High-Yield Nursing Study Guide: Respiratory, Gastrointestinal, and Endocrine Systems

Comprehensive vocabulary review of high-yield respiratory, gastrointestinal, and endocrine disorders for clinical nursing practice, including disease definitions, key pathophysiology, diagnostic criteria, and nursing protocols.

Epistaxis

Hemorrhage arising from vascular structures in either the anterior (Kiesselbach's plexus) or posterior (Woodruff's plexus) nasal cavity, managed by leaning forward and applying direct pressure to the soft septum for $10\text{--}15\,\text{mins}$.

Kiesselbach's Plexus

The superficial vascular network located in the anterior nasal cavity that represents the most common site of anterior epistaxis.

Woodruff's Plexus

The deep venous and arterial vascular network located in the posterior nasal cavity associated with posterior epistaxis.

Obstructive Sleep Apnea (OSA)

A disorder involving recurrent partial or complete upper airway collapse during sleep resulting in repetitive apneic episodes ($\ge 10\,\text{seconds}$), arterial hypoxemia, and sleep fragmentation.

Tonsillitis

Acute or chronic inflammation of the palatine tonsils and surrounding lymphatic mucosa, commonly caused by Group A Beta-Hemolytic Streptococcus (GABHS) or viral pathogens such as EBV and Adenovirus.

Asthma

A chronic inflammatory airway disease characterized by bronchial hyperresponsiveness, mucosal edema, and reversible airflow limitation triggered by IgE-mediated mast cell degranulation.

Chronic Bronchitis

A phenotype of COPD clinically defined as a productive cough lasting for at least $3\,\text{consecutive months}$ in $2\,\text{consecutive years}$, characterized by goblet cell hypertrophy, low V/Q mismatch, cyanosis ("Blue Bloater"), and secondary pulmonary hypertension.

Emphysema

A phenotype of COPD marked by permanent enlargement and destruction of alveolar walls distal to terminal bronchioles without obvious fibrosis, caused by elastase-driven breakdown of elastin and presenting with air trapping and barrel chest ("Pink Puffer").

Alpha-1 Antitrypsin (AAT) Deficiency

A hereditary genetic disorder predisposing individuals to early-onset emphysema due to the uninhibited proteolytic destruction of alveolar elastin by elastase.

Pulmonary Embolism (PE)

Occlusion of one or more branches of the pulmonary arterial bed by a thrombus, fat, air, or tumor embolus, leading to high V/Q dead-space ventilation, reflex bronchoconstriction, and right ventricular strain.

Virchow's Triad

The triad of venous stasis, endothelial injury, and hypercoagulability, representing the primary pathophysiological risk factors for deep vein thrombosis and pulmonary embolism.

Acute Respiratory Distress Syndrome (ARDS)

A severe, life-threatening form of acute, diffuse, non-cardiogenic inflammatory lung injury characterized by increased pulmonary capillary permeability, diffuse atelectasis, and refractory hypoxemia.

Type I Acute Respiratory Failure

Oxygenation failure of the respiratory system defined by a $\text{PaO}_2 < 60\,\text{mmHg}$, resulting from ventilation-perfusion (V/Q) mismatch or intrapulmonary shunting.

Type II Acute Respiratory Failure

Ventilatory failure characterized by inadequate carbon dioxide elimination, defined as a $\text{PaCO}_2 > 50\,\text{mmHg}$ with a $\text{pH} < 7.35$.

Pneumonia

Acute inflammation and infection of the lung parenchyma causing alveolar consolidation and exudate accumulation, most commonly caused in community-acquired settings by Streptococcus pneumoniae.

Respiratory Pandemics

Widespread global outbreaks of novel viral respiratory pathogens (such as SARS-CoV-2 or Influenza A H1N1) characterized by attachment to host receptors (e.g., ACE2 on Type II alveolar pneumocytes), rapid cell lysis, and cytokine storm.

Pneumothorax

A collection of air within the pleural cavity caused by a breach in the visceral or parietal pleura, disrupting normal negative intrapleural pressure and causing partial or complete collapse of the underlying lung.

Tension Pneumothorax

A medical emergency caused by continuous one-way air entry into the pleural space, leading to elevated intrapleural pressure, severe mediastinal shift, compression of the vena cava and contralateral lung, requiring immediate $14\text{G}$ needle decompression.

Chest Tube Drainage System

A closed drainage system inserted into the pleural space that maintains a one-way water-seal barrier to evacuate air, blood, or fluid while restoring sub-atmospheric negative intrapleural pressure.

Gastroesophageal Reflux Disease (GERD)

A chronic digestive disorder where transient or sustained relaxation of an incompetent lower esophageal sphincter (LES) allows acidic gastric juice and pepsin to backflow into the esophagus.

Barrett's Esophagus

Pre-malignant intestinal metaplasia of the lower esophageal mucosal lining resulting from chronic, unrepaired acid exposure and inflammation due to GERD.

Hiatal Hernia

Herniation of a portion of the stomach above the diaphragm into the thoracic cavity, categorized as Type I (Sliding) or Type II (Paraesophageal/rolling).

Peptic Ulcer Disease (PUD)

An ulcerative excoriation forming in the mucosal wall of the stomach (Gastric) or duodenum (Duodenal) that extends through the muscularis mucosae, most commonly caused by Helicobacter pylori or chronic NSAID use.

Triple Therapy (H. pylori)

A standard pharmacological treatment regimen for Helicobacter pylori eradication consisting of a Proton Pump Inhibitor (PPI), Amoxicillin, and Clarithromycin.

Appendicitis

Acute inflammation of the vermiform appendix resulting from luminal obstruction (fecaliths, lymphoid hyperplasia), with risk of gangrenous necrosis and perforation within $24\text{--}48\,\text{hours}$.

Crohn's Disease

A subacute/chronic inflammatory bowel disease causing transmural (all layers) inflammation that can involve any section of the gastrointestinal tract from mouth to anus, typically featuring non-continuous "skip lesions" and a "cobblestone" mucosal appearance.

Ulcerative Colitis

A chronic inflammatory bowel disease strictly limited to the mucosal and submucosal layers of the colon and rectum, featuring continuous retrograde inflammation and loss of colonic haustra ("lead-pipe" sign on X-ray).

Celiac Disease

A hereditary autoimmune enteropathy linked to HLA-DQ2/HLA-DQ8 markers, where ingestion of gluten peptide (gliadin) triggers immune-mediated blunting and complete flattening of small bowel villi.

BROW

A dietary mnemonic representing the four primary gluten-containing grains that must be eliminated in Celiac disease: Barley, Rye, Oats, and Wheat.

Diabetes Mellitus (DM)

A group of metabolic disorders characterized by chronic hyperglycemia resulting from autoimmune beta-cell destruction and absolute insulin deficiency (Type 1) or peripheral insulin resistance and secretory defects (Type 2).

Rule of 15

A standardized nursing protocol for managing hypoglycemia requiring administration of $15\,\text{g}$ of fast-acting simple carbohydrates followed by rechecking blood glucose levels after $15\,\text{minutes}$.

Addison's Disease

Primary adrenocortical insufficiency caused by destruction of $>90\%$ of the adrenal cortex, leading to deficient glucocorticoids (cortisol), mineralocorticoids (aldosterone), and androgens.

Rule of 3s (Steroid Therapy)

A critical educational guideline for patients with Addison's disease advising them to double or triple their regular maintenance steroid dose during periods of acute physiological stress, trauma, or illness.

Cushing's Syndrome

A clinical syndrome resulting from chronic, excessive systemic exposure to glucocorticoids (cortisol), characterized by exaggerated protein catabolism, central adiposity (buffalo hump, moon face), and immune suppression.