Bartonella henselae: Difference between revisions
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Bartonella henselae
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==Background== |
==Background== |
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* Causes '''cat-scratch disease''' |
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*Causes '''cat-scratch disease''' |
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===Epidemiology=== |
===Epidemiology=== |
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* Present worldwide |
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* Main reservoir is cats, and especially kittens |
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* Infections are more common in children, likely due to increased exposure to kittens |
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* Transmitted to humans by inoculation of cat flea (''[[Ctenocephalides felis]]'') feces into a cat scratch or bite |
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*Present worldwide |
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==Clinical Presentation== |
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*Main reservoir is cats, and especially kittens |
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* Typical cat-scratch disease is a self-limited febrile illness with [[Causes::regional lymphadenopathy]] |
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*Infections are more common in children, likely due to increased exposure to kittens |
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** Following an incubation period of 3 to 10 days, and initial pustule develops at site of inoculation which may last for up to 3 weeks |
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*Transmitted to humans by inoculation of cat flea (''[[Vector::Ctenocephalides felis]]'') feces into a cat scratch or bite |
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** This is followed in 1 to 7 weeks by ipsilateral [[Causes::lymphadenopathy]] (usually the head or neck) |
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*** May involve one or more lymph nodes |
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==Clinical Manifestations== |
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*** May drain pus |
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*** Will eventually resolve, over months or longer |
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=== Cat Scratch Disease === |
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** There may be a concurrent low-grade [[Causes::fever]] for several days, with [[Causes::malaise]] or [[Causes::fatigue]] |
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** May have [[Causes::headache,]] sore throat, transient rash, or, rarely, [[Causes::erythema nodosum]] |
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*Typical cat-scratch disease is a self-limited febrile illness with [[Causes::regional lymphadenopathy]] |
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** May have mild leukocytosis (neutrophils or eosinophils) |
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**Following an incubation period of [[Usual incubation period::3 to 10 days]], and initial pustule develops at site of inoculation which may last for up to 3 weeks |
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* CSD may be complicated by [[Causes::encephalopathy]] in 2 to 4% of cases |
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**Usually a history of cat exposure (adult or kitten), but 5-10% have no known exposure |
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** Headache is common, and they may develop seizures and neurologic deficits |
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**This is followed in 1 to 7 weeks by ipsilateral [[Causes::lymphadenopathy]] (usually the head or neck) |
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** Resolves over weeks to months (to as long as a year) |
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***May involve one or more lymph nodes |
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** CSF is usually normal, although lymphocytic pleiocytosis and elevated protein are seen in one third |
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***May drain pus |
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** MRI brain is almost always normal |
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***Will eventually resolve, over months or longer |
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** EEG is nonspecific |
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**There may be a concurrent low-grade [[Causes::fever]] for several days, with [[Causes::malaise]] or [[Causes::fatigue]] |
|||
** Proportionally less common in children |
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**May have [[Causes::headache,]] sore throat, transient rash, or, rarely, [[Causes::erythema nodosum]] |
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* Other syndromes include: |
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**May have mild leukocytosis (neutrophils or eosinophils), mildly elevated C-reactive protein or ESR |
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** [[Causes::Parinaud oculoglandular syndrome]], with granulomatous conjunctivitis and ipsilateral (usually preauricular) lymphadenopathy |
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*CSD may be complicated by [[Causes::encephalopathy]] in 2 to 4% of cases |
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** [[Causes::Neuroretinitis]] and other ophthalmic complications |
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**Headache is common, and they may develop seizures and neurologic deficits |
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** [[Causes::Fever of unknown origin]], in children |
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**Resolves over weeks to months (to as long as a year) |
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** Culture-negative [[Causes::endocarditis]] in patients with existing valve abnormalities |
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**CSF is usually normal, although lymphocytic pleiocytosis and elevated protein are seen in one third |
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** Chronic endocarditis, with [[Causes::vasculitis]] and [[Causes::glomerulonephritis]] |
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**MRI brain is almost always normal |
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* Disseminated disease is possible in immunocompromised patients, including bacteremia, disseminated skin lesions, and hepatosplenic lesions |
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**EEG is nonspecific |
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**Proportionally less common in children |
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=== Other Syndromes === |
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*Other syndromes include: |
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**[[Causes::Parinaud oculoglandular syndrome]], with granulomatous conjunctivitis and ipsilateral (usually preauricular) lymphadenopathy |
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**[[Causes::Neuroretinitis]] and other ophthalmic complications |
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**[[Causes::Fever of unknown origin]], in children |
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**Culture-negative [[Causes::endocarditis]] in patients with existing valve abnormalities |
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**Chronic endocarditis, with [[Causes::vasculitis]] and [[Causes::glomerulonephritis]] |
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*Disseminated disease is possible in immunocompromised patients, including bacteremia, disseminated skin lesions, and hepatosplenic lesions |
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==Diagnosis== |
==Diagnosis== |
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* Histopathology of node aspirate shows nonspecific inflammation, with granulomas and stellate ncerosis |
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*Histopathology of node aspirate shows nonspecific inflammation, with granulomas and stellate necrosis |
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** Microabscesses are classic finding |
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**Microabscesses are classic finding |
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** Bacilli may be seen with Warthin-Starry staining |
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**Bacilli may be seen with Warthin-Starry staining |
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* Culture |
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*Culture |
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** Fastidious organism which may not be detected by automated blood culture systems |
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**Fastidious organism which may not be detected by automated blood culture systems |
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** If suspected, cultures should be held for 21 days |
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**If suspected, cultures should be held for 21 days |
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* Molecular |
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*Molecular |
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** PCR of node aspirate (or blood) is the best and most sensitive test |
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**PCR of node aspirate (or blood) is the best and most sensitive test |
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* Serology |
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*Serology |
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** 1:64 is suggestive, 1:256 is strongly suggestive, and a four-fold rise from acute to convalescent titres is diagnostic |
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**1:64 is suggestive, 1:256 is strongly suggestive, and a four-fold rise from acute to convalescent titres is diagnostic |
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** Cross-reacts with other ''[[Bartonella]]'' species, but possibly also with ''[[Chlamydia]]'' and ''[[Coxiella burnetii]]'' |
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**Cross-reacts with other ''[[Bartonella]]'' species, but possibly also with ''[[Chlamydia]]'' and ''[[Coxiella burnetii]]'' |
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==Management== |
==Management== |
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===Cat- |
===Cat-Scratch Disease=== |
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* Disease is usually self-limited in immunocompetent patients |
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*Disease is usually self-limited in immunocompetent patients |
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* May wish to treat if extensive lymphadenitis |
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*May wish to treat if extensive lymphadenitis |
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* First-line: [[Is treated by::azithromycin]] 500 mg po on day 1 followed by 250 mg po daily for 4 more days (10 mg/kg and 5 mg/kg for children) |
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* |
*First-line: [[Is treated by::azithromycin]] 500 mg po on day 1 followed by 250 mg po daily for 4 more days (10 mg/kg and 5 mg/kg for children) |
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*Hepatosplenic CSD in children may respond to combination [[Is treated by::azithromycin]] ± [[Is treated by::rifampin]] for 14 days |
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===Endocarditis=== |
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*[[Is treated by::Doxycycline]] and [[Is treated by::gentamicin]] for 14 days followed by [[doxycycline]] alone for three months, or until 6 weeks after valve replacement (if done) |
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{{DISPLAYTITLE:''Bartonella henselae''}} |
{{DISPLAYTITLE:''Bartonella henselae''}} |
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Latest revision as of 15:23, 17 October 2024
Background
- Causes cat-scratch disease
Epidemiology
- Present worldwide
- Main reservoir is cats, and especially kittens
- Infections are more common in children, likely due to increased exposure to kittens
- Transmitted to humans by inoculation of cat flea (Ctenocephalides felis) feces into a cat scratch or bite
Clinical Manifestations
Cat Scratch Disease
- Typical cat-scratch disease is a self-limited febrile illness with regional lymphadenopathy
- Following an incubation period of 3 to 10 days, and initial pustule develops at site of inoculation which may last for up to 3 weeks
- Usually a history of cat exposure (adult or kitten), but 5-10% have no known exposure
- This is followed in 1 to 7 weeks by ipsilateral lymphadenopathy (usually the head or neck)
- May involve one or more lymph nodes
- May drain pus
- Will eventually resolve, over months or longer
- There may be a concurrent low-grade fever for several days, with malaise or fatigue
- May have headache, sore throat, transient rash, or, rarely, erythema nodosum
- May have mild leukocytosis (neutrophils or eosinophils), mildly elevated C-reactive protein or ESR
- CSD may be complicated by encephalopathy in 2 to 4% of cases
- Headache is common, and they may develop seizures and neurologic deficits
- Resolves over weeks to months (to as long as a year)
- CSF is usually normal, although lymphocytic pleiocytosis and elevated protein are seen in one third
- MRI brain is almost always normal
- EEG is nonspecific
- Proportionally less common in children
Other Syndromes
- Other syndromes include:
- Parinaud oculoglandular syndrome, with granulomatous conjunctivitis and ipsilateral (usually preauricular) lymphadenopathy
- Neuroretinitis and other ophthalmic complications
- Fever of unknown origin, in children
- Culture-negative endocarditis in patients with existing valve abnormalities
- Chronic endocarditis, with vasculitis and glomerulonephritis
- Disseminated disease is possible in immunocompromised patients, including bacteremia, disseminated skin lesions, and hepatosplenic lesions
Diagnosis
- Histopathology of node aspirate shows nonspecific inflammation, with granulomas and stellate necrosis
- Microabscesses are classic finding
- Bacilli may be seen with Warthin-Starry staining
- Culture
- Fastidious organism which may not be detected by automated blood culture systems
- If suspected, cultures should be held for 21 days
- Molecular
- PCR of node aspirate (or blood) is the best and most sensitive test
- Serology
- 1:64 is suggestive, 1:256 is strongly suggestive, and a four-fold rise from acute to convalescent titres is diagnostic
- Cross-reacts with other Bartonella species, but possibly also with Chlamydia and Coxiella burnetii
Management
Cat-Scratch Disease
- Disease is usually self-limited in immunocompetent patients
- May wish to treat if extensive lymphadenitis
- First-line: azithromycin 500 mg po on day 1 followed by 250 mg po daily for 4 more days (10 mg/kg and 5 mg/kg for children)
- Hepatosplenic CSD in children may respond to combination azithromycin ± rifampin for 14 days
Endocarditis
- Doxycycline and gentamicin for 14 days followed by doxycycline alone for three months, or until 6 weeks after valve replacement (if done)
