Headaches are a very common chief complaint. The overall prevalence of headaches is up to 20-30% in general population.
The headache mind map is organized based upon:
Life-threatening conditions (listed on the top of the clinical mind map, such as a concussion, intracranial hemorrhage, meningitis/encephalitis, and space occupying lesions). Together, these diagnoses can be grouped as one chunk “CIMS”.
Non-life-threatening conditions which are further organized based upon the location, and in some instances unilaterality versus bi-laterality of the headache (listed in the middle section of the clinical mind map). A mnemonic to memorize these conditions is “MATT SaT on a C-CaT” where all of the capital letters represent a diagnosis.
General headaches from external causes or causes outside of the head and neck area (listed in the bottom section of the mind map) can be memorized as dig spelled as “DDIGH”
Some sources divide headache differentials based upon primary and secondary causes. This method of division is useful in epidemiological studies and when clinicians are reviewing causes of headache from a pathophysiology standpoint. However, since most pathophysiologic phenomenon cannot be elicited at a bed side (a clinician cannot get a patient to identify if their headache feels primary or secondary), this method is not conducive in leading to diagnostic efficiency in the reasoning process. Therefore, this clinical mind map does not follow the organization of differentials based upon primary versus secondary causes.
Using the Epi-logical approach, after considering probable diagnoses, urgent/emergent situations must be addressed. Clinical features which point to the presence of an urgent/emergent situation are altered mental status, abnormal vital signs, and stroke related signs such as facial asymmetry, slurred speech, and limb weakness. “CIMS” can give rise to urgent/emergent situations, but so can a few other conditions if left untreated. Examples of these other conditions include severe dehydration, and carbon monoxide or a poisonous gas exposure. Urgent/emergent situations must also be considered when patients describe their headache as the first that they ever have experienced and they are over 50 years of age and/or it is the worst headache of their life. In addition to these, acute angle closure glaucoma and temporal arteritis must be considered in appropriate age groups. Although not life threatening, these are organ threatening conditions.
In order to weigh and remove anchor bias, a clinician can ask high yield questions (about the location and duration of the headache) to narrow the differentials into a smaller list or category, which improves efficiency. Medium yield questions can be asked next. After a narrow list of working diagnoses (1-3 diagnoses) has been built, additional questions can be asked to remove any anchor bias. Although a physical exam and diagnostics labs/imaging add to diagnostic certainty and help with management, most diagnoses can be made based upon a careful history