Table 18.1 Nomenclature of bone tumors
Cat-scratch disease is a subacute, usually self-limiting, granulomatous lymphadenitis that follows an infection with Bartonella henselae (previously named Rochalimaea henselae). The pathogen reservoir consists of healthy cats. The course of the fever is extremely variable. General symptoms can be present. The primary lesion (red papule) after injury by a cat is not always visible or discernible from the medical history. The lymphadenitis of a regional lymph node usually occurs approximately two weeks after infection and an extensive, purulent inflammation can result.
Rare, clinical manifestations are a generalized lymphadenitis, which can persist for weeks to months, oculoglandular syndrome (Parinaud) after inoculation of the pathogen into the eyes, encephalitis, optic neuritis, osteolytic lesions, or granulomas in the liver and spleen.
In immunocompromised individuals (especially HIV-infected persons) the infection with Bartonella can lead to bacteremia, hepatic peliosis, or bacillary angiomatosis (Fig. 4.8).
Diagnosis is based on the serological detection of antibodies. Routine cultures always remain sterile and the pathogen can only be cultivated using specialized methodology. The histological confirmation of Bartonella with a silver stain is partially successful. The histology of lymphadenitis can indicate cat-scratch disease, but it is nonspecific.
• Malaise and headache in fewer than a third of patients
• Atypical presentations in fewer than 18% of cases
1. Usually in association with lymphadenopathy and a low-grade or frank fever (>101° F, >38.3° C)
2. Include granulomatous involvement of the conjunctiva (Pari-naud’s oculoglandular syndrome) and focal masses in the liver, spleen, and mesenteric nodes
• CNS involvement: neuroretinitis, encephalopathy, encephalitis, transverse myelitis, seizure activity, and coma
• Possible osteomyelitis in children
• Major cause: Bartonella (Rochalimaea) henselae
• Mode of transmission: predominantly by direct inoculation through the scratch, bite, or lick of a cat, especially a kitten
• Limited evidence in support of an arthropod (flea) as an alternative vector of infection arising from bacteremic felines.
• Rarely, associated with dogs, monkeys, and inanimate objects with which a feline has been in recent contact
• Approximately 2 weeks after introduction of the bacteria into the host, regional lymphatic tissues displaying granulomatous infiltration associated with gradual hypertrophy
• Possible dissemination to distant sites (e.g., liver, spleen, and bone), usually characterized by focal masses or discrete parenchymal lesions
Granulomas of this syndrome must be differentiated from those associated with tularemia, tuberculosis, sarcoidosis, sporotrichosis, toxoplasmosis, lymphogranuloma venerum, fungal diseases, and benign and malignant tumors.
Diagnosis should be considered in patients who present with a predominant complaint of gradually enlarging regional (focal) lymphadenopathy, often with fever and a recent history of having contact with a cat.
• Three of four of the following criteria are required:
1. History of animal contact in the presence of a scratch, dermal, or eye lesion
2. Culture of lymphatic aspirate that is negative for other causes
3. Positive CSD skin test
4. Biopsied lymph node histology consistent with CSD
• Enhanced culture techniques and serologies will augment establishment of the diagnosis.
• Histopathologically, Warthin-Starry silver stain has been used to identify the bacillus.
• Routine laboratory findings:
1. Mild leukocytosis or leukopenia
2. Infrequent eosinophilia
3. Elevated ESR
• Abnormalities of bilirubin excretion and elevated hepatic transaminases are usually secondary to hepatic obstruction by granuloma, mass, or lymph node
• In patients with neurologic manifestations, lumbar puncture usually reveals normal CSF, although there may be a mild pleocytosis and modest elevation in protein.
• Warm compresses to the affected nodes
• In cases of encephalitis or coma: supportive care
ACUTE GENERAL Rx
• There is no consensus over therapy, especially as the disease is self-limited in a majority of cases.
• It would be prudent to treat severely ill patients, especially if immunocompromised, with antibiotic therapy, because these patients tend to suffer dissemination of infection and increased morbidity.
• Bartonella is usually sensitive to aminoglycosides, tetracycline, erythromycin, and the quinolones.
• When the isolate is proven by culture, the patient should receive antibiotic therapy as directed by the obtained sensitivities.
• Antipyretics and NSAIDs may also be used.
Overall prognosis is good.
Benign inoculation lymphoreticulosis
Nonbacterial regional lymphadenitis
EPIDEMIOLOGY & DEMOGRAPHICS
INCIDENCE (IN U.S.):
• Majority of reported cases in children
PEAK INCIDENCE: August through January
PHYSICAL FINDINGS & CLINICAL PRESENTATION
• Classic, most common finding: regional lymphadenopathy occurring within 2 weeks of a scratch or contact with felines
• Tender, swollen lymph nodes most commonly found in the head and neck, followed by the axilla and the epitrochlear, inguinal, and femoral areas
• Erythematous overlying skin, showing signs of suppuration from involved lymph nodes
• On careful examination; evidence of cutaneous inoculation in the form of a nonpruritic, slightly tender pustule or papule
• Fever in most patients