HEMODYNAMICS - I

DERANGEMENTS OF BODY FLUIDS - OEDEMA

Dr. Jyothi Reshma STutor Dept of Pathology

The mechanism by which the constancy of the internal environment is maintained and ensured is called the homeostasis.

Claude Bernarde (1949) – internal environment or milieu interieur

Internal envt – water and electrolytes

HOMEOSTASIS

FLUID COMPARTMENTS

STARLING’S FORCES HYDROSTATIC PRESSURE - capillary blood

pressure - drives fluid through the capillary wall into the interstitial space.

COLLOID OSMOTIC PRESSURE - exerted by proteins present in the ECF - tends to draw fluid into the vessels.

NORMAL FLUID EXCHANGES

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DISTURBANCES OF BODY FLUIDS

Oedema

Dehydration

Overhydration

OEDEMAAbnormal and excessive accumulation of “free fluid” in the interstitial tissue spaces and serous cavities

NORMAL FLUID EXCHANGES

INCREASED HYDROSTATIC PRESSURE

Impaired venous return

Congestive heart failure

Constrictive pericarditis

Ascites (liver cirrhosis)

Venous obstruction or compression

Thrombosis

External pressure (e.g., mass)

Lower extremity inactivity with prolonged dependency

Arteriolar dilation Heat Neurohumoral

dysregulation

REDUCED PLASMA OSMOTIC PRESSURE (HYPOPROTEINEMIA)

Liver cirrhosis (ascites)  Malnutrition

Protein-losing glomerulopathies (nephrotic syndrome)

Protein-losing gastroenteropathy

LYMPHATIC OBSTRUCTION

Inflammatory  Neoplastic

Postsurgical

Postirradiation

Milroy’s disease

INCREASED CAPILLARY PERMEABILITY

Acute inflammation

Chronic inflammation Angiogenesis

Burns

ARDS

SODIUM RETENTION

Excessive salt intake with renal insufficiency  Increased tubular reabsorption of sodium  Renal hypoperfusion  Increased renin-angiotensin-aldosterone secretion

PATHOGENESIS

TYPES

limited to an organ or limb

e.g. lymphatic oedema,

inflammatory oedema, allergic oedema

Anasarca or dropsy

systemic in distribution

subcutaneous tissues

Localised Generalised

TRANSUDATE EXUDATEDefinition Filtrate of blood plasma

without changes in endothelial permeability

Oedema of inflamed tissue associated withincreased vascular permeability

Character Non-inflammatory oedema Inflammatory oedema

Protein content

Low (less than 1 gm/dl); mainly albumin, low fibrinogen; hence no tendency to coagulate

High ( 2.5-3.5 gm/dl), readily coagulates due to high content of fibrinogen and other coagulationfactors

Glucose content

Same as in plasma Low (less than 60 mg/dl)

TRANSUDATE EXUDATESpecific gravity Low (less than 1.015) High (more than

1.018)pH > 7.3 < 7.3

LDH Low High

Effusion LDH/ Serum LDH ratio

< 0.6 > 0.6

Cells Few cells, mainly mesothelial cells

Many cells, inflammatory as well as parenchymaland cellular debris

Examples Oedema in congestive cardiac failure

Purulent exudate such as pus

SPECIAL FORMS

RENAL OEDEMA

Renal dysfunction - all parts of the body

Initially manifests in tissues with loose connective tissue matrix – eyelids

Periorbital edema - characteristic - severe renal disease.

COMPARE & CONTRAST Feature Nephrotic Nephritic

Cause Nephrotic syndrome Glomerulonephritis (acute, rapidly progressive)

Proteinuria Heavy Moderate

Mechanism ↓Plasma oncoticpressureNa+ and water retention

Na+ and water retention

Degree of oedema Severe, generalised Mild

Distribution Subcutaneous tissues as well as visceral organs

Loose tissues mainly (face, eyes, ankles, genitalia)

PULMONARY OEDEMA

CAUSES - left ventricular failure, renal failure, acute respiratory distress syndrome and pulmonary inflammation or infection

CONSEQUENCES - impede oxygen diffusion- hypoxia – hypercapnia - favorable environment - bacterial infection

HAPEAfter an altitude of 2500 metres

Without acclimatisationAppearance of oedema fluid - lungs, congestion - widespread minute haemorrhages

MORPHOLOGY Gross- the lungs are heavy Moist and subcrepitant. Cut surface exudes frothy fluid (mixture of air

and fluid).

M/S Interstitial

oedema - alveolar oedema

Congestion -alveolar capillaries

Alveoli filled

with a homogeneous, pink-staining fluid permeated by air bubbles

If pulmonary edema is caused by alveolar damage, cell debris, fibrin and proteins form films of proteinaceous material in the alveoli - hyaline membranes

X RAY Fluid accumulation - basal regions of lungs. Thickened interlobular septa + dilated

lymphatics - linear lines - perpendicular to the pleura - “Kerley B lines”

CARDIOGENIC OEDEMA

CONSEQUENCESFailure of the left ventricle - passive congestion -

lungs and pulmonary edema

When chronic - result in pulmonary hypertension

Right ventricular failure - generalized subcutaneous edema - ascites and pleural

effusions

The liver, spleen and other splanchnic organs - congested.

Distribution is influenced by gravity - dependent oedema (legs - standing, sacrum - recumbent).

CEREBRAL OEDEMA Brain edema -localized or generalized - nature

extent - pathologic process or injury.

VASOGENIC OEDEMA : increased filtration pressure or increased capillary permeability

CYTOTOXIC OEDEMA : disturbance in the cellular osmoregulation – response to cell injury

INTERSTITIAL OEDEMA : hydrocephalus

Generalized edema - grossly swollen- narrowed sulci - distended gyri - evidence of compression against the

unyielding skull

M/S Separation of tissue elements - oedema fluid Swelling of astrocytes Widening - Perivascular (Virchow-Robin)

space Clear halos - small blood vessels.

CONSEQUENCES - life-threatening brain substance can herniate (extrude) through

the foramen magnum the brain stem vascular supply – compressed injure the medullary centers and cause death

HEPATIC OEDEMA

i) Hypoproteinaemia - impaired synthesis of proteins

ii) Portal hypertension - increased venous pressure in the abdomen - raised hydrostatic pressure.

iii) Failure of inactivation of aldosterone - hyperaldosteronism.

iv) Secondary stimulation of RAAS- sodium and water retention.

MISCELLANEOUS

Kwashiorkor, prolonged starvation, famine, fasting

Vitamins (beri-beri due to vitamin B1 deficiency)

Chronic alcoholism Hypoproteinaemia Sodium-water retention

Hypothyroidism - nonpitting

Skin of face - internal organs

Excessive deposition of glycosaminoglycans in the interstitium

Microscopically - basophilic mucopolysaccharides.

Nutritional Oedema

Myxoedema

PLEURAL SPACE Pleural effusion - straw- colored -

transudate - low specific gravity - few cells mainly exfoliated mesothelial cells

Nephrotic syndrome, cirrhosis of the liver and congestive heart failure

Pleural effusion response to an inflammatory process or tumor in the lung or on the pleural surface

PERICARDIUM Hemorrhage (hemopericardium) / injury (pericardial

effusion).

Pericardial infections, metastatic neoplasms to the pericardium, uremia , systemic lupus erythematosus (postpericardiotomy syndrome) or radiation therapy for cancer.

Rapid accumulation of fluid - hemorrhage from a ruptured myocardial infarct, dissecting aortic aneurysm or trauma - pericardial cavity pressure rises & exceed the filling pressure of the heart - cardiac tamponade

PERITONEUM

Peritoneal effusion – ascites

Cirrhosis of the liver, abdominal neoplasms, pancreatitis, cardiac failure, the nephrotic syndrome and hepatic venous obstruction (Budd-Chiari syndrome).

Obstruction of the thoracic duct - cancer - chylous ascites - milky appearance - high fat content

GLOMERULONEPHRITIS

A 6-year-old boy presents with a new onset of oliguria and hematuria shortly after he has recovered from an untreated sore throat. Additional workup finds hypertension, periorbital edema, and impaired renal function with slightly increased amounts of protein in the urine.

COMPREHENSION QUESTIONS

A 27-year-old man presents to the outpatient clinic complaining of 2 days of facial and hand swelling. He first noticed swelling around his eyes 2 days ago, along with difficulty putting on his wedding ring because of swollen fingers. Additionally, he noticed that his urine appears reddish-brown and that he has had less urine output over the last several days. He has no significant medical history. His only medication is ibuprofen that he took 2 weeks ago for fever and a sore throat, which have since resolved. On examination, he is afebrile, with heart rate 85 bpm and blood pressure 172/110 mm Hg. He has periorbital edema; his funduscopic examination is normal without arteriovenous nicking or papilledema. His chest is clear to auscultation, his heart rhythm is regular with a nondisplaced point of maximal impulse (PMI), and he has no abdominal masses or bruits. He does have edema of his feet, hands, andface. A dipstick urinalysis in the clinic shows specific gravity of 1.025 with 3+ blood and 2+ protein, but it is otherwise negative. PostStreptococcal GN

Which of the following combinations of signs and symptoms is most consistent with a diagnosis of nephrotic syndrome?

A. Hematuria, hypertension, and proteinuria B. Massive proteinuria, edema, and hyperlipidemia C. Oliguria, hydronephrosis, and abdominal rebound

tenderness D. Painful hematuria, flank pain, and palpable

abdominal mass E. Painless hematuria, polycythemia, and increased

skin pigmentation

CONGESTIVE HEART FAILURE

A55-year-old woman presents to your clinic complaining of ankle swelling and increasing shortness of breath with exertion. Upon directed questioning, she reveals that she also experiences shortness of breath when she is lying down. Physical examination reveals marked hepatosplenomegaly, distended neck veins, and pedal edema. A chest x-ray is suggestive of cardiomegaly. You start the patient on an ACE inhibitor, diuretic, and a low-sodium diet and you refer her to a cardiologist.

Fluid is aspirated from the grossly distended abdomen of a 47-year-old chronic alcoholic man. The fluid is straw colored and clear and is found to have a protein content (largely albumin) of 2.5 g/dL. Which of the following is a major contributor to the fluid accumulation in this patient?

(A) Blockage of lymphatics (B) Decreased oncotic pressure (C) Decreased sodium retention (D) Increased capillary permeability (E) Inflammatory exudation

ARDS – PULMONARY OEDEMA

A 63-year-old man is hospitalized for a severe case of lobar pneumonia with sepsis. Within the first 24 hours of his hospitalization, he develops worsening respiratory failure and requires intubation. A chest x-ray reveals bilateral patchy opacities. He becomes progressively hypoxemic even with increased oxygen delivery via the ventilator. You continue to treat the patient’s pneumonia, but you worry that he will have up to a 40% mortality rate given his current condition.

CARDIAC TAMPONADE

A 75-year-old woman with a history of metastatic breast cancer presents to the emergency department complaining of weakness and difficulty breathing. On physical examination, her blood pressure is 90/50 and her heart sounds are distant and faint. You also note that she has an increased JVP. When an ECG reveals a QRS complex height that varies from one heart beat to the next, you prepare for an immediate pericardiocentesis.

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