Impairment of memory and at least one other cognitive function (e.g., language, visual-spatial orientation, judgement) without alteration in consciousness; representing a decline from previous level of ability,
and interfering with daily functioning and independent living.
Mild Cognitive Impairement
Dementia with Lewy bodies
Normal pressure hydrocephalus
Ddx: Confusional State
Inflammatory and autoimmune
Most common cause of dementia (60%-80% of cases). The result of structural neuronal changes with pathologic features including deposition of insoluble, neurotoxic β-amyloid protein in extracellular parenchymal plaques and intracellular accumulation of neurofibrillary tangles composed of abnormal tau protein.
Early Manifestations: MCI; Impairment of recent memory is typically the first sign of Alzheimer disease and may be noticed only by family members. As the memory disorder progresses over months to several years, the patient becomes disoriented to time and then to place. Aphasia, anomia, and acalculia may develop, forcing the patient to leave work or give up the management of family finances. The depression apparent in the earlier stages of the disorder may give way to an agitated, restless state. Apraxias and visuospatial disorientation ensue, causing the patient to become lost easily. Primitive reflexes are commonly found. A frontal lobe gait disorder may become apparent, with short, slow, shuffling steps, flexed posture, wide base, and difficulty in initiating walking.
Late Manifestations: Late manifestations—In the late stages, previously preserved social graces are lost, and psychiatric symptoms, including psychosis with paranoia, hallucinations, or delusions, may be prominent. Seizures occur in some cases. Examination at this stage may show rigidity and bradykinesia. Rare and usually late features of the disease include myoclonus, incontinence, spasticity, extensor plantar responses, and hemiparesis. Mutism, incontinence, and a bedridden state are terminal manifestations.
Dx: CT scan or MRI often shows temporal and parietal (especially medial temporal lobe) atrophy and enlarged ventricles, but such changes are nonspecific.
Tx: Cholinesterase inhibitor (Donepezil)
The N-methyl-D-aspartate receptor antagonist memantine is the only drug approved by the Food and Drug Administration as first-line treatment of moderate to advanced Alzheimer disease.
Non pharmacologic: Cognitive stimulation included a range of activities designed to stimulate thinking, concentration, and memory. Cognitive stimulation was associated with improved cognitive function immediately after treatment. Quality of life also improved, but there was no impact on mood, overall functional level, or caregiver outcomes.
Mild Cognitive Impairment
Mild cognitive impairment (MCI) describes a loss of cognitive ability that exceeds the expected age-related memory loss but does not interfere significantly with daily activities. The term is sometimes used to describe the early phase of cognitive decline observed in patients who later receive a diagnosis of Alzheimer disease.
There are universal age-related declines in cognition that chiefly affect memory, learning, and problem solving beginning around age 40 years, and these changes may be noticeable to patients.
Progressive neuropsychiatric disorder characterized by early behavioral and personality changes that range from apathy to social disinhibition. Patients may fail to change their clothes, brush their teeth, pursue their former interests, or initiate many of their previous activities that constituted a normal day. They may fixate, in a seemingly idiosyncratic fashion, on a particular activity, such as going to the bathroom, sorting through a wallet, hoarding magazines, or watching television. Some patients have greater disinhibition and emotional lability (crying or laughing inappropriately).
Behavioral changes often precede memory impairments (in contrast to AD).
Dx: Disproportionate atrophy of the frontal and anterior temporal brain regions.
Dementia with Lewy bodies
Characterized by parkinsonism that is responsive to dopaminergic therapy, visual hallucinations, and/or fluctuating cognition. The characteristic cognitive profile of dementia in patients with dementia with Lewy bodies includes impaired learning and attention, psychomotor slowing, constructional apraxia, and more profound visuospatial impairment but less memory impairment than in similarly staged patients with Alzheimer disease.
Dx: Intraneuronal Lewy body inclusions in the cerebral cortex.
Consequence of progressive ischemic brain injury; stepwise deterioration; early executive dysfunction.
Dx: Patients with this diagnosis may have multiple large (>1 cm in diameter) cortical infarcts; strategic infarcts involving hippocampus or thalamus; multiple small (eg, lacunar) infarcts affecting subcortical white matter, basal ganglia, or thalamus; diffuse ischemic lesions of subcortical white matter (Binswanger disease); intracerebral hemorrhages (eg, cerebral amyloid angiopathy); or combinations of these.
Px: The neurologic examination may show pseudobulbar palsy with dysarthria, dysphagia, and pathologic emotionality (pseudobulbar affect); focal motor and sensory deficits; ataxia; gait apraxia; hyperreflexia; and extensor plantar responses.
Normal pressure hydrocephalus
A potentially reversible cause of dementia, is characterized by the clinical triad of dementia, gait apraxia, and incontinence. The dementia is often mild and insidious in onset and is typically preceded by gait disorder and incontinence. It is characterized initially by mental slowness and apathy and later by global cognitive dysfunction.
Normal-pressure hydrocephalus is sometimes called communicating hydrocephalus (because the lateral, third, and fourth ventricles remain in communication) or nonobstructive hydrocephalus (because the flow of CSF between the ventricles is not impaired). It is presumed to be caused by impaired CSF absorption from arachnoid granulations in the subarachnoid space over the cerebral hemispheres. In contrast, noncommunicating or obstructive hydrocephalus is caused by a blockade of CSF circulation within the ventricular system (eg, by an intraventricular cyst or tumor) and is associated with increased CSF pressure and often with headache and papilledema.
Urinary incontinence is a later development, and patients may be unaware of it; fecal incontinence is uncommon.
Gait apraxia: Characterized by unsteadiness on standing and difficulty in initiating walking (magnetic gait), even though there is no weakness or ataxia. The patient can perform the leg movements associated with walking, bicycling, or kicking a ball and can trace figures with the feet while lying or sitting but is unable to do so with the legs bearing weight. The patient typically appears to be glued to the floor; walking, once underway, is slow and shuffling.
Dementia is manifested by psychomotor slowing, inattention, and impaired decision making and spatial recognition. Urinary incontinence is a later development, and patients may be unaware of it; fecal incontinence is uncommon.
Dx: Lumbar puncture reveals normal or low opening pressure and is both diagnostic and theraputic.
Tx: LP; Ventriculoatrial, ventriculoperitoneal, or lumboperitoneal shunting.
Inflammatory and autoimmune
SLE, CNS vasculitis, sarcoidosis, granulomatosis with polyangiitis, paraneoplastic disease
Nutritional (B12 and Wernicke)
Vitamin B12 deficiency
Vitamin B12 (cyanocobalamin) deficiency produces polyneuropathy, subacute combined degeneration of the spinal cord (combined systems disease) affecting the corticospinal tracts and dorsal columns, nutritional amblyopia (visual loss), and cognitive dysfunction that ranges from a mild confusional state to dementia or psychosis (megaloblastic madness). The most frequent cause of vitamin B12 deficiency is pernicious anemia, a defect in the production of intrinsic factor associated with atrophic gastritis, anti-parietal cell antibodies, and achlorhydria. Other causes include gastric resection
and vegan diet.
Hx: The presentation is usually with anemia or orthostatic lightheadedness but may also be neurologic. Distal paresthesias, gait ataxia, a bandlike sensation of tightness around the trunk or limbs, and Lhermitte sign (an electric shock–like sensation along the spine precipitated by neck flexion) may be present.
Px: Physical examination may show low-grade fever, glossitis (beefy red tongue), lemon-yellow discoloration of the skin, and cutaneous hyperpigmentation. Cerebral involvement produces confusion, depression, agitation, or psychosis with hallucinations. Spinal cord involvement causes impaired vibratory and joint position sense, sensory gait ataxia, ataxic heel-knee-shin and spastic paraparesis with extensor plantar responses. Associated peripheral nerve involvement may lead to loss of tendon reflexes in the legs and urinary retention.
Dx: Because folate deficiency can produce identical changes, the diagnosis
must be confirmed by measuring the serum vitamin B12 level. When this is low (<100 pg/mL), a Schilling test can determine whether defective intestinal absorption of vitamin B12 (as in pernicious anemia) is the cause, but the test is now rarely used. Diagnosis may be difficult when cerebral symptoms occur without anemia or spinal cord disease, so the serum vitamin B12 level should be determined routinely in patients with cognitive disorders, myelopathy, or peripheral neuropathy, regardless of whether
anemia is present.
Tx: Treatment of neurologic manifestations is by prompt intramuscular
administration of cyanocobalamin (1,000 μg), as soon as blood is drawn to determine the serum vitamin B12 level. Daily injections are continued for 1 week, and further testing is performed to determine the cause of deficiency. If, as in pernicious anemia, deficiency is not correctable by
dietary supplementation or treatment of an underlying cause (eg, intestinal malabsorption), intramuscular vitamin B12 (typically 1,000 μg) is given at weekly intervals for several months and monthly thereafter.
Is caused by deficiency of thiamine (vitamin B1). Wernicke encephalopathy is usually a complication of chronic alcoholism, but it also occurs in other disorders associated with malnutrition, such as cancer, and after bariatric surgery. Pathologic features include neuronal loss, demyelination, and gliosis in periventricular gray matter. Proliferation of small blood vessels and petechial hemorrhages may be seen. The areas most commonly involved are the medial thalamus, mammillary bodies, periaqueductal gray matter, cerebellar vermis, and oculomotor, abducens, and vestibular nuclei.
The classic syndrome comprises the triad of ophthalmoplegia, ataxia, and confusional state.
The mental status examination reveals global confusion with a prominent disorder of immediate recall and recent memory.
Tx: Treatment is prompt administration of thiamine. An initial dose of 500 mg is given intravenously, before or with dextrose (which might otherwise precipitate or exacerbate the disorder).
Brain abscess, chronic meningitis, HIV, CNS Whipple disease, syphilis, viral encephalitis (CMV, HSV)
Hypothyroidism, hyperthyroidism, hypoparathyroidism
Hydrocephalus, brain tumor, subdural hematoma, postconcussive syndrome
Concussion: Until all symptoms abate at rest without use of medication and objective testing is normal, the athlete should not play.
Drugs, heavy metal exposure
Depression Both dementia and depression can be characterized by mental slowness, apathy, self-neglect, withdrawal, irritability, difficulty with memory and concentration, and changes in behavior and personality.
Hypertensive Encephalopathy : A sudden increase in blood pressure may result in encephalopathy and headache, which develop over a period of hours to days. Impaired autoregulation of cerebral blood flow, vasospasm, and intravascular coagulation have all been proposed as causes. Stroke and subarachnoid hemorrhage also produce encephalopathy with acutely elevated blood pressure; when focal neurologic abnormalities are also present, stroke is most likely. A similar syndrome, Posterior Reversivle Encephalopathy Syndrome (PRES) can occur in normotensive individuals and may be related to autoimmune-induced endothelial dysfunction or immunosuppressive drug treatment.
Hx: Blood pressure in excess of 250/150 mm Hg is usually required to precipitate the syndrome in patients with chronic hypertension, but previously normotensive patients may be affected at lower pressures.
Px: Papilledema, retinal hemorrhages, and exudates are usually present.
Dx: Areas of edema, located especially in parietooccipital white matter, are seen on CT scan and MRI and are reversible with treatment. The diagnosis of hypertensive encephalopathy is established when lowering the blood pressure results in rapid resolution of symptoms.
Tx: Accomplished with sodium nitroprusside, given by continuous intravenous infusion at an initial rate of 0.25 μg/kg/min and increased to as much as 10 μg/kg/min as required. Mean arterial blood pressure should be reduced by no more than 25% in the first 2 hours of treatment, and a target of 160/100 mm Hg should be aimed for in the following 4 hours.
TBI of any severity can lead to (a few hours or days later) postconcussive syndrome, which is clinically described by the following constellation of symptoms: headache, confusion, amnesia, difficulty concentrating or with multitasking, vertigo, mood alteration, sleep disturbance, and anxiety.
Typically, these symptoms resolve with symptomatic treatment within a few weeks to months following TBI; however, some patients may have persistent symptoms lasting >6 months.
Resume sports 1 week post resolution of symptoms