Cat Scratch Disease Treatment
Cat Scratch Disease Treatment
Article by islam khalil
It is now known that cat scratch disease (CSD) is a multisystem disease caused by a small Gram negative bacillus named Bartonella henselae, formerly known as Rochalimaea henselae. As early as 1932, physicians in the United States recognized patients with CSD, but the cause of the disease eluded detection until 1983 when researchers at the Armed Forces Institute of Pathology at Walter Reed Army Medical Center in Washington, D.C. detected the organism in lymph node tissue from patients with clinical CSD. Identification of the causative organism has allowed researchers to identify the epidemiology and transmission of the disease, identify atypical forms of CSD, develop serologic diagnostic tests, and perform placebo-controlled treatment trials.
A four year old girl presents to the pediatric clinic with a chief complaint of a slowly enlarging mass in her right armpit for the past two weeks. She has had no fever, but has had some loss of appetite. The mass was initially small and did not hurt; however, it has now grown to the size of an orange and has become painful. She cannot lower her arm due to the pain from the mass, and she carries her arm extended at 90 degrees to her body.
Movement of her arm exacerbates the pain. She does have a 3 month old kitten at home that she “rescued from a sewer”. It was covered with fleas when she found it. It playfully bites and scratches her. Three weeks ago it scratched her right thumb. The scratch healed, but a small “wart” has developed in the line of the scratch. There is a scab on the wart and her mother has tried to squeeze the wart, but no pus has come out.
ROS: Non-contributory. No cough. No weight loss. No change in activity other than being unable to use her right arm well.Exam: VS T 37.2, RR 18, P 102, BP 100/60. She is alert and very cooperative. HEENT is negative. Neck is supple without adenopathy. Chest is clear. Heart regular without murmur. Abdomen exam is normal without hepatosplenomegaly. Neurologic exam is normal (mental status, gait, strength, and reflexes). Her right axilla reveals an 8×8 cm firm, tender, mobile, warm, non-erythematous, non-fluctuant mass that is consistent with an enlarged axillary lymph node. Her right thumb has a 1 cm linear, non-inflamed, healing scar that is consistent with a kitten scratch. In the middle of the linear scar, there is a 3 mm brownish-red papule with a small central crust.
Lab: CBC WBC 8.0, 62% segs, 10% bands. Ultrasonography of the mass reveals that it is a matted group of about 5 lymph nodes which are mostly solid in appearance. There is evidence of a small amount of necrosis at the periphery of one of the lymph nodes.
Impression: Lymphadenopathy due to cat scratch disease.
Clinical course: Because the axillary node is enlarged and painful, you elect to treat her with oral azithromycin at a dose of 10 mg/kg/day for the first day and 5 mg/kg/day for the next 4 days. Serology for Bartonella henselae is obtained, and the result returns one week later with an IgG of 1:512 (a positive result is a value greater than 1:64). The node remains the same size for a week and then begins to get smaller. The adenopathy resolves in one month.
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