Ques. 1 What is Jaundice?
Ans. It is a syndrome characterized by yellowish discolouration of the skin, sclera, and other mucous membrane of body due to hyper bilirubinaemia. Normal blood bilirubin content is 1/400,000 to 1/1000,000, i.e. 0.2-0.5 units, a unit being 1/200,000 or 0.5 mg percent. The renal threshold is 1/50,000 or 4 units or 2 mg percent. Clinically manifestation of the Jaundice occurs when 1/80,000 is exceeded, but when hyper bilirubinaemia is below level there is no yellow staining of the tissues (Latent Jaundice) as is cancer and cirrhosis of liver and pernicious anaemia.
Ques. 2 What are the various types of Jaundice seen in clinics?
Ans. The various types of jaundice seen in clinics are :
- According to Richs Jaundice are of 3 types: (i) Regurgitation Jaundice. (ii) Mixed Jaundice. (iii) Retention Jaundice.
- According to McNee’s – Clinically Jaundice are of 3 types: (i) Obstructive.
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Haemolytic Jaundice – (Pre-hepatic Jaundice)
This is due to increased bilirubin in plasma with excessive breakdown of R.B.C. due to some toxic effect; resulting in:
Ques. 3 What are the causes and clinical manifestations of Jaundice?
Ans. Causes : This generally occur in malaria, black water fever, alcoholic family jaundice, incompletible blood transfusion, snake bite, paxorysmal haemoglobinuria & acute streptococcal infections.
The conjunctive being rarely affected, staining colour is lemon yellow, splenomegaly is frequent, liver is enlarged or normal, anaemia profound, the sedimentation rate of the RBC increased, Vanden Bergh’s test is indirect.
Obstructive Jaundice (Post-hepatic Jaundice).
It is due to obstruction of passage of conjucated bilirubin from liver cell to intestine. It is mainly due to obstruction of extrahepatic origin, and some time due to intrahepatic obstruction. It is also known as cholestasis.
Causes: (a) Extra-hepatic :
- Blockage of common bile duct by gallstone, congenital stenosis, growth stricture etc.
- Obstruction of ampula of vater due to carcinoma.
(b) Intra-hepatic :
Clinical manifestations :
In obstructive Jaundice, the onset is stormy, the conjunctivae are more pigmented than the skin, colour being dirty yellow, pruritus is severe, the liver is enlarged, stools bulky whitish and Vanden Bergh’s test is direct immediate positive.
In this case –
Toxic Jaundice (Hepatic Jaundice).
It is due to some of the toxins & produced by certain virus or some by injections (chloropromazine).
Main Causes: It is found in catarrhal jaundice, weil’s disease, infective hepatitis, chemical poisonings, bacterial infections (pneumonia, typhoid) & drug toxicity.
Clinical manifestation: The onset is quiet, skin is affected before the conjunctiva, the colour being orange-yellow; pruritus is slight, liver is enlarged or dormal, Vanden Bergh’s test show delayed direct response or biphasic.
Arnold Rich classifies Jaundics as:
Ques. 4 What is Latent Jaundice?
Ans. It is a condition where increase bilirution in blood without any clinical manifestations of Jaundice. In this case inner cells completely turn into yellowish greenish except cells of brain matterOne of the major areas of interest, however, involves the early labeled bilirubin that bilirubin which is synthesized from heme other than that of the circulating RBCs, early labeled bilirubin comprises 10 to 20 percent of bilirubin secreted under normal circum stances, but upto 80 percent of that secreted by patients with pernicious anaemia, thalacemia, & erythropoitic porphyria. Early labeled bilirubin is heterogeneous; the first major component arises from noneryth ropoietic heme, has its origin primarily in liver, and is related in part of the turnover of heme-containing enzymes in liver. The second major component is crythropoietic in origin & includes both Hb and non-Hb heme.
Plasma transport :
Bilirubin, which is insoluble in water, is transported in plasma bound to albumin. Although the binding is light, it is weakend under certain conditions, such as acidosis, and there is competition for binding sites. For example, by certain antibiotiotics, thyroxine & free fatty acids. This circulating unconjugated (in direct-reacting) bilirubin cannot difuse across cell membranes other than those in the liver & therefore, does not appear in the urine.
The details of bilirubin uptake by liver have not been worked out, the process is rapid, does not involve the uptake of serum albumin & probably involves active transport. The role of ligandin (Y protein) & other intracellular binding proteins remains to be defined.
Free bilirubin is concentrated in liver and then conjugated with glucuronic acid to from bilirubin diglucuronide, or conjugated (“direct-reacting”) bilirubin. This reaction, catalyzed by microsomal enzyme glocoronyl transferase, renders to pigment water soluble. Bilirubin conjugates other than diglucuronide are also formed but their significance is uncertain.
Biliary excretion :
Conjugated bilirubin is secreted into bile canaliculus alongwith the other constituents of bile. This process is complex and can be affected by the presence of other organic anions or drugs. In gut, the pigment is deconjugated and reduced by bacterial flora to various compounds collectively called stercobilinogens. Most of these are excreted in the faeces, but substantial amounts are absorbed & re-excreted in bile; small amounts reach the urine as urobilinogen. The Kidney can also excrete bilirubin diglucuronide, but not unconjugated bilirubin. Renal excretion of bile pigments is not important normally but may become so with deep Jaundice.
So from above discussion it is seen that-increased formation, impaired hepatic uptake, or decreased conjugation cause unconjugated hyperbilirubinemia. Impaired biliary excretion also they produce conjugated byperbilinemia. In practice, however, hepatic diseases & biliary obstruction usually create multiple defects, resulting in a mixed hyperbilirubinemia. In most patients with obvious hepatobiliary disease, bilirubin fractionation is, therefore, of little diagnostic value.
Haemolysis & several uncommon disorders of bilirubin metarbolism produce jaundice in the absence of demonstrable liver disease.
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