New approach to treat an old problem: Mannitol for post dural puncture headache!

Sir,

Post-dural puncture headache (PDPH) is as old as spinal anaesthesia and was described by Bier during his initial attempts to produce the cessation of impulses from lower half of the body.[1] As with time, the technique was refined, the needles got smaller, the needles got different shapes and this led to the incidence being reduced drastically. Also with the development of anaesthesiology as a speciality, PDPH was recognised as an entity and management protocols were developed to prevent and manage it specifically. PDPH is less prevalent than before because of various reasons, primarily due to finer needles and better techniques.[2] Obstetric patients undergoing caesarean sections under spinal anaesthesia are the most common subgroup to experience PDPH, and it is usually devastating for them, particularly after a trying surgical period and therefore they are usually unable to enjoy motherhood (especially primi-gravida).[3,4,5] I have had the opportunity to learn from Bishop Conrad Memorial Hospital (Khairabad, Uttar Pradesh) a novel approach to tackle this age old problem. The staff used mannitol infusions to treat PDPH successfully for years with much success. If post-operative patient complains of headache that is characteristic of PDPH, 20% mannitol (100 ml) is given over ½ h intravenously and followed by 100 ml on a 12 hourly basis. The first dose of mannitol usually settles the PDPH over 6–8 h and no analgesics are required thereafter. Intravenous fluids are given to the patient as per normal body requirement, and input/output chart is maintained. Frequent assessment is done and after 48 h it is unusual to need mannitol infusions. I had adopted this practice while I was employed there and continue to do so. I also extend this to patients who have had a dural puncture on attempting epidural technique with a Tuohy needle, to preempt the PDPH that develops in them. In another case, mannitol infusion was successfully used by the author to treat a patient who developed unilateral facial nerve palsy after caesarean section under spinal anaesthesia, 4 days after discharge. At the time of readmission, unilateral facial palsy was well established, and patient was greatly stressed. After institution of mannitol therapy, it vanished by the 3^rd day, and she was discharged with no neurological deficit. The postulation and possibly the reason for improvement in the PDPH status is mannitol draws fluid from inside the neurons and glia, by osmotic diuresis, thereby the actual effective weight of the brain is reduced and it “refloats” in an improved cerebrospinal fluid volume. This relieves the pressure or traction on the meninges and vessels at the base of the brain that causes PDPH and thus mitigates it.[6] I have not found any side effects of mannitol therapy in patients who were given this therapy. Can this be the best non-invasive option to reduce PDPH in patients? This management method has not been described before in any scientific journal or text. Studies can be carried out to establish/refute this claim and to know the risks associated with this approach.