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Raised Intercranial Pressure

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Another type of headache, which occurs fairly commonly in arachnoiditis, is an occipital (back of the head) one radiating forward to behind the eyes, with possible feeling of pressure around the temple:  onset is usually after exertion, valsalva manoeuvre (bearing down to open the bowels, for example) or bending forward.

These seem like those due to raised intracranial pressure and are also similar to those seen in Chiari malformation Type 1. (CM-1)

*Neurosurgeon Michael Rosner in USA suggests that Chiari malformation may be seen in Chronic Fatigue (CFIDS) and Fibromyalgia (FMS), both of which are quite often diagnosed in arachnoiditis patients.

A recent study in USA ([i]) has linked Chiari with FMS: of 364 patients with Chiari, nearly 60% had a prior diagnosis of Fibromyalgia, 12% of CFS, 31% migraine/sinus headache, 9% MS and 63% psychiatric/malingering.

Features of Chiari include: occipital headache radiating behind eyes* (exacerbated by exertion, especially leaning the head backward or coughing; may be brief or longer-lasting); disordered eye movements, vision changes; dizziness, autonomic symptoms such as postural hypotension i.e. dizziness on standing up; muscle weakness; unsteady gait; cold, numbness and paraesthesiae (tingling) in extremities; chronic fatigue; tinnitus; sleep apnoea; hearing loss; Irritable Bowel Syndrome (IBS); frequent urination; difficulty swallowing.

As we have seen from the survey results, many of these symptoms are seen in arachnoiditis.

However, it must be noted that the majority are non-specific symptoms so do not necessarily imply that Chiari malformation is the cause: it is one of a list of possible causes.  (* headache occurs in about 50% of Chiari cases and the brief type tend to be caused by transient herniation of the base of the brain, part of the brain stem called the tonsils down through the hole at the base of the skull into the spinal canal)

A further possibility is intermittent raised intracranial pressure similar to that seen in a condition called pseudotumour cerebri or benign intracranial hypertension (BIH).

In this condition, there may be severe, frequent headaches, which are worst in the morning (and may indeed waken the patient), visual disturbances (transient blurring or loss of part of the visual field) and sometimes a pulsatile tinnitus (pulsing sound in the ears).

This has not been proven as such in arachnoiditis, but there is a known association between arachnoiditis and a condition called hydrocephalus which leads to enlarged ventricles in the brain due to raised pressure of the CSF; another similar condition affects the spinal part of the CSF: syringomyelia.

It may well be that the scar tissue of arachnoiditis impairs normal CSF circulation and this affects the pressure gradient in what is a closed system.

Meningism: not quite the same thing as meningitis: it means irritated meninges: which we have chronically, especially if we have chemically-induced arachnoiditis, in particular from pantopaque or depo-medrol which are oil-based and tend to hang around in irritative droplets.

There may be a diffuse, constant low-grade headache and stiffness in the neck, with possible discomfort from bright light. There may be flare-ups, which cause more severe symptoms.


[i] Milhorat TH, Chou MW, Trinidad EM, Kula RW, Mandell M, Wolpert C, Speer MC Neurosurgery 1999 May; 44(5): 1005-17 Chiari I malformation redefined: clinical and radiographic findings for 364 symptomatic patients.