BI 231 Pathophysiology Unit 3 Study Guide

Pain

Personal, unpleasant sensory and emotional experience associated with actual or potential tissue damage.

Nociception

The process of detecting, transmitting, and processing pain signals.

Nociceptors

Specialized pain receptors found in skin, muscles, joints, and viscera that respond to noxious stimuli.

Spinothalamic tract

The main ascending pain pathway in the spinal cord.

Acute pain

Short-term, protective pain that resolves with healing.

Somatic pain

Sharp, localized pain from skin, muscles, or joints.

Visceral pain

Dull, aching, or cramping pain from internal organs; often poorly localized.

Referred pain

Pain felt in a different location than its origin (e.g. heart attack pain in the left arm).

Chronic pain

Persistent pain lasting >3 months, often with no clear cause.

Neuropathic pain

Pain caused by nerve damage or dysfunction, often burning, tingling, or shooting in nature (e.g. diabetic neuropathy).

Endorphins

The body's natural opioids, which inhibit pain perception.

Transduction

Conversion of painful stimuli into electrical signals.

Transmission

Movement of signals via A-delta fibers (sharp pain) and C fibers (dull, aching pain).

Perception

Conscious awareness of pain in the brain.

Modulation

Inhibition or amplification of pain signals (e.g. via endorphins, opioids).

Consciousness

Awareness of self and the environment.

Arousal

State of wakefulness, controlled by the reticular activating system.

Awareness

The cognitive aspect of consciousness, involving attention, memory, and reasoning.

Altered Level of Consciousness (ALOC)

Variations in arousal (e.g., coma, stupor, lethargy).

Cerebral Death (Irreversible Coma)

Permanent loss of brain function, excluding the brainstem.

Brain Death (Total Brain Death)

Irreversible cessation of all brain activity, including the brainstem.

Memory Disorders

Impairments in forming, storing, or retrieving information (e.g., amnesia, dementia).

Agnosia

Inability to recognize objects, sounds, or smells despite intact sensory function.

Dysphasia (Aphasia)

Impairment of language comprehension or production.

Acute confusional states (ACS)

Transient disorders of cognitive function, consciousness, or perception.

Delirium

Acute, often reversible, disturbance in awareness and cognition (e.g., caused by infection, toxins, or metabolic imbalance).

Dementia

Progressive loss of awareness, cognition, and executive function (e.g., Alzheimer's disease).

Seizure

Sudden, abnormal electrical activity in the brain.

Epilepsy

Recurrent, unprovoked seizures.

Aura

A warning sensation before a seizure.

Prodroma

Early signs of a seizure before the actual event.

Tonic

A state of muscle contraction in which there is excessive muscle tone.

Clonic

A state of alternating contraction and relaxation of muscles.

Postictal State

The recovery phase following a seizure.

Intracranial Pressure (ICP)

Pressure within the skull; normal: 5-15 mmHg.

Increased ICP (IICP)

Elevated pressure due to trauma, infection, or mass effect.

Cerebral Edema

Swelling of brain tissue due to fluid accumulation.

Hydrocephalus

Excess cerebrospinal fluid (CSF) accumulation in the brain ventricles.

Herniation Syndromes

Brain tissue displacement due to increased pressure (e.g., uncal, transtentorial herniation).

Cerebral Perfusion Pressure (CPP)

The pressure needed to ensure blood flow to the brain (CPP = MAP - ICP).

Hypotonia

Decreased muscle tone.

Hypertonia

Increased muscle tone (includes spasticity, rigidity, dystonia).

Paresis

Partial loss of voluntary movement (weakness).

Paralysis

Complete loss of motor function.

Hemiparesis/Hemiplegia

Weakness/paralysis of one side of the body.

Paraparesis/Paraplegia

Weakness/paralysis of the lower body.

Quadriparesis/Quadriplegia

Weakness/paralysis of all four limbs.

Hyperkinesia

Excessive, involuntary movements (e.g., Huntington's disease).

Hypokinesia

Decreased movement (e.g., Parkinson's disease).

Dyskinesia

Abnormal, involuntary movements (e.g., chorea, athetosis, ballismus).

Bradykinesia

Slowness of movement (common in Parkinson's disease).

Akinesia

Absence or loss of voluntary movement.

Tremor

Rhythmic, involuntary movement.

Level of consciousness

Communicates orientation to self, place, time

Breathing pattern

Rhythmic, symmetric, non-labored

Apnea

Temporary cessation or absence of breathing

Cheyne-Stokes respirations

Alternating deep and shallow breathing followed by apnea

Ataxic breathing

Completely irregular breathing with unpredictable periods of apnea

Gasping (Agonal) breathing

Slow, irregular, gasping breaths

Kussmaul respirations

Deep, rapid breathing with no pauses

Pupillary changes

Equally round and reactive to light/accommodation

Eye movements & Reflexes

Symmetric, appropriate, normal reflexes

Motor responses

Purposeful, appropriate, normal reflexes

Full Consciousness

Alert and oriented to person, place, time, and situation

Confusion

Disoriented, difficulty processing thoughts, impaired memory and judgement

Disorientation

Loss of awareness regarding time (first), then place, then person (last)

Lethargy

Severe drowsiness but able to wake to mild stimulation

Obtundation

More severe than lethargy, requires repeated stimulation to maintain wakefulness

Stupor

Deeply unresponsive but can be aroused with vigorous/painful stimulation

Coma

Complete unresponsiveness to stimuli, no purposeful movement, speech, response to pain

Light coma

Reflexes and some movement may still be present

Deep coma

No motor response or reflexes

Brain death

Complete loss of all brain function, including brainstem reflexes

Alzheimer Disease

Progressive, neurodegenerative brain disorder that affects a person's ability to think, remember, and carry out daily activities; most common form of dementia in older people

Seizure Disorders

Represent a manifestation of disease; any disorder that alters the neuronal environment may cause seizure activity

Patho

abnormal, excessive, and synchronized neuronal activity in the brain due to an imbalance between excitatory and inhibitory signals leading to uncontrolled electrical discharges that can spread across brain networks, causing various motor, sensory, or cognitive symptoms

Preictal phase

preceding the seizure including prodroma and aura

Ictal phase

the event of the seizure with tonic-clonic activity

Postictal phase

following the seizure

Dx/Tx

medical history and physical exam, imaging; meds, diet/lifestyle modifications, surgery, neurostimulation devices

Focal (partial) seizures

seizures originating in one area of the brain; frequently described by the area in which they originate; +/- loss of consciousness

Generalized seizures

seizures originating in both sides of the brain simultaneously; may cause loss of consciousness, falls, or massive muscle contractions

IICP

may result from an increase in intracranial content as occurs with tumor growth, cerebral edema, excess CSF, or hemorrhage

Stage 1: Compensation

The brain compensates by shifting CSF and venous blood to maintain normal ICP. Few or no symptoms due to successful autoregulation.

Stage 2: Beginning of Decompensation

Compensation starts failing, and ICP begins to rise. Symptoms: Subtle confusion, restlessness, slight pupil changes, normal vital signs.

Stage 3: Decompensation (Failing Autoregulation)

ICP rises significantly, causing brain hypoxia and hypercapnia. Symptoms: Decreased consciousness, sluggish pupils, increased BP, widened pulse pressure, bradycardia (Cushing's Triad may appear). Urgent intervention is needed to prevent herniation.

Stage 4: Herniation & Brainstem Failure

Brain tissue is forced downward (herniation), compressing the brainstem. Symptoms: Fixed, dilated pupils, abnormal posturing, irregular breathing, and coma. Fatal if not treated immediately.

Vasogenic edema

Most important and common type; results from disruption of the blood-brain-barrier that cause increased vascular permeability.

Cytotoxic/metabolic edema

Accumulation of fluid in the cells of the brain from Na+/K+ imbalances.

Interstitial/hydrocephalic edema

Caused by the movement of CSF from the ventricles into the extracellular spaces.

Risk Factors for Hydrocephalus

Tumors, infection, trauma.

Pathophysiology of Hydrocephalus

Occurs due to obstruction, impaired absorption, or overproduction of CSF.

Obstruction in Hydrocephalus

Blockage of the CSF pathways.

Impaired absorption in Hydrocephalus

Failure of the arachnoid granulations to absorb CSF.

Overproduction in Hydrocephalus

Brain produces too much CSF.

Symptoms of Hydrocephalus

Headache, nausea/vomiting, blurry vision, balance problems, bladder control problems, thinking/memory problems.

Diagnosis and Treatment of Hydrocephalus

Neurological exam, imaging; surgery.

Types of Hydrocephalus

Communicating, non-communicating, normal pressure.

Communicating Hydrocephalus

Usually occurs in adults due to decreased CSF absorption.

Non-communicating Hydrocephalus

Usually occurs in kids due to ventricular obstruction.