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.

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

  • Wendy Brown
    11/21/2020 (11:53 am)

    My son had western Blot showed band 18 present back in Feb 2020, doctor did a repeat test in August with band 93 present only. He is having memory changes. I hear there are lyme specific bands and if present should be treated. Any suggestions.? He does have a appt follow up Infectious Disease next few weeks.

    • Dr. Daniel Cameron
      11/22/2020 (7:21 am)

      Each of the ten IgG bands were identified to identify Lyme disease. Some are better than others. I do not find focusing on one or two bands all that helpful. I prefer to use clinical judgement based on the complete presentation to determine whether I should treat.

  • Christopher A Binkley
    02/27/2020 (9:49 am)

    I’m a 48 year old man. Recently I have been having problems with memory (remembering where to turn for work, finding the right words to say and such). I have also had strange bouts with massive mood swings and strange chest/lung pain. Night time is the worst part. Bed soaking sweats, nightmares, fevers and chills. I figured I was just getting the flu. A new problem started to occur when I decided to go to the dr. I woke up one morning and it felt as if I was having micro seizures. Only lasting for a few seconds each occurence. Let the Dr know about the problems she ordered blood panel tests. The results came back with 1.256 positive Ehrlichiosis. Having had no idea or memory of being bitten by a tick in the past 6 months. Can Ehrlichiosis cause such problems? I am now on Doxycycline 100mg twice a day. As of now it’s the 3rd day. Still have stabbing chest pain and breathing issues with occasional mood swings out of the blue, all which is abnormal for me. How long does it take to subside if it’s related to Ehrlichiosis or should they also look for another firm of tick-borne illness as wellm

    • Dr. Daniel Cameron
      02/28/2020 (10:24 am)

      I have seen patients with evidence of one tick-borne-illness who have another without a positive test. I have to individualize treatment. I also follow them to rule out other medical problems.

    • Andreina Barthly
      02/25/2022 (4:47 am)

      Hi Christopher,

      I know this is a late response but I was infected with Erhlichiosos 3 years ago. I went a few months untreated, and even though I have recovered, I still get occasional seizures. I have never really been the same since, and I still suffer from a lot of the symptoms that you’ve described.

  • Heidi
    06/09/2019 (6:53 pm)

    Hello. My husband was bit by a deer tick around May 1st of this year and we found it and removed it on the 4th of May. He had symptoms he hadn’t had before (he’s had Lyme disease once before this one) he had joint and leg pain, and he had a stiff neck that lasted a couple of days and he wouldn’t go get checked out even though I insisted he go get checked out because of the tick that removed was a deer tick and I was worried about Lyme.. he finally got checked out after he discovered he had swollen lymph nodes and the aches and pains got worse. He went to the hospital on May 23rd and was given the antibiotic Doxycycline 100mg. The hospital tested for Lyme disease and we got a call that he tested positive for Lyme just this past week (June 5th). The other nite (July 7th) he was asleep and he often wakes form what I believe are night terrors.. well he sat up and I grabbed his arm and when he I did he just fell back down on the bed and his entire body was shaking like convulsing and at that exact moment I felt like he was having a seizure (growing up my parents neighbor has epilepsy and I have seen and helped with him having seizures so I know what they look like) and I did everything I could to wake him up.. He finally woke up and had couldnt remember what had happened and what he was dreaming about. He went back to sleep and we didn’t talk about the incident until he had gotten home later that nite and he said that he had a strange dream the nite before that he was a local hospital sitting outside and a woman was standing there and she just started having a seizure and when he went to help her something stopped him ( in real life that was me grabbing his arm) and then he fell and started having a seizure (which is what was happening in real life).. I am curious and I can’t seem to find this anywhere on the internet is there any way to have more than one tick borne disease/virus at the same time from the same tick? He tested positive for Lyme but could it be more serious? He has never had prior seizures and also he has been having cognitive difficulties (memory loss, confusion, etc.) I am really worried and not really sure what to do from here. This is his 2nd time being infected with Lyme disease could it just be the Lyme disease causing this or could it be something different? I have done as much research as possible about this but am extremely worried about him..

    • Dr. Daniel Cameron
      06/09/2019 (11:59 pm)

      It is worth looking at a recurrence or reinfection. You also need to rule out another illness.

  • Chuck
    05/13/2019 (6:00 pm)

    About 12 years ago, while camping, I got a tick stuck in me in the worst place imaginable for a man (yep, ouch.) My wife removed it from me. I never got tested for Lyme’s Disease. However, about 3 years later, I started having seizures. I am on two anti-seizure meds (4000mg daily of Keppra and 900mg daily of Trileptal) because it’s the only thing that is currently keeping me seizure free. I also have chronic fatigue, and I’ve noticed my memory is getting worse lately when it comes to remembering names, dates, etc. I’m only 51. Do you recommend that I get tested for Lyme’s Disease?

    • Dr. Daniel Cameron
      05/14/2019 (11:21 am)


      • Gavin Mews
        06/26/2020 (7:07 am)

        25 years ago when 9Years Old when bitten by a tick but never tested for Lyme Off shore in diagnosed with epilepsy 2.5years after bitten currently on 2000mg Keppra & 600mg epilim daily to easing pain. while marginally reducing seizures .Having Chronic fatigue & noticing Rhinitis with my memory getting massively worse only being 34years not being able to remember what I had for breakfast or what day it is along with names & events.Is there still a point in getting Lyme tested ?As have always wanted to get well as my greatest wish since a child.

        • Dr. Daniel Cameron
          06/26/2020 (9:41 am)

          I have had patients with both Lyme disease and epilepsy. It is not clear if they are connected. I typically recommend adding a Lyme disease specialist if there are unresolved problems. Call my office at 914 666 4665 if you need our help.

  • William Vandehey
    08/16/2018 (5:05 pm)

    My husband was diagnosed with Lyme’s 12 yrs. Ago. Had 4 months of rocephin and a yr of triple antibiotics. He now has severe fatigue, dizziness, and tremors. Has been diagnosed with Parkinson’s. Can another round of I’ve rocephin help him this late in the disease. He has been on a constant decline for the past 12 yrs.

    • Dr. Daniel Cameron
      08/19/2018 (1:27 am)

      Doctors are divided on an approach. It might help to have doctor familiar with tick borne illnesses e.g. Babesia to look again. He may even have been reinfected with another tick borne illness. I would also be important to make sure there in not a third illness.

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