OEDEMA: Etiology,Clinical Signs and Treatment



OEDEMA

Definition:-  It   means  excessive   accumulation  of  fluid  in the  tissue spaces.


Aetiology:

1) Increased  hydrostatic  pressure:

a) Congestive  heart  failure resulting from pericarditis, valvular diseases and myocarditis.

b) Portal hypertension due to hepatic fibrosis causes ascites in small animals.

c) Periparturient   udder  oedema :

· It is Physiological oedema.

· It  is due  to pressure  on mammary vein by a large foetus in late

pregnancy.

· It is common  in high yielding particularly first calvers in cattle.

2. Decreased  plasma  colloidal  osmotic pressure  :

It is  due to hypoproteinemia caused by -

a) Malnutrition: Low  protein diet results in inadequate plasma protein synthesis.

b) Liver disorders: Failure of synthesis of plasma proteins.

c) Renal diseases : Continued loss of proteins through urine.

d) Chronic haemorrhage : Continued blood loss  results  in hypoproteinaemia.

The common causes of chronic blood loss are as follows :

i. Heavy infestation: blood-sucking endoparasites.

e.g. Fasciola  spp, Bunostomu  spp, Haemonchus spp, in ruminants. Ancylostoma in dog and Strongyles in horses.

ii. Heavy ectoparasitic tick infestation.

iii. Gastric / Abomasal  ulcers :

e) Protein-losing enteropathy (malabsorption ): This  condition is  seen in chronic  intestinal  disease. (e.g. Oesophagostomiasis, Johne’s disease  which results in  leakage of  protein from the body  in  to  GI tract)

3.Obstruction of lymph/blood vessels:

a. Pressure   on lymph  / blood  vessels  from outside  by cyst, abscess, tumours etc.

b. Lymphangitis, phlebitis, venous  thrombosis  . 

c. Blockage of lymph vessels by parasites e.g. filaria.

4.  Damage to  blood   vessels :

a. Bacterial  diseases:- H.S., Anthrax, gas gangrene, Malignant oedema.

b.Viral diseases : Equine infectious anaemia, Equine viral arteritis.

c. Allergic conditions:- Release of vasodilators viz. Histamine resulting in increased capillary permeability favouring passage of fluids and proteins to the interstitial spaces.

d. Snakebite.

e. Some plant poisonings.

f. Anaemic anoxia.

g. Vitamin A deficiency.

Pathogenesis:  To understand how and why fluid accumulates in the tissue spaces,  it is necessary to  consider capillary  and interstitial fluid dynamics.

Blood capillary has two ends.

Arterial  end

Venous  end

  1. Hydrostatic pressure:
  1. Blood – 45mm  Hg
  2. Tissue fluid -  1-2mm Hg

:.  Filtration effect = 45-2=43mm Hg


2.Colloidal osmotic pressure :

a. Blood  plasma: 30mm Hg

b.  Tissue fluid: 2-3 mm Hg

Absorption effect = 30-3=27mm  Hg


3.Net  filtration effect =16mm Hg


4. At the arterial  end  hydrostatic  pressure 

is  more  than colloidal  osmotic pressure  so  fluid pass into tissue spaces.

1.Hydrostatic pressure:

a. Blood  -15mm Hg

b. Tissue fluid 1-2mm  Hg

Filtration  effect =15-2=13mm Hg

2.Colloidal  osmotic pressure :

a. Blood  plasma   30 mm  Hg

b. Tissue fluid 2-3mm  Hg

Absorption effect  30-3=27mm Hg

3.Net  absorption  effect =14mm Hg

4. At  venous end, colloidal osmotic  pressure is more than the hydrostatic pressure so fluid enters into vessels.

 


Causes and Pathogenesis  of Generalized oedema:

Causes and Pathogenesis  of Generalized oedema

Causes and pathogenesis of local oedema:

Causes and pathogenesis of local oedema


Clinical findings :

· Oedema  may be  local  or  generalised

· Oedema maybe inflammatory or non – inflammatory.

1. Oedematous  swellings   are  soft  painless,  pits on pressure.

2. Ascites: Distension of the abdomen, fluid thrill on percussion. It is  common in dogs.

3. Hydrothorax:- Dyspnoea, muffled or  splashing  sound on  auscultation  of  lower thorax.

4. Hydropericardicum:- Muffled or splashing heart sounds, tachycardia.

5. Cerebral oedema:- Nervous  singes.

6. Brisket oedema:-  Swelling of brisket region.

7. Anasarca:- Oedema of  indermandibular  space, brisket  ventral aspect of the thorax and abdomen.

8. Allergic oedema:- Urticaria, itching and exudation.

Diagnosis:-

1.History of undernutrition, diarrhoea, bleeding, insect bite.

2. Symptoms of  involvement of liver, heart, kidney  &  intestine.

3. Biochemistry:- Hypoproteinemia.

4. Haematology:- Decrease in Hb.PCV& TEC (anaemia), Eosinophilia in allergic oedema.

5. Urine  analysis:  Proteinuria  in kidney disorders.

6. Faecal examination:- Parasitic eggs in endoparasitism.

7. Liver function test  (e.g.  Icterus  index, Vanden  bergh  test , Fouchets test positive) serum protein  decrease (normal:6-8gl/dl).

Differential diagnosis:-

· Pleurisy:- Abdominal  respiration, Inspiratory  dyspnoea, chest pain, rubbing sound in the lung area.

· Pericarditis: - Tachycardia, tubular  pulsation, brisket  oedema, muffled/ splashing  heart  sounds.

· Uroperitoneum:- History of complete cessation of urination and on abdomeanocentesis. There is evidence of urine.

· Peritonitis:- Reluctance to move, arching of back, serosanguinous or purulent fluid on abdomencentesis  X-RAY positive for foreign body.

Treatment:-

a) Allergic oedema-  antihistaminics :

(e.g. inj. Avil @ 0.5-1mg/kg IM) and corticosteroids  ex .inj. dexona @ 0.04.mg/kg IM.

b) Cardiac oedema : Rest, salt free diet, diuretics (e.g. inj Frusonamide @ 1-2 mg/kg  IM) and cardiac tonics (digoxia@1-2mg/kg IM).

c)Hepatic oedema: rest, salt-free diet, diuretic, liver extract, dextrose 10% oral antibiotics.

d) Renal oedema: Rest, salt-free diet, antibiotics,  corticosteroids. 

e) Nutritional oedema - haematinics, (Iron, copper, cobalt) Multivitamins (Vit.A, Vit. B12),protein-rich diet and plasma expanders.

f) Parasitic oedema : Anthelmintics (e.g. Albendazole @ 5 -10mg/kg PO).

Ectoparasiticides (e.g. Butox 2ml/lit spray) protein supplements and haematinics.

g) Mammary oedema: Rest, diuretics, Protein rich diet.

h) Inflammatory oedema:  Antiinflammatory drugs and antibiotics.

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