Seizures and altered mental status after a tick bite

In a recent issue of the British Medical Journal Case Report, researchers from George Washington University School of Medicine describe the case of a 66-year-old woman who presented to the hospital with lethargy, fever, chills, ataxia, a cough and slurred speech. The woman, who had been treated for presumed community-acquired pneumonia, was ultimately diagnosed with human monocytic ehrlichiosis (HME), one of the most life-threatening tick-borne illnesses in the country. [1]

The patient, who had been well until 5 days prior to her admission into the hospital, displayed atypical symptoms. Her illness was never attributed to a tick-borne disease, although she had reported removing a tick from her groin two weeks prior to being admitted to the hospital.

The patient’s husband reported she began slurring her speech and had gradually worsening fatigue and fevers before admittance. “Additional symptoms included generalized joint pain, most pronounced in the elbow and knee joints as well as a faint rash along the eyelids, anterior neck, chest, abdomen and legs. She noted fevers up to 39.3°C (102.7°F) at home,” wrote Geier in the case report,  Severe human monocytic ehrlichiosis presenting with altered mental status and seizures.

The woman also complained of a constant, throbbing headache; unsteadiness on her feet; the need for assistance while walking; diarrhea with mild abdominal pain; a decrease in appetite, and mild cough with scant non-bloody sputum production, which began two days prior to admission. On the day she was admitted, the rash over her eyelids and anterior neck had begun to resolve, while the rash on her chest remained prominent. She also had severe fatigue.

Initial testing included a hyponatraemia of 127 mm/L, leucopenia of 2.5×103 cells/mL, thrombocytopenia of 37×103 cells/mL, elevated alkaline phosphatase 371 U/L, aspartate aminotransferase of 619 U/L, alanine transaminase of 227 U/L, and elevated C reactive protein of 205 mg/L. Chest X-ray showed mild pulmonary oedema and small bilateral pleural effusions.

The patient was empirically treated with intravenous azithromycin 500 mg and ceftriaxone 1 g intravenously every 12 hours for presumed community-acquired pneumonia on the medical ward.

“Approximately 12 hours after initial presentation, the patient developed worsening respiratory distress and marked confusion,” described Geier. “She was transferred to the intensive care unit where vancomycin 500 mg intravenously every 6 hours was empirically added to her antibiotic regimen.” Due to a deterioration in her mental status, the ceftriaxone dose was increased to 2 g intravenously every 12 hours, Geier pointed out. And the azithromycin was discontinued.

“Around 38 hours into her hospitalization, she experienced generalized tonic–clonic seizures, which were treated with intravenous lorazepam and levetiracetam,” stated Geier.

Infectious disease specialists evaluated the patient and immediately recommended starting intravenous doxycycline 100 mg intravenously every 12 hours due to their concern for a tick-borne infection.

The diagnosis of HME was confirmed. A Wright-Giemsa peripheral smear demonstrated cytoplasmic Ehrlichia morulae in a monocyte. E. chaffeensis was also identified by PCR of the patient’s blood. Other co-infections including Lyme disease and Babesia were ruled out by the authors.

It is not uncommon for patients with HME to have neurologic problems, according to Geier.  “Neurological findings have been reported in 22% of patients, most commonly in the form of photophobia, confusion, hallucinations, stupor, meningitis and coma.” Seizures, however, are rare, occurring in only 2.4% of patients.

“The patient was treated for severe HME with neurological involvement with a 10-day course of doxycycline 100 mg twice daily given intravenously for the first 4 days until the patient was alert enough to tolerate taking this orally.”

The 66-year-old woman made a complete recovery and was able to return to work as a language professor at a local university.

This case reminds us how important it is to consider a tick-borne infection following a tick bite, even if illness is atypical. The woman’s neurologic and physical deterioration, including the onset of seizures and altered mental status and her admission into the intensive care unit may have been prevented if physicians had considered a tick-borne disease early on.


  1. Geier C, Davis J, Siegel M. Severe human monocytic ehrlichiosis presenting with altered mental status and seizur. BMJ Case Rep. 2016;doi:10.1136/bcr-2016-215967.

23 Replies to "Seizures and altered mental status after a tick bite"

  • Vanessa
    07/09/2023 (6:41 pm)

    I am currenlty being treated for borrelia and Rickettsia bugs, which I have had for eight years, despite “recommended” treatment with Doxy TWICE. Now that I have learned that Lyme (AKA many tick borne diseases) can survive two courses of Doxy and my symptoms would just come back each time, I have been reading and reading. During my learning curve, I realized I might have ANOTHER bug. I was scratched by a cat when I was six (I am 60) and nearly died. i was hospitalized and had surgery and penicillin. About six years later, I started having “absence seizures.” I had IBS from my early teens onwards for my whole life. My absence seizures continued and became more frequent until, at 28, I had my first “grand mal” seizure. My brain scans and MRI showed nothing, so they don’t know what part of my brain is wonky. I read some studies that showed a correlation between Bartonella (Cat Scratch Fever bug – it didn’t have a name when I was scratched) and epilepsy, and I was told by the author of one of these studies that it is quite possible that the Bartonella has survived 54 years and upteem illnesses with short courses of antibiotics. So, I see my Lyme doctor tomorrow to ask if my current antibiotic regime will take care of Bartonella in my body as well, but the other question is, what are the chances of my epilepsy being cured after 50 years if I get rid of all these bugs? Are there ANY neurologists who specialize in epilepsy caused by infections?

    • Dr. Daniel Cameron
      07/11/2023 (7:46 am)

      I have Lyme patients with absence seizures. I include a neurologist to evaluate for other causes. I have not been able to answer address your questions on Bartonella.

  • Dee
    02/08/2023 (9:52 pm)

    Any one have an idea about prevalence in relationship between seizures and Lyme disease (only detected at a very late stage, and which I continue to have to this day)? Please help!!!

    • Dr. Daniel Cameron
      02/09/2023 (1:12 pm)

      I have not read any information of the prevalence. We are still dealing with case reports.

  • Hollie
    08/31/2022 (6:14 pm)

    My son who is now 19 had contracted Luke’s disease at the age of 5, luckily I caught it with the rash and he was treated right away. Fast forward to several years later my son started having seizures after many test mris eeg blood work etc they never could exactly find out what has been causing them so they just diagnosed him as epileptic. I did however mention that he had lymes disease when he was little. Dr said yes I can see the scarring in the mri from the lymes disease. My question is. Can this be the cause of the seizures? He does suffer from insomnia depression and anxiety as well. And I have read that a lot of people with lymes disease even after treatment can be effected with these things. So is it possible that it could be causing his seizures even 14 years later?

    • Dr. Daniel Cameron
      09/01/2022 (6:35 am)

      I advise my patients to look a second time at Lyme disease while working with their neurologist. It could have been a reinfection. The “scarring” that you refer to may be demyelination that comes from many causes.

  • Mike Grant
    06/18/2022 (2:31 pm)

    I contracted Lyme Disease in 2007 which went undiagnosed for 9 months but when diagnosed was treated with doxycycline . During the course of the 9 months I suffered various monthly symptoms including Tinnitus, Bell’s palsy, the phrenic nerve on L side freezing causing difficulty in breathing , violent headaches and aura migraines . I also suffered two tonic clonic seizures. All symptoms disappeared under exception of the migraines and the two seizures I had were preceded half hour earlier by an aura migraine. I was prescribed Epilim to inhibit further risk of seizure and albeit I have experienced aura migraines since diagnosis none has been followed by a seizure until recently. I had been advised to reduce my reliance on Epilim 6 months ago. I had been taking 1400mg pd but during the 6 month period had reduced to 200 pd alternating occasionally with 400pd . 7 days ago ( 13th June 2022) I suffered an aura migraine whilst on my own at home. I lay down in the expectation that it would dissipate in about 20 minutes as usual and leaving me slightly nauseous . I fell asleep and about 15 mins later woke up with a start and screaming . I got up but remember nothing further until sometime later ( half hour?) I woke up on the floor in another room with a very painful back and sides (cause -seizure ?) as also did my wife notice when she returned other areas of my back which were bruised – I assume from falling . The experience was terrifying I have put myself back on to 600mg Epilim pending an appointment with my GP. The reason why my GP recommended reduction of Epilim was that he advised that long term use could cause Parkinson’s Disease. I appear to be between a rock and a hard place ! Any advice ?

    • Dr. Daniel Cameron
      06/19/2022 (6:31 am)

      I also find it hard to balance the risk rare events with the risk of seizures. I am sorry I do not have and insight to offer.

  • Colleen Moran
    05/10/2021 (3:10 pm)

    Great article. In your practice, are patients with pre-existing concussions/migraines are more likely to present with headaches, seizures, etc as main symptoms of Lyme disease?

    • Dr. Daniel Cameron
      05/11/2021 (8:07 am)

      My Lyme disease patients with a history of concussions/migraines are more likely to delay treatment as they assume their symptoms are related to headaches and seizures.

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