Table 1 ICD-10 codes pre-selected for possible Lyme borreliosis in the Norwegian Patient Registry

Lyme borreliosis:

• A69.2 – Lyme disease (Erythema chronicum migrans due to Borrelia burgdorferi)

• M01.2 – Arthritis in Lyme disease

Possible Lyme borreliosis:

• G04.2 - Bacterial meningoencephalitis and meningomyelitis, not elsewhere classified

• G04.8 – Other encephalitis, myelitis and encephalomyelitis (Postinfectious encephalitis and encephalomyelitis NOS)

• G51.0 – Bell palsy (facial palsy)

• G51.8 – Other disorders of facial nerve

• G51.9 – Disorder of facial nerve, unspecified

• G63.0 – Polyneuropathy in infectious and parasitic diseases classified elsewhere