About 24 litres of fluid are filtered through the capillaries per day. 85% - reabsorbed into the capillaries. 15% - returned to the circulation via lymphatics The formation of ISF is regulated according to the Starling hypothesis, which incorporates 5 factors – capillary hydrostatic pressure, interstitial tissue pressure, plasma oncotic pressure, endothelial permeability and lymphatic function. 8 8.3.2013
The arterial hydrostatic pressure, in excess of tissue pressure, tends to cause transudation of salt and water out of the capillaries The oncotic pressure of plasma proteins tends to draw fluid back in. There is thus on overall loss of fluid from the capillary at its arterial end, reabsorption at the venous end. About 15% of fluid accumulating in the interstitial space passes into lymphatic vessels. From here, it passes into the general circulation via the main lymphatic channels. . 10 8.3.2013
• A low plasma oncotic pressure or increased hydrostatic pressure at the venous end of capillary will tend to cause edema. 11 8.3.2013
Generalized Edema• Na+ is the most important osmotically active constituent of the ECF.• The control of EFC volume ( & the formation of edema) mainly control by the factors that regulate the accumulation of Na+ in the body and excretion of Na+ by the kidneys.• About 85% of filtered Na+ is reabsorbed in proximal convoluted tubules.• The remaining 15% is variably reabsorbed in the distal tubule, partly with Cl- ions and partly in exchange for K + and H+ ions. 12 8.3.2013
The regulation of sodium excretion is probably mainly through adjustment of this 15%. Aldosterone effects on distal renal tubule, causing Na+ reabsorption and K+ excretion. This effect is blocked by spironolactone. 13 8.3.2013
An important stimulus to aldosterone release comes from Renin-Angiotensin-AldosteroneSystem. Any fall in ECF volume (e.g- hypotension, hemorrhage or dehydration) Simulate Juxtaglomerular Apparatus of Kidney Renin secretion ACE Angiotensinogen Angiotensin I Angiotensin II . (Liver) (Lung) 14 8.3.2013
Angiotensin II Stimulate "aldosterone" secretion from adrenal cortex Vasoconstriction Secretion of ADH by acting on hypothalamus Final result is salt & water retentions. 15 8.3.2013
Hypoproteinemic State The major part of plasma oncotic pressure can be attributed to its albumin content. Hypoalbuminemia may be due to - failure of synthesis protein malnutrition (Kwashiorkor) cirrhosis long lasting ill-health from many causes increased loss as in nrephrotic syndrome. When serum albumin falls below 25 g/l, there is transudation of solutes (mainly salt and water) out of the capillaries into intercellular space. When this comportment is expanded by about 10%, clinically evident edema appears. 17 8.3.2013
↓ Plasma protein level (esp. albumin) ↓oncotic pressure • . transudation of solutes Edema. 18 8.3.2013
Heart Failure Left Heart Failure ↓Cardiac output ↓Effective arterial blood volume Accumulation of fluid in LV ↓Renal perfusion Congestion of blood in LA RAA System activation ↑ADH Congestion of blood in pulmonary veins ↑aldosterone ↑ Capillary hydrostatic pressure Salt & water retentions Pulmonary edema Fluid overload 19 8.3.2013
Right Heart Failure ↓ Contraction of RV ↓Cardiac output from LV Congestion of RA ↓Arterial Blood Volume Congestion of SVC & IVC RAA System activation ↑ADH ↑Congestion in venules & capillaries Salt & Water retentions Generalized Edema. 20 8.3.2013
Passive congestion of "Liver“ Liver function ↓ Plasma protein synthesis ↓ Plasma oncotic pressure Generalized Edema In Heart failure, unless the cardiac output is restored or renal sodium and water retention is reduced (e.g.- diuretics, or aldosterone antagonists), fluid retentions occurs and edema worsens. 21 8.3.2013
Investigations of Generalized edema Chest X-ray - sign of heart failure, cardiomegaly Plasma albumin - low in nephrotic syndrome, cirrhosis, malnutrition Blood urea and electrolytes - diminished GFR in renal disease or in severe cardiac failure 27 8.3.2013
Localized edema1. Oedema due to increased Permeability of small Blood vessels Increased permeability is due to local release of inflammatory mediators, e.g.-histamine, bradykinin , and cytokines ,which cause vasodilation and increase capillary permeability. e.g. Acute inflammatory edema(e.g.-infection) Allergic edema 28 8.3.2013
Angio-edema is a specific form of allergic edema, affecting face, lip & mouth. Swelling may develop rapidly and may be life- threatening if upper airway is involved.. 30 8.3.2013
(2)Lymphatic Obstruction• Impaired lymphatic drainage result in edema (lymphedema).• Lymph vessels have a large collateral circulation, so that , with any block, edema extend over a wide area.• Secondary cancer in lymph nodes may cause edema , but usually the block is more extensive by dissection of nodes and radiography, e.g.-in the treatment of breast cancer.• In filariasis, lymphatic obstruction occurs due to the widespread fibrosis in lymphatic channels caused by the adult filarial worms.. 31 8.3.2013
(3)Venous obstructionMajor cause - deep vein thrombosis, external pressure from a tumor or pregnancy, or valvular incompitance. SVCO is caused by a tumor in superior mediastinum, commonly lung cancer.. 33 8.3.2013
Investigations of Localized edema• Chest X-ray – SVCO• Pelvic ultrasound or CT scan – pelvic tumor or lymphatic enlargement• Lymphangiography – abnormal lymphatic architecture, lymph nodes replaced by tumor• Doppler ultrasound or venography – to confirm diagnosis of venous obstruction 35 8.3.2013
Examination of Edema Apply firm pressure with your thumb for at least 15 sec on antero-medial aspect of shin. (Macleod’s) Finger pressure leaves temporary indentions in the skin Pitting Edema Lymphoedema and myxoedema do not pit on pressure. 36 8.3.2013
References• Macleods Clinical Examination, 12th Edition• Robbins and Cotran Pathologic Basis of Disease,8th Edition• Davidsons Principles & Practice of Medicine, 21st Edition• Tutorials in Differential Diagnosis, 4th Edition• Dr. Daw Myint Myint Khins Symptom Analysis• Internet Websites. 37 8.3.2013
Patient’s HistoryParticulars of the patient• A 64 year old, gentleman, U Hla Win, a bank manager, was admitted to MU (II), MGH on 23.2.2013 with the chief complaint of - Breathlessness for 3 months Swelling of the leg for 2 weeks Cough for 2 weeks
History of Present Illness Breathlessness- The patient complained of breathlessness for 3 months which worsen in cold weather and at night. He was not able to lie flat (orthopnoea) and woke up at night due to difficulty in breathing (PND). He was dyspnoeic at rest and couldn’t do light works. (Dyspnoea on exertion) NYHA- grade IV Cough- The patient complained of dry cough sometimes with sputum (white color). He became dyspnoeic after coughing and also complained of wheezing. Swelling of the leg- He had swelling of the leg for 2 weeks. It started from foot and progressed to the knee. There is swelling of the abdomen. Associated symptoms- He has palpitation when hungry but no chest pain.
System Review• On reviewing respiratory system, he has cough sometimes with sputum, dyspnoea, wheezing but no haemoptysis and chest pain.• On reviewing gastrointestinal system, he has loss of appetite, abdominal distension but no vomiting, nausea, indigestion, heartburn, abdominal pain and change in bowel habit.• On reviewing genito-urinary system, he has reduced urine output but no dysuria and haematuria.• There are no cardinal symptoms of central nervous system such as headache, dizziness, faints, fits, altered sensation, weakness, visual disturbance, hearing problems.• On reviewing endocrine system, he has palpitation but neither fine finger tremor nor eye signs.
Past Medical and Surgical History • The patient has a history of tuberculosis in 1994 and took proper medication. He has no history of hospitalization, blood transfusion, rheumatic fever, hepatitis, heart disease, diabetes mellitus and hypertension.
Family History• He is married and has 9 children. All are healthy. There is no sign of similar illness in his family.
Drug History• He has no regular taking drugs and no known drug allergy.
Social History• He had been smoking for about 30 years and betel chewing for about 20years. He has a habit of alcohol drinking.
Physical ExaminationGeneral Survey• A 64 year old gentleman with average height and weight is lying in his bed. He is well conscious and well cooperated. He is rather dyspnoeic but not restless. (He is given oxygen). A canular is inserted in the right hand. No gynaecomastia and no spider naevi.
General Examination• Forehead- febrile• Eye-pallor (-), jaundice (+), subconjunctival hemorrhage (-), xanthelesma (-), corneal arcus (+), features of Horner’s syndrome• Nose- nasal flaring (-), nasal polyp (-)• Ear and nose discharge- discharge (-)• Mouth- angular stomatitis (-)• Lips- tobacco staining (-), pursed lip breathing (-)
• Tongue- central cyanosis (-), oral thrush (-)• Teeth and gums- dental caries (+)• Tonsillar enlargement (-)• Neck- dilated veins (+), visible neck gland enlargement (-), accessory muscles of respiration are working, supraclavicular excavatum (+)• Upper extremities- clubbing (+), peripheral cyanosis (-), pallor (-), flapping tremor (-), features of CO2 retention (-), Osler’s node (-), Janeway’s leision (-)• Lower extremities- peripheral cyanosis (-), clubbing (+), dependent oedema (+)
Systemic Examination Cardiovascular System Pulse • Rate-68 beats/min • Rhythm- regular • Volume- moderate • Character- no special character • Condition of the vessel wall- not thickened • Equality on both sides-equal on both sides • Radio-femoral delay- no radio-femoral delay • All peripheral pulses are intact Blood pressure-100/ 70 mmHg JVP-5.5cm above the sternal angle(raised)
Examination of the Precordium • Inspection-shape of the chest is symmetrical on both side and there is no precordial bulging. Diffuse precordial pulsation is not seen. Apex beat not visible. There is no epigastric pulsation. There is no scar, skin lesion, dilated veins over the Precordium.
• Palpation- apex beat is palpable at left 5th ICS within the midclavicular line with normal character and no thrill. There is no left parasternal heave. There is no epigastric pulsation. There is palpable P2 but no palpable A2.• Percussion- is omitted. (not pericardial effusion)• Auscultation- - At the MITRAL AREA-normal first and second heart sounds. No added sound and no murmur. - At the TRICUSPID AREA- normal first and second heart sounds. No added sound and no murmur. - At the PULMONARY AREA-normal first heart sound and loud second heart sound. No added sound and no murmur. - At the AORTIC AREA- normal first and second heart sounds. No added sound and no murmur.
Respiratory System Lying position • Inspection -Shape of the chest is symmetrical on both sides. Respiratory rate is 15 times/min. -Chest wall movement is symmetrical on both sides. -Apex beat is not visible. -There is no scar, skin lesion, dilated veins. There is no supraclavicular, suprasternal, intercostal, sub costal muscles indrawing.
• Palpation- trachea is slightly deviated to right. Chest wall movement is symmetrical on both sides. Vocal fremitus is reduced on left lower zone. Palpable accompaniments are absent.• Percussion- normal resonance (+). Liver dullness starts at 5th ICS. Cardiac dullness is from 2nd to 5th ICS.• Auscultation- vesicular breath sound with ronchi is heard all over the lungs field. Vocal resonance is reduced on the left lower zone.
Sitting position• Inspection-shape of the chest wall is symmetrical on both sides. Chest wall movements are equal on both sides. There is a cyst on the right upper part of the back.• Palpation-chest wall movements are symmetrical on both sides. Vocal fremitus is reduced on the left lower zone.• Percussion- normal resonance ispressent all over the lungs field.• Auscultation- vesicular breath sound with bilateral basal crepitation is heard. Vocal resonance is reduced on the left lower zone.
Abdominal Examination• Inspection- Contour is normal, flanks are full, abdomen moves with respiration, no visible mass, no visible peristalsis, no scar, skin lesions and dilated veins.• Palpation- There is no tenderness and no palpable mass. Liver and spleen are not palpable. Kidneys are not blottable.• Percussion-shifting dullness (+)• Auscultation- Normal bowel sounds are present.
Differential diagnosis Generalize oedema and ascities are present, so this may be due to• Congested cardiac failure• Acute glomerulonephritis• Nephrotic syndrome• Cirrhosis of liver The patients has clubbed fingers and ascites which are the characteristics of cirrhosis of liver but no palmar erythema,no spider naevi, no gynaecomastia, no splenomegaly,no haematamesis, no malena. Therefore cirrhosis of liver is excluded.
The patient has no smoky urine(no proteinuria), no haematuria. So, Nephrotic syndrome and acute glomerulonephritis are excluded. And there is no weight loss, no diarrhea, and no steatorrhoea. Therefore nutritional disorder is excluded. Signs of heart failure such as dyspnoea, orthopnoea, PND, cough, ascites, ankle oedema are present.