Exam3BEST

Labs to Assess Connective Tissue Diseases

• Antinuclear Antibody (ANA): High sensitivity, low specificity; positive results may also occur in aging, HIV, and certain cancers.
• Double-Stranded DNA (dsDNA): Indicates autoimmune activity; often associated with systemic lupus erythematosus (SLE).
• Anti-Smith Antibodies: Highly specific for SLE; targets specific nuclear proteins.
• SS-A (Ro) and SS-B (La) Antibodies: Linked to Sjögren's Syndrome and sometimes SLE.
• Anti-Scl-70 (Topoisomerase 1) Antibodies: Associated with systemic scleroderma; characterized by thickened skin and potential lung issues.
• Anti-Centromere Antibodies: Indicate limited scleroderma (CREST syndrome); primarily affects skin without significant internal organ involvement.

RA versus OA

• Osteoarthritis (OA): Typically affects small joints, develops with age (45-55 years), worsens with activity; lab tests show normal ESR and negative RF.
• Rheumatoid Arthritis (RA): Can be indicated by specific markers, different pathophysiology than OA.

Evaluation and Diagnosis of Pneumonia

• Chest X-ray: Essential for identifying pneumonia; shows consolidation in affected alveoli.
• Clinical Signs: Dullness over consolidation, crackles, fever, malaise, and respiratory distress.
• Lung-Related Symptoms: Cough with purulent sputum, pleuritic chest pain, shortness of breath.

Pneumonia Pathogens

• Community-Acquired Pneumonia (CAP): Common pathogens include Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, and Legionella pneumophila.
• Hospital-Acquired Pneumonia (HAP): Includes Klebsiella pneumoniae, Staphylococcus aureus (MRSA), and Acinetobacter baumannii.
• Immunocompromised Hosts: Vulnerable to fungal (Histoplasma, Coccidioides) and viral pathogens (CMV).

TB Pathogenesis

• Transmission: TB spreads via inhalation of droplets from an infected person.
• Survival Mechanism: TB bacteria evade immune responses, surviving within macrophages.
• Granulomas: Formed as immune response aggregates; key sign of TB.
• Types of TB: Pulmonary TB (lungs) and extrapulmonary TB (other body parts).

Pathology of ARDS

• Inflammatory Response: Triggered by various factors leading to endothelial and epithelial damage.
• Fluid Leakage: Results in pulmonary edema, causing hypoxemia.
• Clinical Presentation: Rapid breathlessness, hypoxemia, bilateral shadowing on chest X-rays.

Evaluation of Wheezing

• History and Physical Exam: Assess frequency, triggers, allergies, and overall respiratory function.
• Pulmonary Function Tests (PFTs): Spirometry assesses airway obstruction; peak expiratory flow indicates asthma.

Chest X-rays and Pulmonary Diseases

• Emphysema: Shows hyperinflation and flattened diaphragm.
• Pneumonia: Identified by consolidation and air bronchograms in imaging.
• Tuberculosis: Characterized by cavitary lesions and Ghon complexes.

Cystic Fibrosis Pathophysiology

• Genetic Defect: CFTR gene mutation leads to thick mucus in lungs and pancreas.
• Pulmonary Complications: Chronic infections, respiratory failure, and bronchiectasis.
• Gastrointestinal Effects: Malabsorption, meconium ileus, and liver disease.

Diagnosing Cystic Fibrosis

• Sweat Test: Elevated chloride levels confirm CF diagnosis.
• Clinical Manifestations: Persistent cough, lung infections, and pancreatic insufficiency.

Common Causes of Lung Cancer

• Primary Cause: Cigarette smoking accounts for 90% of lung cancer cases.
• Non-Smoker Cases: Adenocarcinoma prevalent in females; other factors include asbestos and radon exposure.

Chronic Hypoxemia and Hypercapnia

• Type I Respiratory Failure: Characterized by low oxygen levels; often seen in pneumonia.
• Type II Respiratory Failure: High CO2 levels; associated with conditions reducing lung function (e.g., COPD).

CPAP Therapy for OSA

• Mechanism: Delivers continuous air pressure to keep airways open during sleep, preventing obstructive episodes.

Origin of Pulmonary Emboli

• Deep Vein Thrombosis (DVT): Most emboli originate from blood clots in leg veins; clots travel to pulmonary arteries.

Types of Pneumothorax

• Primary Spontaneous Pneumothorax (PSP): Common in tall, young males; often idiopathic.
• Secondary Spontaneous Pneumothorax (SSP): Associated with chronic lung diseases in older adults.

Multiple Sclerosis Overview

• Autoimmune Condition: Attacks CNS; causes demyelination and formation of lesions.

• Clinical Features: Includes visual impairment, ataxia, and urinary symptoms.

• Types of Lesions: Periventricular, juxtacortical, infratentorial, and spinal cord lesions with specific implications for function.### Types of Seizures

• Bright lesions indicate active inflammation and fluid accumulation.

Epilepsy

• Characterized by unprovoked seizures resulting from hypersynchronous electrical activities in the brain.
• Risk factors include:
  • TORCH infections (Toxoplasma, Rubella, Cytomegalovirus, Herpes)
  • Prematurity
  • Hypoxic ischemic injury at birth
  • Family history of seizures
  • History of febrile seizures in childhood
  • History of meningitis, encephalitis, or head trauma

Epidemiology

• Up to 10% of individuals will experience a seizure at some point in their lives.
• After one unprovoked seizure, there is a 30% chance of experiencing a second seizure.
• Approximately 1% of the population has epilepsy.
• New onset seizures are most common in very young children and older adults.

Febrile Seizures

• Most prevalent cause of new onset seizures in children.
• Typically occur in children aged six months to five years.
• Triggered by fever; usually absent of any intracranial infection.
• Can be generalized at onset and may recur with future fevers.
• Not classified as epilepsy since they are provoked by fever.

Clinical Pearls

• Seizures in children generally have a favorable prognosis.
• Focal onset seizures may occur with prolonged duration.
• Presence of other neurologic abnormalities or family history of epilepsy can be noted.
• A small percentage of children with febrile seizures may develop epilepsy with unprovoked seizures in the future.

Management

• Involves prompt treatment of fever.
• Antiepileptic drugs may be considered if seizures are prolonged or if fever control is insufficient.

Seizure Types

• Focal Seizures: Affect one part of the brain.

  • Simple Partial: No loss of awareness, symptoms include twitching or tingling. Mnemonic: "Simple, Stay Sharp."
  • Complex Partial: Awareness impaired; features repetitive actions like lip-smacking. Mnemonic: "Complex, Conscious Cloudy."

• Generalized Seizures: Involve the entire brain.

  • Tonic-Clonic (Grand Mal): Whole body shaking, consists of tonic (stiffening) and clonic (jerking) phases. Mnemonic: "Tonic-Clonic, Total Chaos."
  • Absence: Brief periods of being "absent" or spaced out, typically involves staring. Mnemonic: "Absence, Away Awhile."

Clinical Presentation of Meningitis

• Common Symptoms: Headache, neck rigidity, nausea/vomiting.

• Classic Triad in Bacterial Meningitis:

  • Altered Mental Status: Glasgow coma scale score < 14.
  • Fever: > 38℃.
  • Stiff Neck.

• Symptoms of Meningitis: Severe headache, lethargy, nausea, vomiting, photophobia.

• Signs of Meningeal Irritation:

  • Stiff Neck: Difficulty touching chin to sternum.
  • Kernig Sign: Pain when extending knee while hip is flexed.
  • Brudzinski Sign: Involuntary knee flexion when neck is flexed.

• CSF Analysis:

  • Normal CSF-to-blood glucose ratio: 0.6; ≤ 0.5 indicates bacterial meningitis.
  • Elevated lactate (≥ 35 mg/dL) and protein in bacterial cases.

Neurotransmitters and Their Functions

• Acetylcholine (ACh):

  • Primary neurotransmitter for preganglionic neurons in both sympathetic and parasympathetic systems.
  • Nicotinic Receptors: Found on postganglionic neurons.
  • Muscarinic Receptors: Target cells in parasympathetic and some sympathetic systems (e.g., sweat glands).

• Norepinephrine (NE):

  • Main neurotransmitter for most postganglionic sympathetic neurons utilizing adrenergic receptors.

• Epinephrine:

  • Released by the adrenal medulla during sympathetic response; acts on adrenergic receptors similarly to NE.

Sympathetic vs. Parasympathetic Nervous System

• Preganglionic Fibers:
  • PSNS: Long preganglionic, short postganglionic fibers.
  • SNS: Short preganglionic, long postganglionic fibers.
• Neurotransmitters:
  • Both release ACh from preganglionic neurons; PSNS also releases ACh from postganglionic neurons, while SNS typically releases NE (except in sweat glands).

Clinical Manifestations of Horner’s Syndrome

• Characteristics:
  • Unilateral condition involving ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (absence of sweating).
• Common Cause: Pancoast lung tumor affecting sympathetic structures.

Ischemic Stroke Types

• Focal Ischemic Stroke:

  • Occurs due to compromised blood vessel; commonly caused by thrombi from the heart (e.g., atrial fibrillation).

• Global Ischemic Stroke:

  • Results from low systemic blood pressure affecting brain blood supply.

Stroke Causes and Common Affected Areas

• Focal Cerebral Ischemia: Atherosclerosis is the most common cause.
• Global Cerebral Ischemia: Linked to hypotension from acute blood loss.
• Thrombus Formation: Often occurs at the bifurcation of the carotid artery.

Hemorrhagic Stroke

• Causes:
  • Intracerebral hemorrhage due to hypertension, berry aneurysms, and mass lesions (e.g., cancer).
• Clinical Presentation:
  • Thunderclap headache indicates subarachnoid hemorrhage; observational features may include motor deficits depending on the affected region.
• Diagnosis and Management:
  • Fresh frozen plasma is used for coagulopathy; surgical management is for deteriorating patients.

Cerebral Aneurysm

• Berry Aneurysm:
  • Weakened blood vessel wall leads to a sac-like bulge, commonly resulting in rupture and subarachnoid hemorrhage.
• Location:
  • More prevalent in the anterior portion of the Circle of Willis; can compress nearby cranial nerves leading to pupil abnormalities.

Characteristics of Insomnia

• Difficulty initiating or maintaining sleep, waking too early, daytime impairments, and symptoms persisting for at least three months.

Clinical Manifestations of Headache Types

• Primary Headaches: Include migraines (throbbing pain, nausea), cluster headaches (severe, unilateral pain), and tension-type headaches (band-like pressure).
• Secondary Headaches: Result from underlying conditions like subarachnoid hemorrhage, meningitis, or tumors, presenting acute or chronic pain based on the etiology.

Common Causes of Headaches

• Triggered by stress, hormonal fluctuations, or specific foods for primary headaches; secondary headaches may arise from infections, vascular issues, or brain masses.### Headache Types
• Cluster Headache: Severe, unilateral pain around the eye; associated with autonomic symptoms like lacrimation and nasal congestion.
• Post-Coital Headache: Sudden, intense headache occurring during or after sexual activity.

Secondary Headaches

• Intracerebral Hemorrhage: Acute headache with focal neurological deficits; results from ruptured brain blood vessel.
• Subarachnoid Hemorrhage: Sudden, severe headache ("thunderclap"); often caused by a ruptured aneurysm.
• Meningitis: Severe headache accompanied by fever and neck stiffness; caused by infection of the meninges.
• Temporal Arteritis: Unilateral, continuous headache with scalp tenderness; results from inflammation of temporal arteries.
• Hypertensive Urgency: Dull, bilateral headache; linked to severe, uncontrolled hypertension.
• Venous Sinus Thrombosis: Diffuse headache with papilledema; caused by blood clot in the brain's venous sinuses.
• Brain Tumor: Insidious headache worsening in the morning; associated with tumor growth in the brain.

Alzheimer’s Disease Pathophysiology

• Key Proteins Implicated: Beta-amyloid and tau.
• Beta-Amyloid: Formed from amyloid precursor protein (APP) breakdown; abnormal levels pool as neuritic plaques that disrupt neuron function.
• Tau: Stabilizes microtubules; undergoes abnormal changes in Alzheimer's, leading to neurofibrillary tangles that disrupt neuron functions.

Gastroesophageal Reflux Disease (GERD) Pathophysiology

• LES Dysfunction: Inadequate closure allows stomach acid to backflow.
• Transient LES Relaxations: Occurs inappropriately, causing acid reflux.
• Hiatal Hernia: Stomach bulges through diaphragm, disrupting LES function.
• Impaired Esophageal Clearance: Reduced peristalsis allows acid reflux.
• Delayed Gastric Emptying: Accumulated pressure increases reflux risk.
• Increased Intra-Abdominal Pressure: Factors like obesity exacerbate reflux.
• Esophageal Mucosal Damage: Chronic acid exposure causes esophagitis and complications like Barrett's esophagus.

Risks of Chronic GERD

• Esophagitis: Inflammation from acid exposure.
• Esophageal Stricture: Narrowing from scar tissue; difficulty swallowing.
• Barrett’s Esophagus: Pre-cancerous changes; increased risk of esophageal adenocarcinoma.
• Esophageal Ulcers: Sores due to acid exposure.
• Chronic Cough/Laryngitis: Irritation from acid.
• Asthma Exacerbation: Triggered by reflux.
• Dental Erosion: Acid effects on tooth enamel.
• Increased Cancer Risk: Particularly adenocarcinoma from chronic inflammation.
• Aspiration Pneumonia: Stomach contents aspirated into lungs.

Cells of the Stomach

• Parietal Cells: Produce gastric acid and intrinsic factor.
• Chief Cells: Produce pepsinogen for protein digestion.
• Mucous Cells: Protect stomach lining.
• Enteroendocrine Cells: Secrete hormones for digestive regulation.
• Stem Cells: Renew stomach lining.

Gastric Anatomy

• Cardia: Secretes mucus for protection; contains foveolar and sensory tuft cells.
• Corpus (Body): Major site for acid production; contains parietal and chief cells.
• Antrum: Regulates acid production; contains G cells (gastrin) and D cells (somatostatin).

Etiology of Peptic Ulcer Disease (PUD)

• Helicobacter pylori: Major contributor; causes most duodenal and gastric ulcers.
• Medications: NSAIDs reduce mucosal defenses.
• Alcohol/Smoking: Increase acid secretion and reduce mucus.
• Hormonal Factors: Excess gastrin increases acid production.
• Chronic Diseases: Poor blood supply from conditions like COPD.
• Stress: Elevates glucocorticoids affecting GI vasculature.

NSAID Impact on GI Function

• Reduced Protective Prostaglandins: Leads to gastric irritation and bleeding.
• Decreased Mucosal Blood Flow: Impairs mucosal defense against acid.
• Increased Acid Secretion: Causes further mucosal damage.
• Impaired Healing: Complicates recovery from ulcers.

Clinical Presentation of Pyloric Stenosis

• Projectile Vomiting: Forceful, occurring shortly after feeding.
• Persistent Hunger: Despite frequent vomiting.
• Dehydration Signs: Dry mouth, low urine output.
• Weight Loss: Due to inadequate intake.
• Olive-like Mass: Palpable mass in the right upper quadrant.
• Hypochloremic Metabolic Alkalosis: Lab findings from loss of gastric acid.
• Visible Peristalsis: Movements in the abdomen after feeding.

Types of Colitis

• Ulcerative Colitis (UC): Chronic, affects colon/rectum, bloody diarrhea.
• Crohn's Disease: Affects any GI tract section; patchy inflammation.
• Infectious Colitis: Caused by pathogens; presents with bloody diarrhea.
• Ischemic Colitis: Reduced blood flow; sudden pain and bloody diarrhea.
• Microscopic Colitis: Chronic watery diarrhea, not visible.
• Chemical Colitis: Caused by harsh chemicals; leads to abdominal issues.
• Radiation Colitis: Post-radiation therapy complications.
• Pseudomembranous Colitis: Linked to C. difficile; severe diarrhea.
• Eosinophilic Colitis: Eosinophil increase; linked to allergies.

Causes of Bowel Obstruction

• Small Bowel Obstruction: Commonly caused by adhesions, hernias, or tumors.
• Large Bowel Obstruction: Often due to colorectal cancer or volvulus.

Osmotic Diarrhea

• Mechanism: Occurs when substances remain unabsorbed, drawing water and leading to bacterial fermentation.
• Clinical Features: Loose stools and gas production.

GI System Innervation

• Extrinsic Innervation: Managed by the autonomic nervous system (SNS and PNS).
• Intrinsic Innervation: Enteric nervous system (ENS) controls local functions.
• Coordination: ENS operates independently, but influenced by SNS and PNS.

Clinical Manifestations of Celiac Disease

• Gastrointestinal Symptoms: Diarrhea, steatorrhea, bloating, and cramping.
• Extra-Intestinal Symptoms: Malnutrition, anemia, and dermatitis herpetiformis.

Differences Between Crohn’s Disease and Ulcerative Colitis

• Crohn's Disease: Skip lesions, can affect any GI section, typically non-bloody diarrhea.
• UC: Continuous lesions, rectal onset, classical bloody diarrhea.

Complications of Diverticulitis

• Abscess Formation: Pocket of pus in the colon wall.
• Perforation: Leads to peritonitis.
• Fistulas: Abnormal connections between colon and other organs.
• Bowel Obstruction: Due to scarring/inflammation.
• Bleeding: From diverticula inflammation.

Hepatic Injury

• Hepatocyte Damage: Releases inflammatory mediators and activates Kupffer cells.
• Stellate Cell Activation: Regenerates hepatocytes and causes fibrosis with recurrent injury.

Clinical Manifestations of Cirrhosis

• Liver Changes: Irregular, scarred liver structure.
• Portal Hypertension: Causes ascites and varices.
• Spleen Issues: Enlarged spleen and low platelet count.
• Liver Dysfunction: Impaired synthetic and metabolic functions.

Types of Irritable Bowel Syndrome (IBS)

• IBS-D: Predominance of diarrhea.
• IBS-C: Predominance of constipation.
• IBS-M: Mixed symptoms of diarrhea and constipation.### IBS Types
• IBS-D (Diarrhea-predominant): Symptoms include frequent, loose, watery stools, urgency, and potential incontinence. Pain is often relieved by bowel movements.
• IBS-C (Constipation-predominant): Characterized by hard, dry stools, infrequent bowel movements, and straining. Pain may improve with bowel movements but frequently is linked to discomfort from constipation.
• IBS-M (Mixed): Symptoms alternate between diarrhea and constipation. Pain can vary based on bowel movement patterns.

Diagnostics for GI Cancers

• Primary Diagnostic Method: Esophagogastroduodenoscopy (EGD), which uses a flexible tube to examine the esophagus, stomach, and duodenum.
• Specific Findings:
  • Ulcerated Masses: Open sores in the stomach lining that do not heal.
  • Irregular, Heaped-Up Margins: Uneven or raised edges in the stomach.
  • Induration: Hardness or thickening within the stomach wall.
• Linitis Plastica Characteristics: A subtype of gastric carcinoma indicating stiffening of the stomach wall, absence of normal folds, and diffuse infiltrative appearance.
• Less Effective Method: Barium imaging, which has lower sensitivity than EGD, potentially missing early gastric carcinoma signs, thus less reliable for diagnosis.
• Early Surveillance: Regular EGD is essential for high-risk individuals for early detection of gastric carcinoma, improving treatment effectiveness.
• Benefits of EGD: Direct visualization of the stomach lining allows for accurate detection of abnormalities.
• Barium Imaging Limitations: Less invasive, but lower sensitivity may necessitate reliance on EGD for definitive diagnosis and monitoring.

ETOH and PUD

• Alcohol and smoking contribute to ulcer formation by decreasing mucus production and increasing gastric acid secretion.

Clinical Manifestations of Appendicitis

• Abdominal Pain: Begins around the belly button, later shifting to the lower right quadrant (McBurney's point).
• Nausea and Vomiting: Commonly accompany the abdominal pain.
• Loss of Appetite: Often noted with the onset of pain and nausea.
• Fever and Chills: May indicate systemic inflammation.
• Tenderness: Notable at McBurney’s Point (2/3 from umbilicus to anterior iliac spine).
• Psoas Sign: Pain on hip flexion against resistance or extension of the hip when on the left side indicates irritation of the psoas muscle.
• Obturator Sign: Pain on internal rotation of the right hip when flexed indicates irritation of the obturator muscle.
• Rovsing Sign: Pain in the right lower quadrant when the left lower quadrant is palpated, suggesting appendicitis.

Explanation of Signs

• Psoas Sign Testing: Pain during hip flexion against resistance or hip extension when on the left side indicates inflammation.
• Obturator Sign Testing: Pain during internal rotation of the hip while flexed suggests irritation.
• Rovsing Sign Testing: Pain in the right lower quadrant when palpating the left indicates possible appendicitis.

These tests are crucial for diagnosing appendicitis by assessing pain responses to specific movements or palpation.