Postdural Puncture Headache

Etiology

The underlying cause of the PDPH is an intentional dural puncture performed during a lumbar puncture that is necessary for diagnostic myelography, the instillation of various therapeutic medications into lumbar subarachnoid space, or following the inadvertent dural puncture that results while administering epidural anesthesia or when medications are injected for spinal pain.[5] Other low-CSF pressure symptoms suggestive of intracranial hypotension can also develop spontaneously or following craniotomy, placement of intraventricular shunts for CSF diversion, brain/spinal trauma, or spinal surgery.[6][7][8]

Postdural Puncture Headache Risk Factors

Factors associated with a higher risk for PDPH include: 

• Dehydration
• Various systemic illnesses
• Use of a large caliber or cutting needle to access the CSF
• Female gender
• Pregnancy
• Younger age (20 to 40 years)
• Prior history of headaches
• Inexperienced proceduralist [1]

Additionally, PDPH is more common in patients with a low body mass index and those patients with prior headaches, especially after a prior PDPH. PDPH is uncommon in older adults, most likely due to the presence of cerebral atrophy. Other risk factors for PDPH include the caliber of the spinal needle and the use of a cutting needle, especially if, after insertion, the needle is rotated perpendicular to the long axis of the dural fibers. Using a small caliber pencil-tipped needle will decrease the risk of PDPH, as does the reinsertion of the stylet into the needle. The physician's experience in performing a lumbar puncture, the number of lumbar punctures performed, and the removal of large amounts of CSF fluid may or may not be related to the incidence of PDPH. The patient in a sitting or lateral decubitus position either during or after the lumbar puncture is unrelated to the development of a PDPH.[1]

Epidemiology

The reported incidence in the literature has been estimated to be quite variable but may result after approximately 10% to 40% of lumbar puncture procedures or may be as low as 2% when small gauge (≤24 gauge) noncutting spinal needles are used. Symptoms of PDPH typically occur within 48 to 72 hours of having the lumbar puncture but can be delayed for as long as months after the procedure.[9][10]

Pathophysiology

PDPH occurs when the CSF volume is low due to leakage from the dural puncture site that exceeds the normal rate of CSF production, resulting in intracranial hypotension. Traction on neural tissue precipitates symptoms from pain-sensitive structures, eg, the meninges, blood vessels, cranial nerves, and upper cervical nerves. Displacement of the brain downward when the patient is in the upright position contributes to orthostatic symptoms.

Magnetic resonance imaging (MRI) studies have demonstrated evidence of vascular dilation, eg, engorgement of the venous sinuses, enhancement of meninges, and enlargement of the pituitary gland, in an attempt to compensate for the diminished volume of the CSF. Physical maneuvers that increase intracranial venous volume, including coughing, laughing, the Valsalva maneuver, or internal jugular venous compression, are known to worsen headaches, suggesting that the compensatory central venous dilation associated with PDPH contributes to worsening symptoms.[11][12]

History and Physical

Clinical History

The symptoms of PDPH include bilateral frontal or occipital headaches that are worse when the patient is in the upright position and will improve when the patient is supine. Other associated clinical symptoms include nausea, dizziness, neck pain, visual changes, and occasionally tinnitus, hearing loss, or radicular symptoms that radiate into the arms. Symptoms, primarily headache, may worsen with coughing or the Valsalva maneuver, even when the patient is in a supine position.[1]

Physical Examination

The physical examination in patients with PDPH is usually unremarkable; typically, the patient should not have a fever or demonstrate meningismus, altered mentation, or focal neurologic findings. In atypical cases, focal neurological findings might include nystagmus, horizontal diplopia, and facial numbness or weakness. Involvement of the abducens nerve (cranial nerve VI) is uncommon but may result in diplopia on neurological examination. Firm continuous pressure in the abdomen may temporarily improve the headache associated with PDPH by indirectly increasing the CSF pressure in the intrathecal space. In contrast, direct physical pressure on the jugular vein can worsen the PDPH. 

Evaluation

The diagnosis of PDPH is made on clinical examination, and laboratory or imaging studies are usually unnecessary. However, in patients with severe and persistent symptoms, particularly those where positional changes of the patient have no effect, neuroimaging is indicated. Furthermore, patients with atypical symptoms, eg, focal neurological deficits, visual changes, alterations in consciousness, or seizures, to neuroimaging is indicated to exclude differential diagnoses, including the presence of a subdural hematoma or cerebral or venous thrombosis.[1]

Lumbar puncture in patients suspected of having PDPH is discouraged because a second dural puncture site may actually worsen the symptoms. In cases where a second lumbar puncture has been performed, the CSF pressure will often demonstrate a low to even negative opening pressure. The CSF indices where a second lumbar puncture has been performed may reveal the presence of white and red blood cells, an elevated protein level, or xanthochromia.

In those patients with long-standing PDPH or intracranial hypotension, an MRI with intravenous gadolinium administration may demonstrate descent of the cerebellar tonsils below the foramen magnum, effacement of the basilar cisterns, thickening of the meninges, subdural fluid accumulation, venous sinus engorgement, and an enlarged pituitary gland. These changes are reversible with appropriate treatment. Effacement of the basilar cisterns can also be visualized on computerized tomography (CT) imaging of the brain and could be confused with subarachnoid hemorrhage. CT myelography or spine MRI may reveal the location and extent of the CSF leak.[13][14]

Treatment / Management

Conservative Management

The initial management of PDPH symptoms involves administering analgesics, oral or intravenous hydration, and avoiding having the patient in the upright position. This approach is often effective. In over two-thirds of patients, PDPH symptoms can resolve spontaneously within 1 to 2 weeks. However, therapeutic intervention is required when severe symptoms are persistent.

Some evidence has demonstrated that oral caffeine (300 mg once or twice) or intravenous caffeine (300 mg to 500 mg in 1 L of intravenous fluid over 1 hour) for 24 hours is effective for treating PDPH. Although the beneficial effects for the patient may be transient, some report high failure rates and recurrent symptoms. Specific treatment of the dural leak may not be required in all cases because some patients experience spontaneous resolution that typically occurs within days to weeks. However, prolonged symptoms have been reported when treatment is not administered.

Invasive Management Approaches

Epidural blood patch

In 1960, Dr. James Gorley, a surgeon from Pennsylvania, described instilling blood in the epidural space to patch the hole in the dura. He placed small volumes of blood adjacent to the dura to treat PDPH with very good results. This technique later became the rationale for performing the epidural blood patch.

Definitive treatment by administering an epidural blood patch is usually recommended when symptoms persist after conservative treatment has failed.[15] For postpartum mothers recovering from childbirth and with the responsibility of caring for their newborn, having a persistent PDPH can be quite disabling. Therefore, many clinicians in this situation will administer an epidural blood patch early after delivery. For this procedure, 10 mL to 30 mL of autologous venous blood is injected by an anesthesiologist into the epidural space at the spinal level where the catheter was previously placed to administer anesthesia during the delivery. This procedure is thought to create a "patch" over the dural puncture to decrease or prevent CSF leakage while increasing the intracranial pressure. Success rates are >75% to 90%, particularly if repeated, but can occasionally result in back pain, meningeal irritation, radiculopathy, bulbar neuropathy, meningeal infection, hematoma formation, or cauda equina syndrome.

Alternative invasive therapies

A 2- to 3-day continuous epidural saline infusion may be less effective and have fewer adverse effects than a blood patch, but it requires that the indwelling epidural catheter remains in place and the patient stays on bed rest during the hospitalization. This practice is rarely followed.

Multiple experimental treatments have been recommended that include administering oral or parenteral steroids, intramuscular adrenocorticotrophic hormone (ACTH) injection, oral gabapentin, methylxanthines such as intravenous aminophylline (5 mg/kg to 6 mg/kg over 20 min) or oral theophylline (300 mg every 6 to 8 hours) which decrease central venous blood volume, or triptan administration using sumatriptan which acts through vasoconstriction. Several cases have reported the successful use of a localized injection of cyanoacrylate adhesive or fibrin glue for refractory cases. Due to the high success rates and low complication rates of the epidural blood patch, it remains the primary therapy for PDPH.[16][17][18]

In some studies, frovatriptan use for 5 days before performing lumbar puncture seems to reduce the incidence of postlumbar puncture headaches. Sumatriptan did not demonstrate benefit when used for just 1 day before the lumbar puncture.

Differential Diagnosis

Several other disease conditions can result in a headache that can mimic the headache associated with PDPH. These conditions can include caffeine withdrawal, intracranial pathology, meningitis, migraines, pneumocephalus, and sinus-related preeclampsia. Each of these conditions is distinct and can easily be evaluated by clinical examination. Caffeine withdrawal can be determined by taking a careful medical history regarding coffee or energy drink consumption. The presence of intracranial pathology can be effectively evaluated by either CT or MR imaging. Meningitis manifests on a clinical exam demonstrating meningismus, typically with a clinical history consistent with meningitis. Migraine headaches are often familial and have a characteristic clinical prodrome. Pneumocephalus is most commonly associated with cranial trauma or with the recent performance of neurosurgery. Sinus-related preeclampsia requires the presence of pregnancy to occur.

Prognosis

The prognosis for PDPH is generally excellent, with the majority of cases resolving with bed rest, analgesics, and hydration.[19] More refractory cases of PDPH can be effectively treated with an epidural blood patch. Surgical exploration with a direct dural repair is exceedingly rare. 

Complications

Rarely, prolonged or severe cases of PDPH can result in cerebral venous thrombosis, subdural hematoma from traction and rupture of dural veins, seizures, hypopituitarism, syringomyelia, cerebral herniation, coma, and death. Chronic headache, backache, and cranial nerve dysfunction are complications that have also been associated with PDPH.[1]