Spencer RC.: Invasive streptococc European Journal of Clinical Microbiology & Infectious Diseases. 14 Suppl. 1:S26-32, 1995. Before the introduction of antibiotics, serious infections caused by Streptococcus pyogenes (Lancefield Group A streptococci) were common. Before World War II, this bacterium was responsible for as many as 50% of postpartum deaths and was the major cause of death in patients with burns. Also common were the sequelae of streptococcal infections-rheumatic fever and post-streptococcal glomerulonephritis. With the use of penicillin, however, Streptococcus pyogenes was believed to be virtually eliminated as a pathogen. The organism was consigned to the history books, but not for long. In the mid-1980s, focal resurgences of rheumatic fever began to be reported from different areas in the USA, such as Salt Lake City, Utah. In such communities, where increases in cases of rheumatic fever had been reported, the serotypes M-1, 3, 5, 6 and 18 were isolated which, on culture, produced characteristic mucoid colonies. At the same time, reports of increases in invasive streptococcal disease began to surface in both the US and Europe. Two syndromes were described; invasive streptococcal infection, occurring in previously healthy children and adults, commonly associated with septicaemia resulting from a deep focus of infection such as bone or lung; and streptococcal toxic shock syndrome, involving a cutaneous focus, accompanied by necrotizing or bullous soft tissue changes. Septicaemia is rare in streptococcal toxic shock syndrome, but the most characteristic feature is one of rapidly progressing multi-organ failure. A high proportion of the strains of Streptococcus pyogenes associated with this condition are serotype M-1, and fatality rates approaching 50% have been reported.
|What is a major complication of toxic shock syndrome related to group A streptococci, leading to 50% mortality?||View Page|
Cunningham MW.: Pathogenesis of group A streptococcal infections. Clinical Microbiology Reviews. 13):470-511, 2000 Group A streptococci are model extracellular gram-positive pathogens responsible for pharyngitis, impetigo, rheumatic fever, and acute glomerulonephritis. A resurgence of invasive streptococcal diseases and rheumatic fever has appeared in outbreaks over the past 10 years, with a predominant M1 serotype as well as others identified with the outbreaks. Emm (M protein) gene sequencing has changed serotyping, and new virulence genes and new virulence regulatory networks have been defined. The emm gene superfamily has expanded to include antiphagocytic molecules and immunoglobulin-binding proteins with common structural features. At least nine superantigens have been characterized, all of which may contribute to toxic streptococcal syndrome. An emerging theme is the dichotomy between skin and throat strains in their epidemiology and genetic makeup. Eleven adhesions have been reported, and surface plasmin-binding proteins have been defined. The strong resistance of the group A streptococcus to phagocytosis is related to factor H and fibrinogen binding by M protein and to disarming complement component C5a by the C5a peptidase. Molecular mimicry appears to play a role in autoimmune mechanisms involved in rheumatic fever, while nephritis strain-associated proteins may lead to immune-mediated acute glomerulonephritis. Vaccine strategies have focused on recombinant M protein and C5a peptidase vaccines, and mucosal vaccine delivery systems are under investigation.
Staphylococci are non-motile, non-spore-forming, gram-positive organisms occurring singly, in pairs, tetrads or in clusters resembling grapes. More than 20 species have been identified; three species are significant in their interactions with humans - S. aureus, S. epidermidis and S. saprophyticus.The staphylococci are members of the normal flora of the skin and mucous membranes of humans and warm-blooded animals. Colonization of the nares (nostrils) and skin can provide large reservoirs of organisms for transmission. Approximately 25-30% of the general population are colonized by Staphylococcus aureus, mainly in the nasal passages, but the organism can be found in most anatomical sites including the skin, oral cavity and GI tract.Infections are frequently acquired when the colonizing strain gains access to a normally sterile site as a result of trauma or abrasion to skin or mucosal surface. S. aureus infections range from superficial, localized skin infections, such as folliculitis, to deeper, more serious skin lesions and the more serious toxin mediated conditions – scalded skin syndrome and toxic shock syndrome.
|Clinical significance of Staphylococcus aureus|
In general, the infection that develops is dependent on the virulence of the particular strain, the inoculum size, and immune status of the host. Staphylococcal infections are typically suppurative, producing abscesses filled with pus and damaged leukocytes surrounded by necrotic tissue. Skin infections range from superficial - boils, carbuncles and furuncles, to bullous impetigo; largely opportunistic infections that develop as a result of previous injury e.g., cuts, burns, surgical wounds - and scalded skin syndrome (extensive exfoliative dermatitis; also known as Ritter's Disease). Other major infections include pneumonia, osteomyelitis (localized infection of bone), and septic arthritis. S. aureus also causes food poisoning as a result of ingestion of food contaminated with an enterotoxin producing strain (enterotoxins A&D) and the potentially fatal toxic shock syndrome, a multisystem disease most often associated with the use of highly absorbent tampons. Toxic shock syndrome is attributed to another toxin (enterotoxin F – TSST1) released by certain strains of S. aureus.Human staphylococcal infections usually remain localized by the normal host defenses. Foreign objects (fomites) such as sutures or intravenous (IV) lines - are readily colonized by S. aureus from skin and can allow the organism to spread systemically via the blood stream – bacteremia/septicemia - leading to more serious infections. Staphylococcal pneumonia is becoming a frequent complication of influenza. Whatever the mode of entry, the invasive nature of S. aureus always poses the threat of more serious deeper tissue invasion and/or bacteremia and hematogenous spread.
|Cell Cytotoxicity Neutralization Assay|
The Cell Cytotoxicity Neutralization Assay (CCNA) was developed to detect the presence of C. difficile toxin in fecal samples.In this assay, a filtrate of stool sample is prepared and inoculated onto sensitive tissue culture cells. Typically human fibroblast cells are utilized; if toxin is present in the filtrate, it causes the fibroblasts to round up in a characteristic cytopathic effect.To verify that the cytopathic effect is in fact caused by C. difficile toxin (and not by some other toxic component or viral agent) the filtrate is also inoculated in parallel onto a second set of tissue culture cells, to which C. difficile specific anti-toxin has been added.Absence of the cytopathic effect in the second set of cell cultures provides evidence that the cellular changes in the first set were caused by C. difficile toxin.Although CCNA is considered a gold standard for the detection of C. difficile toxin, it is labor intensive, requires the use of cell cultures, and requires at least 48 hours incubation.
|Treatment of CDI/CDAD|
The first step in treating patients with CDAD is to discontinue the causative agent wherever possible. The choice for initial antibiotic therapy depends on the severity of disease. Oral vancomycin or metronidazole remain the mainstays of therapy for C. difficile infection, with vancomycin reserved for patients with more severe disease and/or those who have not responded to metronidazole. Metronidazole is currently favored in guidelines from the CDC on the basis of cost and concern that oral vancomycin promotes colonization with vancomycin-resistant Enterococcus. Oral fluids (water and electrolytes) may be necessary to counteract fluid loss as a result of excessive diarrhea, which can quickly lead to dehydration. Patients with fulminant disease and toxic megacolon may require colectomy. Recurrence of C. difficile infection (CDI) is becoming an increasing problem. Most recurrences happen 7 - 14 days after completion of therapy, suggesting relapse rather than re-infection. If a patient develops a second episode of CDI following initial successful treatment, it is recommended that if possible, the same drug be used to treat the second episode. Contributing factors to recurrent CDI include: Continuing exposure to organisms either through re-infection (via contaminated environment or poor hand hygiene) or an endogenous source, such as C. difficile spores in GI tract. An inability to mount an adequate anti-Toxin A IgM and/or IgG antibody response (i.e., poor host immune response); a likely reason why CDI affects an increasingly elderly population. Unfortunately a vicious cycle can arise whereby the initial treatment prescribed, vancomycin or metronidazole, significally disrupts normal colonic flora reducing colonization resistance and leaving the patient vulnerable to the next recurrent episode.Other treatments including the use of probiotics or anion-exchange resins to absorb toxins, may work in some cases but none work in every case.The goal of all treatment is to reestablish normal colonic flora so as to control C. difficile (over)growth.
|Pathogenisis of C. Difficile-Associated Diarrhea|
Clostridium difficile is the leading cause of hospital-acquired diarrhea in the United States, with the number of cases rising annually over the last three decades. This is largely due to the increased frequency of antibiotic usage, the development of better detection methods, and the fact that hospital environments are increasingly contaminated with spores of C. difficile. The definition of C. difficile diarrhea includes > 6 episodes of non-formed diarrheic stool per 24 hours, along with prior antibiotic treatment. At least three events must occur in the pathogenesis of C. difficile-associated diarrhea (CDAD): Alteration of the normal fecal flora Colonic colonization with toxigenic C. difficile Growth of the organism with elaboration of its toxins"Colonization resistance" is the term used to describe the mechanism by which indigenous flora control overgrowth of C. difficile. This resistance may be compromised by the use of antimicrobial compounds, underlying illness, or therapeutic procedures. Infection begins with the ingestion of either the organism itself or spores, usually via the fecal-oral route. Spores in particular are able to survive the acidity of the stomach and germinate in the colon to produce vegetative organisms. Toxinogenic strains subsequently produce Toxin A, Toxin B, and/or the Binary Toxin leading to colitis, pseudomembrane formation, and watery diarrhea. Significant complications of the clinical disease associated with infection are hypoalbuminemia, toxic megacolon (acute toxic colitis with dilatation of colon), and pseudomembranous colitis (PMC).
In order to discuss TDM and PGx we need to also introduce the concept of pharmacokinetics. Pharmacokinetics is the study of drug disposition in the body: how and when drugs enter the circulation, how long they remain in the blood, and how they are eliminated. TDM is the clinical assessment of a drug's pharmacokinetic properties. Physicians and pharmacists need to establish that a drug is present at an effective concentration but not at a toxic concentration. The next few pages will describe some of the factors that determine a drug's disposition in the body. These factors ultimately decide the need for therapeutic drug monitoring.
|TDM for all drugs?|
Can all drugs benefit from TDM? Not really. For TDM to be effective and useful, one or more of the following should apply: The effective concentration and toxic concentrations must be well-defined. The pharmacokinetics of the drug are known to be variable. The drug is given chronically. There is the potential for drug-to-drug interactions. The drug exhibits high protein binding. The toxicity will mimic the indication for the drug; toxicity may not be visible during an exam but will only be revealed with TDM. The patient is pregnant, very young, or elderly. Compliance or history with the drug is poor.
|A physician needs to prescribe a drug with a narrow therapeutic window. He is concerned about possible toxic effects. To assess the upper concentration of such a drug, which time for drawing the specimen do you think makes the most sense?||View Page|
|Protein Availability and Drug Dosing|
Drug-binding proteins in serum can fluctuate in disease states. For example, if albumin levels fall, as can occur in liver failure or nephrotic syndrome, less albumin will be available for drug binding; a subsequent dose may produce a toxic concentration of free drug.The image on the right illustrates the loss of equilibrium between a protein-bound drug and a free drug when drug-binding proteins are diminished.Doses of drugs that are highly protein-bound may need to be adjusted in patients with lower drug-binding protein levels. Examples of some common drugs that are highly protein-bound include thyroxine, warfarin, diazepam, heparin, imipramine and phenytoin.
Every drug has a sub-clinical concentration (a concentration at which effective therapy won't be achieved) and a toxic concentration (a concentration at which the drug will be harmful to the patient.)For some drugs, the range between the minimum effective concentration and the toxic concentration is large. These drugs are thus relatively safe. Other drugs have a very narrow therapeutic window and need closer monitoring. This is the role of TDM.Medications with narrow therapeutic windows, like the anticonvulsant carbamazepine (Tegretol), should be closely monitored since elevated doses can cause serious conditions such as agranulocytosis.
|When is TDM Not Useful?|
TDM is not useful for these drugs or in these specific situations: Intracelluar drugs that need to be converted to active forms (like AZT) Drugs in which the effects last much longer than the serum concentrations of the drugs; examples include antineoplastics (cancer chemotherapies) and warfarin Narcotic pain medications where continued use can lead to tolerance such that the levels needed for pain relief in one person would be toxic to another person
|The hematology analyzer reported an elevated white blood cell count and flagged for manual review due to the suspected presence of immature cells. What is the arrowed cell's identity, and what name is given to its inclusion?||View Page|
|What morphological change is present in the neutrophil that is present in this image?||View Page|
|What is the identity of the white blood cell inclusions present in this image?||View Page|
|What morphological change is present in the image indicated by the arrow?||View Page|
|What cytoplasmic inclusion is indicated by the arrow in this image?||View Page|
|The inclusions that are seen in the white cell indicated by the arrow in this image are characteristic of which of the following conditions?||View Page|
|Conditions Associated with Hypersegmented Neutrophils|
There are a number of conditions in which hypersegmented neutrophils may be seen, such as megaloblastic anemias (including folic acid deficiency and pernicious anemia). Individuals who are receiving chemotherapy or have long-term chronic infections may also have hypersegmented neutrophils.The cells seen in these conditions would be classified as pathological since the body is responding abnormally as a result of either a deficiency of a component needed for DNA production or because of the toxic effect that chemotherapy drugs have on DNA.
|Toxic Granulation and Vacuolation|
Vacuoles are frequently seen in conditions such as infection or burns when toxic granulation is also present. The cell in this image exhibits toxic vacuolation as well as toxic granulation. Note: Toxic vacuolation and toxic granulation are classified as reactive and not pathologic since the body is responding normally in an effort to rid itself of infection caused by bacteria.
Vacuoles, toxic granulation and degranulation are classified as reactive since the body is responding normally in an effort to rid itself of infection caused by bacteria. Morphological changes related to aging are also classified as reactive.
Toxic granulation is present in the neutrophil in this image.
|Match each of the following. Answers may be used more than once or not at all.||View Page|
|The cell in this image is typical of other neutrophils on this peripheral blood smear from a patient with sepsis. Which morphologic term describes the cellular morphology in this image?||View Page|
|Which morphologic term describes this slide?||View Page|
|What type of inclusions are present in the cell that is indicated by the arrow?||View Page|
|Döhle Bodies, continued|
Döhle bodies are seen in a number of conditions, including:infections burns measles leukemia chemotherapyDöhle bodies are only present when the body is responding to unusually severe stress or stimulus. This severe stress may cause the cytoplasm of some cells to mature improperly. Their presence does not aid in the diagnosis of the disorders in which they are found, but they are frequently seen along with toxic granulation and/or vacuoles in cases of infection or burns.
Toxic granulation is manifested by the presence of large granules in the cytoplasm of segmented and band neutrophils in the peripheral blood. The color of these granules can range from dark purplish blue to an almost red appearance. Toxic granules are actually azurophilic granules, normally present in early myeloid forms, but are not normally seen at the band and segmented stages of neutrophil maturation. These granules contain peroxidases and hydrolases. Toxic granulation is seen in cases of severe infection, as a result of denatured proteins in rheumatoid arthritis or, less frequently, as a result of autophagocytosis. Infection is the most frequent cause of toxic granulation. This phenomenon may be seen in cells which also contain Döhle bodies and/or vacuoles. Cells containing toxic granules may have decreased numbers of specific granules. Note: Cells containing only a few specific granules, with or without toxic granules, are said to be degranulated. The nucleus in degranulated cells may often be round-bilobed, smooth and pyknotic. This type of nucleus is the result of aging and will disintegrate soon. Increased basophilia of azurophilic granules simulating toxic granules may occur in normal cells with prolonged staining time or decreased pH of the stain. The blue arrow in the image points to a neutrophil with toxic granulation. Döhle bodies are also present in the cell, indicated by the red arrows.
|Which morphologic term describes the condition present in this image?||View Page|
|Band Neutrophil Showing Toxic Granulation|
This image shows a band neutrophil with toxic granulation. The granules scattered throughout the cytoplasm are larger, more numerous and darker than those of normal neutrophils.
|Chediak-Higashi Anomaly vs. Toxic Granulation|
The neutrophils found in Chediak-Higashi must be differentiated from toxic granulation. In conditions causing toxic granulation, the granules are smaller and more numerous. In toxic granulation, neutrophils are usually the only cells affected. In Chediak-Higashi anomaly, eosinophils, basophils, lymphocytes and monocytes are affected. In eosinophils larger than normal eosinophilic granules may be seen, basophils may exhibit larger than normal basophilic granules, lymphocytes, large azurophilic granules. Larger pale granules/bodies may appear in monocytes.
An example of a normal neutrophil, lower left, and one showing some increased granulation, typical of that seen in Alder-Reilly anomaly. Morphologically, it may be difficult to distinguish these granules from toxic granulation; however, the diagnosis is made on the basis of the presence of the many distinctive physical characteristics.
|The inclusions that are frequently seen on the same peripheral blood smear with toxic granulation include: (Choose ALL that apply)||View Page|
|Toxic granulation is seen most frequently in:||View Page|
|Another Example of Toxic Granulation|
Another example of toxic granulation. Notice that the granules are larger and redder than those in the previous slide.
|Alder Anomaly (Alder-Reilly Anomaly )|
Alder anomaly is a rare autosomal recessive disorder in which the basic defect involves protein-carbohydrate complexes called mucopolysaccharides. The accumulation of partially degraded (broken down) protein-carbohydrate complexes within the lysosomes account for the larger than normal purple-staining inclusions seen in all types of mature white blood cells, and sometimes in earlier cells. The granules may occur in clusters, rather than diffusely, throughout the cytoplasm as in toxic granulation. These inclusions may be seen in the bone marrow more frequently than in peripheral blood. The physical characteristics associated with this disorder include gargoylism and dwarfism. The function of the cells involved is not affected. This morpholical change would be classified as pathological since the body is responding abnormally even though the function is not affected.
|Which morphologic term describes this slide?||View Page|
|Which morphologic term describes this slide?||View Page|
|The white blood cell indicated by the arrow is representative of the atypical white blood cell associated with infectious mononucleosis.||View Page|
The following pages in this presentation includes a series of white blood cell and platelet abnormalities (nonneoplastic) that may be identified in a peripheral blood smear. Many cases will simulate the practice of a peripheral smear review by a hematology technologist. He or she must assess what responses in patient care may be triggered by the clinician attempting to interpret the reported findings on a peripheral smear.Observations of white blood cell abnormalities in the peripheral blood smear should be reported in order to direct the physician to an immediate specific diagnosis, such as: Atypical lymphocytes, suggesting infectious mononucleosis rather than leukemia Toxic granules in neutrophils, as found in acute infections, or atypical granules suggesting a genetic disorder An unusual mix of cells, such as too many or too few neutrophils, monocytes, or other myeloid cells The presence of giant platelets, myelocytes, or other cells, suggesting a myelodysplastic syndromeIn summary, laboratory data should be presented to clinicians in a user-friendly fashion to promote effective decision making.
|The neutrophils illustrated in this image are representative of those seen in a female patient's peripheral blood smear. The total WBC was 28.5 X 109/L (reference interval = 4.0 - 11.0). Which of the following BEST describes the condition associated with this WBC count and the white blood cells that are present in the image?||View Page|
|Cells that appeared similar to those illustrated in this image were repeatedly encountered as the smear was reviewed. The peripheral white blood cell count was 51.0 X 109/L with an orderly maturation sequence. The comment "leukemoid reaction" may properly be appended to the report.||View Page|
|A peripheral blood smear with many myeloid cells was presented for morphology review (see image on the right). Toxic granulation and vacuoles in the neutrophil most likely represent which of the following conditions?||View Page|
|The association of increased platelets accompanying neutrophilia and toxic granulation, as illustrated in this image, is called thrombocytopenia.||View Page|
|Toxic granulation noted in the neutrophils' cytoplasm reflects an increase in activity of which of the following?(Choose all that apply)||View Page|
The term "leukemoid reaction" is used to describe a condition where peripheral white blood cells on a stained blood smear may have some resemblance to leukemia cells. Quantatively, in a leukemoid reaction, the neutrophil count may be as high as 50.0 X 109/L with more immature cells, particularly myelocytes, than are usually present in toxic left-shift syndromes. The presence of immature cells in a leukemoid reaction awakens thoughts of leukemia. Great care must be taken to make a distinct differentiation between aberrant white blood cell proliferations (possible leukemia) and a benign but exaggerated granulocytic proliferative response (leukemoid reaction). The leukocyte alkaline phosphatase (LAP) score is low in myelocytic leukemia and high in leukemoid reaction. This particular peripheral smear represents a leukemoid reaction.
|Familial disorders: summary|
Several additional familial and congenital disorders associated with atypical inclusions in WBCs are now recorded. These individual syndromes carry the following names: Fechtner, Alport, Epstein, Sebastian, and Paris-Trousseau.Fechtner syndrome( Peterson etal,Blood 65:397-406,1985)was described with 8 family members spanning 4 generations presenting with varying degrees of nephritis, deafness,and congenital cataracts. The syndrome is likely a variant of Alport syndrome with the addition of leukocyte inclusions and macrocytothemia. Several more cases involving other families have been reported. The inclusions resemble toxic Doehle bodies or those of the May-Hegglin anomaly by light microscopy, but are ultrastructurally unique.Alport syndrome is autosomal dominant, X-linked , hereditary and characterized by sensorineural deafness and hereditary nephritis. It is believed to result from abnormal glycopeptide synthesis in renal basement membranes. Recurrent hematuria and slowly progressive renal insufficiency are clinical findings. Cataracts and platelet abnormalities may be added features.Epstein syndrome is essentially Alport syndrome with the addition of macrothrombocytopenia (Seri, et al. Hum Genet 110:182-186, 2002). Neutrophil inclusions are absent in this disorder; neutrophilic inclusions are considered part of the Fechtner syndrome.The Sebastian platelet syndrome is a variant of hereditary macrothrombocytopenia combined with neutrophil inclusions that differ from Doehle bodies, but are similar to those inclusions in Fechtner syndrome. (Greinacher, et al, Blut 61:282-288, 1990).Paris-Trousseau syndrome includes large platelets containing giant alpha granules identifiable in the peripheral blood.(Breton-Gorius, Blood 85:1805,1995)
Alder anomaly is characterized by large azurophilic granules that stain dark-purple and are seen throughout the leukocyte cytoplasm, even covering the nucleus. The inclusions (granules) are seen in the cytoplasm of almost all mature leukocytes i.e., granulocytes, lymphocytes, and monocytes. This distinguishes Alder anomaly inclusions from toxic granulation, which is only observed in neutrophils. Another feature that distinguishes Alder anomaly from toxic changes is the lack of cytoplasmic vacuoles of toxic origin in the neutrophils of Alder anomaly.The background condition in Alder anomaly is mucopolysaccharidosis, collectively, a group of inherited disorders where a deficiency of lysosomal enzymes are lacking that are needed to degrade mucopolysaccharides. The inclusions observed in the leukocytes represent partially degraded mucopolysaccharides within lysosomes. Accompanying conditions are hepatosplenomegaly, corneal opacities, and mental retardation.
|WBC inclusions: Summary|
The presence of atypical inclusions within the cytoplasm of neutrophils and other leukocytes should lead to a clinical investigation of the setting for these findings. Atypical neutrophil inclusions may be seen in the following disorders: Chediak-Higashi syndrome, May-Hegglin anomaly, Alder-Reilly anomaly, Fechtner , Sebastian, Epstein and Alport-like syndromes and in infectious and toxic conditions (in the form of Dohle bodies).Although a specific entity may not be evident from examination of the peripheral blood alone, it is important that hematology technologists include a comment reporting on the presence of these inclusions or granules. A clinical investigation with further hematologic and genetic studies may then appropriately be considered. Many of the disorders with atypical neutrophil cytoplasmic granules are also associated with platelet abnormalities, particularly giant platelets (lower image). Therefore, when atypical granules are recognized, scanning of the peripheral blood smear for atypical platelets may be revealing. These observations serve as readily identifiable markers for acquired and genetic human maladies, and as a guide for unraveling the reasons for a patient's suffering and impaired health.
|The pale-staining cytoplasmic bodies marked by the arrow in the image may be seen in each of the following conditions except:||View Page|
May-Hegglin anomaly is an inherited dominant condition in which large (2 - 5 um) basophilic inclusions, resembling Döhle bodies, are present in granulocytes, including neutrophils, eosinophils, basophils, and monocytes. The inclusions are caused by accumulation of free ribosomes. A May-Hegglin body is indicated by the black arrow in the image on the right. Note that this inclusion is well-defined and there is no evidence of toxic granulation in the cytoplasm. When Döhle-like bodies are identified, May-Hegglin anomaly should be considered in the differential diagnosis, even though this entity is rare. Giant platelets containing few fine granules are also characteristic of May-Hegglin anomaly. The red arrow in the image on the right points to a giant platelet, observed in the same field as a neutrophil containing a May-Hegglin body. Sometimes the platelets have bizarre shapes and variable sizes. Variable degrees of thrombocytopenia complicated by mild bleeding problems and purpura may accompany the aberrant platelets.
A 17-year-old female was admitted to the hospital with abdominal pain and a tentative diagnosis of appendicitis. The total white blood count was 14.5 X 109/L with a left shift and neutrophils with changes tagged by the arrow in the image (see blue arrow). The bluish-staining, blurred accumulations in the cytoplasm (Döhle bodies), are located at the cell periphery in neutrophils with toxic changes.Döhle bodies are remnants of endocytoplasmic reticulum and are products of cytokine activity in the induction and shortened activity of neutrophil activation. They are often present in conditions with increased neutrophil lysosomal activity, manifest as toxic granulation.In this case, the presence of Döhle bodies serves as markers for infection-induced leukocytosis and supports the diagnosis of acute appendicitis.
|The cytoplasmic inclusion illustrated at the tip of the blue arrow is characteristic of:||View Page|
A basophil and a small lymphocyte are compared in the same field in the upper image, while a single basophil is shown in the lower image.The cytoplasmic granules of the basophil are larger than the granules of toxic granulation.They contain chemical mediators of immediate hypersensitivity, and are found in the cytoplasm and overlying the nucleus (better seen in the lower image). Basophilic granules stain metachromatically with toluidine blue indicating the presence of acid mucopolysaccharide or proteoglycans, both thought to be heparin or heparin-like substances.Basophils are related to mast cells (tissue basophils), each involved in hypersensitivity responses and following anaphylactic episodes. Under the stimulation of complement components C3a and C5a, many mediators are released from the basophil granules, including histamine, heparin, and eosinophil chemotactic factors of anaphylaxis, or ECF-A.Basophils are the least common granulocytes in the peripheral blood, comprising 2% or less of the differential count. The presence of large granules of irregular size in basophils and the admixture of eosinophilic granules may indicate dysplastic changes associated with myelodysplastic disorders and leukemia. Basophils may be increased in:Myeloproliferative disordersChronic metabolic conditions Myxedema Diabetes mellitusHypersensitivity responses Tuberculosis
|A peripheral blood smear is observed during a manual differental review. The patient is a 10 year-old boy with symptoms suggesting appendicitis and an appendectomy is being considered. The total WBC is 18.5 X 1000/uL, RBC's = 5.45 X 1M/uL, hemoglobin = 16.0 g/dL, hematocrit 48.2%.WBC differential:Segs = 53%, bands = 42% (two of which are shown in the image) monocytes = 2% lymphocytes= 2% These findings support the diagnosis of appendicitis.||View Page|
|Case One Follow-up|
The blood count alone might be interpreted as reflecting infection, possibly supporting a diagnosis of acute appendicitis. However, the technologist performing the differential noted that more than 70% of the segmented neutrophils had bi-lobed or mono-lobed nuclei, strongly suggesting Pelger-Huet anomaly. Since the peripheral blood smear did not support the diagnosis of appendicitis in this patient, and since abdominal pain localized to the right lower quadrant never developed, the boy was hydrated with intravenous fluid and observed. After hydration, his constitutional symptoms improved and the abdominal pain subsided. People entering high altitude where the humidity may be very low are susceptible to dehydration and may experience symptoms related to mountain sickness.
|Case History Two|
An 80-year-old man was seen in the emergency room with sudden onset of right-side chest pain accentuated on inspiration. His cough was productive of yellow sputum, and he was short of breath. His temperature was 101.2°F. A chest X-ray revealed right middle lobe pneumonia. A complete blood count (CBC) was ordered. The results were as follows:CBC ParameterPatient ResultReference IntervalWBC33.0 x 109/L4.0 - 11.0 x 109/LRBC4.5 x 1012/L4.5 - 5.9 x 1012/LHemoglobin15.2 g/dL13.5 - 17.5 g/dLHematocrit44%41 - 53%Platelet200 x 109/L150 - 450 x 109/LSegmented neutrophil6540 - 80%Band neutrophil100 - 5%Lymphocyte 525 - 35%Eosinophil 30 - 5%Basophil 20 - 2%Monocyte252 - 10%A peripheral smear was reviewed based on the elevated WBC and increased monocyte count. A representative field from the Wright-Giemsa stained smear (1000X magnification) is shown on the right. The cells indicated by the blue arrows are atypical monocytes. They have abundant cytoplasm that is more blue than the typical gray-blue cytoplasm of normal monoctes. A few scattered vacuoles are also present. The atypical monocytes, in company with toxic neutrophils (indicated by the red arrow), appeared to be a response to infection. The patient had a past history of tuberculosis, which may account for the monocytosis.
Plasma cells are uncommonly observed in the peripheral blood smear. They are normal constituents of lymph nodes, spleen, connective tissue and bone marrow. The presence of plasma cells in the peripheral blood is indicative of a large number of conditions, mostly related to infections , immune disorders, malignancies, toxic exposures, hypersensitivity reactions and their responses.Although mature plasma cells have a distinct appearance, they still may be confused morphologically with immature plasma cells and other cells with inclusions, reactive changes or nucleated red bloods cell with altered identities. In the image to the right, a plasma cell is present. The plasma cell has an eccentric immature nucleus with a muddy chromatin pattern. Note also clumping and stacking of the erythrocytes, typical of rouleaux formation, implicating an increase in plasma gamma globulin. Further studies are in order, including a bone marrow examination, where at least 30% of bone marrow cells should be variations of mature and immature plasma cells. Serum protein electrophoresis will reveal a monoclonal globulin spike, and light chains in excess of 1.0 gm/24 hours may be seen in the urine. The presence of lytic bone lesions is a convincing clinical clue. With these findings in combination, a diagnosis of myeloma can be made with assurance.