Daily Archives: 28/12/2012

behavioral emergencies

_Patients who are experiencing severe changes in mood, thoughts, or behavior or severe, potentially life-threatening drug adverse effects need urgent assessment and treatment. Nonspecialists are often the first care providers for outpatients and inpatients on medical units, but whenever possible, such cases should also be evaluated by a psychiatrist. When a patient’s mood, thoughts, or […]

medical assessment of patient with psychiatric disorder

Medical assessment of patients with mental symptoms seeks to identify 2 things: Physical disorders mimicking mental disorders Physical disorders accompanying mental disorders Numerous physical disorders cause symptoms mimicking specific mental disorders (see Table 3: Approach to the Patient With Mental Symptoms: Selected Mental Symptoms Due to Physical Disorders). Other physical disorders may not mimic specific […]

drug categories of concern in elderly

Some drug categories (eg, analgesics, anticoagulants, antihypertensives, antiparkinsonian drugs, diuretics, hypoglycemic drugs, psychoactive drugs) pose special risks for elderly patients. Some, although reasonable for use in younger adults, are so risky as to be considered inappropriate for the elderly. The Beers Criteria are most commonly used to identify such inappropriate drugs (see Table 5: Drug […]

drug related problems in the elderly

Drug-related problems include Adverse effects Ineffectiveness Adverse drug effects are effects that are unwanted, uncomfortable, or dangerous. Common examples are oversedation, confusion, hallucinations, falls, and bleeding. Among ambulatory people ≥ 65, adverse drug effects occur at a rate of about 50 events per 1000 person-years. Hospitalization rates due to adverse drug effects are 4 times […]

pharmacodynamics in elderly

Pharmacodynamics is defined as what the drug does to the body or the response of the body to the drug; it is affected by receptor binding, postreceptor effects, and chemical interactions (see Pharmacodynamics: Drug-Receptor Interactions). In the elderly, the effects of similar drug concentrations at the site of action (sensitivity) may be greater or smaller […]

pharmacokinetics in elderly

Pharmacokinetics (see Pharmacokinetics) is best defined as what the body does to the drug; it includes absorption, distribution across body compartments, metabolism, and excretion. With aging, the metabolism and excretion of many drugs decrease, requiring that doses of some drugs be adjusted. Toxicity may develop slowly because levels of chronically used drugs tend to increase […]

neuromyelitis optica

Neuromyelitis optica affects only the eyes and spinal cord. It causes acute optic neuritis, sometimes bilateral, plus demyelination of the cervical or thoracic spinal cord. Neuromyelitis optica was previously considered to be a variant of multiple sclerosis (MS) but is now recognized as a different disorder. Symptoms include visual loss, paraparesis or quadriparesis, and incontinence. […]

ms

Multiple sclerosis (MS) is characterized by disseminated patches of demyelination in the brain and spinal cord. Common symptoms include visual and oculomotor abnormalities, paresthesias, weakness, spasticity, urinary dysfunction, and mild cognitive impairment. Typically, neurologic deficits are multiple, with remissions and exacerbations gradually producing disability. Diagnosis is by history of remissions and exacerbations plus clinical signs, […]

demyelinating disorders

Myelin sheaths cover many nerve fibers in the central and peripheral nervous system; they accelerate axonal transmission of neural impulses. Disorders that affect myelin interrupt nerve transmission; symptoms may reflect deficits in any part of the nervous system. Myelin formed by oligodendroglia in the CNS differs chemically and immunologically from that formed by Schwann cells […]

cerebellar disorders

Cerebellar disorders have numerous causes, including congenital malformations, hereditary ataxias, and acquired conditions. Symptoms vary with the cause but typically include ataxia (impaired muscle coordination). Diagnosis is clinical and often by imaging and sometimes genetic testing. Treatment is usually supportive unless the cause is acquired and reversible. The cerebellum has 3 parts: Archicerebellum (vestibulocerebellum): It […]

tremors

Tremors are involuntary, rhythmic, alternating, or oscillatory movements of interrelated muscle groups. They typically involve the hands, head, facial structures, vocal cords, trunk, or legs. Tremors can be characterized by Frequency of oscillation (rapid or slow) Amplitude of movement (fine or coarse) Movements or postures that evoke them (eg, rest, action, certain positions) Pathophysiology Tremors […]

parkinsons disease

Parkinson’s disease is an idiopathic, slowly progressive, degenerative CNS disorder characterized by resting tremor, muscular rigidity, slow and decreased movement, and postural instability. Diagnosis is clinical. Treatment is with levodopa plus carbidopa, other drugs, and, for refractory symptoms, surgery. Parkinson’s disease affects about 0.4% of people > 40 yr, 1% of people ≥ 65 yr, […]

myoclonus

Myoclonus is a brief, shocklike contraction of a muscle or group of muscles. Diagnosis is clinical and by selective testing. Treatment includes correction of reversible causes and sometimes oral drugs (eg, clonazepam, valproate). Physiologic myoclonus may occur as a person falls asleep (nocturnal myoclonus). Myoclonus can result from other disorders and certain drugs (see Table […]

huntington’s disease

Huntington’s disease is an autosomal dominant disorder characterized by chorea and progressive cognitive deterioration, usually beginning in middle age. Diagnosis is by genetic testing. Treatment is supportive. First-degree relatives are encouraged to have genetic testing. Huntington’s disease affects both sexes equally. The caudate nucleus atrophies, the inhibitory medium spiny neurons in the corpus striatum degenerate, […]

Fragile X–associated tremor/ataxia syndrome (FXTAS

Fragile X–associated tremor/ataxia syndrome (FXTAS) is a genetic disorder affecting mostly men and causing tremor, ataxia, and dementia. FXTAS affects about 1/3000 men. A premutation (an increased number of CGG repeats) occurs in the fragile X mental retardation (FMR1) gene on the X chromosome; if the mutation is full, > 200 repeats occur, causing fragile […]

dystonia

Dystonias are sustained involuntary muscle contractions, often distorting body posture. Dystonias can be primary or secondary, and they can be generalized, focal, or segmental. Diagnosis is clinical. Treatment of generalized dystonia is often with a combination of anticholinergic drugs, muscle relaxants, and benzodiazepines. Treatment of focal or segmental dystonias is often with botulinum toxin; more […]

chorea,athetosis and hemiballismus

Chorea is nonrhythmic, jerky, rapid, nonsuppressible involuntary movements, mostly of distal muscles or the face; movements may merge imperceptibly into purposeful or semipurposeful acts that mask the involuntary movements. Athetosis is nonrhythmic, slow, writhing, sinuous movements predominantly in distal muscles, often alternating with postures of the proximal limbs to produce a continuous, flowing stream of […]

overview of movement and cerebellar disorders

Voluntary movement requires interaction of the corticospinal (pyramidal) tracts, basal ganglia, and cerebellum (the center for motor coordination). The pyramidal tracts pass through the medullary pyramids to connect the cerebral cortex to lower motor centers of the brain stem and spinal cord. The basal ganglia (caudate nucleus, putamen, globus pallidus, subthalamic nucleus, and substantia nigra) […]

Craniocervical junction abnormalities

Craniocervical junction abnormalities are congenital or acquired abnormalities of the occipital bone, foramen magnum, or first two cervical vertebrae that decrease the space for the lower brain stem and cervical cord. These abnormalities can result in neck pain; syringomyelia; cerebellar, lower cranial nerve, and spinal cord deficits; and vertebrobasilar ischemia. Diagnosis is by MRI or […]

glossophyarngeal neuralgia

Glossopharyngeal neuralgia is characterized by recurrent attacks of severe pain in the 9th and 10th cranial nerve distribution (posterior pharynx, tonsils, back of the tongue, middle ear, under the angle of the jaw). Diagnosis is clinical. Treatment is usually with carbamazepine or gabapentin. Glossopharyngeal neuralgia sometimes results from nerve compression by an aberrant, pulsating artery […]

7th cn

Facial nerve (7th cranial nerve) palsy is often idiopathic (formerly called Bell palsy). Idiopathic facial nerve palsy is sudden, unilateral peripheral facial nerve palsy. Symptoms of facial nerve palsy are hemifacial paresis of the upper and lower face. Tests (eg, chest x-ray, serum ACE level) are done to diagnose treatable causes. Treatment may include lubrication […]

hemifacial spasm

Hemifacial spasm refers to unilateral painless, synchronous contractions of facial muscles due to dysfunction of the 7th cranial (facial) nerve and/or its motor nucleus. Hemifacial spasm results from nerve compression by a pulsating blood vessel, similar to that in trigeminal neuralgia. The pulsating blood vessel is often visible on MRI, but diagnosis is ultimately clinical. […]

6th cn

Trigeminal neuralgia is severe paroxysmal, lancinating facial pain due to a disorder of the 5th cranial nerve. Diagnosis is clinical. Treatment is usually with carbamazepine or gabapentin; sometimes surgery is required. Trigeminal neuralgia affects mainly adults, especially the elderly. Etiology Trigeminal neuralgia is usually caused by an intracranial artery (eg, anterior inferior cerebellar artery, ectatic […]

6th cn

Sixth cranial nerve palsy affects the lateral rectus muscle, impairing eye abduction. The eye may be slightly adducted when the patient looks straight ahead. The palsy may be secondary to nerve infarction, Wernicke encephalopathy, trauma, infection, or increased intracranial pressure, or it may be idiopathic. Determining the cause requires MRI and often lumbar puncture and […]

4th cn

Fourth cranial nerve palsy impairs the superior oblique muscle, causing paresis of vertical gaze, mainly in adduction. Fourth cranial (trochlear) nerve palsy is often idiopathic. Few causes have been identified. Causes include closed head injury (common), which may cause unilateral or bilateral palsies, and infarction due to small-vessel disease (eg, in diabetes). Rarely, this palsy […]

Third cranial nerve disorders

Third cranial nerve disorders can impair ocular motility, pupillary function, or both. Symptoms and signs include diplopia, ptosis, and paresis of eye adduction and of upward and downward gaze. If the pupil is affected, it is dilated, and light reflexes are impaired. If the pupil is affected or patients are increasingly unresponsive, CT is done […]

Internuclear ophthalmoplegia

Internuclear ophthalmoplegia is characterized by paresis of eye adduction in horizontal gaze but not in convergence. It can be unilateral or bilateral. During horizontal gaze, the medial longitudinal fasciculus (MLF) on each side of the brain stem enables abduction of one eye to be coordinated with adduction of the other. The MLF connects the following […]

conjugate gaze palsies

A conjugate gaze palsy is inability to move both eyes in a single horizontal (most commonly) or vertical direction. Gaze palsies most commonly affect horizontal gaze; some affect upward gaze, and fewer affect downward gaze. Horizontal gaze palsies: Conjugate horizontal gaze is controlled by neural input from the cerebral hemispheres, cerebellum, vestibular nuclei, and neck. […]

Neuro-ophthalmologic disorders

Dysfunction of certain cranial nerves may affect the eye, pupil, optic nerve, or extraocular muscles and their nerves; thus, they can be considered cranial nerve disorders, neuro-ophthalmologic disorders, or both. Neuro-ophthalmologic disorders may also involve dysfunction of the central pathways that control and integrate ocular movement and vision. Cranial nerve disorders can also involve dysfunction […]

subacute meningitis

Meningeal inflammation that lasts > 2 wk (subacute meningitis) or > 1 mo (chronic meningitis) may have infectious or noninfectious causes (eg, cancer). Diagnosis requires CSF analysis, usually after CT or MRI. Treatment is directed at the cause. Etiology Subacute or chronic meningitis may have infectious or noninfectious causes and may be an aseptic meningitis […]

meningitis

For brain infections, see Brain Infections, for neonatal meningitis, see Infections in Neonates: Neonatal Bacterial Meningitis ) Meningitis is inflammation of the meninges of the brain or spinal cord. Meningitis is often infectious and is one of the most common CNS infections. Inflammation involves both the meninges and brain parenchyma (meningoencephalitis). Meningitis may become evident […]

overview of cerebellar functions

The cerebrum is divided by a longitudinal fissure into 2 hemispheres, each containing 5 discrete lobes. The frontal, temporal, parietal, and occipital lobes cover the brain’s surface; the insula is hidden under the Sylvian fissure (see Fig. 1: Function and Dysfunction of the Cerebral Lobes: Areas of the brain.). Although specific functions are attributed to […]

Neuropathic Pain

Neuropathic Pain Share This view related topics in this manual Neuropathic pain results from damage to or dysfunction of the peripheral or central nervous system, rather than stimulation of pain receptors. Diagnosis is suggested by pain out of proportion to tissue injury, dysesthesia (eg, burning, tingling), and signs of nerve injury detected during neurologic examination. […]

chronic pain

Chronic pain is pain that persists or recurs for > 3 mo, persists > 1 mo after resolution of an acute tissue injury, or accompanies a nonhealing lesion. Causes include chronic disorders (eg, cancer, arthritis, diabetes) and injuries (eg, herniated disk, torn ligament), and many primary pain disorders (eg, neuropathic pain, fibromyalgia, chronic headache). Various […]

treatment of pain

Nonopioid and opioid analgesics are the main drugs used to treat pain. Antidepressants, anticonvulsants, and other CNS-active drugs may also be used for chronic or neuropathic pain and are first-line therapy for some conditions. Neuraxial infusion, nerve stimulation, injection therapies, and neural blockade can help selected patients. Cognitive-behavioral interventions (eg, incremental gains in function; changes […]

evaluation of pain

Clinicians should evaluate the cause, severity, and nature of the pain and its effect on activities and psychologic well-being. Evaluation of the cause of acute pain (eg, back pain, chest pain—see elsewhere in The Manual) differs from that of chronic pain (see Pain: Symptoms and Signs). The history should include the following information about the […]

overview of pain

Overview of Pain Share This Pain is the most common reason patients seek medical care. Pain has sensory and emotional components and is often classified as acute or chronic. Acute pain is frequently associated with anxiety and hyperactivity of the sympathetic nervous system (eg, tachycardia, increased respiratory rate and BP, diaphoresis, dilated pupils). Chronic pain […]

Pure autonomic failure

Pure autonomic failure results from neuronal loss in autonomic ganglia, causing orthostatic hypotension and other autonomic symptoms. Pure autonomic failure, previously called idiopathic orthostatic hypotension or Bradbury-Eggleston syndrome, denotes generalized autonomic failure without CNS involvement. This disorder differs from multiple system atrophy because it lacks central or preganglionic involvement. Pure autonomic failure affects more women, […]

multiple system atrophy

Multiple System Atrophy view related topics in this manual Multiple system atrophy is a relentlessly progressive neurodegenerative disorder causing pyramidal, cerebellar, and autonomic dysfunction. It includes 3 disorders previously thought to be distinct: olivopontocerebellar atrophy, striatonigral degeneration, and Shy-Drager syndrome. Symptoms include hypotension, urinary retention, constipation, ataxia, rigidity, and postural instability. Diagnosis is clinical. Treatment […]

horner’s syndrome

Horner’s Syndrome Horner’s syndrome is ptosis, miosis, and anhidrosis due to dysfunction of cervical sympathetic output. Etiology Horner’s syndrome results when the cervical sympathetic pathway running from the hypothalamus to the eye is disrupted. The causative lesion may be primary (including congenital) or secondary to another disorder. Lesions are usually divided into Central (eg, brain […]

Autonomic Neuropathies

Autonomic Neuropathies Share This view related topics in this manual Autonomic neuropathies are peripheral nerve disorders with disproportionate involvement of autonomic fibers. The best known autonomic neuropathies are those accompanying peripheral neuropathy due to diabetes, amyloidosis, or autoimmune disorders. Autoimmune autonomic neuropathy is an idiopathic disorder that often develops after a viral infection; onset may […]

ans

Overview of the Autonomic Nervous System Share This The autonomic nervous system (ANS) regulates physiologic processes. Regulation occurs without conscious control, ie, autonomously. The 2 major divisions are the sympathetic and parasympathetic systems. Disorders of the ANS cause autonomic insufficiency or failure and can affect any system of the body. Anatomy The ANS receives input […]

pain

Overview of Pain Share This Pain is the most common reason patients seek medical care. Pain has sensory and emotional components and is often classified as acute or chronic. Acute pain is frequently associated with anxiety and hyperactivity of the sympathetic nervous system (eg, tachycardia, increased respiratory rate and BP, diaphoresis, dilated pupils). Chronic pain […]

fatal insomnia

Fatal insomnia is a typically hereditary prion disorder causing difficulty sleeping, motor dysfunction, and death. FI, a very rare disease, usually results from an autosomal dominant mutation, but several sporadic cases have been identified. Average age at onset is 40 yr (ranging from the late 30s to the early 60s). Common early symptoms include difficulty […]

creutzfeldt jacob disease

Creutzfeldt-Jakob Disease (CJD) Share This Creutzfeldt-Jakob disease is a sporadic or familial prion disease. Bovine spongiform encephalopathy (mad cow disease) is a variant form. Symptoms include dementia, myoclonus, and other CNS deficits; death occurs in 1 to 2 yr. Transmission can be prevented by taking precautions when handling infected tissues and using bleach to clean […]

prions disease

Overview of Prion Diseases (Transmissible Spongiform Encephalopathies) Share This Prion diseases are progressive, fatal, and untreatable degenerative brain disorders. They include Creutzfeldt-Jakob disease (CJD), the prototypic example Gerstmann-Sträussler-Scheinker disease (GSS) Fatal insomnia (FI) Variant CJD (vCJD) Kuru Prion diseases usually occur sporadically, with a worldwide annual incidence of about 1/1 million. Prion diseases result from […]

psp

Progressive supranuclear palsy is a rare, degenerative CNS disorder causing loss of voluntary eye movements, bradykinesia, muscular rigidity with progressive axial dystonia, pseudobulbar palsy, and dementia. The cause of progressive supranuclear palsy is unknown. Neurons in the basal ganglia and brain stem degenerate; neurofibrillary tangles containing an abnormally phosphorylated tau protein are also present. Multiple […]