Bartonella henselae: Difference between revisions

Latest revision as of 10:23, 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)

@@ Line 1: / Line 1: @@
+==Background==
-* Causes '''cat-scratch disease'''
+*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 (''[[Vector::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 [[Causes::regional lymphadenopathy]]
+**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
+**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 [[Causes::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 [[Causes::fever]] for several days, with [[Causes::malaise]] or [[Causes::fatigue]]
+**May have [[Causes::headache,]] sore throat, transient rash, or, rarely, [[Causes::erythema nodosum]]
+**May have mild leukocytosis (neutrophils or eosinophils), mildly elevated C-reactive protein or ESR
+*CSD may be complicated by [[Causes::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:
+**[[Causes::Parinaud oculoglandular syndrome]], with granulomatous conjunctivitis and ipsilateral (usually preauricular) lymphadenopathy
+**[[Causes::Neuroretinitis]] and other ophthalmic complications
+**[[Causes::Fever of unknown origin]], in children
+**Culture-negative [[Causes::endocarditis]] in patients with existing valve abnormalities
+**Chronic endocarditis, with [[Causes::vasculitis]] and [[Causes::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: [[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)
+*Hepatosplenic CSD in children may respond to combination [[Is treated by::azithromycin]] ± [[Is treated by::rifampin]] for 14 days
+===Endocarditis===
+*[[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)
 {{DISPLAYTITLE:''Bartonella henselae''}}