Spinal headache — prevention and treatment

0 Department of Anaesthesia, Royal Victoria Hospital , Montreal , Quebec fronto-occipital radiating to the neck and shoulders. Neck stiffness may be present. Other symptoms may include nausea, vomiting, diplopia and other visual disturbances, tinnitus and deafness. Abducen's palsy is occasionally present. Differential diagnosis Stein et al. 4 found that headache unrelated to anaesthesia is quite common (39 per cent) during the first p o s t p a r t u m week. Rarely, headache may be caused by brain tumours, intracranial haemorrhage or vascular malformations. - History The German surgeon, August Bier, published a paper in 1899 entitled "Researches on Cocainisation of the Spinal Cord." During the course of these pioneering studies on spinal anaesthesia he submitted himself to lumbar puncture and later developed a spinal headache. Bier described disappearance of symptoms in the supine position with aggravation in the upright position and postulated that the headache was caused by loss of spinal fluid. Aetiology The main source of CSF secretion is the choroid plexus but there is also evidence of extrachoroidal formation. The average rate of fluid production is 0.35 ml-min -t (500 ml. day-i). The total CSF volume is approximately 150 ml of which half is within the cranial cavity. Lumbar CSF pres.ure normally increases from 5-15 cm H20 when horizontal to over 40 cm H20 in the sitting position. Most studies of patients with spinal headache confirm that loss of spinal fluid through a dural rent leads to low CSF pressure. This is thought to lead to sagging of the brain in the upright position with traction on pain-sensitive structures within the cranium thus producing headache. Reflex cerebral vasodilatation may also cause pain. Support for this theory was obtained by Kunkle et al. who showed that removal of 20 ml of CSF in volunteers reliably produced an immediate headache which could be promptly relieved by subarachnoid injection of saline. Ahearn 2 subsequently used subarachnoid injection of saline to treat spinal headache in clinical practice. Although he caused a second dural puncture, this treatment was often permanently successful. Further evidence that CSF leak is the major aetiological factor is gained from the association of needle size with headache incidence, and from the therapeutic effect of blood patch. Some believe spinal headache to be influenced by psychological factors. Kaplan 3 studied headache following lumbar puncture or sham lumbar puncture in healthy volunteers and found the incidence to be the same in both groups. Symptoms Bier described a classical spinal headache, aggravated in the upright position and relieved supine, and unless these postural differences are present the diagnosis must be questioned. Pain, which may be severe, is typically Duration Crawford5 states that spinal headache following dural puncture with an 18-gauge needle in obstetrical patients usually lasts for six days. Vandam and Dripps6 reported that after spinal anaesthsesia in an obstetric and surgical population, 28 per cent of patients complained of headache for longer than one week. There are occasional reports of spinal headache lasting for many months, even years. Incidence Headache is more common in women than men and is higher in the obstetrical population than in any other group. In Vandam's study of spinal anaesthesia, the overall incidence of headache was seven per cent in men and 14 per cent in women, but 22 per cent in women having anaesthesia for vaginal delivery. The incidence of spinal headache decreases with increasing age and is quite uncommon above 60 years. The reported incidence of spinal headache in obstetrical patients using a 25- or 26gauge needle varies enormously, e.g., 0.4 per cent (Greene), 7 28 per cent (Thornberry and Thomas). s Little is known of the incidence of spinal headache in the paediatric population. Bolder, 9 in a study of paediatric oncology patients, found headache to be rare under 13 years of age and common in older children. Benzon et al. io studied spinal headache following dural puncture in the treatment of chronic pain and found the incidence to be similar to that in a general surgical population. Dural puncture with a needle 18 gauge or larger predictably leads to a headache incidence of 7 0 - 8 0 per cent. The reason for the particular post partum susceptibility to spinal headache is unclear. Contribution factors may be relative dehydration, bearing down with contractions and hormonal changes. There is overwhelming evidence that headache incidence increases with larger needle size. Tourtelotte et al. i i in a randomized double-blind trial of 22- vs 26-gauge needles for dural puncture in healthy young volunteers discovered the incidence of headache to be 36 per cent (22 gauge) and 12 per cent (26 gauge). Psychological A patient who develops spinal headache may reveal a wide range of emotions from misery, tears, panic, anger and resentment, to aggression. The possibility of headache occurring should be discussed prior to anaesthesia but this seldom prepares the patient for feeling so uncomfortable. The obstetrical patient is particularly vulnerable since she expects to feel well and happy and to be able to look after her new baby. A thorough explanation of the reason for the headache, expected time-course and therapeutic options is essential and the patient must be seen regularly. Whenever possible, the spouse should also be included in these discussions. Breast feeding should be encouraged and moral support continued until symptoms have subsided. Posture If headache develops, the patient should lie in a comfortable horizontal position. Marx favours the lateral rather than the supine position which she feels reduces dural tension. The prone position is advocated by some but it is not a comfortable position for the post partum patient. In this position intra-abdominal pressure is raised and transmitted to the epidural space. Hydration Additional hydration in an attempt to restore CSF volume has been a time honoured therapy for spinal headache. However, there is little convincing evidence to suggest that hydration relieves headache. CSF production is thought to be constant over a wide range of physiological variables. Obviously it would not be wise to allow a woman, especially if lactating, to become dehydrated. Intravenous fluids are sometimes needed if the patient cannot tolerate oral fluids. Drugs A multiplicity of drugs - vasopressin, antihistamines, steroids, alcohol, etc., have been tried without proven effect. Simple oral analgesics are often effective in the treatment of mild to moderate pain. Caffeine was popular in the past in the treatment of spinal headache. Sechzer and Abel 12 have revived interest in the use of IV caffeine sodium benzoate. They found a singificant reduction in the incidence of headache in a double-blind trial of IV caffeine vs placebo. Caffeine is thought to exert its beneficial effect by cerebra (...truncated)