hematology and oncology
Neutropenia
Diagnosis of Neutropenia
Clinical suspicion (repeated or unusual infections) Confirmatory complete blood count (CBC) with differential Evaluation for infection with cultures and imaging Identification of mechanism and cause of neutropenia Neutropenia is suspected in patients with frequent, severe, or unusual infections or in patients at risk (eg, those receiving cytotoxic drugs or radiation therapy). Confirmation is by CBC with a differential count. The first priority is to determine whether an infection is present. Because infection may be subtle,physical examinationsystematically assesses the most common primary sites of infection: Mucosal surfaces, such as the alimentary tract (gums, pharynx, anus) Sinuses Lungs Abdomen Urinary tract Skin and fingernails Venipuncture sites Vascular catheters If neutropenia is acute or severe, laboratory evaluation must proceed rapidly. Culturesare the mainstay of evaluation. At least 2 sets of samples for bacterial and fungal blood cultures are obtained from all febrile patients. If an indwelling IV catheter is present, samples are drawn from the catheter and from a separate peripheral vein. Persistent or chronic drainage material is also cultured for bacteria, fungi, and atypical mycobacteria. Mucosal ulcers are swabbed and cultured for herpes virus andCandida. Skin lesions are aspirated or biopsied for cytology and culture. Samples for urinalysis and urine cultures are obtained from all patients. If diarrhea is present, stool is evaluated for enteric bacterial pathogens andClostridioides(formerlyClostridium)difficiletoxins. Sputum cultures are obtained to evaluate for pulmonary infections. Imaging studiesare helpful. Chest x-rays are done on all patients. A chest CT may also be necessary in patients with neutropenia. CT of the paranasal sinuses may be helpful if symptoms or signs of sinusitis (eg, positional headache, upper tooth or maxillary pain, facial swelling, nasal discharge) are present. CT scan of the abdomen is usually done if symptoms (eg, pain) or history (eg, recent surgery) suggests an intra-abdominal infection. Next, the mechanism and cause of neutropenia are determined. Thehistoryaddresses family history, presence of other disorders, all medications or other preparations being taken, pets, and possible toxin exposure or ingestion. addresses the presence of Splenomegaly , lymphadenopathy, skin lesions (eg, areas of erythema, macules, papules, pustules), and signs of other underlying disorders (eg, arthritis). If no obvious cause is identified (eg, chemotherapy), the most important test is Bone marrow examination determines whether neutropenia is due to decreased marrow production or is secondary to increased cell destruction (determined by normal or increased production of the myeloid cells). Bone marrow examination may also indicate the specific cause of the neutropenia (eg, Aplastic Anemia , Further testing, such as flow cytometry and T-cell receptor gene rearrangement for the LGL syndrome, may be needed to determine the cause of neutropenia, depending on the diagnoses suspected. In patients at risk of nutritional deficiencies, levels of Acquired Copper Deficiency , Differentiation between neutropenia caused by certain antibiotics and infection can sometimes be difficult. The white blood cell count just before the start of antibiotic treatment usually reflects the change in blood count due to the infection. Patients who have had chronic neutropenia since infancy and a history of recurrent fevers and chronic gingivitis should have white cell counts with differential done 3 times/week for 6 weeks, so that periodicity suggestive of cyclic neutropenia can be evaluated. Platelet and reticulocyte counts are done simultaneously. In patients with cyclic neutropenia, eosinophils, reticulocytes, and platelets frequently cycle synchronously with the neutrophils, whereas monocytes and lymphocytes may cycle out of phase. Molecular genetic testing forELANEand other genes is appropriate when congenital causes are considered. 