N120A Diseases: what they are

[Cardio] What is atherosclerosis?

A disease from the build up of plaque inside the artery walls. It narrows the vessel and chokes off flow, and is the common root of ischemic heart disease, cerebrovascular disease, and disease of the aorta and peripheral arteries. The herald lesion is endothelial dysfunction (oxidized LDL, free radicals, homocysteine, chronic infection), then leukocytes enter, foam cells form, platelets stick and the fatty streak matures into plaque. Risk factors: tobacco, inactivity, unhealthy diet, alcohol, high blood pressure, diabetes, high cholesterol, obesity, age.

[Cardio] How is atherosclerosis diagnosed and treated?

Risk factors are managed (BP, blood sugar, LDL, smoking). High LDL is treated with statins, which inhibit cholesterol synthesis in the liver and stabilize plaque.

[Cardio] What is hypertension and a hypertrophic heart?

Under sustained high pressure vessels build more muscle and become rigid, which raises resistance and pressure further. The heart muscle thickens, the chamber volume shrinks, and it becomes harder to pump blood through the heart.

[Cardio] How is hypertension and a hypertrophic heart diagnosed and treated?

Four main drug classes: ACE inhibitors, angiotensin receptor blockers, calcium channel blockers and thiazide diuretics. ACE inhibitors block angiotensin I to II conversion; ARBs block the angiotensin II receptor, lowering vasoconstriction, aldosterone and fluid retention.

[Cardio] What is a myocardial infarction (heart attack)?

A clot chokes off blood to heart tissue, so that area of the heart dies (ischemic event, same mechanism as an ischemic stroke). If enough muscle dies the heart can no longer pump and fails. Women can present more subtly (nausea, indigestion, weakness, jaw or back pain, cold sweat).

[Cardio] How is a myocardial infarction (heart attack) diagnosed and treated?

Diagnosed with EKG (ST elevation), troponin over 14 ng/L, then coronary angiography. Treated with PCI (balloon and drug-eluting stent coated with everolimus or zotarolimus), dual antiplatelet therapy (aspirin plus ticagrelor, prasugrel or clopidogrel), high-intensity statin (LDL under 55), ACE inhibitor, soluble fiber and sodium under 1,500 mg/day.

[Cardio] What is ischemic vs hemorrhagic stroke?

Ischemic: blocked blood flow to part of the brain, often an embolus (a clot that broke free from a vein or the heart) lodging in a cerebral artery. Hemorrhagic: increased blood pressure causes tears and blood leaks into the brain (intracerebral or subarachnoid). The most common cause of dementia is high blood pressure and cerebral small vessel disease.

[Cardio] What is a thrombus vs embolus vs embolism?

Thrombus: a clot that forms and stays where it formed, often in a vein. Embolus: a blood clot that breaks free and travels. Embolism: what happens when the embolus lodges in a vessel and blocks blood supply.

[Pulmonary] What is COPD?

Chronic obstructive pulmonary disease: fixed airflow obstruction (FEV1/FVC under 0.70) from chronic bronchitis plus emphysema. Dyspnea is caused by elevated CO2, elevated H+ and decreased O2. Risk factors: smoking, occupational dust and fumes (up to 14% of COPD), diesel exhaust, air pollution, alpha-1 antitrypsin deficiency. Women are about 37% more likely to develop it.

[Pulmonary] How is COPD diagnosed and treated?

Diagnosed with spirometry before and after a bronchodilator, staged by GOLD 1 to 4, supported by ABG, chest X-ray and CT, with AAT, sputum and V/Q to rule out alternatives. Treated with SABA rescue (albuterol), LAMA (tiotropium), LABA (formoterol), inhaled steroids when eosinophils are high, prednisone only for acute flares, oxygen, BiPAP, pursed-lip breathing, rehab, smoking cessation, vaccines.

[Pulmonary] What is chronic bronchitis?

The mucus disease, located in the bronchial tubes. Airway inflammation destroys cilia and drives excess mucus production, narrowing the airways. The mucus is filled with white blood cells and the mechanism is very similar to arterial plaques. Presents as a daily productive cough.

[Pulmonary] What is emphysema?

The scar tissue disease, located in the alveoli. Chronic inflammation releases enzymes that damage elastic fibers and alveolar walls, so the lungs lose elastic recoil and trap air. Presents as severe shortness of breath. Air trapping from chronic bronchitis leads into emphysema; most COPD patients have both.

[Pulmonary] What is asthma vs COPD?

Both are obstructive diseases. After a bronchodilator, an increase of 12% or more in FEV1 or FVC means reversible obstruction (asthma). If the airways do not open significantly, the obstruction is fixed (COPD).

[Pulmonary] What is obstructive vs restrictive lung disease?

Obstructive: difficulty exhaling through narrowed airways, air trapped, residual volume up, lungs overinflated (asthma, COPD, emphysema, chronic bronchitis, bronchiectasis, cystic fibrosis). Restrictive: difficulty expanding the lungs, reduced total lung capacity (pulmonary fibrosis, pneumonia, obesity).

[Pulmonary] What is respiratory failure?

Hypoxemic: oxygenation failure, PaO2 60 mmHg or lower on 60% oxygen. Hypercapnic: ventilatory failure, PaCO2 over 45 mmHg AND pH under 7.35. Either can be acute (minutes to hours) or chronic (days or longer).

[Renal] What is diabetic nephropathy?

Chronic hyperglycemia damages vessels. The afferent arteriole dilates and the efferent constricts, glomerular pressure rises, the filtration barrier is damaged, albumin leaks into urine, tubules are injured and scarred, and function is lost. It is the leading cause of chronic kidney failure. Stage 1: GFR spikes 20 to 50% above normal. Stage 2: GFR returns to normal, microalbuminuria. Stage 3: GFR falls steeply, macroalbuminuria. Stage 4: ESRD, GFR under 10.

[Renal] How is diabetic nephropathy diagnosed and treated?

Dipstick, uACR, eGFR, BUN and creatinine, cystatin C, nephrin, casts and imaging. Treated with SGLT2 inhibitors (empagliflozin, lowers glucose and hyperfiltration), ACE inhibitors (lisinopril) and ARBs (losartan) that relax the efferent arteriole and lower glomerular pressure, and GLP-1 receptor agonists (semaglutide). Stage 5 needs dialysis or transplant.

[Renal] What is chronic kidney disease?

Long-term gradual loss of kidney function and structure over months: eGFR under 60 for 3 months or more, or protein or albumin in urine lasting 3 months. Stages 1 and 2 are asymptomatic. Symptoms from 3a: fatigue, ankle and foot swelling, foamy urine. Stage 4 brings waste buildup, high BP, heart disease and marked swelling.

[Renal] How is chronic kidney disease diagnosed and treated?

Stages 1 and 2: prevent hypertension and diabetes from progressing, lifestyle change, control BP, avoid nephrotoxic drugs. Stage 3b: refer to nephrology. Stage 5: dialysis or transplant.

[Renal] What is acute kidney injury?

A sudden and rapid decrease in kidney function over hours to seven days. Hallmarks: sudden loss of excretory function, serum creatinine rising over 0.3 mg/dL in 48 hours, and urine output under 0.5 mL/kg/hr for 6 hours.

[Renal] What is polycystic kidney disease?

A genetic disorder causing fluid-filled cysts to grow in the kidneys, reducing function over time. Hereditary, 90% of cases autosomal dominant, massively enlarged kidneys, caused by PKD1 or PKD2 mutations.

[Renal] What is dialysis?

Does not cure chronic kidney disease; it removes waste and excess fluid and maintains electrolyte and fluid balance. Hemodialysis: blood through a dialyzer with a semipermeable membrane, about 3 sessions a week for 3 to 5 hours, through an arteriovenous fistula. Peritoneal: dialysis fluid in the abdomen, the peritoneum is the membrane, can be done at home, infection risk, glucose in the fluid makes blood sugar harder to manage. Transplant remains the best option.

[Renal] What is the glomerular barrier and what breaks it?

The kidneys filter only low molecular weight materials; proteins and blood cells must stay in. Podocytes with filtration slits, fenestrations in the capillary and the basement membrane filter by size. When it is damaged, albumin leaks into urine, blood colloid osmotic pressure drops and fluid is pulled into tissues (swelling).

[Diabetes] What is Type 1 diabetes?

An autoimmune disorder of unknown cause that destroys insulin-secreting beta cells, so there is no insulin and blood glucose rises unchecked. Also called insulin-dependent or juvenile diabetes, typically diagnosed in children and young adults, about 5% of diabetes. Polygenic (MHC II variants) with environmental triggers (low vitamin D, Coxsackie B4 virus); only about 30% of identical twins are both affected.

[Diabetes] How is Type 1 diabetes diagnosed and treated?

Low C-peptide and positive autoantibodies (GAD65, IAA, IA-2, ZnT8). Treated with exogenous insulin, 0.5 to 1 unit/kg/day: rapid-acting dose 20 to 30 minutes before a meal, long-acting 1 to 2 injections a day.

[Diabetes] What is Type 2 diabetes?

Insulin resistance: cells fail to respond to insulin, so glucose stays in the blood even though insulin is present. Early the pancreas overcompensates with excess insulin; late the beta cells are overworked and stop functioning, so it resembles Type 1. Symptoms: thirst, frequent urination, fatigue, hunger, blurred vision, slow healing, numbness, acanthosis nigricans.

[Diabetes] How is Type 2 diabetes diagnosed and treated?

High C-peptide and negative antibodies, plus HbA1c, glucose and OGTT. Treated with lifestyle, metformin (inhibits liver gluconeogenesis, raises insulin sensitivity), GLP-1 agonists (trigger insulin release, slow gastric emptying), DPP-4 inhibitors (keep GLP-1 and GIP higher), and insulin if needed.

[Diabetes] What is gestational diabetes?

The placenta produces hormones (estrogen, cortisol, human placental lactogen) that inhibit insulin function. If the pancreas cannot overcome that inhibition, gestational diabetes occurs. Risk factors: obesity, advanced maternal age, family history. Usually resolves after delivery but raises later Type 2 risk.

[Diabetes] What is prediabetes?

HbA1c 5.7 to 6.4%, fasting glucose 100 to 125 mg/dL, OGTT 140 to 199 mg/dL.

[Diabetes] How is prediabetes diagnosed and treated?

Regular exercise and a balanced diet: high-fiber foods, portion control, reduced sugars, less sedentary time, glucose monitoring, sleep management and smoking cessation.

[Diabetes] What is diabetic complications?

Diabetic gastroparesis (high sugar damages the vagus nerve, food sits and ferments), optic neuropathy and retinopathy (blurry vision), poor circulation in the legs (smoking plus sugary blood narrows arteries, leg pain and hair loss), osmotic diuresis (sugar in urine pulls water out), and diabetic nephropathy.

[Diabetes] What is the stress response and glucose?

Stress inhibits insulin release, increases glucagon, inhibits glycogen storage, increases lipolysis and gluconeogenesis, so everything is mobilized into the blood and diabetes management is thrown out of balance. Prolonged high cortisol breaks down muscle protein and causes central fat deposition.