Borrelia miyamotoi disease presenting with hyperCKemia and severe glycemic destabilization in type 1 diabetes mellitus

Abstract

Borrelia miyamotoi is a relapsing-fever spirochete that conventional tick-borne testing does not detect. We report a case notable for two findings not emphasized in prior series: creatine kinase elevation to 1464 U/L and glucose concentrations above 500 mg/dL without ketoacidosis in a pump-treated patient with type 1 diabetes mellitus. A 36-year-old man with frequent wooded exposure presented with fever, headache, myalgias, and rash, along with leukopenia, thrombocytopenia, and mild transaminitis. Lyme serology, Babesia smear, Anaplasma and Ehrlichia PCR, spotted-fever group Rickettsia serology, and blood cultures were negative; blood real-time PCR identified B. miyamotoi after discharge. The hyperglycemia was attributable to infection-related insulin resistance and interruption of pump delivery. Seventeen days of doxycycline produced full clinical and laboratory recovery. Exercise and dehydration may have contributed to the hyperCKemia. This case supports early blood PCR during the febrile illness in culture-negative tick-borne disease and illustrates that insulin requirements may rise sharply when infection coincides with failure of insulin-delivery technology.

Highlights

• •Borrelia miyamotoi can mimic anaplasmosis or ehrlichiosis.
• •Acute infection caused cytopenias, transaminitis, and hyperCKemia.
• •Routine Lyme and common tick-borne testing was negative.
• •Blood real-time PCR established the diagnosis after discharge.
• •Doxycycline produced rapid and sustained clinical recovery.

Introduction

Borrelia miyamotoi is a relapsing-fever group spirochete transmitted by hard-bodied Ixodes ticks, including Ixodes scapularis in the northeastern and midwestern United States [[1], [2], [3]]. Human infection was first recognized in Russia and subsequently documented in the United States, where surveillance data suggest that the disease remains underrecognized [[2], [3], [4], [5]]. Typical manifestations include an acute febrile illness with chills, headache, fatigue, and myalgias; leukopenia, thrombocytopenia, and elevated aminotransferases are common laboratory findings [[2], [3], [4], [5]]. Unlike Lyme disease, erythema migrans is generally absent, and standard Lyme serologic testing does not reliably diagnose B. miyamotoi infection [3,6]. We describe a polymerase chain reaction-confirmed case with hyperCKemia and severe glycemic destabilization in a patient with type 1 diabetes mellitus.

Case presentation

A 36-year-old man with type 1 diabetes mellitus managed with an insulin pump and continuous glucose monitor, Hashimoto thyroiditis, hypertension, hyperlipidemia, diabetic neuropathy, nephrolithiasis, and opioid use disorder in sustained remission was admitted on June 11, 2026, with acute fever, shaking chills, headache, diffuse myalgias, and lower-back pain. He frequently hiked, fished, camped, and worked outdoors in wooded areas but did not recall a tick bite. Approximately two weeks before admission, an intensely pruritic erythematous lesion developed on the left posterior calf and later involved both lower extremities, feet, and soles. On the day of presentation, after walking outdoors, participating in an intense boxing class, and rock climbing, he developed malaise, diaphoresis, chills, generalized body aches, posterior headache with retro-orbital discomfort, and fever to 102.7–103 °F (39.3–39.4 °C). He also noted unusually difficult glycemic control despite corrective insulin and increased fluid intake.

In the emergency department, his temperature was 102.6 °F (39.2 °C), heart rate 123 beats/min, blood pressure 151/93 mm Hg, and oxygen saturation 99% on room air. He appeared mildly ill but remained hemodynamically stable and neurologically intact. Examination showed diffuse blanching erythema of the upper torso and extremities, bilateral lower-extremity erythematous macules and excoriations, and a raised linear or papular lesion over the left posterior calf. There was no cellulitis or classic erythema migrans lesion.

Initial laboratory testing showed a leukocyte count of 3.0 × 10 ³ /µL, platelet count of 127 × 10 ³ /µL, sodium 131 mmol/L, bicarbonate 19 mmol/L, glucose 257 mg/dL, creatinine 1.17 mg/dL, aspartate aminotransferase 71 U/L, alanine aminotransferase 61 U/L, C-reactive protein 140 mg/L, procalcitonin 3.24 ng/mL, and creatine kinase 1464 U/L. Hemoglobin A1c was 7.7%, and lactate was 0.8 mmol/L. The following morning, the leukocyte count decreased to 1.9 × 10 ³ /µL, the platelet count decreased to 110 × 10 ³ /µL, aspartate aminotransferase increased to 85 U/L, and alanine aminotransferase increased to 69 U/L. The platelet nadir was 98 × 10 ³ /µL.

Urinalysis showed no pyuria or bacteriuria and was negative for ketones. Respiratory viral polymerase chain reaction testing, including SARS-CoV-2 and influenza, was negative. A Babesia smear was negative. Chest radiography showed no active pulmonary disease, head computed tomography showed no acute intracranial abnormality, and computed tomography of the abdomen and pelvis showed no nephrolithiasis or hydronephrosis. Blood cultures remained negative.

An acute tick-borne infection was suspected because of the high fever, headache, myalgias, wooded exposure, cytopenias, transaminitis, and elevated creatine kinase. Specimens for tick-borne testing, including B. miyamotoi real-time PCR, were collected before antibiotic administration. Intravenous fluids, ceftriaxone, and doxycycline were administered in the emergency department. Ceftriaxone was discontinued after no pulmonary, urinary, or bloodstream source was identified, and doxycycline 100 mg twice daily was continued. Fever and systemic symptoms improved rapidly. The rash became less pruritic and flattened with topical hydrocortisone. The serum sodium concentration normalized with hydration, and creatine kinase and aminotransferase levels declined.

The hospital course was complicated by severe hyperglycemia. Glycemic control had become difficult before admission, consistent with increased insulin requirements during acute infection. During hospitalization, the insulin pump ran out of insulin and the continuous glucose-monitoring sensor required replacement, further worsening glycemic control. Glucose concentrations exceeded 500 mg/dL, requiring temporary basal-bolus insulin therapy with glargine and lispro before the patient's pump was resumed. Diabetic ketoacidosis did not develop: urine ketones were negative, venous pH was 7.39, and there was no sustained anion-gap metabolic acidosis.

He was discharged clinically improved and afebrile on June 14, 2026. The positive B. miyamotoi PCR result became available on June 16, 2026. Testing was performed by Mayo Clinic Laboratories using a laboratory-developed qualitative real-time PCR assay targeting the glpQ gene. The assay is qualitative rather than a commercial qPCR kit, and a cycle-threshold value was not reported. DNA was extracted on the Roche MagNA Pure platform and amplified on the Roche LightCycler 480 (Roche Diagnostics) [7]. Lyme serology, Anaplasma and Ehrlichia PCR, Babesia smear, spotted-fever group Rickettsia serology, HIV testing, respiratory viral testing, and blood cultures were negative. He completed 17 total days of doxycycline. At follow-up, the fever, chills, headache, myalgias, and rash had completely resolved. On June 24, the leukocyte count was 6.1 × 10 ³ /µL, platelet count was 304 × 10 ³ /µL, aspartate aminotransferase was 30 U/L, alanine aminotransferase was 48 U/L, and creatine kinase was 272 U/L. He remained clinically well off antibiotics without recurrent fever or neurologic symptoms (Table 1).

Table 1.

Clinical timeline, selected laboratory values, treatment, and diagnostic milestones.

Date/time	WBC / platelets (×10 ³/µL)	AST / ALT (U/L)	CK / glucose (U/L; mg/dL)	Clinical, treatment, and diagnostic events
Jun 11, 2026	3.0 / 127	71 / 61	1464 / 257	ED presentation with fever, headache, and myalgias. IV fluids and ceftriaxone. B. miyamotoi PCR specimen collected before antibiotic administration.
Jun 12, 2026	1.9 / 110	85 / 69	1190 / 515	Doxycycline 100 mg twice daily initiated. Tick-borne testing pending; no alternative infectious source identified.
Jun 13, 2026	3.4 / 98	61 / 64	NR / 161	Afebrile; systemic symptoms and rash improving; doxycycline continued.
Jun 14, 2026	3.7 / 130	40 / 55	229 / 180	Discharged clinically improved on doxycycline.
Jun 16, 2026	—	—	—	Post-discharge B. miyamotoi real-time PCR reported positive.
Jun 24, 2026	6.1 / 304	30 / 48	272 / NR	Outpatient clinical and laboratory recovery.

Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; CK, creatine kinase; NR, not reported at the selected time point; PCR, polymerase chain reaction; WBC, white blood cell count.

Discussion

This case demonstrates several features that should prompt consideration of B. miyamotoi disease: an acute nonspecific febrile syndrome after potential Ixodes exposure, leukopenia, thrombocytopenia, transaminitis, and negative testing for more commonly recognized tick-borne infections. In a multistate US surveillance series, fever, chills, headache, and myalgia were frequent, and thrombocytopenia, leukopenia, and elevated aminotransferases were common among patients with available laboratory data [2]. Because the clinical overlap with anaplasmosis and ehrlichiosis is substantial, empiric doxycycline is appropriate when those infections are suspected while diagnostic studies are pending.

Molecular detection of B. miyamotoi in blood or cerebrospinal fluid provides the most direct diagnosis during acute illness. Polymerase chain reaction sensitivity is expected to be greatest during spirochetemia and before or shortly after antimicrobial therapy begins [3,8]. In this patient, the diagnostic blood specimen was obtained on the first day of systemic symptoms and before the first doxycycline dose, strengthening interpretation of the positive result. Because this pre-antibiotic specimen was PCR-positive, repeat PCR or anti-GlpQ serology was not pursued. Conventional Lyme serology should not be used to exclude B. miyamotoi disease. Serologic assays using glycerophosphodiester phosphodiesterase and variable major proteins have been studied, but their performance and availability remain variable [6,9]. Blood PCR established the diagnosis after discharge, while testing for Lyme disease, Babesia, Anaplasma, Ehrlichia, and spotted-fever group Rickettsia was negative.

The creatine kinase elevation was clinically notable. Myalgias are well recognized in B. miyamotoi disease, but substantial hyperCKemia is not emphasized in major surveillance series or reviews [2,3]. Vigorous exercise before presentation and dehydration may have contributed; therefore, the creatine kinase elevation cannot be attributed solely to infection. Nevertheless, its temporal association with the febrile illness and improvement with hydration and antimicrobial therapy suggest that acute systemic inflammation may also have contributed. Clinicians should consider measuring creatine kinase when severe myalgias or muscle injury are suspected.

Severe hyperglycemia was also multifactorial. Acute infection likely increased counter-regulatory hormone release and insulin resistance, while interruption of pump delivery provided a clear additional mechanism. The absence of ketonemia, acidemia, or sustained anion-gap acidosis argued against diabetic ketoacidosis. Autoimmune endocrine disease has not been established as a specific susceptibility factor for B. miyamotoi infection, and this case does not establish a causal association. The practical lesson is that insulin requirements may increase substantially during acute tick-borne illness and that glycemic deterioration can become dangerous when insulin-delivery technology fails.

Published experience supports treatment with agents used for Lyme disease. The US Centers for Disease Control and Prevention notes that a 2-week course of doxycycline or amoxicillin has been effective for most patients, with intravenous ceftriaxone reserved for severe disease such as meningoencephalitis [10]. This patient had rapid defervescence with doxycycline and complete clinical recovery after a 17-day course. No Jarisch-Herxheimer reaction was observed.

In conclusion, B. miyamotoi should be considered in patients from Ixodes-endemic regions who present with an acute sepsis-like illness, headache, myalgias, cytopenias, and transaminitis despite negative conventional tick-borne testing. Acute-phase blood polymerase chain reaction testing can provide a definitive diagnosis. HyperCKemia and severe glycemic destabilization may accompany the illness, but potential contributions from exercise, dehydration, and interruption of insulin delivery should be acknowledged.

CRediT authorship contribution statement

Kairui Sun: Writing – review & editing, Writing – original draft, Investigation, Data curation, Conceptualization. Yuhao Guo: Writing – review & editing, Writing – original draft.

Ethics declaration

Written informed consent to take part in the study and to publish the article has been obtained from all participants or their legal representatives. The privacy rights of participants have been observed.

This study was performed in compliance with relevant laws, regulatory frameworks and guidelines where the research took place. Ethics committee approval was not required under relevant laws and institutional guidelines. This single-patient case report was prepared in accordance with applicable institutional policies and the principles of the Declaration of Helsinki. Formal ethics committee review was not required under institutional guidelines for the publication of an individual case report. Written informed consent for publication was obtained from the patient, and all clinical information was de-identified.

This research follows the CARE guidelines and the CARE checklist.

Patient consent and ethics statement

Written informed consent for publication of this case report was obtained from the patient. The report contains no direct patient identifiers. Formal institutional review board review was not required for this single-patient case report under institutional policy.

Declaration of Generative AI and AI-assisted technologies in the writing process

During the preparation of this work, the authors used ChatGPT (OpenAI) to assist with manuscript organization and language editing. After using this tool, the authors reviewed and edited the content, verified the clinical information and references, and take full responsibility for the content of the published article.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability

The clinical data underlying this case report are not publicly available because they contain confidential patient information. De-identified information may be available from the corresponding author upon reasonable request and subject to institutional and privacy requirements.