dyscrasias attributed to chloramphenicol. By the early 1960s, more than 1000 cases of severe bone marrow aplasia were attributed to use of chloramphenicol and it was widely banned or placed under restrictions, particularly in children. Currently, chloramphenicol is available only in parenteral forms, and its use is restricted to severe, life-threatening infections for which no other antibiotic is available because of antibiotic resistance or drug allergy. Several generic forms of chloramphenicol for intravenous administration are available and the recommended dose is 50 mg/kg daily in 4 divided doses. Monitoring for blood counts is recommended and prompt discontinuation for any evidence of myelosuppression. HepatotoxicityA proportion of patients with blood dyscrasias due to chloramphenicol also developed clinically apparent liver injury with jaundice, usually occurring before the appearance of aplastic anemia or severe thrombocytopenia. Jaundice arises in 10% to 25% of cases of aplastic anemia, usually within 1 to 2 months of starting chloramphenicol and often shortly after it is stopped. Aplastic anemia and the accompanying liver injury occur most frequently in patients who receive multiple courses of chloramphenicol or prolonged therapy. The serum enzyme pattern is usually hepatocellular and the clinical presentation is an acute hepatitis-like syndrome with onset of fatigue, nausea, anorexia and abdominal discomfort followed by dark urine and jaundice. Rare instances have a cholestatic pattern of presentation with jaundice and itching and prominent elevations in alkaline phosphatase. Some cases occur in the absence of bone marrow involvement. Immunoallergic and autoimmune features are rarely present. The course is self-limited in most instances, but examples of acute liver failure have been reported, particularly in patients without aplastic anemia. In most cases, however, the liver injury associated with chloramphenicol use is eclipsed by the severe bone marrow aplasia. Likelihood score: B (highly likely cause of clinically apparent liver injury, now rarely seen). Mechanism of InjuryThe etiology of liver injury associated with chloramphenicol is likely idiosyncratic and probably immunological. The hepatitis that accompanies chloramphenicol induced aplastic anemia is similar to the hepatitis that occurs with spontaneous or idiopathic aplastic anemia, suggesting a common pathogenesis of bone marrow and hepatic progenitor cell injury and loss. The marrow toxicity of chloramphenicol has been attributed to the nitrophenyl group in the molecule which is unique among microbial derived antibiotics. Outcome and ManagementThe liver injury accompanying blood dyscrasias caused by chloramphenicol is often severe, but resolves rapidly in most cases only to be followed by signs and symptoms of bone marrow failure. Acute liver failure can result, but the role of liver transplantation in this situation is difficult because of the accompanying marrow damage and aplasia. Blood dyscrasias may affect blood components, bone marrow, lymph tissue, or blood vessels. They can be cancerous or benign, common or not, and they can range from mild to life-threatening. This article discusses blood dyscrasias, their causes, types, and common symptoms. It also discusses what you can expect during diagnosis and treatment. Andrew Brookes / Getty Images Blood Dyscrasia: Conflicting DefinitionsBlood dyscrasias relate to conditions pertaining to:
The exact definition of the term can vary depending on the healthcare practitioner and situation, however—sometimes in conflicting ways. The term blood dyscrasia may be used:
Blood ComponentsBefore looking at specific diagnoses, it’s helpful to look at the components of blood and lymph tissues. Blood is made up of both plasma (the liquid component) and cells.
Causes of Blood DyscrasiasThe causes of blood dyscrasias are not always known. When this is the case, healthcare providers often use the term idiopathic. This means the cause is uncertain or even totally unknown at the time. Causes and risk factors can fall into several categories, which sometimes overlap.
Blood Dyscrasia Types and ClassificationThere are a number of different blood dyscrasia types. Some conditions affect only one type of blood cell. Commonly, these conditions will cause either an increase or decrease in this blood cell type If all major types of blood cells are affected, the condition is called a pancytopenia. Terminology for an Increase or Decrease in Blood CellsCell TypeExcessDeficiencyRed blood cellsErythrocytosis or polycythemiaAnemiaWhite blood cellsLeukocytosisLeukopeniaPlateletsThrombocytosisThrombocytopenia Red Blood Cell and Hemoglobin DisordersRed blood cells may be abnormal in a number of different ways. When there are too few of them, it’s called anemia. It is also possible to have too many red blood cells, cells with abnormal structure, or cells that contain abnormal hemoglobins. Some red blood cell disorders include:
White Blood Cell DisordersIn white blood cell disorders, there may be too much or too little of all or one type of white blood cell. There could also be a normal number of abnormally functioning cells. Some white blood cell disorders include:
White Blood Cell Disorders Platelet DisordersPlatelet disorders may be caused by too many (thrombocytosis) or too few (thrombocytopenia) platelets. They can also be caused by a normal number of platelets that function abnormally. They can be genetic or they may develop later in life. Platelets are an essential part of the clotting process, so there is some overlap with bleeding disorders and clotting disorders. Thrombocytopenia (a low platelet count) may be caused by:
Thrombocytosis (thrombocythemia) is an elevated platelet count. It can be seen with some cancers and inflammatory conditions, such as essential thrombocythemia. Platelet disorders that affect normal functioning can be caused by liver or kidney disease. They can also be caused by inherited conditions such as Wiskott-Aldrich syndrome. These conditions may affect the ability of platelets to come together or stick together. Overview of Platelet Disorders Bleeding DisordersBleeding disorders can be broken down into four major categories:
Clotting Disorders (Thrombosis)Some types of blood dyscrasias cause the blood to clot too easily. Some of these conditions are hereditary, such as:
Others are related to conditions like:
Medications like estrogen can also cause this type of blood dyscrasia. Bone Marrow DisordersDiseases related to the bone marrow are another important cause of blood dyscrasias. In some cases, the bone marrow is infiltrated with abnormal cells. This limits the production of normal blood cells and often leads to a deficiency of all blood cell types. It may be seen with:
Failure of the bone marrow can occur for other reasons, too, such as:
SymptomsMany of the symptoms of blood dyscrasias are related to having too much or too little of the different types of blood cells. Symptoms can also be caused by the build-up of these cells within the lymph nodes or spleen. Red Blood CellsAnemia can cause a number of symptoms, including:
When red blood cells are the wrong shape, such as in sickle cell anemia, they may get “stuck” in blood vessels in various tissues. This can cause cell death and pain that is often severe. An increase of red blood cells can result in a red facial complexion and headaches. White Blood CellsWhen white blood cells levels are low, infections may develop. Symptoms are usually related to the site of infection, such as:
PlateletsDepending on the severity, a low level of platelets can also cause symptoms. These may include:
Bleeding DisordersThe symptoms of bleeding disorders overlap with platelet conditions. Specific symptoms often depend on the severity of the disease. If the condition is mild, you may notice increased bleeding after surgery or dental procedures. With more serious disorders you may have spontaneous bleedings. Signs and Symptoms of Abnormal Bruising in Children Clotting DisordersRisk factors for blood clots include bed rest, recent surgery, cancer, travel, and more. Sometimes blood clots occur without these risk factors in someone who is otherwise healthy and has not been sedentary. When this happens, your healthcare provider will consider the possibility of a clotting disorder. Bone Marrow Disorders and MalignanciesBone marrow disorders may affect all types of blood cells. Symptoms of these conditions can be similar to those of blood cell disorders. Blood-related cancers may produce symptoms such as:
Other SymptomsA wide range of symptoms may be seen with different blood dyscrasias. Many of these are not obvious. A few examples include:
DiagnosisBlood dyscrasias are often diagnosed with multiple steps. These depend on symptoms, family history, physical findings, and more. A blood dyscrasia is often suspected when a person sees a primary care provider. A workup may be started with your healthcare provider, or you may be referred to a hematologist/oncologist. A hematologist is a physician who specializes in the diagnosis of blood dyscrasias, whether benign or cancerous. Your healthcare provider will start by asking you about your family and medical history, symptoms, medications, and possible exposures. Make sure to mention anything abnormal in your history, such as heavy menstrual periods. During your medical exam, your healthcare provider will evaluate your lymph nodes and look for signs of blood dyscrasias like pale skin or bruising. After the initial exam, you may be referred for testing. Tests to Evaluate Blood Dyscrasias
Supplemental TestsBased on your CBC results, other tests may be recommended:
Evaluation of Bone MarrowA bone marrow biopsy and aspiration can provide a lot of information about the health of the bone marrow. This test is essential in diagnosing some types of leukemia. When cancer is suspected, further tests such as biomarker testing will be done on the cells. Coagulation StudiesYour history and physical exam may provide clues as to whether you have a platelet disorder or another type of bleeding disorder. Tests to evaluate platelet function may include:
Coagulation studies may include a prothrombin time (and INR) and partial thromboplastin time. If a clotting factor abnormality is suspected, specific testing will be done. What do Your PT, PTT, and INR Results Mean? If your healthcare provider suspects your blood clots more easily than usual, you may be referred for tests such as:
TreatmentThe treatment of blood dycrasias depends on the cause. Sometimes it’s enough to just treat the underlying condition. Other times, a deficiency in blood cells or absence of clotting factors will need to be treated directly. For severe anemia, a blood transfusion may be needed until the underlying cause can be addressed. If your platelet count is very low, platelet transfusions may be needed to stop or prevent bleeding. If you have a very low white blood cell count, you may be prescribed a medication that stimulates the production of white blood cells. Since the most important complications related to a low white count are infections, it’s also important to take steps to reduce infections. Clotting disorders require treatments that help reduce the risk of clotting. Bleeding disorders require treatments that help the blood clot. Fresh frozen plasma and/or replacement of missing clotting factors are also often needed. SummaryA blood dyscrasia is any condition that affects the blood, bone marrow, or lymph tissue. Blood dyscrasias can have many different causes, ranging from mild to life-threatening. The term “blood dyscrasia” is often used during diagnosis, before the cause of symptoms is known. Some potential causes can include different types of anemia, blood cancers, medication use, and platelet disorders. Blood dyscrasias are usually diagnosed with a combination of medical history, exam, and tests. Treatment may involve treating the underlying cause or treating the condition directly. A Word From VerywellIf your healthcare provider believes you have a blood dyscrasia, you may be feeling anxious and impatient. It can take time to diagnose a blood dyscrasia. The process is a little like putting together a large jigsaw puzzle without a reference photo. Make sure to ask a lot of questions so you understand why any recommended tests are being done. Because there is such a diverse array of conditions and causes, many healthcare providers are hesitant to bring up all possibilities, especially worst-case scenarios. Still, our minds sometimes try to fill in the answers by going straight to those possibilities. Learning about your condition can not only help you feel more in control, it may even help you recall important symptoms that could otherwise be easily overlooked. Is blood dyscrasia is a potentially lifeBlood dyscrasia is a potentially life-threatening condition.
What type of anemia characterized by an absence of all formed blood elements?(ay-PLASS-tik uh-NEE_mee-uh) A rare and serious condition in which the bone marrow fails to make enough blood cells - red blood cells, white blood cells, and platelets. The term aplastic is a Greek word meaning not to form.
What condition is characterized by attacks of pallor cyanosis?Raynaud's phenomenon – intermittent attacks of pallor, cyanosis, and redness of the fingers and toes due to arterial contraction.
Which specialist treats diseases and disorders of the blood and blood forming tissues?Hematologists and hematopathologists are highly trained healthcare providers who specialize in diseases of the blood and blood components. These include blood and bone marrow cells. Hematological tests can help diagnose anemia, infection, hemophilia, blood-clotting disorders, and leukemia.
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