Updated: 2/22/2020

Bartonella henselae

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Snapshot
  • A 26-year-old woman presents to the urgent care clinic because of fever, weight loss, night sweats, and a red rash on her trunk, legs, and arms for the past week. She has a past medical history of HIV infection and currently is not on any anti-retroviral medications. She recently adopted a cat from the shelter 3 months ago and has been training it to not scratch when approached; however, she has been sustaining scratches during the training process. On physical exam, she has generalized lymphadenopathy and multiple clusters of violaceous papules and plaques. Her CD4 count is 100 cells/mm3. A skin biopsy was done and shows a neutrophilic infiltrate and granulomatous changes.
Introduction
  • Classification
    • Bartonella henselae 
      • facultative intracellular, gram-negative rod 
      • transmission
        • scratch or bite from a cat (more common) or dog
      • clinical syndromes
        • bacillary angiomatosis, a vasoproliferative disease 
          • benign capillary tumors of the skin
          • immunosuppressed patients
        • cat scratch disease
          • tender lymphadenopathy
        • bacterial endocarditis (culture-negative)
  • Epidemiology
    • incidence
      • more common in the southern US
    • demographics
      • bacillary angiomatosis
        • immunosuppressed patients
      • cat scratch disease
        • children and adolescents > adults
    • risk factors
      • HIV/AIDS
      • immunosuppression
      • cat scratch, bite, or lick
  • Pathogenesis 
    • B. henselae replicates in red blood cells
    • granulomatous inflammation
      • mediated by CD4+ T-cells
      • secretes γ-interferon and activates macrophages
  • Associated conditions
    • culture-negative bacterial endocarditis
  • Prognosis
    • cat scratch disease typically resolves within a few months
    • bacillary angiomatosis typically resolves completely with treatment
Presentation
  • Cat scratch disease 
    • tender lymphadenopathy 2 weeks after exposure
    • vesicle, wheal, or papule at site of trauma
    • systemic symptoms
      • low-grade fever
      • myalgias
      • fatigue
  • Bacillary angiomatosis
    • multiple clustered red or violaceous papules, plaques, or nodules on skin and mucosa
    • bone pain
    • systemic symptoms
      • fever
      • night sweats
      • weight loss
Studies
  • Labs
    • serologic detection of immunoglobulins
      • via enzyme-linked immunosorbent assay (ELISA) or indirect immunofluorescence assay (IFA)
    • detection of bacterial DNA on polymerase chain reaction (PCR)
    • culture is not useful as the bacteria is fastidious and hard to culture
  • Biopsy of skin lesions or lymph node
    • neutrophilic infiltrate
    • granulomatous changes
  • Making the diagnosis
    • based on clinical presentation and laboratory studies
Differential
  • Kaposi sarcoma
    • distinguishing factor
      • presents clinically similar to bacillary angiomatosis but biopsy reveals lymphocytic infiltrate
Treatment
  • Management approach
    • cat scratch disease is self-limited and guidelines for antibiotics is unclear
    • bacillary angiomatosis requires treatment with antibiotics
  • Medical
    • azithromycin
      • indication
        • cat scratch disease
    • erythromycin or doxycycline
      • indication
        • bacillary angiomatosis
Complications
  • Persistent lymphadenopathy
  • Aseptic meningitis
  • Disfigurement
 

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Questions (2)
Lab Values
Blood, Plasma, Serum Reference Range
ALT 8-20 U/L
Amylase, serum 25-125 U/L
AST 8-20 U/L
Bilirubin, serum (adult) Total // Direct 0.1-1.0 mg/dL // 0.0-0.3 mg/dL
Calcium, serum (Ca2+) 8.4-10.2 mg/dL
Cholesterol, serum Rec: < 200 mg/dL
Cortisol, serum 0800 h: 5-23 μg/dL //1600 h:
3-15 μg/dL
2000 h: ≤ 50% of 0800 h
Creatine kinase, serum Male: 25-90 U/L
Female: 10-70 U/L
Creatinine, serum 0.6-1.2 mg/dL
Electrolytes, serum  
Sodium (Na+) 136-145 mEq/L
Chloride (Cl-) 95-105 mEq/L
Potassium (K+) 3.5-5.0 mEq/L
Bicarbonate (HCO3-) 22-28 mEq/L
Magnesium (Mg2+) 1.5-2.0 mEq/L
Estriol, total, serum (in pregnancy)  
24-28 wks // 32-36 wks 30-170 ng/mL // 60-280 ng/mL
28-32 wk // 36-40 wks 40-220 ng/mL // 80-350 ng/mL
Ferritin, serum Male: 15-200 ng/mL
Female: 12-150 ng/mL
Follicle-stimulating hormone, serum/plasma Male: 4-25 mIU/mL
Female: premenopause: 4-30 mIU/mL
midcycle peak: 10-90 mIU/mL
postmenopause: 40-250
pH 7.35-7.45
PCO2 33-45 mmHg
PO2 75-105 mmHg
Glucose, serum Fasting: 70-110 mg/dL
2-h postprandial:<120 mg/dL
Growth hormone - arginine stimulation Fasting: <5 ng/mL
Provocative stimuli: > 7ng/mL
Immunoglobulins, serum  
IgA 76-390 mg/dL
IgE 0-380 IU/mL
IgG 650-1500 mg/dL
IgM 40-345 mg/dL
Iron 50-170 μg/dL
Lactate dehydrogenase, serum 45-90 U/L
Luteinizing hormone, serum/plasma Male: 6-23 mIU/mL
Female: follicular phase: 5-30 mIU/mL
midcycle: 75-150 mIU/mL
postmenopause 30-200 mIU/mL
Osmolality, serum 275-295 mOsmol/kd H2O
Parathyroid hormone, serume, N-terminal 230-630 pg/mL
Phosphatase (alkaline), serum (p-NPP at 30° C) 20-70 U/L
Phosphorus (inorganic), serum 3.0-4.5 mg/dL
Prolactin, serum (hPRL) < 20 ng/mL
Proteins, serum  
Total (recumbent) 6.0-7.8 g/dL
Albumin 3.5-5.5 g/dL
Globulin 2.3-3.5 g/dL
Thyroid-stimulating hormone, serum or plasma .5-5.0 μU/mL
Thyroidal iodine (123I) uptake 8%-30% of administered dose/24h
Thyroxine (T4), serum 5-12 μg/dL
Triglycerides, serum 35-160 mg/dL
Triiodothyronine (T3), serum (RIA) 115-190 ng/dL
Triiodothyronine (T3) resin uptake 25%-35%
Urea nitrogen, serum 7-18 mg/dL
Uric acid, serum 3.0-8.2 mg/dL
Hematologic Reference Range
Bleeding time 2-7 minutes
Erythrocyte count Male: 4.3-5.9 million/mm3
Female: 3.5-5.5 million mm3
Erythrocyte sedimentation rate (Westergren) Male: 0-15 mm/h
Female: 0-20 mm/h
Hematocrit Male: 41%-53%
Female: 36%-46%
Hemoglobin A1c ≤ 6 %
Hemoglobin, blood Male: 13.5-17.5 g/dL
Female: 12.0-16.0 g/dL
Hemoglobin, plasma 1-4 mg/dL
Leukocyte count and differential  
Leukocyte count 4,500-11,000/mm3
Segmented neutrophils 54%-62%
Bands 3%-5%
Eosinophils 1%-3%
Basophils 0%-0.75%
Lymphocytes 25%-33%
Monocytes 3%-7%
Mean corpuscular hemoglobin 25.4-34.6 pg/cell
Mean corpuscular hemoglobin concentration 31%-36% Hb/cell
Mean corpuscular volume 80-100 μm3
Partial thromboplastin time (activated) 25-40 seconds
Platelet count 150,000-400,000/mm3
Prothrombin time 11-15 seconds
Reticulocyte count 0.5%-1.5% of red cells
Thrombin time < 2 seconds deviation from control
Volume  
Plasma Male: 25-43 mL/kg
Female: 28-45 mL/kg
Red cell Male: 20-36 mL/kg
Female: 19-31 mL/kg
Cerebrospinal Fluid Reference Range
Cell count 0-5/mm3
Chloride 118-132 mEq/L
Gamma globulin 3%-12% total proteins
Glucose 40-70 mg/dL
Pressure 70-180 mm H2O
Proteins, total < 40 mg/dL
Sweat Reference Range
Chloride 0-35 mmol/L
Urine  
Calcium 100-300 mg/24 h
Chloride Varies with intake
Creatinine clearance Male: 97-137 mL/min
Female: 88-128 mL/min
Estriol, total (in pregnancy)  
30 wks 6-18 mg/24 h
35 wks 9-28 mg/24 h
40 wks 13-42 mg/24 h
17-Hydroxycorticosteroids Male: 3.0-10.0 mg/24 h
Female: 2.0-8.0 mg/24 h
17-Ketosteroids, total Male: 8-20 mg/24 h
Female: 6-15 mg/24 h
Osmolality 50-1400 mOsmol/kg H2O
Oxalate 8-40 μg/mL
Potassium Varies with diet
Proteins, total < 150 mg/24 h
Sodium Varies with diet
Uric acid Varies with diet
Body Mass Index (BMI) Adult: 19-25 kg/m2
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(M1.MC.14.1) A 16-year-old female presents to her pediatrician complaining of 2 weeks of fever and 1 week of swollen lumps in her left armpit. Upon examination of the left upper extremity, her physician notes the presence of a single papule which the patient claimed appeared one week ago. The patient started her first job at a pet store 2.5 weeks ago. Which of the following is the vector of transmission of the causative agent? Review Topic | Tested Concept

QID: 106429
FIGURES:
1

Animal urine

2%

(1/50)

2

Cats

80%

(40/50)

3

Parrots

6%

(3/50)

4

Armadillos

6%

(3/50)

5

Rabbits

4%

(2/50)

L 2 D

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