Hematopathology Case Study: An 85 Year Old Man with Pancytopenia

Case History

An 85 year old man presented with pancytopenia and weakness. His labs include WBC of 3.2, HgB of 9.9 and platelets of 137.

Bone Marrow Biopsy

hairycellbm10x
Bone Marrow Aspirate, 10x
hairycellbm40x
Bone Marrow Aspirate, 40x
hairycellcore10x
Core Biopsy, 10x
hairycellcore40x
Core Biopsy, 40x

Flow Cytometry

hairycellflow

hairycellplasmacell

hairycellplasmacellgate

Diagnosis

The bone marrow aspirate shows multiple cellular spicules with a prominent population of lymphoid cells with oval to reniform nuclei, dispersed chromatin and abundant pale cytoplasm. Scattered plasma cells are also present.

The core biopsy shows an infiltrating population of atypical lymphocytes with moderate amounts of pale eosinophilic cytoplasm and mature chromatin that stain positive for CD20. Frequent mononuclear cells consistent with plasma cells are also seen scattered throughout the bone marrow and stain positive for CD138.

Flow cytometry revealed that 80% of the lymphoid gate represented a kappa light chain restricted population that co-expressed B-cell markers CD19, CD20 and CD22 along with classic hairy cell leukemia specific markers CD11c, CD25 and CD103. A second population of kappa restricted cells fell in the plasma cell gate. The cells co-expressed CD138, CD56 and were largely negative for CD19 and CD20.

Overall, there is a hypercellular bone marrow with a prominent mononuclear lymphoid infiltrate consistent with hairy cell leukemia and a concurrent population of plasma cells consistent with plasma cell neoplasm.

Discussion

Hairy cell leukemia is a rare lymphoid neoplasm that accounts for only 2% of lymphoid leukemias. Patients tend to be in their 50s-60s with a 4:1 male predominance. The tumor is generally found in the bone marrow and spleen with rare circulating cells in the peripheral blood. Patients are generally cytopenic at presentation and symptoms include weakness and fatigue. Splenomegaly is common and hepatomegaly can also be seen.. 1

Hairy cell leukemia involves the clonal expansion of B-cells with a unique immunophenotypic profile. They are bright for CD19, CD20, CD22 and CD200, negative or dim for CD5, CD23 and CD10 and positive for CD11c, CD103, CD123 and CD25. Hairy cell leukemia must be distinguished from two provisional entities, hairy cell leukemia-variant and splenic diffuse red pulp lymphoma. These two entities do not have the classic morphology or staining profile of hairy cell leukemia.2

BRAF V600E mutations are detected in more than 80% of cases of classic hairy cell leukemia. The mutation is considered to be a driver mutation, but additional mutations are usually present that lead to disease progression. Hairy cell leukemia-variant is usually negative for BRAF mutations and has a more aggressive clinical course.3

Patients with hairy cell leukemia are given purine analogues as first line treatment and generally do well. However, patients who do not respond or who undergo relapse have few options. Increasingly, BRAF V600E inhibitors are being used for patients with hairy cell leukemia. Multiple studies have now confirmed the efficacy of vemurafenib and dabrafenib, however patients can be quick to relapse once off the drugs. Combination approaches should be considered for the most effective treatment. 4

References

  1. Swerdlow SH, Campo E, Harris NL, et al. WHO Classification of Tumours of Haematopoetic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017.
  2. Troussard X, Cornet E. Hairy cell leukemia 2018: Update on diagnosis, risk‐stratification, and treatment. American Journal of Hematology. 2017;92(12):1382-1390. doi:10.1002/ajh.24936.
  3. Maitre E, Bertrand P, Maingonnat C, et al. New generation sequencing of targeted genes in the classical and the variant form of hairy cell leukemia highlights mutations in epigenetic regulation genes. Oncotarget. 2018;9(48):28866-28876. doi:10.18632/oncotarget.25601.
  4. Roider T, Falini B, Dietrich S. Recent advances in understanding and managing hairy cell leukemia. F1000Research. 2018;7:F1000 Faculty Rev-509. doi:10.12688/f1000research.13265.1.

 

Marcus, Chelsea_099-Edit

Chelsea Marcus, MD is a third year resident in anatomic and clinical pathology at Beth Israel Deaconess Medical Center in Boston, MA and will be starting her fellowship in Hematopathology at BIDMC in July. She has a particular interest in High-grade B-Cell lymphomas and the genetic alterations of these lymphomas.

Microbiology Case Study: A 49 Year Old with HIV and CNS Lymphoma

Case History 

A 49 year old African American female was transferred from an outside hospital due to orbital cellulitis. Her past medical history was significant for HIV, CNS lymphoma, for which she was taking methotrexate & rituximab, and type II diabetes. Her vitals were: blood pressure 181/145, heart rate 145, temperature 98.6°F and respiratory rate 20. On physical examination, her right eye was bulging, with conjunctiva & eyelid swelling, and her iris was non-reactive. Scant serous drainage was noted. Admission labs showed a normal white blood cell count (9.8 TH/cm2), glucose of 211 mg/dL (normal: 74-106 mg/dL), hemoglobin A1C of 7.7% (normal: 4.2-6.0%) and platelets were low at 41,000 TH/cm2. An infection was suspected and the patient was started on vancomycin and piperacillin-tazobactam. She had a head CT scan which showed right periorbital cellulitis and diffuse sinus disease but no abscess formation. Nasal endoscopy was performed and extensive adhesions & black colored, necrotic tissue of the right nasal cavity was noted in addition to whitish debris, consistent with fungal overgrowth extending into the nasopharynx. Biopsies were taken for frozen section and bacterial & fungal culture and Infectious Disease was consulted for management of a probable rhinocerebral fungal infection.

Laboratory Identification

rhiz1
Image 1. Biopsy of the right nasal wall showed tissue invasion and necrosis with broad, ribbon like hyphae that were pauciseptate and branched at right angles (H&E, 40x).
rhiz2
Image 2. Fluffy, white fungal growth on Sabouraud Dextrose and Sabouraud Dextrose with Chloramphenicol agars at 72 hours of incubation at 25°C. There was no growth on the Mycobiotic agar slant.
rhiz3
Image 3. Tape prep showed a round sporangium containing small sporgangiospores located directly below the rhizoids of the mold which is consistent with the diagnosis of Rhizopus spp. (lactophenol cotton blue, 40x).

Discussion 

Rhizopus spp. belong to the order Mucorales, are ubiquitous in the environment and are the most common etiologic agents of mucormycosis. Rhizopus spp. typically cause invasive infections in the nasal sinus, brain, eye and lung, particularly in patients that have uncontrolled diabetes, HIV or are immunosuppressed. Mucorales are angioinvasive, exhibit perineural invasion and there is usually thrombosis, infraction and necrosis of surrounding tissue. As the illness can progress quite rapidly, prompt diagnosis and treatment is necessary.

If a Mucorales is suspected, tissue specimens obtained during a surgical procedure should be sent for frozen section, direct examination with calcofluor white/KOH and fungal culture. On histologic exam or microscopic exam in the microbiology laboratory, the hyphae of Rhizopus spp. are wide & ribbion-like with few to no septations (pauci- or aseptate) and wide angle branching (90°) (Image 1). Further classification requires culture.

If a Mucorales is suspected, the tissue submitted for fungal culture should be minced into small pieces and directly applied to the appropriate fungal media. Grinding of tissue will kill the hyphae and result in no growth from culture. Mucorales will not grow on media containing cycloheximide. Rhizopus spp. grow rapidly within 1-4 days and start as white, fluffy colonies that become grey or brown in color as they mature (Image 2). The Mucorales are described as “lid lifters” due to their rapid growth and “cotton candy” like colonies that fill the plate. On lactophenol cotton blue prep, Rhizopus spp. have unbranching sporangiophores that terminate in a round sporangium and arise directly under well-developed rhizoids (Image 3). The sporangium ruptures when mature and releases many oval sporangiospores.

Treatment of patients with mucormycosis is usually a dual approach with wide surgical excision and amphotericin B, which has been shown to be an effective anti-fungal drug in the majority of Mucorales. In contrast, voriconazole has poor activity against these isolates. If susceptibility testing is needed, CLSI provides reference broth microdilution guidelines. In the case of our patient, due to the grave prognosis of her condition, in addition to her other comorbidities, the family elected for comfort care measures only and board spectrum anti-fungals were not started.

 

Stempak

-Lisa Stempak, MD, is an Assistant Professor of Pathology at the University of Mississippi Medical Center in Jackson, MS. She is certified by the American Board of Pathology in Anatomic and Clinical Pathology as well as Medical Microbiology. She is the Director of Clinical Pathology as well as the Microbiology and Serology Laboratories.  Her interests include infectious disease histology, process and quality improvement and resident education.

Beyond the CBC and Reticulocyte Count: Early Detection of Iron Deficiency Anemia

In my May 2018 post (Not your Grandmother’s Hematology), I discussed the history of hematology and chronicled how far we have come in the last 60 years. We have progressed from manual counting of cells to the first Coulter Counter in 1956, which revolutionized hematology by being able to automate the counting of red blood cells, to modern instruments that can report up to 30 parameters and perform up to 400 CBCs an hour. Among these parameters are what are termed advanced clinical parameters, new parameters which provide physicians with additional information about the state of blood cells. In this blog I will explore how one of these advanced clinical parameters, the Reticulocyte Hemoglobin content, can provide physicians with information that can assist them with earlier detection, differential diagnosis and better management of iron deficiency and iron deficiency anemia. 

Case Study 

A 29 year old female was seen by her gynecologist reporting a history of heavy menstrual bleeding with current bleeding lasting 15 days. The doctor discussed various treatment options with the patient and a CBC was performed. CBC results are shown below.

Test Result Flags Reference
WBC 7.23   4.5-10.5 K/CMM
RBC 4.38   3.70-5.30 M/CMM
HGB 12.0   12.0-15.5 GM/DL
HCT 36.2   36.0-46.0 %
MCV 82.6   80-100 FL
MCH 27.4   27.0-34.0 PG
MCHC 33.1   32.0-36.0 %
PLT 243   150-450 K/CMM
MPV 11.0   9.6-12.0 FL
RDW 12.5   0-15.1 %

This CBC shows no abnormal flags. Based on patient history and presentation, the physician questioned iron deficiency despite normal hemoglobin and hematocrit, MCV and MCHC. He ordered a reticulocyte profile on the same specimen with the following results:

Test Result Flags Reference Range
Retic 1.55   0.5-2.0 %
Abs Retic 0.0679 H 0.0391-0.057 M/CMM
Imm Retic Frac 14.9   2.3-15.9 %
Ret-Hgb 24.6 L 30-35 PG

Reticulocyte counts are the quantity of the youngest red blood cells released from the bone marrow into the peripheral blood. Reticulocytes are reported as a % and the absolute reticulocyte count is calculated by multiplying the Retic% by the RBC. The immature reticulocyte fraction (IRF) is the rate of production of reticulocytes and depends largely on the ability of the bone marrow to respond to erythropoietin. The reticulocyte hemoglobin (Ret-He) content is the amount of hemoglobin in newly formed red blood cells. (There are two different hematology systems that report reticulocyte hemoglobin content. The two nomenclatures used for reticulocyte hemoglobin are Ret-He and CHr and studies have been done that demonstrate their equivalence)

Note that the Ret-He reflects the quality of the newly formed reticulocytes. Ret-He is a direct measurement of the amount of hemoglobin in each reticulocyte, which indicates the amount of iron available for incorporation into the precursors of mature red cells. This patient’s retic% and IRF are within normal ranges, but her absolute reticulocyte count is high. A Ret-He less than 29 pg in an adult is indicative of iron deficiency. With a normal CBC and low Ret-He, this is an early indication that iron deficiency is indeed present. With the absence of sufficient iron, this patient would eventually develop a microcytic, hypochromic anemia. Therefore, Ret-He can measure and indicate inadequate hemoglobin production before the hemoglobin and hematocrit decrease.

In this case the importance of clinical awareness is illustrated. This physician remembered a recent laboratory technical bulletin announcing implementation of a new hematology analyzer system with the availability of new parameters for reticulocyte counts. When the CBC results came back from the laboratory, the patient had already gone home, and no serum had been drawn to perform a ferritin level. Rather than calling the patient back to have another sample drawn, the Ret-He could be done from the same blood sample already in the lab. Ret-He is a faster, easier and less expensive test than additional iron studies and bone marrow iron stains. Ret-He can easily be used at a very low cost to get that first piece of information to decide whether or not iron deficiency is a concern. A high or normal Ret-He would have ruled out an iron deficiency with a fairly high confidence level. In this case, the low Ret-He could be used to guide further workups. A subsequent blood drawn revealed a low ferritin and iron deficiency was confirmed. The patient was advised to take an iron supplement along with ongoing treatment for the bleeding.

This case is just one example of the clinical utility of the Ret-He. Using the Ret-He, physicians can determine iron deficiency before iron deficiency IDA develops. A low Ret-He can alert a physician to iron deficiency without the presence of anemia, microcytosis or hypochromia. Ret-He can also be used to monitor and show early response to iron therapy before any other parameters change. A case example is that of a 5 month old who was brought to the emergency room with a Hgb of 7 g/dl and a Ret-He of 11.9 pg. In pediatric patients, a Ret-He less than 27.5 is an indicator of IDA. In this child, treatment with oral iron showed that the Ret-He had risen to 24.6 pg seven days after the onset of iron therapy, while the CBC remained virtually the same. This provided a very early indication that the iron therapy was effective.1 The Ret-He can also been used to minimize transfusions. The AABB Choosing Wisely Campaign lists 5 things that physicians and patients should questions before transfusion. One of the guidelines states “Don’t transfuse red blood cells for iron deficiency without hemodynamic instability.“2 Historically, physicians have used a ‘wait and see’ approach and watched Hgb levels drop before they start looking at iron. Using a Ret-He, iron deficiency could be determined, for example, in a patient with a Hgb of 11 g/dl. Oral or intravenous iron could be started before the Hgb drops below 7 g/dl and transfusion becomes necessary. The AABB Choosing Wisely Campaign emphasizes this by stating that patients with chronic iron deficiency or pre-operative patients with iron deficiency should be given iron therapy before transfusion is considered.2 Ret-He can give the earliest indication of iron deficiency and can be used to monitor the response to iron therapy. Another clinical utility of Ret-He has been to help diagnose or rule out iron deficiency in oncology patients. Additionally, Ret-He has been included in guidelines for anemia management in end stage renal disease patients on dialysis and who get erythropoietin.

The Ret-He parameter has proved clinically useful in early determination of functional iron deficiency. Traditionally ordered chemistry iron studies are indirect measures that have certain inherent inaccuracies due to the presence of inflammation and infection, or in patients on iron therapy. Ret-He is a direct and very effective screening tool and physicians can use Ret-He with other RBC indicies to improve anemia diagnosis and management in many patient populations. Ret-He can be used as a screening measure, and used to reflex for iron studies. Therefore, laboratories who have instruments that can report Ret-He and CHr should develop an education program to help clinicians effectively use Ret-He. Together physicians and laboratorians can develop their own guidelines for reflex testing and improvement for patient care.

References

  1. Case Studies Demonstrating the Clinical Application of the Advanced Clinical Parameters (1/20/2016) Chantale Pambrun, MD, FRCPC, Head of Division of Hematopathology and Assistant Professor of Pathology and Laboratory Medicine, IWK Children’s & Women’s Health Centre and Dalhousie University
  2. https://www.aabb.org/pbm/Documents/Choosing-Wisely-Five-Things-Physicians-and-Patients-Should-Question.PDF
  3. Advanced parameters offer faster, surer guidance to cancer care. Anne Paxton. CAP Today. Sept 2017
  4. The Value-driven Laboratory. Reticulocyte Hemoglobin Content (Ret-He): A Parameter Well-Established Clinical Value. Sysmex America White Paper.
  5. Sysmex Clinical Support Team. Utility of RET-He, August 10. 2015
  6. Brugnara C, Schiller B, Moran J. Reticulocyte hemoglobin equivalent (Ret-He) and assessment of iron-deficient states. Clinical Laboratory Hematology 2006;28:303 – 308.

 

Socha-small

-Becky Socha, MS, MLS(ASCP)CM BB CM graduated from Merrimack College in N. Andover, Massachusetts with a BS in Medical Technology and completed her MS in Clinical Laboratory Sciences at the University of Massachusetts, Lowell. She has worked as a Medical Technologist for over 30 years. She’s worked in all areas of the clinical laboratory, but has a special interest in Hematology and Blood Banking. When she’s not busy being a mad scientist, she can be found outside riding her bicycle.

Microbiology Case Study: A 22 Year Old Female with Wound Infection

 

Case History

22 year old female with a past medical history of scoliosis presents for routine follow-up after hospital discharge for post-op wound infection following a spinal fusion surgery. Patient had an anterior and posterior spinal fusion with allograft and hardware on 1/18/18. She had a laminectomy and irrigation for post-op epidural hematoma on 1/19/18. Subsequently, she developed a lumbar spine abscess and underwent irrigation and debridement of the abscess on 3/1/18. Two operative cultures of the left paraspinal musculature grew only tiny clear colonies on the anaerobic blood plates. Gram stain of these colonies did not show any organism. MALDI-ToF MS identified these colonies as Mycoplasma hominis which was confirmed at a reference laboratory by PCR. The patient was given daptomycin plus levofloxacin. Since discharge from the hospital, she had wound healing with intermittent discharge.

Lab Identification

Mycoplasma hominis requires a specific rich and complex agar medium for growth and grows tiny colonies on standard media such as Columbia agar. In a patient with urogenital disease, Mycoplasma hominis is diagnosed with a urogenital specimen culture and confirmed by PCR. In a patient with spinal hardware infection, Mycoplasma hominis is diagnosed by a culture of infected tissue with PCR confirmation.

Discussion

Mycoplasma is a bacteria that lacks a cell wall and contains the smallest bacterial genome totally sequenced. Due to its lack of cell wall, Mycoplasma cannot be visualized with a Gram stain, and it is innately resistant to b-lactams.1 Due to its small bacterial genome, 580 kpb, it cannot be detected by light microscopy and requires complex nutrients for growth1.

Mycoplasmas are frequently part of the oropharyngeal and genital tract flora among healthy subjects.1 There are more than 200 Mycoplasma species, of which 13 have been isolated from humans. Only 6 species, among which 5 are pathogens, live in the urogenital tract.2 As one of the Mycoplasma species detected in the genitourinary tract, M. hominis can be either a pathogen or part of the normal flora.1 Colonization with M. hominis is associated with younger age, lower socioeconomic status, multiple sexual partners, African American ethnicity, and hormonal status.1 Infection with M. hominis is more common among pregnant women.1

Mycoplasma hominis is associated with genital infections in females but not in males. Examples of infections include pelvic inflammatory disease and bacterial vaginosis.1 In addition, it is responsible for pregnancy-related infections such as chorioamnionitis and post-partum fever secondary to endometritis.1 Moreover, M. hominis is associated with infections of the newborns, meningitis among premature babies, and low birth weight among neonates.1 Lastly, M. hominis can lead to extragenital infections including spinal hardware infections, septic arthritis, retroperitoneal abscess, hematoma infection, and osteitis.1

Infections by Mycoplasma hominis are infrequent and difficult to confirm prior to the start of empiric therapy.2 Urogenital and systemic infections due to Mycoplasma hominis are treated with oral tetracycline.1 For organisms resistant to tetracycline, fluoroquinolones are recommended.1 For wound infections or abscesses, doxycycline, clindamycin, or fluoroquinolones are recommended for at least 2 weeks.1 Drainage and debridement may be necessary.1

References

  1. Pereyre S. et Mycoplasma hominis, M. genitalium and Ureaplasma spp.  Antimicrobe http://www.antimicrobe.org/m06.asp
  1. Baum S. Mycoplasma hominis and ureaplasma urealyticum infections. (2017, Dec. 7th).  Last retrieved on March 27, 2018 from https://www.uptodate.com/contents/mycoplasma-hominis-and-ureaplasma-urealyticum-infections

 

-Ting Chen, MD is a 1st year anatomic and clinical pathology resident at the University of Vermont Medical Center.

Wojewoda-small

-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

Microbiology Case Study: A 70 Year Old Female with Bronchiectasis

Case History 

A 70 year old female presents with bronchiectasis with acute exacerbation. She is a non-smoker, although claims to have been exposed to secondhand smoke, and she has chronic sinusitis. The patient recently traveled to Savannah, Georgia where she developed a productive cough. She was prescribed doxycycline and was then sent home. She returned to the pulmonary clinic for a follow up consultation after her cough worsened.

Laboratory Identification

hflu1
Image 1. Intracellular gram negative coccobacilli with polymorphonuclear cells found in the sputum smear (100x oil immersion).
hflu2
Image 2. The predominant organism found in this patient’s sputum culture is growing 4+ on chocolate agar, but not growing on blood and MacConkey agars.
hflu3
Image 3. Close up of chocolate agar showing 4+ growth of wet, translucent colonies.

The Gram stain and smear showed 4+ neutrophils, 4+ gram negative coccobacilli and little to no mixed respiratory flora. The following day, the culture grew 1+ respiratory flora on the blood plate, no growth on the MacConkey plate, and 4+ translucent colonies on the chocolate plate. 

Discussion 

The predominant organism was identified by the MALDI-TOF as Haemophilus influenzae. The Gram stain and culture findings are consistent with the MALDI-TOF identification. H. influenzae is an oxidase positive, gram negative coccobacilli known for its requirement of X (hemin) and V (NAD) factors found in chocolate agar. Because of its growth requirements, H. influenzae will not grow on MacConkey agar despite being a gram negative organism. It may be cultured on blood agar if the agar is inoculated with an organism such as Staphylococcus aureus, which can provide the V factor, while the X factor is provided by the agar itself. This phenomenon is known as satelliting. Identification of H. influenzae may also be done using a Haemophilus ID Quad plate. Each section of the plate contains varying factors and allows for Haemophilus identification to the species level based on the growth and hemolysis pattern.

H. influenzae is normal flora of mucous membranes and frequently colonizes the human oral cavity and upper respiratory tract. Commonly, H. influenzae causes pneumonia, as with our patient, bronchitis, and ear infections. However, it is also a known cause for bacterial meningitis, endocarditis, and osteomyelitis. Transmission of H. influenzae occurs through respiratory droplets so proper PPE precautions must be taken by clinicians when working with infected patients. It is important for laboratory professionals to work with the organism using proper PPE and BSL-2 practices and plating of respiratory specimens should occur in a biosafety cabinet.

Susceptibility testing is not routinely performed on isolates of H. influenzae. β-lactamase production can be determined by using nitrocefin, a chromogenic cephalosporin spot test. 

References

  1. Haemophilus influenzae Disease (Including Hib). (2018, February 13). Retrieved June 28, 2018, from https://www.cdc.gov/hi-disease/index.html
  2. (2012, March 15). Retrieved June 28, 2018, from https://www.cdc.gov/meningitis/lab-manual/chpt09-id-characterization-hi.html. Identification and Characterization of Haemophilus influenzae
  3. Manual of Clinical Microbiology, 11th edition

 

MS

-Madaine Saguinsin, MLS (ASCP), graduated from Purdue University with a BS in Medical Laboratory Sciences and is a medical technologist at NorthShore University Health System. Her interests are microbiology and parasitology.

-Erin McElvania, PhD, D(ABMM), is the Director of Clinical Microbiology NorthShore University Health System in Evanston, Illinois.

Microbiology Case Study: A 60 Year Old Female with Right Ear Pain

Case History

60 year old female presents to the emergency department with increased pain in her right ear and decreased hearing. She denies ear discharge. She endorses vertigo for 7 months that is precipitated by sudden changes in head position. On physical exam, the right ear canal is obscured by a foreign body. Ear swab is positive for growth on fungal culture.

Lab Identification

Image 1. Salt and pepper fungal colonies isolated from ear swab.

aspniger
Image 1. Salt and pepper fungal colonies isolated from ear swab.
aspniger2
Image 2. Septate hyphae with unbranched condidiophore connected to a swollen vesicle covered in phialides that produce chains of conidia.

The identification of Aspergillus niger is made based on macroscopic colony morphology and microscopic structures. On the potato flake agar, Aspergillus niger grows salt and pepper colonies. For microscopic examination, a slide is made by touching the colonies with a piece of clear tape, putting a drop of lactophenol analine blue on a glass slide, and placing the tape on the slide. Microscopically, Aspergillus niger appears as septate hyphae with long smooth unbranched conidiophores. Compared with other Aspergillus species, the phialides of niger cover the entire vesicle and form a “radiate” head, which splits into several loose columns.

Discussion

Aspergillus is a common mold that lives both indoors and outdoors. The Aspergillus genus is composed of 180 species, among which 34 are associated with human disease.1 A. fumigatus is the most common cause of aspergillosis syndromes. A. terreus is a species of particular concern due to its resistance to amphotericin. An invasive disease due to A. terreus has a poor prognosis.1

Healthy individuals inhale hundreds of conidia of Aspergillus per day without illness. However, people with a weakened immune system or lung disease are at higher risk of developing infections from inhaling the condidia. Presentations of aspergillosis range from allergy to fungal balls, to dissemination.1 Examples of aspergillosis include asthma, allergic bronchopulmonary aspergillosis, and allergic sinusitis.1

Invasive otitis externa due to Aspergillus is a rare, potentially life-threatening invasive fungal infection affecting immunocompromised patients.2 It spreads from the external auditory canal to adjacent anatomical structures such as soft tissues, cartilage, and bone.2 The condition can lead to osteomyelitis of the base of the skull with progressive cranial nerve palsies, irreversible hearing, and neurological impairment.2 The infection can be treated with antifungals.

References

  1. Barnes PD, Marr KA. Aspergillosis: spectrum of disease, diagnosis, and treatment. Infect Dis Clin North Am. 2006 Sep;20(3):545-61, vi.
  2. Parize, P. et al. Antifungal Therapy of Aspergillus Invasive Otitis Externa: Efficacy of Voriconazole and Review. Antimicrobial agents and chemotherapy. 2018 April; 62(4). http://aac.asm.org/content/53/3/1048.long

 

 

-Ting Chen, MD is a 1st year anatomic and clinical pathology resident at the University of Vermont Medical Center.

Wojewoda-small

-Christi Wojewoda, MD, is the Director of Clinical Microbiology at the University of Vermont Medical Center and an Associate Professor at the University of Vermont.

Microbiology Case Study: A 10 Year Old with Fever and Chills

Case History

A 10 year old female presented to the pediatric emergency department (ED) with a chief complaint of persistent fever and chills for the past 10 days. Her mother reported the fevers reached up to 103°F and temporarily would respond to ibuprofen.  She also noted a decrease in the patient’s appetite, tiredness and a bumpy rash on her truck and extremities. In the ED, she was clinically stable but her temperature reached a max of 104.7°F. On physical examination, shotty cervical lymphadenopathy was noted and there was no appreciable enlargement of the liver or spleen. Initial laboratory testing showed a white blood cell count of 10.6 TH/cm2 (normal range: 4.3-11.4 TH/cm2) and elevated acute phase proteins (ESR 45 mm/HR and CRP 2.6 mg/dL). Blood cultures were collected and the patient was started on ceftriaxone. Pediatric infectious disease was consulted and a thorough infectious work up was completed.

Laboratory Identification 

  • Rapid influenza antigen test: Negative
  • Rapid Group A Strep antigen test: Negative
  • Rapid Monospot: Negative
  • HIV antigen/antibody (4th generation) test: Negative
  • Legionella urinary antigen: Negative
  • Histoplasma urinary antigen: Negative
  • Antinuclear antibody: Negative
  • Rheumatoid factor: Negative
  • Urine culture: Negative
  • Blood cultures: Negative
  • Bartonella henselae IgM: ≥1:20 (normal <1:20)
  • Bartonella henselae IgG: ≥1:1024 (normal <1:128)

Infectious disease and rheumatologic work ups, as listed above, were negative with the exception of a positive IgM and IgG serologic testing for Bartonella henselae, with the results suggesting a recent infection based on the elevated titers. Upon further questioning, the family did have many outdoor cats and dogs; however, the child denied any recent bites or scratches.

Discussion 

Bartonella henselae is a facultative, Gram negative coccobacillary rod that is the causative agent of cat scratch disease and bacillary angiomatosis. The main reservoir for B. henselae is cats and the disease is spread from cat to cat via the cat flea. Feral cats, outdoor cats and young kittens, especially those living in hot, humid environments where fleas are plentiful, are more likely to be infected and spread the disease to humans via infective flea feces during a scratch or bite from the cat.

The incubation period for B. henselae ranges from 1-3 weeks and the majority of patients present with systemic symptoms including fever, chills, malaise, anorexia and headache. In addition, painful lymphadenopathy, on the side of the body where the scratch occurred (most common upper extremity), can be present in the epitrochlear, axillary and cervical regions. Less frequently, B. henselae causing bacillary angiomatosis can result in the proliferation of vessels in organs (liver and spleen). Though rare, encephalopathy and endocarditis due to B. henselae are the most severe manifestations of disease.

In the microbiology laboratory, the diagnosis of B. henselae is challenging due to the fact it is slow growing, highly hemin dependent and requires high humidity conditions for growth. The organism will grow on chocolate and heart infusion agars containing 5% fresh rabbit blood. Plates should be incubated at 35°C with 5% CO2 with high humidity for at least 4 weeks. Colonies are irregular and off-white in color and B. henselae is negative for both catalase & oxidase and asaccharolytic.

Due to the identification difficulties with culture, serologic testing is the main methodology for the diagnosis of B. henselae. Enzyme linked immunosorbent assays (ELISA) are relatively easy to perform and provides good results, although the provider should be aware of the sensitivity of the particular platform, the fact that cross reactivity with other Bartonella spp. can occur and seronegative infections can sometimes occur. Warthin-Starry silver stain on fixed tissue sections from lymph nodes and other organs can be helpful as well; however, it is relatively insensitive and not highly specific.   

 With regards to treatment, there are no agreed upon breakpoints for B. henselae published by CLSI or EUCAST. Microdilution or Etests can be used for testing and isolates have been susceptible to many antibiotics. In general, for cat scratch disease, it does not respond to antibiotic therapy and there is only a minimal benefit of antimicrobial agents. In the case of our patient, she was switched from ceftriaxone to a five day course of azithromycin with a gradual improvement of her fever curve. She was scheduled to follow up with pediatric infectious disease in 2-3 weeks.

 

Stempak

-Lisa Stempak, MD, is an Assistant Professor of Pathology at the University of Mississippi Medical Center in Jackson, MS. She is certified by the American Board of Pathology in Anatomic and Clinical Pathology as well as Medical Microbiology. She is the Director of Clinical Pathology as well as the Microbiology and Serology Laboratories.  Her interests include infectious disease histology, process and quality improvement and resident education.