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MASQUERADES OF CLUSTER HEADACHE

Table 2: Characteristic features of cluster headache4

Pain is described as:

Character - Lancinating and severe

Sudden onset - Peaks in 10-15 minutes

Unilateral facial - Remains on the same side during the cluster period

Duration - 10 minutes to 3 hours per episode

Character - Boring and lancinating, as if eye is being pushed out

Distribution - First and second divisions of the trigeminal nerve (Approximately 18%  - 20% of patients complain of pain in the extratrigeminal areas [e.g. back of the neck, along carotid artery])

Frequency - May occur several times a day for 1 - 4 months (often nocturnal)

Periodicity - Circadian regularity in 47%

Remission - Long symptom-free intervals occur in some patients. The average remission is 2 years but ranges from 2 months to 20 years

Associated autonomic signs of parasympathetic hyperactivity and sympathetic impairment include ipsilateral ptosis, miosis, lacrimation, conjunctival injection and rhinorrhoea.⁴ Other clinical presentations include facial flushing or pallor, tenderness on palpation of the ipsilateral carotid artery, bradycardia and abnormal feeling of scalp hairs.⁶ The absence of aura, nausea or vomiting has helped distinguish cluster from migraine headaches, but recent studies indicated that 14% of patients with cluster headache experienced aura, 51% had a personal or family history of migraine, 56% reported photophobia, 43% reported phonophobia and 23% reported osmophobia⁶ (Table 3).

Table 3: Autonomic involvement in cluster headache^3,4

Parasympathetic overactivity

Ipsilateral lacrimation and conjunctival injection (84% - 91%)

Nasal congestion and rhinorrhea(48% - 75%)

Ipsilateral eyelid edema and droopy eye

Ipsilateral miosis or ptosis

Ipsilateral forehead and facial perspiration (26%)

Restlessness/agitation (90%)

Intolerance to light and noise

Ocular sympathetics paralysis

Mild Horner syndrome (e.g. ptosis, miosis, anhidrosis)

Other autonomic presentation

Bradycardia

Facial flushing or pallor

Scalp and facial tenderness

Ipsilateral carotid tenderness (in some patients)

Cluster headache is sometimes described as "suicide headache" because of its severity and "alarm clock" headache because of its periodicity.^3,6 The 2 existing forms of cluster headache are:

1. Episodic clusters with at least 2 cluster phases lasting 7 days to 1 year separated by a cluster free interval of 1 month or longer.
2. Chronic form, in which the clusters occur more than once a year without remission or the cluster-free interval is less than 1 month.^3,4

Criteria for diagnosis of cluster headache are listed in Table 4.

Table 4: Diagnostic criteria of cluster headache²

The International Classification of Headache Disorders

A: At least five headache attacks fulfilling criteria B - D

B: Severe or very severe unilateral orbital, supraorbital and/or temporal headache attacks, which last untreated for 15-180 minutes. During part (but less than half) of the time course of the cluster headache, attacks may be less severe, less frequent or of shorter or longer duration

C: The headache is accompanied by at least one of the following symptoms ipsilateral to the pain:

1. Conjunctival injection or lacrimation

2. Nasal congestion and/or rhinorrhoea

3. Eyelid oedema

4. Forehead and facial sweating

5. Miosis and/or ptosis

6. A sense of restlessness and agitation

D: The attacks have a frequency from one every other day to 8 per day

E: History or physical and neurological examination do not suggest any other disorder and/or they are ruled out by appropriate investigations

Episodic cluster headache:

At least two cluster periods lasting 7 days to 1 year separated by pain-free periods lasting >1 month

Chronic cluster headache:

Attacks occur for more than 1 year without remission or with remission <1 month

Probable cluster headache:

Attacks fulfilling all but one criteria for cluster headache

Diagnosis is based on historical and physical findings. The pattern of recurrence, periodicity and rhythmicity of near-daily attacks lasting for days, weeks or months are the keys to diagnosis. There are no abnormalities to be found upon a physical or laboratory investigation other than Horner's syndrome occasionally.  In approximately 70% of patients with cluster headaches, the carotid artery is palpably tender at several points in the neck.⁷ The cluster headache syndrome, with all autonomic symptoms, on-off alcohol sensitivity, ipsilateral tender carotid artery and clocklike periodicity of attacks, has not been associated with any underlying intracranial structural abnormalities.¹ Imaging studies are not diagnostic but are useful to exclude other causes in selected patients at the early stage.⁶

A transitory, partial Horner's syndrome (pupillary miosis and lid ptosis) occurs in two-thirds of patients when they are examined during attacks and is a useful sign in the differential diagnosis of facial pain. It is highly characteristic of the cluster headache syndrome and, after repeated occurrences; it may become a permanent feature.⁷

In Michelle’s case, periodicity and rhythmicity of headaches with its characteristic features that conforms to that of an excruciating neuropathic pain, points towards the diagnosis of episodic cluster headache. Ipsilateral presentation of eye and ear swelling with redness, presence of transient Horner’s syndrome and dramatic response to empirical treatment with prednisolone further supports the diagnosis. Confirmation by the ophthalmologists that there was no primary eye disorder ruled out important differential diagnoses of acute glaucoma, uveitis, scleritis, allergic or infective conjunctivitis.

WHAT ARE THE FACTORS CONTRIBUTING TO THE DELAY IN DIAGNOSIS OF CLUSTER HEADACHE IN THIS CASE?

Despite a cluster headache's distinguishing characteristics, its relative infrequency and similarity to such disorders as sinusitis, acute eye problems and dental disorders can lead to misdiagnosis. Some cluster patients have had tooth extractions, sinus surgery or psychiatric treatment in futile efforts to cure their pain.⁸

In this case report patient’s cluster headache was wrongly perceived to be due to acute primary eye disorders for several years. Factors contributing to delay in the diagnosis include:

• Direct access and self referral of patient to specialist care in our private healthcare system.
• Lack of continuity of care by the same physician.
• Specialised compartmental medical care, whereby ophthalmologists are focused mainly on eye disorders to the exclusion of other general medical conditions.
• Patient’s focus of concern on the eye swelling and redness was partly due to her past experience with problems associated with use of contact lenses and her fear of loss of vision.
• Eye signs were physically visible to both doctor and patient, while headache was not. Hence the importance of red eye overrode that of headache until the excruciating pain became intolerable and not responding to simple analgesia.
• Detailed pain assessment was not done. Pain was assumed to be secondary to the red swollen eye. Red eye was not perceived as epiphenomena of a neurovascular headache.
• Cluster headache is relatively uncommon.
• Because of the periodicity and rhythmicity of the condition, it was not very certain whether the prescribed eye drops and oral medication actually improved the condition or whether the eye redness and pain went off on its own.

HOW CAN GENERAL PRACTITIONERS MANAGE CLUSTER HEADACHE?

Headache diary, lifestyle changes and behavioral therapy³

Patients should be advised to keep a headache diary and record a description of the attacks and possible trigger factors. The patients are advised to avoid alcohol and smoking and other factors that may potentially trigger cluster headache attacks. Behavioral approaches such as relaxation therapy combined with biofeedback can be a helpful accompaniment to drug treatment. These approaches can help with pain management and enable patients to feel more in control of their condition.

Pharmacological treatment

Pharmacological treatment of cluster headache is based on empirical data rather than on a pathophysiological concept of the disease.⁹ Level A recommendation includes the following¹⁰:

Abortive treatment for acute attack
The first option for the treatment of acute attacks of cluster headache should be the inhalation of 100% oxygen with at least 7 l/min over 15 min or with the subcutaneous injection of 6mg sumatriptan. An alternative would be sumatriptan 20mg nasal spray or zolmitriptan 5mg nasal spray, with the disadvantage of a slower onset but the advantage of being able to treat more attacks in 24 hours than with injected sumatriptan.

Prophylaxis treatment
Steroids are very effective initial prophylactic option, rapidly suppressing attacks during the time required for the longer-acting preventive agents to take effect. The use of at least 60 to 100mg prednisone (or equivalent corticosteroid) given orally per day over 5 days (then tapering down) is recommended.

Preventive treatment
As many patients have between one and eight short-lived attacks a day, repeated attempts at abortive therapy may result in overmedication or toxicity. The primary goal of preventive therapy is to produce a suppression of attacks and to maintain remission over the expected duration of the cluster period. Prophylaxis of cluster headache should be tried first with verapamil at a daily dose of at least 240mg. Maximum dose depends on efficacy or tolerability, ECG controls are obligatory with increasing doses. Other prophylactic drugs are lithium (particularly effective for chronic cluster headache), methylsergide, pizotifen, nifedipine, verapamil, phenelzine, amitriptyline, ergonovine, indomethacin and cyproheptadine.

Surgical intervention for difficult cases ^3,10

For patients who are completely refractory to all known medical therapy and continue to experience repeated attacks of pain chronically, a number of aggressive procedures can be attempted. These include percutaneous glycerol injections into the trigeminal cistern, trigeminal sensory rhizotomy, percutaneous radiofrequency trigeminal rhizotomy, superficial petrosal neurectomy, trigeminal branch avulsion and decompression of the nervus intermedius.

CONCLUSION

Pain is a subjective and multidimensional experience consisting of physiological, physical, sensory, affective, cognitive, behavioural and socio-cultural components. For any form of headache or facial pain, pain assessment is important in formulating a correct diagnosis. Good pain assessment itself will give a clue to diagnosis of cluster headache since laboratory and imaging studies are of not much help other than to rule out other differential diagnoses. A greater understanding of cluster headache among primary care physicians, ear/nose/throat specialists, ophthalmologists, psychiatrists and dentists could improve better recognition and treatment of this debilitating disorder.

REFERENCES

1. Vast majority of cluster headache patients are initially misdiagnosed. Dutch Researchers Report. World Headache Alliance. Article 2003-08-21. Available from: http://www.w-h-a.org/
2. Headache Classification Committee of the International Headache Society. The International Classification of Headache Disorders, 2nd ed. Cephalalgia. 2004;24(Suppl 1):1–160
3. Headache, Cluster-In-Depth Report-New York Times Health. Available from: www.nytimes.com
4. Lori K Sargeant, Michelle Blanda. eMedicine Emergency Medicine. Headache, cluster. Available from: http://emedicine.medscape.com/article/792150-overview
5. McKinney AS. Cluster headache developing following ipsilateral orbital exenteration. Headache. 1983;23(6):305-6 [PubMed]
6. Beck E, Sieber WJ, Trejo R. Management of cluster headache. Am Fam Physician. 2005;71(4):717-24 [PubMed] [Full text]
7. World wide cluster headache support group. Medical information about cluster headaches. Available from: www.clusterheadache.com/about.html
8. Headache - Hope through research; NINDS - WrongDiagnosis.com. Available from: http://www.wrongdiagnosis.com/artic/headache_hope_through_research_ninds.htm
9. May A. Cluster headache: pathogenesis, diagnosis, and management. Lancet. 2005;366(9488):843-55 [PubMed]
10. A Maya, M Leoneb, J Afra, et al. EFNS guidelines on the treatment of cluster headache and other trigeminalautonomic cephalalgias. Eur J Neurol. 2006;13(10):1066-77 [PubMed]