A Girl with Seizures

Posted by • May 22nd, 2015

In the latest Case Record of the Massachusetts General Hospital, a 9-year-old girl presented to the emergency department with loss of consciousness and a seizure. She had returned from a trip to Puerto Rico 3 weeks earlier. Unilateral inguinal lymphadenopathy was present, and rapidly progressive encephalopathy developed.

The diagnosis of cat scratch disease is based primarily on the presence of typical clinical findings and a history of exposure to cats or fleas. Testing for antibodies to Bartonella henselae is often helpful in confirming this diagnosis.

Clinical Pearls

What is the most common neurologic presentation of cat scratch disease?

The most common neurologic presentation is acute seizures (status epilepticus), encephalopathy, and hemiparesis.

– What diagnostic tests may be useful to confirm clinically suspected B. henselae infection?

Cultures are usually negative because the gram-negative bacterium is fastidious, slow-growing, and difficult to isolate. Detection of B. henselae DNA by means of polymerase-chain-reaction (PCR) assay is diagnostic, although false negative results may occur. Testing for antibodies to B. henselae is often helpful in confirming this diagnosis. In cases in which serologic tests are equivocal or negative and a PCR assay of the blood is negative, a lymph-node biopsy for the detection of granulomatous inflammation and possibly a PCR assay or Warthin-Starry silver stain for the organism may be helpful.

Morning Report Questions

Q: What IgG antibody titer supports a diagnosis of B. henselae infection?

A: An IgG antibody titer greater than 1:256 strongly supports the diagnosis. A rising titer of IgG antibodies over time would also be convincing serologic evidence of recent infection, but for many patients with cat scratch disease, the IgG antibody titer is already maximally elevated by the time this diagnosis is considered. This is particularly true for patients with encephalopathy, because neurologic manifestations of B. henselae infection typically do not begin until 2 to 3 weeks after the onset of regional lymphadenopathy. IgG antibody titers fall in the months after infection, and only one quarter of patients continue to be seropositive after 1 year.

Q: Does a negative serologic test result for IgM antibodies to B. henselae rule out the possibility of recent infection?

A: IgM antibodies are infrequently found in the serum of patients with cat scratch disease. Titers of IgM antibodies to B. henselae tend to be lower than IgG antibody titers, and IgM antibody titers fall rapidly, generally becoming undetectable less than 3 months after their appearance. Therefore, a negative serologic test result for IgM antibodies does not rule out the possibility of recent infection.

 

3 Responses to “A Girl with Seizures”

  1. Adam says:

    Very nice and full information

  2. Dolores Claesson says:

    I am so glad to see this research and we need more articles like this. Borrelia may also cause seizures as well and we need to figure out all the pathogens that this 9 year old may have. Syphilis, a spirochetal cousin to Borrelia is known to cause seizures and be associated with epilepsy. Physicians do not recognize the signs and symptoms of tick borne diseases and therefore many people go undiagnosed or misdiagnosed for long periods of time. Certain kinds of Bartonella are within ticks and others are within fleas and other vectors.. Henselae, Clarridgaie, Quintana, Elizabethae, Candidatus Bartonella mayotimosensis is the latest.

  3. Rita Rhoads says:

    I have seen complete vision loss in 2 patients from acute bartonella hensalae. However most bartonella’s I have seen are not hensalae, but rather versonii. There is a lab in NC (Galaxy) which does a month culture/PCR’s for bartonella which eliminates some false negatives. They check for more than hensalae. (I have no finanacial interest in Galaxy)