title: Etiology and distribution of headaches in two Brazilian primary care units.
abstract: OBJECTIVE
  To determine (a) which patients seek primary care services with a complaint of headache, (b) the percentages of the various types of headache in this population, and (c) the impact of the care provided to these patients on the basic health care network.
  
  
  BACKGROUND
  Headache is one of the most frequent symptoms reported in medical practice, resulting in significant medical services costs and loss of patient productivity, as well as reduced quality of life.
  
  
  METHODS
  A prospective study was conducted in two towns (Ribeirão Preto and São Carlos) in the State of São Paulo, Brazil. The participants in the study consisted of 6006 patients (52.4% women) with highly varied acute symptoms. The patients ranged in age from 14 to 98 years.
  
  
  RESULTS
  Headache as the main complaint was reported by 561 (9.3%) of the patients considered, with 312 (55.6%) of those patients presenting with primary headache, 221 (39.4%) with headaches secondary to systemic disorders, and 28 (5.0%) with headaches secondary to neurological disorders. Migraine, the most prevalent primary headache, accounted for 45.1% of patients reporting headache as the single symptom. The most frequent etiologies of headaches secondary to systemic disorders were fever, acute hypertension, and sinusitis. The most frequent headaches secondary to neurological disorders were posttraumatic headaches, headaches secondary to cervical disease, and expansive intracranial processes. Of the 26 cases of drug abuse, 20 were secondary to alcohol (hangover). Headaches secondary to systemic disorders were more frequent in the extreme age ranges.
  
  
  CONCLUSIONS
  Headache is a very frequent symptom among patients seen at primary health care units and should be considered a public health problem. The dissemination of the diagnostic criteria of the International Headache Society among primary health care physicians is urgently needed in order to avoid the repeated return of patients or their referral to more differentiated emergency units, which overburden an already insufficient health care network.
authors.affiliation: Department of Neurology, School of Medicine at Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil.
authors.forename: M E
authors.initials: ME
authors.lastname: Bigal
authors.forename: C A
authors.initials: CA
authors.lastname: Bordini
authors.forename: J G
authors.initials: JG
authors.lastname: Speciali
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil; D005260:Female; D006261:Headache / Q000145:classification / Q000453:epidemiology* / Q000209:etiology*; D020773:Headache Disorders / Q000453:epidemiology; D006801:Humans; D006973:Hypertension / Q000150:complications; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009422:Nervous System Diseases / Q000150:complications; D011320:Primary Health Care; D017678:Sex Distribution; D012852:Sinusitis / Q000150:complications; D019966:Substance-Related Disorders / Q000150:complications