A 52-year-old woman presented to the clinic with headaches that began with a sore neck and progressed to the occipital region over a 4-week period. There were no associated symptoms of nausea, photophobia, or phonophobia. The patient felt relief upon lying down and the pain would begin again upon sitting or standing. The symptoms were initially constant but then started to subside to an intermittent basis. However, the pain then involved her whole head with occasional unilateral tinnitus. Over-the-counter non-steroidal anti-inflammatory drugs did not relieve her pain.
The patient had a history of infrequent migraines without aura that were very different from these symptoms. Neurologic and physical exam were normal including no tenderness to palpation of the head or cervical spine. Magnetic resonance imaging (MRI) of the brain performed with and without contrast demonstrated diffuse pachymeningeal enhancement (Fig. 1, long white arrow), low-lying cerebellar tonsils (Fig. 1, short white arrow), and an enlarged pituitary gland (Fig. 1, black arrow) shown here on T1 sequence with contrast.
Subsequently, she underwent cisternography and was found to have an opening pressure of 7-cm H2O, though the computerized tomography (CT) of the sinuses revealed no evidence of a cerebrospinal fluid leak. MRI of the cervical and thoracic spine revealed fluid in the epidural spaces of C1-2 and T1-9 levels (Figs. 2 and 3, respectively). A CT myelography demonstrated fluid but no identifiable source of the leak. After an epidural “blood patch” was performed on the patient in the upper lumbar region, there was immediate symptom relief.
Comment: Spontaneous intracranial hypotension (SIH) is a well-known entity that is often misdiagnosed, particularly in the emergency setting.1 A good history will reveal the typical postural changes of symptoms associated with low cerebrospinal fluid pressure. While MRI of the brain usually shows diffuse pachymeningitis and low-sitting cerebellar tonsils, the enlargement of the pituitary can be quite concerning and physicians will want to rule out adenoma. However, this phenomenon has been described in SIH after viewing MRIs prior to and after treatment, in that the pituitary returns to normal size within a short amount of time.2