Isomer: Definition, Types.

Isomer:

Definition:

Isomers are substances having same molecular (chemical) formula, but different structure or having
same molecular formula and identical structural form, but different spatial configuration around one
or more carbon. Isomerism is the processes of formation of isomers.

Types of isomer:

1. Structural isomer
2. Stereo isomer (Space isomer)
• Geometric isomer
• Cis variety
• Trans variety

•  Optical isomer
• Optical enantiomers
• Diasteroisomers

Structural Isomer:

These are the substances having same molecular (chemical) formula, but different structure. These
type of isomers differ with respect to physical and chemical properties.
e.g.     CH3-CH2-CH2-CH3 (Butane)
           
                     CH3

           CH3-CH-CH3 (Isobutane)

Stereo Isomer (Space Isomer)

Substances having same molecular formula as well as identical structural form, but different with
respect to the spatial configuration of atoms or groups around one or more carbon. This type of
isomers sometimes shows identical physical and chemical properties.
Spatial configuration means
o Arrangement of atoms or groups around a carbon in relation to space,
o Three dimensional space relationship of atoms or groups around a carbon.

Types of stereo isomer:

1. Geometric isomer
2. Optical isomer
• Optical enantiomers
• Diastereoisomers

Chronic liver disease

Introduction:

·         Primary care physicians play a key role in early identification of risk factors, in the management of patients for improving quality and length of life, and for preventing complications.

·         Specialists, by contrast, should guide specific treatments, especially in the case of complications and for selecting patient candidates for liver transplantation.

Etiology:

·         Hepatitis B

·         Hepatitis C

·          Non Alcoholic Steato Hepatitis(NASH)

·         Alcohol abuse

·         Others e.g. Primary biliary cirrhosis, α₁-antitrypsin deficiency, Hemochromatosis, Wilson disease, cryptogenic.

Clinical Features:

·         Often asymptomatic

·         May present with stigmatas of CLD such as vascular spiders, palmar erythema, spider angiomata, palmar erythema, Gynaecomastia, dilated abdominal veins, loss of hair, testicular atrophy.

·          jaundice, ascites, splenomegaly and asterixis  indicate signs of decompensation

·         Patients may be diagnosed incidentally through laboratory findings

Investigations:

• ·         CBC
• ·         Liver function tests ( S. Bilirubin , SGOT, SGPT, ALP, S.albumin, A: G Ratio, Prothrombin Time)
• ·         S. electrolytes,
• ·         S. creatinine
• ·         USG of whole abdomen—coarse liver, splenomegaly, ascites
• ·         Viral Marker ( HBS Ag, Anti HCV)

Management:

A. General

Nutrition, Fluid and Electrolyte:

• Diet according to patient’s status eg.  Malnourished (high protein and carbohydrate), hepatic encephalopathy/precoma (Protein restriction) Ascites (salt restriction).
•  Lactulose in constipation (20 – 30 ml/day)
• Stop OCP, Sedatives, NSAID and Paracetamol.

 B. Management according to presentation:

Ascites

• ·         No added salt,
• ·         Paracentesis  for diagnosis and therapy:
•           Send sample for biochemistry/cytology and C/S if possible.
• ·         Spironolactone (100 mg - 400 mg daily) and/or furosemide (40 mg - 160 mg daily),
•           Measure weight  daily, target weight loss at ~500g/day.
•           The dose of diuretics - increased every 3–4 days to achieve target weight loss.
• ·         For spontaneous bacterial peritonitis (SBP), based on abdominal pain, fever, and ascitic fluid report.
•            Start IV Cefotaxim 1g tds/ ciprofloxacin 200mg IV BD for 7 - 10 days.
•           Antibiotic  prophylaxis  included ciprofloxacin ,750 mg orally once weekly
• ·         If there is massive ascites –   Refer to secondary level/ Tertiary level

Hepatic Encephalopathy  

Grade I: Changes in behaviour with minimal change in level of consciousness

Grade II: Disorientation, drowsiness, asterixis, inappropriate behaviour

Grade III: Marked confusion, incoherent speech, sleeping but rousable

Grade IV: Comatose, unresponsive, decorticate or decerebrate posturing

• ·         Avoid sedatives/ diuretics
• ·         Maintenance of Nutrition and fluid  balance
• ·         Lactulose 20mL tds (titrate dose to achieve at least 2 loose stools/day),  if necessary enema until 2–4 bowel movements/day .
• ·         Amoxicillin (500mg TDS)/ Metronidazole (400mg TDS)/Rifaximin (400 mg TDS) for gut sterilization.
•      Grade 3 or 4 encephalopathy-Refer           

Hematemesis and Melaena

·         I/V Fluid (N/S, Hartman sol.), Immediate blood transfusion and refer.                                                                                                                                                                                                                  

 Coagulopathy  Characterized by  prolonged prothrombin time

·           Vitamin K - 10mg I/V for 3 days.

Severe coagulopathy, Vit K can be given IV 10mg slowly and Refer

Hepatorenal syndrome – Characterized by oliguria in cirrhotic patient without proteinuria and abnormal sediment in urine.

·         Refer.

·         Before referral--   Stop  diuretics & NSAIDs and Catheterise bladder

Indication for Referral:

1.  Decision for antiviral therapy   2.  Variceal   haemorrhage    3.  Massive ascites                4.  Diagnostic and  therapeutic   Endoscopy. 5.  Encephalopathy Grade III & IV                    6.  Hepatorenal syndrome  7. Multi-organ failure   8.  Hepatocellular carcinoma.