HYPERTHYROIDISM

Introduction

Thyrotoxicosis is the clinical syndrome that results from elevated levels of circulating thyroid hormones
Hyperthyroidism (thyroid overactivity, thyrotoxicosis) is common, affecting perhaps 2–5% of all females at some time and with a sex ratio of 5:1, most often between the ages of 20 and 40 years

Pathogenesis

Thyroid hormone increases oxygen consumption by tissues, raising heat production and energy metabolism. It interacts with the sympathetic nervous system in a way that seems to increase tissue sensitivity to catecholamines and adrenergic stimuli (Tachycardia and extremity tremor are the examples of catecholamines hypersensitivity)

HYPOTHYROIDISME

The Principle Effects of The Thyroid Hormones

Primary Effects

1. Aerobic energy metabolism
2. Glucose metabolism
3. Protein metabolism
4. Lipid metabolism
5. Iron transport

Secondary Effects

1. Growth/Development
2. Cardiac output
3. Ventilation
4. CNS activity
5. Thermoregulation (Heat regulation)
6. Muscle function
7. GI activity
8. Reproductive function

Hypothyroidism is a clinical syndrome caused by deficiency of thyroid hormones

The onset of symptoms is usually insidious, and the condition may go undetected for years

LIVER CIRRHOSIS

Definition

Histological features of cirrhosis (3)

• Diffuse distortion of the basic architecture
• Replacement of normal liver parenchyma with scar tissue and fibrosis
• Formation of regenerative nodules

Stage 1 cirrhosis is compensated and asymptomatic, can last for 10-20 yr with almost normal life
expectancy
Stage 2 cirrhosis is the onset of first decompensation, typically development of ascites (most
common), variceal bleeding, encephalopathy, etc.

Anatomopathology
Macroscopic appearance
Consistency hard, sharp inferior edge, dysmorphia: atrophy > hypertrophic
Irregular size: micro nodules (<3mm) and macro nodules (> 3 mm) regeneration
Microscopic appearance
Mutilating fibrosis ring replacing the normal parenchyma
Regenerating nodules limited by fibrosis / diffuse lesions

CHRONIC RENAL DISEASE

Chronic renal failure is defined as a reduction for over 3 months of the filtration of waste with any evidence of kidney damage (in early stage), which glomerular filtration rate: GFR < 60 ml/min according to Gault and Cockcroft, or 60 ml/mn/1.73m2 as MDRD formula

Cockroft-Gault equation
Cr. Cl (mL/min) = (140 – age) x weight / 72 x S. Cr (x 0.85, if female)

Risk factors

NEPHROTIC SYNDROME

A. Physiological Proteinuria

Every day, 10 to 15 kg of serum proteins pass through the kidney, but only 100 to 150 mg are excreted in the urine in 24 hours
The glomerular capillary wall opposes to the filtration effect of these proteins, and the proximal tubule reabsorbs the great amount of filtered proteins
In the normal state, 60% of urinary proteins excreted from plasma proteins: they are mainly low weight proteins molecular (lysozyme, β-2 macroglobulin); the remaining 40% come from the tubular secretion uromodulin (Tamm-Horsfall protein) and urothelium of the urinary tract

BENIGN PROSTATE HYPERPLASIA

Introduction

BPH: Benign and diffuse hyperplasia of prostate

Androgen-dependent

Anatomy review

Prostate lies immediately inferior to the bladder, posterior to the pubic symphysis and anterior to the rectum. It is a gland, consisting of a median lobe (Central lobe) and two lateral lobes (Peripheral lobe), that surrounds the neck of the bladder and the urethra in the male

Diameter of 2 x 4 x 3 cm, and weighing about 15-20 g, and enclosed in a fibrous capsule containing smooth muscle fibers in its inner layer

The gland secretes a thin, opalescent, slightly alkaline fluid that forms part of the seminal fluid. No endocrine function

(Gray's Atlas of Anatomy)

URINARY TRACT INFECTION (UTI)

Definition

To describe urinary tract infections, qualifying: low or high, or primitive Secondary should be avoided; because they are confusing. It's simple to call: complicate and simple
Complicated urinary tract infection
Is a urinary tract infection occurring with risk factor that can make the infection worse and more complex treatment
Risk Factor:
- Pregnancy, elderly (≥ 65 years) associated with disease,
- Organic or functional abnormality of the urinary tract (bladder residue,
reflux, stones, tumor, invasive bladder maneuver)
- Co-morbidity: diabetes, immunosuppression, renal failure

Note: UTI in men is rare to man due to its long urethra and protected by prostatic secretion. Usually accompanied by organic or functional abnormality of the urinary tract
Recurrent cystitis

A recurrent cystitis is described as if there were at least 4 episodes in a year or 2 in 6 months

Urinary Colonization / asymptomatic bacteriuria
It corresponds to the presence of a microorganism in the urine without clinical manifestation associated. Abstention therapeutic is the rule unless the patient is at risk: pregnant, neutropenia, immunosuppression, urological maneuvers

ACID-BASE REGULATION AND DISORDERS

Hydrogen ion (H⁺) is especially reactive; it can attach to negatively charged proteins and, in high concentrations, alter their overall charge, configuration, and function Acid-base equilibrium is closely tied to fluid and electrolyte balance, and disturbances in one of these systems often affect another

Acid-Base Physiology

Most acid comes from carbohydrate and fat metabolism, which generates of CO₂ daily. CO₂ is not an acid itself but combines with water (H₂O) in the blood to create carbonic acid (H₂CO₃), which in the presence of the enzyme carbonic anhydrase dissociates into H+ and HCO₃^-. The H⁺ binds with hemoglobin in RBCs and is released with oxygenation in the alveoli, at which time the reaction is reversed, creating H₂O and CO₂, which is exhaled in each breath

CELLULAR MECHANISMS OF Cl− ABSORPTION AND SECRETION

Cl^- absorption occurs throughout the small and large intestine and is often closely linked to Na⁺ absorption. Cl⁻ and Na⁺ absorption may be coupled through either an electrical potential difference or by pH_i. However, sometimes no coupling takes place, and the route of Cl⁻ movement may be either paracellular or transcellular.

CELLULAR MECHANISMS OF K+ ABSORPTION AND SECRETION (GI Tract)

The pattern of intestinal K⁺ movement parallels that of the kidney: (1) the intestines have the capacity for both K⁺ absorption and secretion, and (2) the intestines absorb K⁺ in the proximal segments but secrete it in the distal segments

Dietary K⁺ furnishes 80 to 120 mmol/day, whereas stool K⁺ output is only ~10 mmol/day. The kidney is responsible for disposal of the remainder of the daily K⁺ intake

Substantial quantities of K⁺ are secreted in gastric, pancreatic, and biliary fluid. Therefore, the total K⁺ load presented to the small intestine is considerably greater than that represented by the diet

CELLULAR MECHANISMS OF Na+ ABSORPTION (GI Tract)

 1. Electrogenic Sodium Absorption

This is an active sodium absorption mechanism present not only in the intestine but also in several other epithelia. Active absorption of sodium creates a negative electrical potential in the compartment which sodium leaves as compared to the one which it enters. In case of the intestinal epithelium, the pump for active absorption is present in the basolateral membrane.

The process may be conceptually broken into two stages:

The process may be broken into two steps: 1 and 2. To understand the process, 2 may be considered before 1. Sodium is actively pumped across the basolateral membrane of intestinal epithelium (2). Since sodium ions are positively charged, it creates a potential difference across the membrane, the outside being positive as compared to inside the cell. As a result of the electrical gradient, sodium ions move passively from the lumen into the enterocyte (1). Active transport (2) is against the electrical and concentration gradient. The electrical gradient generated by the active transport (and hence the name electrogenic) leads to passive transport (1) along the electrical and concentration gradient

Vitamin B12(Cobalamin) Absorption

Cobalamin, or vitamin B₁₂, is synthesized only by microorganisms, not by mammalian cells. Only bacteria and archaea have the enzymes required for its synthesis; neither fungi, plants, nor animals (including humans) are capable of producing vitamin B₁₂. Although many foods (Animal products: meat, fish, shellfish, eggs, and (to a limited extent) milk) are a natural source of B₁₂ because of bacterial symbiosis. The vitamin is the largest and most structurally complicated vitamin and can be produced industrially only through bacterial fermentation-synthesis.

ALCOHOLIC LIVER DISEASE

Disorders that occur in alcohol abusers, often in sequence, include

• Fatty liver (in > 90%)

• Alcoholic hepatitis (in 10 to 35%)

• Cirrhosis (in 10 to 20%)

Hepatocellular carcinoma may also develop, especially in association with iron accumulation.

ATHEROSCLEROSIS

Definition

Arteriosclerosis literally means “hardening of the arteries”; it is a generic term reflecting arterial wall thickening and loss of elasticity; from the Greek αρτηρία, meaning arteary, and σκληρωτικός, meaning sclerotic (Hardened). Three distinct types are recognized, each with different clinical and pathologic consequences:
Arteriolosclerosis
Thickening of the wall in small arteries and arterioles which carry important nutrients and blood to the body’s organs, causes a reduction in lumen size. Often related to systemic hypertension and diabetes mellitus
Atherosclerosis
is the narrowing of arteries from a build up of plaque, made up of cholesterol, fatty substances, cellular waste products, calcium and fibrin, inside the arteries. This affects large and medium-sized arteries; however, its positioning varies person to person
Monckeberg's arteriosclerosis or medial calcific sclerosis
Seen mostly in the elderly, Characterized by calcification of the tunica media (middle layer of the walls of arteries) but without thickening of the intima or narrowing of the vessel lumen

VALVULAR HEART DISEASE

Aortic Stenosis

Definition

• Normal aortic valve area = 3-4 cm²

• Mild AS 1.5-3 cm² / Moderate AS 1.0-1.5 cm² / Severe AS <1.0 cm² / Critical AS < 0.5 cm²

ISCHEMIC HEART DISEASE

Definition

• Chronic Stable Angina = Angina during activity (Work, Exercise, etc.)
• Angina/Angina Pectoris = Secondary pain due to myocardial ischemic
• Stable = Decrease/Absent of pain after arrest activity (<5 min) without Nitroglycerin