Mohammed T. Abou-Saleh

Principles and Practice of Geriatric Psychiatry.Editors: Professor John R. M. Copeland, Dr Mohammed T. Abou-Saleh and Professor Dan G. BlazerCopyright & 2002 John Wiley & Sons LtdPrint ISBN 0-471-98197-4 Online ISBN 0-470-84641-061Peripheral Neuropathyand Peripheral Nerve LesionsJanice M. Massey and E. Wayne MasseyDuke University Medical Center, Durham, NC, USAPeripheral neuropathy is a diffuse process involving either sensorynerves, motor nerves or, more frequently, both. It is the mostcommon neurologic disease of the elderly. The known causes ofpolyneuropathy are numerous and are frequently associated withother systemic illness (Table 61.1). Many occur in patients withpsychiatric symptoms. Additionally, drugs must always beconsidered as possible etiologies.In addition to diffuse peripheral neuropathy, the pattern ofsingle peripheral nerve involvement is termed mononeuropathy.The causes include acute trauma or entrapment butoften are non-traumatic in origin, presumably representingeither chronic trauma or due to other factors, such asinfarction of the nerve (diabetes mellitus or collagen vasculardisease). Patients with many psychiatric diseases are moreprone to these problems, i.e. peroneal or ulnar pressure palsiesin depressed patients.POLYNEUROPATHYSymptoms of diffuse peripheral neuropathy include a ‘‘stockingglove’’ distribution of sensory loss usually involving thefeet and later the hands. With sensory involvement, patientscomplain of numbness and tingling or pain in the feet. Earlyon, the hands are rarely involved to any significant degree.On examination, varying degrees of decreased perception topain, temperature or vibratory sense and, less often, jointposition sense may be seen in the distal extremities,particularly in the feet. When this sensory loss is severe inthe lower extremities, there may be unsteadiness of gait,worse with the eyes closed.When the motor nerves are involved, distal muscles of the feetand hands may be weak. The patient may walk with a ‘‘foot drop’’or be unable to stand on tiptoe due to distal lower extremityweakness. Intrinsic hand muscle weakness produces decreasedhand grip. Reflexes are hypoactive, initially at the ankles, but maysubsequently be absent at the knees and even in the upperextremities. All symptoms and signs, including the reflexes, areusually symmetrical.The temporal profile of the symptoms may suggest possibleetiologies. Neuropathy of sudden onset is seen in inflammatoryor vasculitic disease, whereas patients with familial history andlong-standing neuropathy are more likely to have hereditarydisease.We will discuss only the most common diffuse neuropathies.Landry–Guillain–Barre´–Strohl Syndrome (AIDP)Immune polyradiculoneuropathy (polyradiculoneuropathy, Guillain–Barre´syndrome) may be preceded by a minor febrile illnessor following immunization. Symmetrical motor weakness, oftenbeginning in the legs and ascending, and areflexia with minimalsensory involvement, are the primary features. The cerebrospinalfluid (CSF) protein is usually increased and no cells are present.This relationship is termed cytoalbuminologic dissociation. Facialdiplegia without extra-ocular muscle or pupillary involvementmay occur. Respiratory weakness may develop rapidly. Theseverity of the illness ranges from minimal weakness to flaccidquadriparesis. Although usually idiopathic, known causes includeAIDS, rabies, cytomegalic and other viruses. Porphyria may causeneuropathy along with psychiatric symptoms.Quadriparesis may develop rapidly, requiring respiratorysupport within an hour. Usually the symptoms progress over 3–4 days, although occasionally it may take weeks to develop themaximum deficit. Spontaneous recovery, usually complete, occursover weeks or months as a rule. However, some patients haveserious residual deficits.Respiratory function may deteriorate rapidly, even withoutobvious respiratory distress. When Guillain–Barre´ syndrome issuspected, serial pulmonary functions should be performed. Whenthe forced vital capacity drops below 1–1.5 L, intubation isindicated. Autonomic dysfunction is common, with symptomsranging from bladder dysfunction and labile blood pressures tocardiac rhythm disturbances.Therapy is supportive. Maintenance of adequate respirationand nutrition, treatment of infection and autonomic disturbances,good nursing care and physical therapy to prevent contracturesare required. Plasmapheresis, immunoglobulin therapy (IgG) and,less often, steroid therapy may shorten the course of the illness.A chronic relapsing form of inflammatory demyelinatingneuropathy (CIDP) is an increasingly important neuropathy andoften responds to corticosteroid treatment. Nerve biopsy isoccasionally helpful to confirm the diagnosis.Diabetic NeuropathyVarious portions of the peripheral nervous system can be affectedby diabetes mellitus. Diabetes is common in the elderly.Individuals with psychiatric disease will frequently have diabeteswith neuropathy concomitantly. The most frequent pattern is adistal symmetric predominantly sensory polyneuropathy. PainfulPrinciples and Practice of Geriatric Psychiatry, 2nd edn. Edited by J. R. M. Copeland, M. T. Abou-Saleh and D. G. Blazer&2002 John Wiley & Sons, Ltd