Drug induced
Zimelidine, an antidepressant, had a very favorable safety profile but as a result of rare case reports of Guillain–Barré syndrome was withdrawn from the market. Mechanism
The nerve dysfunction in Guillain–Barré syndrome is caused by an immune attack on the nerve cells of the peripheral nervous system and their support structures. The nerve cells have their body (the soma) in the spinal cord and a long projection (the axon) that carries electrical nerve impulses to the neuromuscular junction, where the impulse is transferred to the muscle. Axons are wrapped in a sheath of Schwann cells that contain myelin. Between Schwann cells are gaps (nodes of Ranvier) where the axon is exposed. Different types of Guillain–Barré syndrome feature different types of immune attack. The demyelinating variant (AIDP, see below) features damage to the myelin sheath by white blood cells (T lymphocytes and macrophages); this process is preceded by activation of a group of blood proteins known as complement. In contrast, the axonal variant is mediated by IgG antibodies and complement against the cell membrane covering the axon without direct lymphocyte involvement.Various antibodies directed at nerve cells have been reported in Guillain–Barré syndrome. In the axonal subtype, these antibodies have been shown to bind to gangliosides, a group of substances found in peripheral nerves. A ganglioside is a molecule consisting of ceramide bound to a small group of hexose-type sugars and containing various numbers of N-acetylneuraminic acid groups.
Post-dural-puncture headache (PDPH) is a complication of puncture of the dura mater (one of the membranes around the brain and spinal cord). The headache is severe and described as "searing and spreading like hot metal", involving the back and front of the head and spreading to the neck and shoulders, sometimes involving neck stiffness. It is exacerbated by movement and sitting or standing and is relieved to some degree by lying down. Nausea, vomiting, pain in arms and legs, hearing loss, tinnitus, vertigo, dizziness and paraesthesia of the scalp are also common.PDPH is a common side effect of lumbar puncture and spinal anesthesia. Leakage of cerebrospinal fluid causes reduced fluid levels in the brain and spinal cord. Onset occurs within two days in 66% of cases and three days in 90%. It occurs so rarely immediately after puncture that other possible causes should be investigated when it does.Using a pencil point needle rather than a cutting spinal needle decreases the risk. The size of the pencil point needle does not appear to make a difference. PDPH is estimated to occur in between 0.1% and 36% people following dural puncture. Signs and symptoms
PDPH typically occurs hours to days after puncture and presents with symptoms such as headache (which is mostly bi-frontal or occipital) and nausea that typically worsen when the patient assumes an upright posture. The headache usually occurs 24–48 hours after puncture but may occur as many as 12 days after.