Comprehensive Study Guide for Vascular, Valvular, and Endocrine, and Rheumatology and Rheumatological Medicine

Acute Aortic Dissection and Vascular Management

• Diagnostics for aortic regurgitation and and dilated aortic roots involve transoesophageal echocardiography (TOE), which provides superior visualization compared to transthoracic echocardiography (TTE) that is limited to the first $3-4\,cm$ of the ascending aorta.

• Advanced imaging modalities such as CT and MRI angiography offer high specificity and sensitivity for identifying intimal flaps in dissections.

• Management of acute dissection is time-critical due to an early mortality rate of approximately $1-5\%$ per hour.

• Initial stabilization focuses on pain control and aggressive antihypertensive therapy.

• Type A dissections involving the ascending aorta are surgical emergencies requiring replacement.

• Type B dissections are managed medically unless complicated by external rupture, vital organ ischemia (gut or kidneys), or limb ischemia.

• Medical targets for Type B management include maintaining a mean arterial pressure (MAP) of $60-75\,mmHg$ to minimize left ventricular (LV) ejection force.

• First-line pharmacological agents include $\beta$-blockers, specifically labetalol for its $\alpha$-blocking properties; alternatives for contraindicated patients include verapamil or diltiazem. Sodium nitroprusside serves as a second-line option.

• Endoluminal repair techniques include fenestrating the intimal flap to decompress the false lumen or implanting stent grafts via the femoral artery.

Hypertension: Definition and Aetiology

• Hypertension is defined as the blood pressure (BP) level where treatment benefits exceed the costs and hazards, utilizing arbitrary thresholds within a population continuum.

• Systemic BP increases with age and correlates strongly with risks of stroke and coronary artery disease.

• Secondary hypertension causes (approximately $5\%$ of cases) include pregnancy-induced pre-eclampsia, renal parenchymal diseases, polycystic kidney disease, and endocrine disorders like phaeochromocytoma or Conn’s syndrome.

• Essential hypertension (over $95\%$ of cases) has an unclear pathogenesis involving factors like renal dysfunction, insulin resistance, and autonomic tone.

• BP Classifications (mmHg):

  • Optimal: $< 120/80$

  • Normal: $< 130/85$

  • High Normal: $130-139/85-89$

  • Grade 1 (Mild): $140-159/90-99$

  • Grade 2 (Moderate): $160-179/100-109$

  • Grade 3 (Severe): $\ge 180/110$

  • Isolated Systolic Hypertension: Grade 1 ($140-159/ < 90$); Grade 2 ($\ge 160/ < 90$).

Acute Rheumatic Fever and Heart Disease

• Acute rheumatic fever is an immune-mediated delayed response to specific group A streptococci strains, occurring typically $2-3$ weeks post-pharyngitis.

• The pathogenesis involves antibodies cross-reacting with cardiac myosin, leading to inflammation in the endocardium, myocardium, and pericardium.

• Pathognomonic histological features include Aschoff nodules, which contain multinucleated giant cells and T lymphocytes.

• Clinical diagnosis follows the revised Jones criteria:

  • Major manifestations: Carditis, polyarthritis, chorea (Sydenham\u2019s chorea), erythema marginatum, and subcutaneous nodules.

  • Minor manifestations: Fever, arthralgia, elevated ESR or CRP, and first-degree AV block.

• The Carey Coombs murmur is a soft mid-diastolic murmur associated with mitral valvulitis and nodules on the valve leaflets.

• Management of acute episodes requires benzyl penicillin ($1.2\,million\,U\,IM$) or oral phenoxymethylpenicillin ($250\,mg$ four times daily for $10$ days).

• Anti-inflammatory therapy includes aspirin ($60-100\,mg/kg/day$) or prednisolone ($1.0-2.0\,mg/kg/day$) for severe carditis.

Valvular Heart Diseases: Mitral and Aortic

• Mitral Stenosis: Primarily rheumatic; causes progressive fibrosis and calcification. The mitral orifice may reduce from $5\,cm^2$ to less than $1\,cm^2$. Symptoms include effort-related dyspnoea, fatigue, and hemoptysis.

• Physical signs of Mitral Stenosis: Loud first heart sound ($S_1$), opening snap, and a mid-diastolic murmur.

• Mitral Regurgitation: Causes include mitral valve prolapse (\u201cfloppy valve\u201d), LV dilatation, and papillary muscle infarction. Signs include an apical pansystolic murmur radiating to the axilla.

• Aortic Stenosis: Etiology involves bicuspid valves in younger patients and senile degenerative calcification in older patients ($70-90$ years). The classic triad of symptoms includes angina, syncope, and breathlessness.

• Physical signs of Aortic Stenosis: Ejection systolic murmur (often musical or harsh like a saw) and a slow-rising carotid pulse.

• Aortic Regurgitation: Characterized by a large-volume or \u201ccollapsing\u201d pulse, Quincke\u2019s sign (capillary pulsation), and an early diastolic murmur. The Austin Flint murmur may occur in severe cases due to the regurgitant jet affecting mitral leaflet closure.

Infective Endocarditis

• This condition involves microbial infection of heart valves or endocardium, often at sites of pre-existing damage like VSDs or valvular regurgitation.

• Common organisms: \u201cViridans\u201d group streptococci (respiratory commensals) and Staphylococcus aureus (highly virulent, leading cause of acute endocarditis).

• Diagnosis utilizes Modified Duke Criteria, emphasizing positive blood cultures ($3-6$ sets) and echocardiographic evidence of vegetations.

• Clinical stigmata: Splinter haemorrhages, Osler\u2019s nodes (painful swellings), and Roth\u2019s spots in the fundi.

• Management involves long-term high-dose antibiotics (e.g., benzyl penicillin and gentamicin) or surgical valve replacement if complications like heart failure or abscess formation occur.

Congenital Heart Disease

• Persistent Ductus Arteriosus (PDA): Failure of the fetal connection between the aorta and pulmonary artery to close, causing a continuous \u201cmachinery\u201d murmur.

• Coarctation of the Aorta: Narrowing near the ductus arteriosus insertion, characterized by hypertension in the upper body and weak, delayed femoral pulses (radiofemoral delay).

• Atrial Septal Defect (ASD): Typically ostium secundum defects at the fossa ovalis; signs include a wide, fixed splitting of the second heart sound ($S_2$).

• Ventricular Septal Defect (VSD): The most common congenital defect; produces a loud pansystolic murmur at the left sternal edge.

• Tetralogy of Fallot: Comprises pulmonary stenosis, overriding aorta, VSD, and right ventricular hypertrophy. Symptoms include cyanosis and relief-seeking by squatting (Fallot\u2019s sign).

• Eisenmenger\u2019s Syndrome: Occurs when a long-standing left-to-right shunt leads to pulmonary hypertension and subsequent shunt reversal (right-to-left), causing cyanosis.

Metabolic and Inflammatory Bone Disorders

• Gout: Caused by monosodium urate crystal deposition. Acute episodes present with severe monoarthritis (often the first MTP joint). Management includes NSAIDs, colchicine ($0.5\,mg$), and long-term xanthine oxidase inhibitors like allopurinol or febuxostat to reach target urate levels ($< 360\,\mu mol/L$).

• Osteoporosis: Characterized by reduced bone density and micro-architectural deterioration. Key treatments include bisphosphonates (alendronic acid, zoledronic acid), denosumab (RANKL monoclonal antibody), and teriparatide (anabolic PTH fragment).

• Calcium Disorders: Hypercalcaemia (\u201cbones, stones, and abdominal groans\u201d) is often caused by primary hyperparathyroidism or malignancy. Hypocalcaemia (tetany) is evidenced by Trousseau\u2019s and Chvostek\u2019s signs.

Endocrine Pathologies: Cushing\u2019s and Diabetes

• Cushing\u2019s Syndrome: Glucocorticoid excess. Diagnosis is confirmed via overnight dexamethasone suppression tests (ONDST) or 24-hour urine free cortisol. Causes include pituitary adenomas ($70\%$), adrenal tumours, or ectopic ACTH production.

• Diabetes Mellitus: Type 1 involves autoimmune $\beta$-cell destruction; Type 2 involves insulin resistance and progressive $\beta$-cell failure. Diagnostic tools include HbA1c and oral glucose tolerance tests (OGTT; $75\,g$ glucose load).

• Maturity-Onset Diabetes of the Young (MODY): Monogenic forms of diabetes (e.g., GCK, HNF-1$\alpha$ mutations) typically presenting under age $25$.

Rheumatology and Advanced Aging

• Rheumatoid Arthritis (RA): A chronic inflammatory arthritis involving synovial infiltration by T cells and macrophages, leading to pannus formation and joint erosion.

• Ankylosing Spondylitis: Predominantly affects sacroiliac joints and the spine, associated with HLA-B27. Advanced disease may result in a \u201cbamboo spine\u201d configuration.

• Fibromyalgia: Characterized by widespread pain, fatigue, and sleep abnormalities (reduced delta waves).

• Normal Ageing: Features include neuronal loss, reduced glomerular filtration rate (GFR), loss of vascular elasticity, and deterioration of pancreatic $\beta$-cell function, leading to reduced physiological reserve.