Transcranial Doppler Role in Prediction of Post-dural Puncture Headache in Parturients Undergoing Elective Caesarean Section

PDPH is described as severe "searing and spreading like hot metal" distributed over the occipital and frontal areas radiating to the neck and shoulders. 90% of headache will occur within three days of the procedure, and 66% within the first 48 hours. The PDPH rarely develops between 5 and 14 days after the technique however it may immediately occur after dural puncture but it is rare and should pay attention of the physician to alternative causes. The pain is increased by head movement, upright posture and relieved by lying down. It resolves either spontaneously within 7 days or within 48 h after effective treatment which is usually consists of fluid therapy, analgesics, sumatriptan and caffeine. Epidural blood patch remained the gold standard therapy but it is an invasive technique.

The exact etiology of PDPH is unknown; there is two hypothesis attempts to explain the cause. First it's known that dural tear leads to cerebrospinal fluid (CSF) leak and decreased volume of CSF result in intracranial hypotension which cause on pain sensitive intracranial structures that become stretched when assuming upright position result in pain. Second, intracranial volume is constant and equal to the sum of intracranial blood, CSF, and brain matter. After loss of CSF a compensatory reflex vasodilatation occur in the same pain sensitive blood vessels and this result in pain.

The association of common risk factors like female gender, particularly females during pregnancy, age groups of 20 - 40 years, a prior history of chronic headache, and a lower body mass index expose the patient to PDPH. The identification of factors that predict the likelihood of PDPH is important so that measures can be taken to minimize this painful complication resulting from spinal anesthesia.

Transcranial Doppler ultrasound (TCD) is a portable, safe, noninvasive and real-time tool for assessing intracranial blood hemodynamics. The first description of the technique was by Rune Aaslid in early 20th century and it has gained increasing acceptance as an accurate diagnostic and therapeutic tool in both cerebrovascular disease and neurocritical care. TCD enables measurement of the blood flow velocity in intracranial arteries and several Studies have shown that its parameters are affected by both fluctuations in intracranial pressure and changes in cerebral vessel diameters. So, as PDPH may be resulted from significant changes in cerebral blood flow, it could be visualized by TCD.

The possibility of equipment mobilization, the opportunity of repeated bedside technique together with the noninvasive nature, makes TCD measurements attractive in the attempt to estimate CBF and offers potential application to predict and follow patients with PDPH.