International Headache Society (IHS) ICHD-II Code: 4.1 Primary stabbing headache

World Health Organization (WHO) ICD-10NA Code: G44.800 Idiopathic stabbing headache

Short description: Transient and localized stabs of pain in the head that occur spontaneously in the absence of organic disease of underlying structures or of the cranial nerves

Previously used terms: Ice-pick pains; jabs and jolts; ophthalmodynia periodica

Prevalence of the ultrashort paroxysms of head pain that characterize primary stabbing headache has been difficult to estimate and results have varied considerably. In two population-based studies, idiopathic stabbing headache was found to be less than 1 to 2% (48,65). However, in a large-scale, cross-sectional study of headache in a parish in the mountainous region of Vågå, Norway, primary stabbing headache was verified in 35.2% of the 1,838 adult parishioners (18 to 65 years of age) who were examined (79).

Prevalence estimates vary depending on the studied population. For example, primary stabbing headache is more prevalent in migraineurs and individuals with tension-type headache. Not surprisingly, given the prevalence of these primary headache disorders in the population, one would expect a prevalence of at least one third in a general unselected population. Indeed, the prevalence of primary stabbing headache in one study of migraine sufferers was 42% compared to only 3% in controls (64). The high prevalence of primary stabbing headache among migraineurs has been confirmed in subsequent studies (20).

The mean age of onset of primary stabbing headache is 47 years (range 12 to 70) (52). The female:male ratio has varied from 1:49 to 6.6.

Diagnostic Criteria for Primary Stabbing Headache (28):

A. Pain occurring as a single stab or a series of stabs confined to the head and exclusively or predominantly felt in the distribution of the first division of the trigeminal nerve (orbit, temple, and parietal areas).

B. Stabs last for up to a few seconds and recur with irregular frequency ranging from one to many per day.

C. No accompanying symptoms.

D. Not attributed to another disorder.

The painful attacks of primary stabbing headache are ultrashort, lasting only 1 second in more than two thirds of cases (52). In some patients, the pain can last up to 10 seconds. The pain is frequently unifocal, often in the orbital region, but multifocal patterns have been described with the pain quickly and erratically changing location. The pain has also been described in the facial, occipital, retroauricular, temporal, and even parietal regions. The attacks are often sudden, and moderate to high intensity, with a pricking or stabbing character. The frequency of attacks vary widely from 1 attack per year to 50 attacks daily. In one study, chronic attacks (>80% of days) occurred in 14% of 38 patients followed over a 1-year period. Most attacks are distributed throughout the day. The paroxysms generally occur spontaneously without provocation. There are seldom associated features such as lacrimation, rhinorrhea, conjunctival injection, nausea, or photophobia. Attack-related conjunctival hemorrhage and monocular visual loss have been described (52,94). Occasionally, bright
light, emotional stress, and postural changes are reported to trigger attacks. The ultrashort duration and lack of cranial autonomic features distinguish this disorder from short-lasting unilateral neuralgiform pain with conjunctival injection and tearing (SUNCT) syndrome, where attacks last from 15 to 180 seconds. The presence of trigger points, duration of a few seconds, and occurrence of pain in the second and third trigeminal distribution are characteristic of trigeminal neuralgia, with which primary stabbing headache can be confused. In addition to a high prevalence in patients with migraine, primary stabbing headache may also be seen in association with tension-type headache, cluster headache, cervicogenic headache, and during painful exacerbations in up to two thirds of patients with hemicrania continua.

Although invariably benign, primary stabbing headache may be associated with intracranial structural lesions such as meningioma and pituitary tumors (38,44). Primary stabbing headache has also been associated with onset of cerebrovascular diseases, cranial and ocular trauma, and herpes zoster (52). An association may also exist between new-onset primary stabbing headache and intraocular pressure elevation. Therefore, when clinically suspect, patients with new-onset primary stabbing headache should undergo a diagnostic evaluation to exclude organic pathology.

Acute treatment of primary stabbing headache is not feasible given its ultrashort duration and repetitive nature. When attacks occur with a frequency that warrants prophylactic therapy, indomethacin is usually the treatment of choice (grade C recommendation). Indomethacin provides complete or partial improvement in two thirds of patients (16,46,52). The usual effective dose range from 25 to 150 mg per day. Recently, melatonin was described as completely effective in three patients at doses ranging from 3 to 9 mg at bedtime (69). A patient with primary stabbing headache and exploding head syndrome was reported to have responded to nifedipine (31). In three patients who began to experience primary stabbing headache after ischemic stroke, complete response was obtained with the use of celecoxib 100 mg twice daily (60).

International Headache Society (IHS) ICHD-II Code: 4.2 Primary cough headache

World Health Organization (WHO) ICD-10NA Code: G44. 803 Benign cough headache

Short description: Headache precipitated by coughing or straining in the absence of any intracranial disorder

Previously used terms: Benign cough headache, valsalva maneuver headache

Cough headache is considered a rare entity. Rasmussen and Olesen (66) have shown that the lifetime prevalence of cough headache is one percent (95% confidence interval [CI] 0 to 2%). Over 15 years, of the 3,498 patients attending a neurology department owing to headache, 20 (0.6%) consulted because of cough headache (54).

Cough headache can be either a primary benign condition or secondary to structural cranial disease. From older case series (prior to computed tomography [CT] and magnetic resonance imaging [MRI]), it was concluded that about 20% of patients with cough headache had structural lesions, most of them a Chiari type I deformity (49,54,68,70,84). However, with modern neuroradiologic techniques, it is clear that almost half of cough headache patients have symptomatic cough headache owing to tonsillar descent or, more rarely, to other space-occupying lesions in the posterior fossa/foramen magnum area (55). Around 30% of patients with Chiari type I malformation experience headache aggravated by Valsalva maneuvers, mainly cough (56) (Fig. 99-1). In summary, it can be concluded that about 50% of the patients with cough headache show no demonstrable etiology, and the other half are secondary to structural lesions, mostly at the foramen magnum level (57).

Secondary cough headache seems to be caused by a temporary impaction of the cerebellar tonsils below the foramen magnum (50,71,90,91). In two patients with cough headache and tonsillar herniation, Williams demonstrated a pressure difference between the ventricle and the lumbar subarachnoid space during coughing (91). This craniospinal pressure dissociation displaces the cerebellar tonsils into the foramen magnum. Williams also observed that the headache disappeared after decompressive craniectomy. Subsequently, Nightingale and Williams described four more patients who had headache from episodic impaction of the cerebellar tonsils in the foramen magnum after abrupt Valsalva maneuvers (50). In our series, not only was it demonstrated that tonsilar descent is the actual cause of cough headache, but it was also shown that the presence of cough headache in Chiari type I patients only correlated with the degree of tonsilar descent (55,56). Pujol et al. (61), using cine phase-contrast MRI, were able to detect this abnormal pulsatile motion of the cerebellar tonsils in Chiari type I patients, but not in controls. This movement produced a selective obstruction of
the cerebrospinal fluid (CSF) flow from the cranial cavity to the spine. The amplitude of the tonsillar pulsation and the severity of the arachnoid space reduction were associated with cough headache (61). Collectively, these data confirm that symptomatic cough headache is usually secondary to Chiari type I deformity and that this pain is caused by compression or traction of the caudally displaced cerebellar tonsils on pain-sensitive dura and other anchoring structures around the foramen magnum that are innervated by the upper cervical nerve roots.

The pathophysiology of primary cough headache is not known. The possibility of a sudden increase in venous pressure being sufficient in itself to cause headache caused by an increase in brain volume has been proposed (88). Other contributing factors, however, may be operant, such as a pressure receptor hypersensitivity hypothetically localized on the venous vessels (63). One of the potential etiologies for this transient receptor sensitization could be a hidden or previous infection (92). Finally, Chen et al. (9) recently found that patients with primary cough headache have a reduction in posterior fossa volume with subsequent crowding of structures, which may be a further contributing factor for the pathogenesis of this headache syndrome.

Diagnostic Criteria of Primary Cough Headache (28):

A. Headache fulfilling criteria B and C

B. Sudden onset, lasting from 1 second to 30 minutes

C. Brought on by and occurring in association with coughing, straining and/or Valsalva maneuver

The clinical picture of primary cough headache is very characteristic, which allows its differentiation from secondary cases (3,53,55,57) (Table 99-1). Primary cough headache does not begin earlier than 40 years; the mean age of onset in modern series is 67 years (range 44 to 81 years). Up to 80% of patients suffering from primary cough headache are men. Primary cough headache is an episodic disorder, ranging from 2 months to 2 years. The pain begins immediately or within seconds after the precipitants, which include cough, sneezing, nose blowing, laughing, crying, singing, lifting a burden, straining at stool, and stooping. Sustained physical exercise is not a precipitating factor for primary cough headache. Primary cough headache is moderate to severe in intensity, with a sharp, stabbing, splitting, or even explosive quality. Most patients have bilateral headaches all the time. The pain is usually maximal in the occipital region, but also in the frontal or temporal region or at the vertex. The pain typically lasts from seconds to several minutes. In a few patients, a dull, aching pain follows the paroxysm for several hours (13). Primary cough headache is not associated with other clinical manifestations, including nausea or vomiting, and responds to indomethacin.

The presence of a Chiari type I malformation or any other lesions causing obstruction of CSF pathways or displacing cerebral structures must be excluded before cough
headache is assumed to be benign. Cough headache may be the only clinical manifestation of Chiari type I malformation for several years in about one fifth of symptomatic patients. In our experience, however, most if not all patients with symptomatic cough headache finally develop posterior fossa symptoms or signs, mainly dizziness or vertigo, unsteadiness, and syncope (55). Symptomatic cough headache begins three decades earlier, on average, than primary cough headache, and does not show a clear male predominance or respond to indomethacin (57).