This chapter provides an overview of a conceptual approach to providing care for the patient with medication-resistant epilepsy (MRE), with consideration of the care sequence and components. This discussion of the gestalt is not intended to provide one established algorithm, as one treatment pathway cannot serve the needs of the diverse MRE patient population. Nevertheless, the considerations described below comprise a generally accepted care process aimed to improve the MRE clinical outcome. Detailed discussions of the care elements are provided in other chapters.

The vagus nerve performs many different functions in the human body. Understanding these functions helps inform the potential side effects of vagus nerve stimulation (VNS). The nerve consists of 80% afferent fibres [1,2]. These include visceral sensory and taste fibres which travel primarily to the nucleus of the tractus solitarius, as well as cutaneous sensation fibres from the external auditory meatus which project to the spinal nucleus of the trigeminal nerve. The efferent component includes branchial motor fibres from the nucleus ambiguus, parasympathetic fibres primarily from the dorsal nucleus of the vagus and parasympathetic fibres from the nucleus ambiguus to the heart. The motor fibres innervate skeletal muscles in the head and neck involved in speech production and swallowing, while the parasympathetic fibres innervate most of the viscera serving to control heart rate, respiration, gastrointestinal motility and many other autonomic functions. The majority of fibres in the vagus nerve consist of unmyelinated C fibres, but commensurate with its wide variety of functions, it also contains larger and faster-conducting A- and B-type fibres. The brainstem nuclei that receive vagal inputs integrate homeostatic information, provide commensurate adjustments to autonomic functions and also send this information to other brainstem nuclei projecting widely throughout the brain.

Introduction

Cervical cancer and pre-cancer form a disease continuum ranging from cervical intraepithelial neoplasia (CIN) through microinvasion to invasive carcinoma; about 70% of the tumours are squamous and 30% are adeno- and adenosquamous carcinomas (Buckley & Fox, 1989). Most tumours are thought to develop from an area of intraepithelial neoplasia within the transformation zone (Coppelston & Reid, 1967). Cervical cancer is estimated to be the second most common female cancer with approximately 500 000 new cases per annum worldwide (Parkin, Laara & Muir, 1980). Sexually transmitted infections are recognized as one of the major risk factors and the active agents are thought to be specific types of human papillomavirus (HPV) (Munoz et al., 1992).

Papillomaviruses are small DNA viruses associated with benign and malignant proliferative lesions of cutaneous epithelium. Over 60 different types of papillomavirus have been described and they can be segregated into groups distinguished by DNA sequence homology and the specific lesions with which they are associated (de Villiers, 1989). HPV 6 and 11 are found most commonly in cervical condyloma, benign lesions that tend to regress spontaneously, and low-grade CIN. HPV 16 and 18 are the types most commonly associated with high-grade CIN lesions and invasive carcinoma of the cervix. The viruses will replicate only in specific differentiation stages of epithelia, which limits the use of in vitro culture methods for producing HPV. To circumvent this, molecular biological techniques have been utilized extensively to characterize HPV.