title: A Cross-Sectional Clinic-Based Study in Patients With Side-Locked Unilateral Headache and Facial Pain.
abstract: OBJECTIVE
  To undertake the epidemiological evaluation of the patients presenting with side-locked headache and facial pain in a tertiary neurology outpatient clinic.
  
  
  BACKGROUND
  Side-locked unilateral headache and facial pain include a large number of primary and secondary headaches and cranial neuropathies. A diagnostic approach for the patients presenting with strictly unilateral headaches is important as many of these headache disorders respond to a highly selective drug. Epidemiological data may guide us to formulate a proper approach for such patients. However, the literature is sparse on strictly unilateral headache and facial pain.
  
  
  METHODS
  We prospectively recruited 307 consecutive adult patients (>18 years) with side-locked headache and facial pain presenting to a neurology outpatient clinic between July 2014 and December 2015. All patients were subjected to MRI brain and other investigations to find out the different secondary causes. The diagnosis was carried out by at least two headache specialists together. All patients were classified according to the International Classification of Headache Disorder-third edition (ICHD-3β).
  
  
  RESULTS
  The mean age at the time of examination was 42.4 ± 13.6 years (range 18-80 years). Forty-eight percent of patients were male. Strictly unilateral headaches accounted for 19.2% of the total headaches seen in the clinic. Headaches were classified as primary in 58%, secondary in 18%, and cranial neuropathies and other facial pain in 16% patients. Five percent of patients could not be classified. Three percent of patients were classified as per the Appendix section of ICHD-3β. The prevalence of secondary headaches and painful cranial neuropathies increased with age. A total of 36 different diagnoses were made. Only two diseases (migraine and cluster headache) had a prevalence of more than 10%. The prevalence of 13 diseases varied between 6 and 9%. The prevalence of other 14 groups was ≤1%. Migraine was the most common diagnosis (15%). Cervicogenic headache was the most common secondary headache. Classical trigeminal neuralgias and persistent idiopathic facial pain were two most common diagnoses in the painful cranial neuropathies and other facial pain groups. Sixty-one percent fulfilled the definition of chronic daily headaches, and hemicrania continua and cervicogenic headache were the two most common diagnoses in this group.
  
  
  CONCLUSIONS
  A large number of primary and secondary headaches and cranial neuropathies may present as side-locked headache and facial pain syndromes. Therefore, a sound knowledge of diagnostic approach is required for the optimal management of side locked headaches and facial pain.
authors.affiliation: Department of Neurology, Smt. B. K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth University, Piperia, Baroda, Gujarat, 3901760, India.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Prakash
authors.affiliation: Department of Neurology, Smt. B. K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth University, Piperia, Baroda, Gujarat, 3901760, India.
authors.forename: Chaturbhuj
authors.initials: C
authors.lastname: Rathore
authors.affiliation: Department of Neurology, Smt. B. K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth University, Piperia, Baroda, Gujarat, 3901760, India.
authors.forename: Prayag
authors.initials: P
authors.lastname: Makwana
authors.affiliation: Department of Neurology, Smt. B. K. Shah Medical Institute and Research Centre, Sumandeep Vidyapeeth University, Piperia, Baroda, Gujarat, 3901760, India.
authors.forename: Ankit
authors.initials: A
authors.lastname: Dave
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005157:Facial Pain / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D005260:Female; D006261:Headache / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011446:Prospective Studies; D012737:Sex Factors; D062606:Tertiary Care Centers; D013997:Time Factors; D055815:Young Adult
keywords: cluster headache; cranial neuralgia; hemicrania continua; side-locked headache; trigeminal autonomic cephalalgia