Post dural puncture headache

Post dural puncture headache (PDPH), or "low Cerebralspinal Fluid (CSF) pressure headache" is a complication of spinal anesthesia, diagnostic spinal puncture, or epidural anesthesia. It can sometimes also happen as a result of a severe physical trauma involving the spine, or can come about with no immediate cause discernable.

PDPH also can sometimes occur hours to days after a lumbar puncture (spinal tap) and presents with symptoms such as headache and nausea that typically worsen when the patient assumes an upright posture. It is thought to result from a leakage of cerebrospinal fluid into the epidural space. A decreased hydrostatic pressure in the subarachnoid space then leads to traction to the meninges with associated symptoms. The incidence of PDPH is higher with younger patients, complicated or repeated puncture, and use of large diameter needles. Modern, atraumatic needles such as the Sprotte spinal needle leave a smaller perforation and reduce the risk for PDPH.

Some patients require no other treatment than analgesics and bed rest. However, persistent and severe PDPH may require an "epidural blood patch". A small amount of the patient's blood is injected into the epidural space near the site of the original puncture; the resulting blood clot then "patches" the meningeal leak. The procedure carries the typical risks of any epidural puncture but is highly effective, and further intervention is rarely necessary.

The main indication of a low pressure headache is headaches and nausea that occur when the patient is upright and go away soon after laying down

Low CSF Headache

What is Low CSF Pressure Headache?Low CSF Pressure Headache is caused by an internal spinal fluid leak and may range from obvious and disabling to subtle and nagging. The brain normally sits inside a “bag” filled with spinal fluid which extends down from the skull into the spine. The “bag” consists of membranes called the meninges (as in meningitis). The fluid helps to circulate waste products out of the brain and provides cushioning and support. When the pressure of this fluid is too low – typically when there is a small leak somewhere in the meninges – the brain may “sag” downward when the patient is upright, stretching the meninges and nerves lining the brain and causing pain.

What are the symptoms of low pressure headaches?The classic symptom is a headache that becomes severe when the patient is upright and quickly disappears when the patient is lying flat. Thus, the headaches are typically absent first thing in the morning, and start or worsen shortly after getting out of bed. The pain is often worse at the back of the head, and may be accompanied by some neck discomfort and nausea. Rarely there are more serious neurological symptoms caused by stretching nerves or the downward displacement of the brain.

What causes low pressure headaches?In most cases, there is an obvious cause of the leak, such as a spinal tap, spinal surgery, or trauma to the head or neck. Cases where postural headaches develop shortly after an obvious potential cause, diagnosis is usually easy to make. Subtle cases can be trickier to diagnose. There may be no obvious precipitating event, or perhaps the leak was caused by a sneeze, a violent cough, or some other unrecognized minor trauma. Some patients – particularly those with hyper-flexibility of the joints – may be born with meninges that are more susceptible to tearing with relatively small degrees of force.

How are low pressure headaches diagnosed?The condition may be frustrating to diagnose even when strongly suspected, particularly in the less dramatic cases.

Brain MRI with injected contrast dye may reveal "enhancement" of the meninges lining of the brain and sometimes indicate evidence of the brain “sagging” downward from the skull toward the neck. MRI of the neck and back occasionally reveals spinal fluid leaking out of its normal location.

CT myelogram (a CT scan of the back after dye is injected into the spinal fluid) may reveal the site of the leak directly.

CSF cisternogram—a procedure where a radioactive dye is injected in the spinal fluid and detected by a special radiation-detecting camera—may reveal the leak directly, or may only show indirect evidence of the leak’s presence but not its exact location.

Lumbar puncture (spinal tap) may reveal lower than normal spinal fluid pressure, and might potentially increase the severity of the symptoms temporarily. there is about 150mls of CSF, but 600mls is formed each day, so it is continually being absorbed

How are low pressure headaches treated?Treatment usually begins conservatively – with strict bed rest, increased fluid intake, and caffeine (either in drink form or by pill). If this cautious approach fails to result in closure of the hole, an Epidural Blood Patch may be performed. In this procedure, a syringe of the patient’s own blood is removed from a vein and injected into the spine, either at the exact site of the leak or at a safe location in the low back. Often a blood patch results in rapid plugging of the hole and near immediate relief of symptoms. This procedure may need to be repeated a few times to be successful.

If the exact site of the leak is known, an interventional radiologist can sometimes “glue” the hole using a needle under x-ray guidance. Sometimes a neurosurgeon is needed to repair larger tears found in the spine, or a neurosurgeon or otolaryngologist (ENT) is needed to fix leaks inside the skull.