Neurology Flashcards
Altered Mental Status DDX
Delirium
Metabolic disorders (hypercalcemia) Oxygen Vascular (MI, CVA) Endocrine (hypoglycemia) Seizure Trauma Uremia Psychiatric Infectious Drugs
AMS gen info
delirium: acute pd of cognitive dysfunction d/t a medical disturbance or condition
elderly patients are esp prone
consciousness = arousal + cognition
- arousal dependent on an intact brainstem (RAS)
- cognition dependent on an intact cerebral cortex
AMS, diminished LOC (drowsiness, stupor, coma), and confusion are caused by many of the same conditions and are often variations of the same theme.
Depressed LOC and coma can be caused by a variety of disorders.
- classify & organize by two categories:
1. diffuse injury to brain d/t metabolic, systemic, or toxic disorder
2. focal intracranial structural lesions like hemorrhage, infarction, tumor
Delirium clinical features
Rapid deterioration in mental status (over hours to days), a fluctuating level of awareness, disorientation, and attention. Waxing and waning, sundowning
+- acute abnormalities of perception (hallucinations)
Agitation (hyperactive)
Slow, blunted responsiveness (hypoactive)
Strongest risk factor is preexisting cognitive impairment
Delirium causes
infections (UTI, systemic infxn) medications (narcotics, benzos) post op delirium (elderly) alcoholism electrolyte imbalances medical conditions (stroke, heart disease, seizures, hepatic, and renal disorders)
Delirium dx
Mc screening; confusion assessment method (CAM) w 4 features; acute onset w fluctuating course, inattention, disorganized thinking, altered LOC
w/u depends on suspected contributing factors and reversible causes (good h&p!), detailed neuro exam, mental status assessment, good review of meds.
Labs, imaging, procedures (LP), workup patient-specific
Delirium
Treat underlying cause
delirium precautions while in hospital; frequent orientation, familiar objects and faces, maintaining a normal sleep-wake cycle with blinds open during day, correcting sensory impairments (hearing aids, glasses)
Avoid restraints and pharmacologic mgmt of agitation as much as possible; if necessary use antipsychotics like haloperidol
Coma gen info
depressed LOC to extent that patient is completely unresponsive to any stimuli
Causes
- structural brain lesions, usu bilateral unless they produce enough mass effect to compress brainstem or opposite cerebral hemisphere
- global brain dysfunction (metabolic or systemic disorders)
- psych causes; conversion disorders and malingering
Coma approach
initial steps
- vitals, ABCs
- always assume underlying trauma (stabilize C spine) and assess signs of underlying trauma
- assess LOC (glasgow coma scale), repeat serially
approach to diagnose
- rapid motor exam (asymmetry –> mass lesion; metabolic or systemic causes –> no asymmetry)
- brainstem reflexes:
1. pupillary light reflex
- round + symmetrically reactive –> midbrain intact
- anisocoria –> uncal herniation
- abnl light reflex –> structural intracranial lesions (hemorrhage, mass), drugs (morphine)
- bilateral fixed, dilated –> severe anoxia
- unilateral fixed, dilated –> herniation CN 3 compression
2. eye movements
- doll’s eye test if not c spine injury; when head turned, eyes should move conjugately to opposite direction if brainstem intact
- if patient breathing on their own –> intact brainstem
Labs
CBC, electrolytes, calcium BUN, creatinine, glucose, plasma osmolarity, ABG, ECG
Blood and urine tox labs
CT or MRI of brain
LP if meningitis or SAH suspected.
Coma treatment
correct reversible causes, treat underlying problem, control airway, give supp O2, naloxone, dextrose, give thiamine before glucose load, correct abnlities in BP, lytes, body temp
ID and treat herniation - lowering ICP
Meningitis gen info
inflammation of meningeal membrane enveloping brain and spinal cord
usu a/w infectious cause but noninfectious (medications, SLE, sarcoidosis, carcinomatosis) exist
Pathophys
infectious agents frequently colonize nasopharynx and resp tract –> enter CNS thru 1) invasion of bloodstream (hematogenous seeding of CNS), 2) retrograde transport along cranial (olfactory) or peripheral nerves, 3) contiguous spread from sinusitis, OM, surgery or trauma
Classification
acute - onset within hrs-days
chronic - onset within wks - mos; commonly caused by mycobacteria, fungi, lyme dz, parasites
Acute bacterial meningitis
*** medical emergency requiring prompt recognition + abx therapy (freq fatal even with abx)
Triad: fever, nuchal rigidity, change in mental status
Causes
neonates - group B strep, E. coli, listeria monocytogenes
children > 3 mos - n meningitidis, step pneumo, h flu
adults (18-50y) - ‘’ “
elderly (>50y) - strep pneumo, n meningitidis, l. monocytogenes, gram-neg bacilli
immunocompromised - l. monocytogenes, gram-neg bacilli, strep pneumo
Complications
Seizures, coma, brain abscess, subdural empyema, DIC, resp arrest
Permanent sequelae - deafness, brain damage, hydrocephalus
Aseptic meningitis
MC d/t variety of nonbacterial pathogens; viruses (enterovirus, HSV), certain bacteria, parasites, fungi
May be difficult to distinguish clinically from bacterial
(tx for bacterial if uncertain)
A/w better prognosis
Meningitis clinical features
Symptoms Headache (-+ worse laying down) Fevers N/V Stiff, painful neck Malaise Photophobia AMS (confusion, lethargy, coma)
Signs
Nuchal rigidity: stiff neck, with resistance to flexion of spine
Rashes (maculopapular w petechiae –> n. meningitidis; vesicular lesions –> HSV, varicella)
Incr ICP (papilledema, seizures)
Cranial nerve palsies
Kernig sign (inability to fully extend knees with hips flexed)
Brudzinski sign (passive flexion of neck causes flexion of legs and thighs)
Jolt test (worsening HA when pt asked to turn head back and forth quickly at freq of 3 turns per sec)*
Meningitis Diagnosis
CSF exam (LP) - performed when meningitis a possibility unless evidence of space-occupying lesion
- examine CSF; cell count, chemistry (protein, glucose), gram stain, culture (including AFB), cryptococcal antigen or india ink
- bacterial –> pyogenic inflammatory response in CSF:
- elevated WBC count - PMNs predominate
- low glc
- high protein
- gram stain
- Aseptic meningitis: non pyogenic inflammatory response
- Increase in mononuclear cells
- lymphocytic pleocytosis
- protein is normal or slightly elevated
- glucose normal
CT scan head before LP if evidence of space occupying lesion + ICP elevations
Blood cultures before antibiotics
Complications of paraplegia and quadriplegia
- SCI above T6 → autonomic dysreflexia aka exaggerated sympathetic response characterized by headache, diaphoresis, incr BP
- incr incidence of CAD
- hemodynamic instability and cardiac arrhythmias
- hard time breathing
- lung infections
- swelling of spinal cord
- pain
- neurogenic pain
- loss of bladder control (neurogenic bladder)
- UTI and kidney infections
- vesicoureteral reflux
- renal failure
- renal calculi
- Bowel dysfunction
- pressure sores
- osteoporosis
- muscle and joint stiffness
- spasticity
- depression
- incr risk for suicidality
- sexual dysfunction
- decr libido
- impotence
- infertility
- ED
- functional neurologic deficits and decline
Meningitis Treatment
Bacterial meningitis
Start empiric antibiotic therapy immediately after LP
- if anticipated delay (CT scan) give antibiotics first
IV antibiotics
- start immediately if CSF is cloudy or bacterial infection suspected
- begin empiric therapy according to patients age
- modify treatment based on Gram stain, culture, and sensitivity findings
Steroids if suspected strep pneumonia to prevent cerebral edema
Vaccination
- all adults over 65 years for strep pneumoniae
- asplenic patients for strep pneumoniae, n meningitidis, H influenzae (encapsulated organisms)
- immunocompromised for n meningitidis
Prophylaxis - rifampin or CTX for all close contacts
Aseptic meningitis
- supportive care; self limiting
- analgesics and fever reduction
Encephalitis gen info
Def: Diffuse inflammation of brain parenchyma often seen with meningitis at same time
Viral mc
herpes (HSV)
arbovirus like Eastern equine Encephalitis, West Nile virus enterovirus like polio
less common causes like measles, mumps, EBV, CMV, vzv, rabies, and prion diseases like creutzfeldt-jakob disease
Nonviral infectious causes toxoplasmosis
cerebral Aspergillosis
Non-infectious causes metabolic encephalopathies
T cell lymphoma
Risk factors
AIDS esp at risk for toxoplasmosis when CD4 count < 200
other forms of immunosuppression
travel in underdeveloped countries
exposure to insect vector and endemic areas
exposure to certain wild animals in an endemic area for rabies
Overall mortality from viral encephalitis ~ 10%
Encephalitis clinical features
Prodrome: headache, malaise, myalgias
Pts become more acutely ill within hours-days
SXS meningitis like headache, fever, photophobia, nuchal rigidity
altered sensorium like confusion, delirium, disorientation, and behavioral abnormalities
focal neurological findings like hemiparesis, Aphasia cranial nerve lesions and seizures
Encephalitis diagnosis
lab tests to rule out non-viral causes
chest x-ray, urine and blood cultures, urine tox screen, serum chemistry
LP to examine CSF (unless with signs of significantly increased ICP)
- Lymphocytosis > 5 wbcs with normal glucose c/w viral encephalitis (similar to viral meningitis). CSF cultures usu negative
- CSF PCR most specific/sensitive test
MRI brain
- r/o focal neuro causes like abscess
- Incr areas of T2 signal in frontotemporal localization c/w HSV encephalitis
EEG (for HSV1 dx showing unilateral or bilateral temp lobe discharges
Brain biospy ind in acutely ill pt w focal, enhancing lesion on MRI w/o clear dx
Encephalitis treatment
Supportive care, mech vent if necessary
antiviral therapy
- no specific antiviral therapy for most causes of viral encephalitis
HSV encephalitis - acyclovir 2-3 wks
CMV encephalitis - ganciclovir or foscarnet
Mgmt complications
seizures - anticonvulsant therapy
cerebral edema - hyperventilation, osmotic diuresis, steroids
Fever + AMS ddx
Infection
Sepsis: UTI/urosepsis, pna, bacterial meningitis, intracranial abscess, subdural empyema, med/drugs
Neuroleptic malignant syndrome (haloperidol, phenothiazines)
DTs, metabolic derangements
Thyroid storm
