D115 Unit 3 Videos: Bacterial Meningitis & Neurologic System Alterations

D115 Unit 3 Videos: Bacterial Meningitis & Neurologic System Alterations

Student Name

Western Governors University

D115 Advanced Pathophysiology for the Advanced Practice Nurse

Prof. Name:

Date

Alterations of the Neurologic and Endocrine Systems – Consolidated Review

Bacterial Meningitis

Definition

Meningitis is inflammation of the meninges (pia mater and arachnoid mater) surrounding the brain and spinal cord. It may be caused by bacteria, viruses, fungi, parasites, toxins, or noninfectious processes.

Pathogens

Most common bacterial causes:

• Neisseria meningitidis (meningococcus)

• Streptococcus pneumoniae (pneumococcus)

  • Drug-resistant strains are increasing

Epidemiology

• Highest risk: Infants <1 year, adolescents, adults >40

• Common in congregate settings:

  • College dormitories

  • Military bases

  • Sub-Saharan Africa

Predisposing Factors

• Otitis media or sinusitis

• Pneumonia

• Immunocompromised state

• Post-splenectomy or sickle cell disease (pneumococcal risk)

Transmission

• Respiratory droplets or saliva

• Close contact: kissing, coughing, sneezing, sharing food/drinks

• Asymptomatic carriers may transmit disease

Pathophysiology

• Pathogens enter via respiratory tract, bloodstream, or neurosurgical procedures

• Cross the blood-brain barrier → multiply in CSF

• Toxins increase vascular permeability → cerebral edema

• CSF obstruction → increased intracranial pressure (ICP)

• Brainstem herniation may result in death

Clinical Manifestations

Systemic signs

• Fever, chills, tachycardia

Meningeal signs

• Severe headache

• Photophobia

• Nuchal rigidity

• Positive Kernig and Brudzinski signs

Neurologic signs

• Decreased level of consciousness

• Seizures

• Hemiparesis, hemiplegia, ataxia

• Confusion

• Projectile vomiting

• Papilledema

• Petechial or purpuric rash

• Bulging fontanels (infants)

• Opisthotonic posturing (children)

Diagnosis

• Lumbar puncture: ↑ WBCs in CSF

• Blood cultures to identify organism

Treatment

• Immediate empiric IV antibiotics

• Adjust therapy based on cultures

• Dexamethasone for pneumococcal meningitis

• Supportive care

Complications

• Septic shock

• DIC

• Purpura fulminans

• Multi-organ failure

Prevention

• Vaccinations:

  • Meningococcal

  • Pneumococcal

  • Haemophilus influenzae type B

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Guillain-Barré Syndrome (GBS)

Definition

An acute, immune-mediated demyelinating disorder of the peripheral nervous system causing ascending muscle weakness.

Etiology

Often follows infection or immune activation:

• Campylobacter jejuni

• CMV, EBV

• Influenza

• Mycoplasma pneumoniae

• Zika virus

• Surgery, immunization

Pathophysiology

• Molecular mimicry leads to antibodies attacking peripheral nerve myelin or axons

• Complement activation disrupts nerve conduction

Subtypes

• Acute inflammatory demyelinating polyneuropathy (most common)

• Acute motor axonal neuropathy

• Acute motor-sensory axonal neuropathy

• Miller Fisher syndrome (rare)

Clinical Manifestations

• Ascending flaccid paralysis

• Paresthesia in hands and feet

• Muscle weakness

• Areflexia

• Autonomic instability

• Respiratory muscle paralysis (within 2 weeks possible)

Diagnostic Criteria

• Progressive weakness in ≥2 limbs

• Areflexia

• Progression ≤4 weeks

Treatment

• IV immunoglobulin (IVIG)

• Plasmapheresis

• Aggressive rehabilitation

Recovery

• Weeks to months (up to 2 years)

• ~30% have residual weakness

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Multiple Sclerosis (MS)

Definition

A chronic autoimmune demyelinating disease of the central nervous system.

Pathophysiology

• T-cells cross the blood-brain barrier and attack myelin

• Cytokine release damages oligodendrocytes

• Demyelination → plaques visible on MRI

• Early remyelination occurs but declines over time

Risk Factors

• Female sex

• HLA-DR2 gene

• Vitamin D deficiency

• Geographic latitude (farther from equator)

Types

1. Relapsing-remitting (most common)

2. Secondary progressive

3. Primary progressive

4. Progressive-relapsing

Symptoms (Ages 20–40)

• Motor: weakness, tremor, spasticity, ataxia

• Sensory: numbness, paresthesia, Lhermitte sign

• Visual: optic neuritis, diplopia

• Speech: dysarthria

• Autonomic: bowel/bladder dysfunction

• Cognitive: depression, anxiety, impaired concentration

Charcot’s Triad

• Dysarthria

• Nystagmus

• Intention tremor

Diagnosis

• MRI showing CNS plaques

• CSF oligoclonal bands

• Visual evoked potentials

• Symptoms separated in time and space

Treatment

• Acute flares: corticosteroids, IVIG, plasmapheresis

• Disease-modifying therapy: interferon-beta, immunosuppressants

• Rehabilitation and symptom management

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Myasthenia Gravis

Definition

A chronic autoimmune disorder causing fluctuating skeletal muscle weakness due to impaired neuromuscular transmission.

Pathophysiology

• Antibodies destroy acetylcholine receptors at the neuromuscular junction

Symptoms

• Ptosis, diplopia

• Facial weakness

• Difficulty chewing, swallowing, speaking

• Limb and neck weakness

• Fatigue improves with rest

Diagnosis

• Acetylcholine receptor antibodies

• Anti-MuSK antibodies

• EMG

• Edrophonium test

• CT/MRI for thymoma

Treatment

• Anticholinesterase drugs

• Immunosuppressants

• Thymectomy

• IVIG or plasmapheresis

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Diabetes Mellitus

Overview

A metabolic disorder characterized by chronic hyperglycemia due to insulin deficiency or resistance.

Hormonal Regulation

• Insulin ↓ blood glucose

• Glucagon ↑ blood glucose

• Produced in pancreatic islets

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Type 1 Diabetes Mellitus

• Autoimmune destruction of β-cells

• Absolute insulin deficiency

• Associated with HLA-DR3 and DR4

Classic Symptoms

• Polyphagia

• Polyuria

• Polydipsia

• Glycosuria

Complication

• Diabetic ketoacidosis (DKA)

Treatment

• Lifelong insulin therapy

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Type 2 Diabetes Mellitus

• Insulin resistance

• Relative insulin deficiency

• Strongly associated with obesity and genetics

Complication

• Hyperosmolar hyperglycemic state (HHS)

Treatment

• Lifestyle modification

• Oral antidiabetic drugs (e.g., metformin)

• Insulin if needed

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Diagnosis (WHO Criteria)

• Fasting glucose ≥126 mg/dL

• Random glucose ≥200 mg/dL

• OGTT ≥200 mg/dL at 2 hours

• HbA1c ≥6.5%

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Hyperparathyroidism

Definition

Excess secretion of parathyroid hormone causing hypercalcemia.

Types

• Primary: Parathyroid adenoma or hyperplasia

• Secondary: Chronic hypocalcemia (CKD, vitamin D deficiency)

• Tertiary: Autonomous PTH secretion after long-standing secondary disease

Clinical Manifestations

• Kidney stones

• Bone pain, fractures, osteoporosis

• GI symptoms (constipation, nausea)

• Neuropsychiatric symptoms

• Polyuria, polydipsia

Treatment

• Surgical removal (primary)

• Calcimimetics (cinacalcet)

• Vitamin D and phosphate management (secondary)

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Thyroid Disorders

Hyperthyroidism (Graves’ Disease)

• Autoimmune stimulation of TSH receptors

• Symptoms: weight loss, tremor, anxiety, heat intolerance

• Labs: ↓ TSH, ↑ T3/T4

• Treatment: antithyroid drugs, beta-blockers, surgery

Thyroid Storm

• Life-threatening thyrotoxicosis

• Triggered by stress or surgery

• Requires ICU management

Hypothyroidism (Hashimoto’s)

• Autoimmune destruction of thyroid

• Symptoms: fatigue, weight gain, cold intolerance

• Treated with levothyroxine

D115 Unit 3 Videos: Bacterial Meningitis & Neurologic System Alterations

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Otitis Media

Definition

Inflammation of the middle ear, primarily in children.

Diagnosis

• Reduced tympanic membrane mobility

• Tympanometry or pneumatic otoscopy

Treatment

• First-line: high-dose amoxicillin

• Watchful waiting recommended for mild cases

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Mental Health Disorders

Depression

• ≥2 weeks of depressed mood or anhedonia

• Treated with SSRIs, psychotherapy, or combination

Generalized Anxiety Disorder

• Excessive worry ≥6 months

• Treated with CBT and SSRIs/SNRIs

Schizophrenia

• Psychotic disorder with positive, negative, and cognitive symptoms

• Treated with antipsychotics and psychosocial therapy