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Three Part Question

In [patients presenting to an Emergency Department with headache] does [acute onset] predict [significant underlying pathology]?

Clinical Scenario

A 57y/o man presents with a sudden onset, severe occipital headache. He has never had a headache this severe and has vomited several times. Neurological examination is normal. You request a CT scan of the patients brain but wonder if the acute onset of the headache is a sensitive predictor of significant underlying pathology.

Search Strategy

Search conducted in April 2007 of CINAHL, EMBASE and MEDLINE through OVID interface.
[abrupt.mp. OR sudden.mp. OR thunderclap.mp. OR warning.mp. OR sentinel.mp.] AND [headache.mp.] LIMIT to humans and English

Search Outcome

2280 papers were found of which 3 papers were relevant

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Linn, F; Wijdicks, E; et al 1994 Holland	148 patients presenting to 252 GPs with a primary complaint of sudden onset (< 1 minute), severe headache over a 5y period were prospectively recruited.	Prospective cohort study examining outcomes	Sub Arachnoid Haemorrhage	37/148 patients	Patients in study selected for inclusion by GPs. Not all of the patients had CT scans or LPs done although the follow up of these patients is described in another paper and none of them subsequently had a SAH.
			Positive CT scan in pts with SAH (excludes 4 pts that died prior to investigation)	31/33 patients
			Positive LP for 2 patients with negative CT scan
Aygun, D; Bildick, F 2003 Turkey	70 consecutive patients presenting with headache with at least one of the following features: worsening; sudden onset; persistence despite analgesia; alteration of character; associated focal neurology.	Examined the clinical warning criteria to see which symptoms suggested significant underlying pathology.	Diagnosis for patients with sudden onset (31 out of 70 patients)	11 SAH, 1 unruptured aneurysm, 1 abscess, 1 intracranial haemorrhage, 1 AVM, 1 IIH, 14 no pathology found.	Small numbers but high incidence of significant pathology.
			Patients with SAH	All had acute onset of headache.
Locker, T; Thompson, C; et al 2006 UK	589 patients presenting to one emergency department with a history of non-traumatic headache over a 14 month period. 558 patients had complete data, up to 3 months follow up.	Univariate analysis was done of the clinical features to see how well they predicted the presence of serious pathology. Features which appeared to predict serious pathology were entered into the multivariate analysis.	Sudden onset as predictor of serious pathology	Sens=65.6%, Spec=62.4%, PLR=1.74 (1.4-2.17), NLR=0.55 (0.39-0.78)	Not all of the presenting patients had the same investigations i.e. CT scan and/or LP. Although the patients were followed up for 3 months, significant pathology presenting after this time period may have been missed.
			Any of selected features as prediction of serious pathology (age >50, sudden onset, neurological abnormality)	Sens=97.8%, Spec=36.6%, PLR = 1.54 (1.4-1.71), NLR = 0.06 (0.01-0.43)

Comment(s)

Only one of the studies looks at an unselected group of patients presenting to an emergency department with headache and attempts to qualify the important clinical features. The abrupt onset of the headache is clearly relevant in this paper alongside the other features (age over fifty and neurological abnormality). The other papers look at cohorts of patients in whom the abrupt onset of the headache is one of the inclusion criteria but this symptom remains clearly linked with significant underlying pathology, particularly sub-arachnoid haemorrhage.

Clinical Bottom Line

Sudden or abrupt onset of a severe headache warrants further investigation to exclude serious underlying pathology.

Level of Evidence

Level 3 - Small numbers of small studies or great heterogeneity or very different population.

References

1. Linn, F; Wijdicks, E; et al Prospective Study of Sentinel Headache in Aneurysmal Subarachnoid Haemorrhage The Lancet 1994; 344: 590-93
2. Linn, F; Rinkel, G; Algra, A; Gijn, J Follow-up of idiopathic thunderclap headache in general practice J Neurol 1999; 246: 946-48
3. Aygun, D; Bildick, F Clinical warning criteria in evalutation by computed tomography the secondary neurological headaches in adults European Journal of Neurology 2003; 10: 437-442
4. Locker, T; Thompson, C; et al The Utility of Clinical Features in Patients Presenting With Nontraumatic Headache: An Investigation of Adult Patients Attending an Emergency Department Headache 2006; 46: 954-961