A PDPH is a debilitating postural headache following therapeutic or diagnostic interventions of the epidural or spinal (intrathecal) space
In all cases of suspected PDPH, other causes of headache must be excluded
Patient factors
Young age
Female gender
Low BMI
Dehydration
Pregnant
Previous PDPH
Procedural factors
Diagnostic lumbar puncture: incidence 30-50%
Epidural anaesthesia
The incidence of dural puncture is 0 - 2.6% (1 in 50)
The risk of developing PDPH after accidental dural puncture occurs is 70 - 80%
The risk is inversely proportional to the experience of the anaesthetist i.e. more common with junior anaesthetist
Loss of resistance to air may increase risk, as use of air can cause pneumocephalus
Spinal anaesthesia
Incidence of PDPH 0 - 5% (1 in 500)
Incidence increased by:
Cutting needle e.g. Quincke
Larger needle i.e. <25G
Multiple attempts e.g. 'pepper-potting' the dura
Large volume CSF escape
No use of intrathecal catheter
Reduced incidence with pencil-point needle e.g. Sprotte, Whitacre or smaller needle >25G
Dural puncture is intentional in spinal anaesthesia and lumbar puncture, and a recognised complication of epidural placement
CSF leaks from the dural tear, causing a fall in ICP and sagging of the brain in the skull vault
This causes downwards traction on pain-sensitive structures e.g. meninges, intra-cranial nerves, blood vessels
Fall in ICP may cause compensatory venodilation, contributing to headache
Headache
90% develop a severe headache within 72hrs of dural puncture
Fronto-occipital headache that may radiate into the neck and shoulders
Frontal headache via ophthalmic branch of trigeminal nerve
Occipital headache via glossopharyngeal and vagus nerves
Typically worse sitting or standing, better lying down
Pressure over the abdomen with the woman in the upright position may give transient relief to the headache by raising intracranial pressure secondary to a rise in intrabdominal pressure (Gutsche sign)
Associated features
Symptom
Notes
Meningism
Vomiting, neck stiffness and photophobia Due to C1-3 nerve root irritation
Diplopia and visual symptoms
Effect on CN III, IV and VI of which abducens (VI) most sensitive to lower CSF volume
Vertigo, tinnitus and hearing loss
From interaction between perilymph and CSF
Scalp paraesthesia
Limb paraesthesia
Cranial nerve palsy
Investigations
Neuro-imaging is indicated when:
The headache is atypical
The headache changes in nature
There are associated neurological signs
There is reduced GCS
>2 EBP's have been unsuccessful
Vascular
PET
Migraine
Central venous sinus thrombosis
Subdural or subarachnoid haemorrhage
PRES
Infectious e.g. meningitis (septic or aseptic)
Neoplastic e.g. space-occupying lesion
Metabolic
Caffeine withdrawal
Dehydration
Other
Tension headache
Lactation headache
Idiopathic intracranial hypertension
Pneumocephalus
Accidental dural puncture during epidural insertion is evidenced by:
Brisk CSF leak from the Tuohy needle
Said fluid is warm (saline used in LOR will be room temperature)
If unsure one could dipstick the fluid:
Factor
CSF
Saline
pH
7.5 - 8.5
5.5
Protein
+ or ++
None
Glucose
Trace or +
None
If a dural tap occurs one is left with two options:
Remove needle and re-site at a different interspace
One should beware intrathecal spread of infused LA
Anaesthetist-only top-ups
If headache develops during labour then consider assisted delivery as excessive straining may cause increased CSF leak
Thread the epidural catheter into the intrathecal space
Intrathecal catheter
Advantages of threading the epidural catheter into the intrathecal space include:
Provides excellent analgesia
Reduces risk of further dural puncture
Reduces risk of PDPH, putatively by fibroblast proliferation around the catheter entry site
Disadvantages include:
Labour intensive for anaesthetist as must deliver all top up doses onself
Risk of high spinal
Risk of infection
If this method is used, then:
Leave at most 3cm in the intrathecal space to reduce risk of neurological damage
Clearly label as a spinal catheter
Anaesthetist-only top-ups
Cautious (1 - 2ml bag mix) top ups every 2 - 4hrs
Inform senior anaesthetist, midwife and woman of the events
Document in notes, incident form etc.
Arrange daily follow up for the patient by a (senior) anaesthetist
Provide written information e.g. local or OAA leaflet
Offer follow-up after discharge to ensure no ongoing complications
Most PDPH's resolve spontaneously by 10 days, but up to 10% still present at 1 month
Conservative treatment
Bed rest
Avoid raising ICP e.g. regular laxatives, avoid straining/lifting
Avoid dehydration (although the historical recommendation of IV fluid administration is not thought to be of benefit)