Abstract
Introduction
Orthostatic headache has been well known in low cerebrospinal fluid pressure syndrome (lower than 6 mmH2O) that is secondary to spinal tapping, trauma, spinal surgery, dehydration, diabetic coma, uraemia, infection, pseudo Arnold-Chiari type I malformation, sexual intercourse or ventricular shunt (1–3). In a few reports intracranial mass such as cerebellar haemorrhage or brain tumour was also noted as a cause of orthostatic headache (4, 5). However, individual patients with brain tumour accompanying orthostatic headache were not described precisely.
We present a patient with skull base tumour suffering from orthostatic headache that rapidly improved after excisional biopsy.
Case report
A 45-year-old woman was admitted to our hospital presenting with orthostatic headache and dysarthria that were accentuated in an upright position. Two years earlier she developed intermittent unilateral throbbing headache easily relieved by NSAIDs or sleep. Ten months prior to admission she began to experience mild difficulties in tongue movement and sometimes in articulation. Three months later she was admitted to a local hospital because of severe left-sided squeezing headache that was provoked within 3 min after sitting or standing and subsided immediately by lying down. Objective dysarthria or tongue atrophy was not found at that time. Brain MRI and conventional cerebral angiography were interpreted as normal. Spinal tapping was performed twice with a normal cerebrospinal fluid (CSF) pressure of 70 mmH2O. Radionuclide cisternography did not reveal any CSF leakage. Despite no evidence of intracranial hypotension being found after extensive investigation, blind blood patch through the lumbar area was tried because the headache did not respond to any medication. However, the headache became progressively worse.
One month before admission to our hospital, the headache extended to the whole head. Moderate to severe headache and dysarthria occurred in any position, while the symptoms were lessened when she lay down. She could not maintain usual daily activities. She had to keep her head flat all day long. On admission her tongue showed asymmetrical left-sided atrophy and was deviated to the left side. She was unable to protrude her tongue fully. Facial motor, facial sensation, hearing and swallowing were normal.
Follow-up brain MRI showed a large skull base tumour (Fig. 1). The mass showed heterogenous signal in T2-weighted images and low signal in T1-weighted images. The post-gadolinium MRI showed strong homogenous enhancement of the mass without dural enhancement. The tumour was located in the clivus and bulged out around the hypoglossal canal. No abnormal signal was detected in the brain parenchyma. After retrospective reviewing of previous MRI that was performed at another hospital, we found a small skull base tumour in the same area.
A skull base tumour on brain magnetic resonance images. The mass shows low signal in T1-weighted image. The tumour is located in the clivus and bulged out around the hypoglossal canal. The post-gadolinium injection T1-weighted image shows strong homogenous enhancement pattern of the tumour without dural or parenchymal enhancement.
The patient underwent excisional biopsy. Pathological examination, including immunohistochemistry, suggested a possible diagnosis of fibrous histiocytoma or pseudotumour. On the following day the orthostatic headache and dysarthria improved dramatically. She could maintain an upright posture for longer periods. No headache symptoms continued when she lay down.
Comments
A few patients with skull base metastasis or pseudotumour presenting with unilateral headache and ipsilateral tongue paralysis have been reported as ‘occipital condyle syndrome’ (6, 7). However, the orthostatic nature of aggravation of headache and dysarthria was not mentioned in these cases.
Three mechanisms of orthostatic headache have been suggested: traction on pain-sensitive structures, especially cranial nerves V, IX and X and the upper three cervical nerves (5, 8); venous vasodilation as a result of secondary increase in blood volume after loss of CSF volume (9); and an activation of adenosine receptors secondary to a sudden decrease in CSF volume (10).
Our patient had a skull base tumour with normal intracranial pressure and no evidence of CSF leakage. In this situation traction and displacement of pain-sensitive structures of the cranium seemed to be a possible mechanism of orthostatic headache. The traction caused by ‘sagging’ of the brain due to lower buoyancy after CSF loss results in low-CSF syndrome in the upright position. In contrast, the cause of traction in our patient may be ‘mass effect’ resulting in compression of pain-sensitive structures and hypoglossal nerve. This hypothesis is supported by rapid improvement of symptoms after mass reduction by excisional biopsy.