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Hepatitis A (HAV): Rapid review


·       Introduction.
·       Signs and symptoms.
·       Diagnosis.
·       Prevention.
·       Treatment.
·       Transmission.
·       Some hygiene information to protect yourself.

Introduction:
·   Hepatitis A(infectious hepatitis) is acute infectiousdisease of the liver caused by hepatitis a virus.
·   The incidence of theinfection is high in the developing countries andin regions with poor hygiene standards and theillness is contracted in early childhood.
·   The incubation period (time between the infection and theappearance of symptoms) is between 2 to 6 weeks{average 28 days}.
·   Hepatitis a doesn'thave chronic stages, isn’t progressive, and doesn’t cause permanent liverdamage.
·   HA infection causes no clinical signs and symptoms in over 90% of theinfected children and the infection confers lifelongimmunity as following the infection, AB are formed that confers immunityagainst further infection.
Signs and symptoms:
·   Symptoms may bemistaken for influenza (fever ,fatigue,abdominal pain , diarrhea, appetite loss, itching, nausea, jaundice, urine of dark color, stool oflight color)
·   The color of urineis due to the excretion of bile in it and the color of feces is due to lack ofbilirubin.
·   Symptoms can returnover the 6-9 months
·   Mortality is lessthan 0.5%
Diagnosis:
·    IgM antibody isonly present in the blood following an acute hepatitis A infection (detectablefrom 1-2 weeks after the infection and persists for up to 14 weeks.
·   the presence of IgGantibody in the blood mean that acute stage is past and the person is immune tofurther infection
·   IgG is also found inthe blood after vaccination and tests for immunity to the virus are based onthe detection of this Ab.
Prevention:
·   Hepatitis A can beprevented by (vaccination,good hygiene and sanitation).
·   The vaccine is givenby injection into the muscle of the upper arm.
·   The vaccines, (e.g. Havrix and VAQTA)contain no live virus and are very safe.
·   Initial doseprovides protection for 2-4 weeks after vaccination and the second dose(booster dose) is given 6-12 months later, provides protection up to 20 years.
·   N.B. vaccine is given before the infection as it doesn'twork after the exposure.
·   Vaccine isn'trecommended for children younger than 2 years as it's ineffective for them.
·   If you have beenexposed to person who is infected with HAV, there is treatment that may preventyou from becoming infected, it’s called immune globulinand is more likely to be effective when given 2 weeks of exposure.
·   [Immune globulin isa preparation of Ab that can fight the virus in the body] given safely inchildren younger than 2 years, pregnant women and breast feeding.
·   some samples takento study ocean water quality was found to have HAV specially after rains soit's advisable not to go to oceans in coastal areas in this time.
Treatment:
·   There is no specific treatment for hepatitis A, but symptomatic treatment (rest, well balanced diet, stay hydrated)and avoid fatty foods and alcohols.
·   N.B. avoid taking medicine or any substance can cause harmto the liver e.g. acetaminophen.
·   The low % of deathsoccur usually in older ages (>50 years) and in those suffering another formof viral hepatitis (C or B).
Transmission:
·   By fecal-oral route, poor sanitation, overcrowding,ingestion of shellfish cultivated in polluted water and by blood transfusionbut this is very rare.
·   Fecal-oral routemean that when a person put something in his mouth that has been contaminatedwith faeces of an affected person.
·   N.B. people whodon't have symptoms can still spread the virus.
Some hygiene information to protectyourself:
·   Wash yourhands thoroughly every time you use the bathroom,before touching or preparing food, and before touching others. Wash carefullywith soap and warm water and dry thoroughly.
·   Contaminated surfaces should be cleaned with household bleach tokill the virus. Heat food or water to 185°F or85°C to kill the virus.
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Prepared by: Pharmacist/ Mustafa Abdel Tawab.
Resources:
-  Color atlas of pharmacology.
-  Drugs.com.                           -  Master of Egyptian drugs.
-  Wikipedia.                            -  Master of Saudi drugs.
Copyrights: All rights are reserved for pharmacist development group 2009 - 2011.
  

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9:06 PM | Posted in , , | Read More »

The use of muscle relaxants in surgical procedures : rapid review

# introduction

* Acetylcholine is a major neurotransmitter in the autonomic nervous system. In the peripheral nervous system, acetylcholine activates muscles .
* The enzyme acetylcholinesterase converts acetylcholine into the inactive metabolites choline and acetate .
* Acetylcholinestrase enzyme is abundant in the synaptic cleft, and its role in rapidly clearing free acetylcholine from the synapse is essential for proper muscle function .
* Acetylcholine receptor agonists and antagonists can either have an effect directly on the receptors or exert their effects indirectly, e.g., by affecting the enzyme acetylcholinesterase, which degrades the receptor ligand. Agonists increase the level of receptor activation. antagonists reduce it.
* Certain neurotoxins work by inhibiting acetylcholinesterase, thus leading to excess acetylcholine at the neuromuscular junction, thus causing paralysis of the muscles needed for breathing and stopping the beating of the heart.

# Muscle relaxants

* Muscle relaxants Used as adjuncts to general anesthesia, to ensure that surgical procedures aren't distributed by muscle contraction of the patient.

* Two types of those muscle relaxants used with anesthesia :

1-Non- depolarizing :-

a- (d-tubocurarin) : it is given intravenously as it is not absorbed in GIT .
* Its effect start within 4 minutes & continues for 30 minutes
* The duration of action of d-tubocurarin can be shortened by administrating its antidote neostigmine (ACH esterase inhibitor) so inhibit ACH breakdown .
* Unwanted side effects result from non immune mediated release of histamine from mast cell leading to hypotension ,urticaria & bronchospasm .

b- Pancuronium (pavulon) : is a synthetic compound now frequently used .
* It's 5 fold more potent than d-tubocurarin & with somewhat longer duration & not likely to cause histamine release .
* Side effects : increase heart rate & blood pressure due to M2 cholinoceptor blockade &this effect not shared by newer congeners like vecuronium & pibecuronium .

2-depolarizing :-

* This class contain only succinylcholines (succinyldicholine & suxamethonium) .
* Its structure has double ACH molecule. it is not hydrolyzed by acetylcholinestrase but by butyrylcholinesterase, (a plasma cholinesterase). This hydrolysis by butyrylcholinesterase is much slower than that of acetylcholine by acetylcholinesterase.
* Its effect start within seconds & continues for 10 minutes so used at the start of the anesthesia to facilitate intubation.
* Side effects :
1- histamine release (scoline apnea).
2- hyperkalemia which may lead to cardiac arrhythmia .
3- bradycardia .
* Care must be taken during eye surgery ,as increasing in intraocular pressure may occur.

*references: color atlas of pharmacology, drugs.com, wikepedia, medicine.net .
*prepared by : Dr. Mustafa abd Eltawab .
*all rights are reserved for pharmacist development group .
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3:10 PM | Posted in , , , | Read More »

Gallstones : rapid review

# How are the gallstones formed :-


* Bile help the body to digest fat , it is made in the liver , stored in the gallbladder until the body need it.
* Cholesterol secreted from the liver into the bile, it's held in solution forming micellar complexes with bile acids & phospholipids . 
* Gallstones : are small pebble-like substances develop in the gall bladder [Cholelithiasis: stones in the gall bladder or in the bile duct, cholidocholilethiasis: obstruction of the common bile duct]

* When cholesterol level increase (secreted more than which can be emulsified ) it precipitates forming gallstones .

* Gallstones may be as small as a grain of sand or as large as a golf ball & may be one or hundred or combination of 2 .

* Gallstones can block the flow of the bile if lodged in any of the ducts  present (types of ducts are hepatic duct: carry the bile out of the liver, cystic duct: carry bile to & from gallbladder, common bile duct: takes bile from cystic & hepatic to the small intestine)

            # Types :-

* Gallstones are of 2 types :
1- cholesterol stones 80% .
2- pigment stones (of bilirubin).

# Causes :-

* Causes of gallstone formation:
1-too much cholesterol or bilirubin .
2-not enough bile salts .
3-gallbladder doesn't empty completely often enough .

# Risk factors :-

* People at risk for gallstones include :-
• women—especially women who are pregnant, use hormone replacement therapy, or take birth control pills .
• people over age 60 .
• overweight or obese men and women .
• people who fast or lose a lot of weight quickly .
• people with a family history of gallstones .
• people with diabetes .
• people who take cholesterol-lowering drugs .

 # Symptoms :-
* Symptoms: (start to appear when stone become more than 8mm)
1-Steady pain in the upper abdomen .
2-pain in the right shoulder.
3-nausea .
4-fever.
5-jaundice .

* The symptoms appear suddenly so ,it's called gallbladder attack & usually follow fatty meals & may be during night .

* Silent stones: with no symptoms & no need for treatment.


# Diagnosis :-

* All stones are of mixed content to some extent (cholesterol 30-70%) + ca salts . so because of their calcium content they can be diagnosed radiologically. (ultrasound & ct) .
*  blood test also needed to look for infection, obstruction & pancrititis .
                      
 # Treatment :-


-drug therapy play a subordinate role compared with surgical therapy (as with drug , gallstones may recur again after stoppage of the drug) therapy .


-administrating more bile acids [ursodeoxycholic acid (ursofalk) ® or chenodeoxycholic acid] decrease gallstones because they emulsify cholesterol and prevent its precipitation .

* Conditions must be provided to attain adv of bile acid administration :
- Gallstones volume less than 15mm, gall bladder with normal function, no liver disease , normal body weight, long term administration of bile acids.


*references: color atlas of pharmacology, drugs.com, wikepedia, medicine.net, master of Egypt's drugs, master of Sadie's drugs .

*prepared by : Dr. Mostafa Abd eltawab .
*all rights are reserved for pharmacist development group .
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10:04 PM | Posted in , , | Read More »

Lipid lowering agents : rapid review

Preface

   Triglycerides:
    * main constituent of vegetable oil & animal fat .
    * High triglycerides (normal range 150mg/dl ) lead to atherogenesis  .
    * It's used by the body as energy store except for the brain
 
 Cholesterol:
* Used as building block of biological membrane & precursor for most steroid hormones .
* Rate limiting enzyme in cholesterol synthesis in the liver is HMGCA reductase enzyme .
* Liver use cholesterol in the synthesis of bile acids & VLDL .
* 85% of the blood cholesterol is produced in the body .

Lipid lowering agents

1- Statins (atorvastatin, fluvastatin, rosuvastatin, simvastatin) .
* Mechanism of action : statins are inhibitors of HMGcoA reductase (hydroxyl methyl glutaryl co A enzyme) so they inhibit cholesterol synthesis .in addition to that, they increase expression of LDL receptor .
* statins may occur naturally in some foods like mushroom & red yeast rice .
* Cholesterol synthesis appears to occur mostly at night so short acting statin e.g.simvastatin ( zocor) must be taken at night to maximize its effect but long acting statin e.g.atorvastatin (lipitor) may be taken at any time .
* The most potent statin [atorvastatin , rosuvastatin (crestor)]
* The least potent statin {fluvastatin (lescol) }
* The result of statin therapy appears rapidly may be after one week
* Side Effects : rarely [skeletal musculature damage , liver enzymes become high ]

2-fibrates (bezofibrate, etofibrate, gemfibrozil, fenofibrate)
* Used as accessory therapy in many forms of hypercholesterolemia usually in combination with statins specially fenofibrate (tricor) and gemfibrozil (lopid600) because using of them with statin will increase muscle toxicity by decreasing statin metabolisms .
* It's indicated solely for patient no tolerant to statin .
* Mechanism of action :- activate PPAR (peroxisome proliferators activated receptor) which induce transcription of number of genes that facilitate lipid metabolism, also it decrease VLDL and increase HDL .
* When triglycerides increase more than 1000mg/dl lead to pancreatitis with abdominal pain  &
   as fibrates decrease triglycerides they decrease pancreatitis .
   * Side effects : high risk of gallstones (use over several years) myopathy, myalgia and     rhabdomyolysis .
   * Usage of statins with fibrates may increase the likelihood of    rhabdomyolysis & liver 
   failure .

3-nicotinic acid [niacin or vit b3 & its derivatives ]
* Mechanism of action : stimulate endolthelial lipoprotein lipase so decease triglycerides .
* At the first of the therapy PG mediated vasodilatation occur leading to 2 side effects {flushing and hypotension} .
* To overcome these 2 side effects 325mg of ASA can be taken 30 min prior to nicotinic acid (niaspan) . also the extended release dosage decrease flushing
* Flushing which occur as side effect of nicotinic acid may make nicotinic acid to be used for male impotence .
* Deficiency of vit b3 may lead to pellagra disease  (3 diseases : diarrhea, dementia & dermatitis)

 4-cholesteramine & colestipol :
* They are bile acid sequestrants which bind bile acid in the GIT & prevent its reabsorbtion . As bile acid decrease , liver convert cholesterol into bile acid so cholesterol decrease .
* Side effects of cholesteran (questran) & colestipol (colestid) :
a- diverse GIT disturbance (constipation , diarrhea) .
 b- decrease the absorption of lipid soluble vitamins (A,D,E,K) .
 c- decrease absorption of vit K antagonist , digitoxin , diuretics .
 * If used with any other drug (statin or other) must be taken 1hour after the
 drug or the other drug taken 4 hour after it as they bind statin in the intestine
 & decrease its absorption .

5- omega-3 (polyunsaturated fatty acid [eicosapentanoate-docosahexapentaneoate]
* Decrease each of (trigycerides, synsises of VLDL lipoprotein B , remnant particles) .
* Although it doesn't decrease LDL or total cholesterol, with increasing some dietary supplements as fish-leafy green vegetables-nuts-hummus-eggs- linseed-flaxseed this decrease Congestive heart disease .
6-probucol :
decrease HDL more than LDL nonetheless decrease atherogenesis and that may be due to decreasing LDL oxidation .


*references: color atlas of pharmacology, drugs.com, wikepedia, medicine.net, master of Egypt's drugs, master of Sadie's drugs . 
*prepared by : Dr. Mostafa Abd eltawab .
*all rights are reserved for pharmacist development group .

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10:53 AM | Posted in , , , | Read More »

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