Tuesday, November 14, 2006

Surgery Consult Wk 10

plavix?

Clopidogrel is a potent oral antiplatelet agent often used in the treatment of coronary artery disease, peripheral vascular disease, and cerebrovascular disease. It is marketed by Bristol-Myers Squibb and Sanofi-Aventis under the trade name Plavix. It is also marketed in the generic form by Apotex, a Canadian generic pharmaceutical company, though an injunction to withhold further shipments of their form is in effect while patent issues are dealt with. In 2005 it was the world's second highest selling pharmaceutical with sales of US$5.9 billion. [1]

Clopidogrel is indicated for (Rossi, 2006):

  • Prevention of vascular ischaemic events in patients with symptomatic atherosclerosis
  • Acute coronary syndrome without ST-segment elevation (NSTEMI), along with aspirin

It is also used, along with aspirin, for the prevention of thromboembolism after placement of intracoronary stent. (Rossi, 2006)

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stenosis of ampulla?

Vater's ampulla
The dilation within the major duodenal papilla, formed by the junction of the common bile duct and the main pancreatic duct.

The hepatopancreatic ampulla. A dilation of the duodenal papilla that is the opening of the juncture of the common bile duct and the main pancreatic duct.

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Intraventricular fistula?

Main Entry: in·ter·ven·tric·u·lar
Pronunciation: secondarystressint-schwar-ven-primarystresstrik-yschwa-lschwar, -vschwan-
Function: adjective
: situated between ventricles interventricular septal defect>

Ventricle is a body filled with fluid*

Crohn's, air/gas in the urine
terminal ileum cecum and bladder adhesion => resected the adhesion
WBC 25
Leak in anastomosis? Is it fluid, blood or contrast material?
Serous urine, hematuria, check the density of fluid in the urine, is it blood, urine or contrast material for CT?
Fistula of bowel and bladder taken down => leakage of something
Urine very bloody, test for bilirubin, creatinine, BUN and cell count
If there's leak from anastomosis, what should be done?
=> ileostomy
terminal ileum to be taken out, side to side anastomosis of ileum to ascending colon

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Bilirubin is a yellow breakdown product of normal heme catabolism. Its levels are elevated in certain diseases and it is responsible for the yellow color of bruises and the brown color of faeces.

Bilirubin is broken down by light, and blood collection tubes (especially serum tubes) should therefore be protected from such exposure.

Bilirubin is either in the insoluble form, unconjugated bilirubin (also indirect bilirubin), or bound to glucuronic acid to form the so called conjugated bilirubin (also direct bilirubin). The indirect form is insoluble and it is transformed into a soluble or direct form, in the liver. Total and direct bilirubin levels can be measured from the blood, but indirect bilirubin is calculated from the total and direct bilirubin.The terms "direct" and "indirect" reflect the way the two types of bilirubin react to certain dyes. Conjugated bilirubin is water-soluble and reacts directly when dyes are added to the blood specimen. The non-water soluble, free bilirubin does not react to the reagents until alcohol is added to the solution. Therefore, the measurement of this type of bilirubin is indirect. Test results may be listed as "BU" for unconjugated bilirubin and "BC" for conjugated bilirubin. Total bilirubin measures both BU and BC. To further elucidate the causes of jaundice or increased bilirubin, it is usually simpler to look at other liver function tests (especially the enzymes ALT, AST, GGT, Alk Phos), blood film examination (hemolysis, etc.) or evidence of infective hepatitis (e.g., Hepatitis A, B, C, delta E, etc).

Bilirubin is an excretion product, and the body does not control levels. Bilirubin levels reflect the balance between production and excretion. Thus, there is no "normal" level of bilirubin.


The reference range for total bilirubin is 2 - 14 μmol/L or 0.3 - 1.9 mg/dL. For direct bilirubin, it is 0 - 4 μmol/L or 0 - 0.3 mg/dL.

Mild rises in bilirubin may be caused by

  • Hemolysis or increased breakdown of blood.
  • Gilbert's syndrome - a genetic disorder of bilirubin metabolism which can result in mild jaundice, found in about 5% of the population.

Moderate rise in bilirubin may be caused by

Very high levels of bilirubin may be caused by

Cirrhosis may cause normal, moderately high or high levels of bilirubin, depending on exact features of the cirrhosis.

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Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass).

[edit] Physiology

It is mainly filtered by the kidney, though a small amount is actively secreted. There is some tubular reabsorption of creatinine, but this is compensated by a roughly equivalent degree of tubular secretion. If the filtering of the kidney is deficient, blood levels rise. This effect is used as an indicator of renal function. However, in cases of severe renal dysfunction, the creatinine clearance rate will be overestimated because the active secretion of creatinine will account for a larger fraction of the total creatinine cleared. A higher than normal creatinine and BUN can also be indicative of dehydration when BUN-to-creatinine ratio is abnormal, with BUN levels rising higher than creatinine levels. Men tend to have higher levels of creatinine because they have more skeletal muscle than women.

Diagnostic use

Measuring serum creatinine is a simple test and it is the most commonly used indicator of renal function. A rise in blood creatinine levels is observed only with marked damage to functioning nephrons. Therefore this test is not suitable for detecting early stage kidney disease. A better estimation of kidney function is given by the creatinine clearance test. Creatinine clearance can be accurately calculated using serum creatinine concentration and some or all of the following variables: sex, age, weight, and race as suggested by the National Diabetes Association without a 24 hour urine collection [1]. Some laboratories will calculate the ClCr if written on the prescription; and, the necessary age, sex, and weight are included in the patient information.

[edit] Interpretation

In the United States, creatinine is typically reported in 0.7 - 1.5 mg/dL, while in Canada and Europe μmol/litre may be used. 1 mg/dL of creatinine is 88.4 μmol/l.

The typical reference range for women is considered 0.5 to 1.0 mg/dL (about 45-90 μmol/l), for men 0.7 to 1.2 mg/dL (60-110 μmol/l). While a baseline serum creatinine of 2.0 mg/dL (150 μmol/l) may indicate normal kidney function in a male body builder, a serum creatinine of 0.7 mg/dL (60 μmol/l) can indicate significant renal disease in a frail old woman. More important than absolute creatinine level is the trend of serum creatinine levels over time. A rising creatinine level indicates kidney damage, while a declining creatinine level indicates improving kidney function.

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The blood urea nitrogen (BUN) test is a measure of the amount of nitrogen in the blood that comes from urea. Urea is a substance secreted by the liver, and removed from the blood by the kidneys.

Physiology

The liver produces urea in the urea cycle as a waste product of the digestion of protein. Normal human adult blood should contain between 7 and 25 mg of urea nitrogen per 100 ml of blood. Individual laboratories may have different "usual clinical ranges", and this is because the procedure may vary.

[edit] Interpretation

The most common cause of an elevated BUN, azotemia, is poor kidney function, although a serum creatinine level is a somewhat more specific measure of renal function.

A greatly elevated BUN (>60 mg/dl) generally indicates a moderate-to-severe degree of renal failure. Impaired renal excretion of urea may be due to temporary conditions such as dehydration or shock, or may be due to either acute or chronic disease of the kidneys themselves.

Elevated BUN in the setting of a relatively normal creatinine may reflect a physiological response to a relative decrease of blood flow to the kidney (as seen in heart failure or dehydration) without indicating any true injury to the kidney. However, an isolated elevation of BUN may also reflect excessive formation of urea without any compromise to the kidneys.

Increased production of urea is seen in cases of moderate or heavy bleeding in the upper gastrointestinal tract (e.g. from ulcers). The nitrogenous compounds from the blood are resorbed as they pass through the rest of the GI tract and then broken down to urea by the liver. Enhanced metabolism of proteins will also increase urea production, as may be seen with high protein diets, steroid use, burns, or fevers.

A low BUN usually has little significance, but its causes include liver problems, malnutrition (insufficient dietary protein), or excessive alcohol consumption. Overhydration from intravenous fluids can result in a low BUN. Normal changes in renal bloodflow during pregnancy will also lower BUN.

Urea itself is not toxic. This was demonstrated by Johnson et al. by adding large amounts of urea to the dialysate of hemodialysis patients for several months and finding no ill effects.[1]. However, BUN is a marker for other nitrogenous waste. Thus, when renal failure leads to a buildup of urea and other nitrogenous wastes (uremia), an individual may suffer neurological disturbances such as altered cognitive function (encephalopathy), impaired taste (dysgeusia) or loss of appetite (anorexia). The individual may also suffer from nausea and vomiting, or bleeding from dysfunctional platelets. Prolonged periods of severe uremia may result in the skin taking on a grey discolouration or even forming frank urea crystals ("uremic frost") on the skin.

Because multiple variables can interfere with the interpretation of a BUN value; GFR and creatinine clearance are more accurate markers of kidney function. Age, sex, and weight will alter the "normal" range for each individual, including race. In renal failure or chronic kidney disease (CKD), BUN will only be elevated outside "normal" when more than 60% of kidney cells are no longer functioning. Hence, more accurate measures of renal function are generally preferred to assess the clearance for purposes of medication dosing.

[edit] Units

In the United States, BUN is measured in mg/dL. To convert BUN to a concentration in mmol/L (SI units), multiply by 0.357 ( (10 dL/1 L)/(28 mg of N/mmol of urea) = 0.357 ).

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A complete blood count (CBC) or full blood count (FBC) or full blood exam (FBE) is a test requested by a doctor or other medical professional that gives information about the cells in a patient's blood. A Medical technologist performs the requested testing and provides the requesting Medical Professional with the results of the CBC. A CBC is also known as a "hemogram".

The cells that circulate in the bloodstream are generally divided into three types: white blood cells (leukocytes), red blood cells (erythrocytes), and platelets or thrombocytes. Abnormally high or low counts may indicate the presence of many forms of disease, and hence blood counts are amongst the most commonly performed blood tests in medicine.

A complete blood count will normally include:

[edit] Red cells

[edit] White cells

  • Total white blood cells - All the white cell types are given as a percentage and as an absolute number per litre.

A complete blood count with differential will also include:

Type of Cell Increase Decrease
Red Blood Cells (RBC) erythrocytosis or polycythemia anemia or erythroblastopenia
White Blood Cells (WBC): leukocytosis leukopenia
-- lymphocytes -- lymphocytosis -- lymphocytopenia
-- granulocytes: -- granulocytosis -- granulocytopenia or agranulocytosis
-- --neutrophils -- --neutrophilia -- --neutropenia
-- --eosinophils -- --eosinophilia -- --eosinopenia
Platelets thrombocytosis thrombocytopenia
All cell lines --- pancytopenia



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Pre-sacral pericolic abscess after APR, ileostomy
abscess with E.coli, P.aeruginosa, and an anaerobe(Bactero~?)
WBC 15

pericolic m. occasional bands of peritoneum extending between the abdominal wall and the serosa of the colon.

A pericolic abscess may result as a pathological complication of acute diverticulitis.
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C-section(Cesarian section), tubule ligation(tubes tied to prevent pregnancy)

hernia + hematoma

gastritis pt

Why is it that tumor in tail of pancreas is later to detect than the tumor of the head of pancreas?
=> bile duct obstruction causes jaundice => early sign

splenic artery supplies blood to spleen

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Seldinger technique?

The Seldinger technique is a medical procedure to obtain safe access to blood vessels and other hollow organs. It is named after Dr Sven-Ivar Seldinger (1921-1998), a Swedish radiologist from Mora, Dalarna County, who introduced the procedure in 1953.

Description

The desired vessel or cavity is punctured with a sharp hollow needle called a trocar, with ultrasound guidance if necessary. A round-tipped guidewire is then advanced through the lumen of the trocar, and the trocar is withdrawn. A "sheath" or blunt cannula can now be passed over the guidewire into the cavity or vessel. Alternatively, drainage tubes are passed over the guidewire (as in chest drains or nephrostomies). After passing a sheath of tube, the guidewire is withdrawn.

If a sheath is used, it can be used to introduce catheters or other devices to perform endoluminal (inside the hollow organ) procedures, such as angioplasty. Fluoroscopy may be used to confirm the position of the catheter and to manoeuvre it to the desired location. Injection of radiocontrast may be used to visualise organs. Interventional procedures, such as thermoablation, angioplasty, embolisation or biopsy, may be performed.

Upon completion of the desired procedure, the sheath is withdrawn. In certain settings, a sealing device may be used to close the hole made by the procedure.

[edit] Uses

The Seldinger technique is used for angiography, insertion of chest drains and central venous catheters, insertion of PEG tubes using the push technique, and numerous other interventional medical procedures.

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What are signs of gallstone?
1) is stone palpable?
2) pancreatitis?
3) obstructive jaundice
4) cholangitis
5) abnormal LT, dilated common duct > 1.5 cm

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IOC(Intraoperative Cholangiography) vs ERCP
Risk of pancreatitis greater from ERCP than IOC

Cholangiography is the testing of the bile duct (also known as the biliary tree) by radiology. There are at least two kinds of cholangiography:

In both cases fluorescent fluids are used to create contrasts that make the diagnosis possible. Cholangiography has largely replaced the previously used method of intravenous cholangiography (IVC).

Endoscopic retrograde cholangiopancreatography (ERCP) is a technique that combines the use of endoscopy and fluoroscopy to diagnose and treat certain problems of the biliary or pancreatic ductal systems. It is an x-ray examination of the bile ducts which is aided by a video endoscope. Through the endoscope, the physician can see the inside of the stomach and duodenum, and inject dyes into the ducts in the biliary tree and pancreas so they can be seen on x rays.

GUT perforation is a risk of any endoscopic procedure as well as the ERCP holding a 5% risk of developing acute pancreatitis.

Dyes: Dyes used to allow the physician to image the organs can cause allergic reactions. Iodine is a component of one of these dyes, and if you are allergic to shellfish, you will be at risk with the dye. Also, the dyes can be harmful to the kidneys. If your kidneys have poor function, the dye could cause renal failure. If you are at such risk, then question the physician, ask about how to promote flushing the dye from your system and how to recover from kidney damage. If you are on dialysis, you should be dialyzed after the procedure to flush out the dyes.

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major risks of lap chole?
=> injuring bile duct

selective vs. routine cholangiogram usage

common duct risk of hole from longitudinal or complete transection

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serosanguinous?

Main Entry: se·ro·san·guin·e·ous
Pronunciation: secondarystresssir-omacr-san-primarystressgwin-emacron-schwas, secondarystressser-omacr-, -saeng-
Variant(s): or se·ro·san·guin·ous /-primarystresssaeng-gwschwa-nschwas/
Function: adjective
: containing or consisting of both blood and serous fluid serosanguineous discharge>

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loop vs. end ileostomy?

blood in the colostomy(done 2 yrs ago) bag, necrotizing fascitis(inflammation of fascia, gangrene)
blood and feces mixed
pouch with mucous fistula is called "Hartmann's pouch"(not to be confused with infidibulum)
reconstruction of anus
blood may come from ulcer

Necrotizing fasciitis or fasciitis necroticans, commonly known as "flesh-eating bacteria", is a rare infection of the deeper layers of skin and subcutaneous tissues (fascia). Many types of bacteria can cause necrotizing fasciitis (eg. Group A streptococcus, Vibrio vulnificus, Clostridium perfringens, Bacteroides fragilis), of which Group A streptococcus is the most common cause.

Symptoms

The infection often starts with pharyngitis (sore throat), but occasionally begins locally, at a site of trauma, which may be severe (such as the result of surgery), minor, or even non-apparent. The affected skin is classically, at first, very painful without any visible change. With progression of the disease, tissues become red, hot and swollen, often within hours. Skin color may progress to violet and blisters may form, with subsequent necrosis (death) of subcutaneous tissues. Patients with necrotizing fasciitis typically have a fever and appear very ill. More severe cases progress within hours, and the death rate is high, about 25%.

Treatment

The diagnosis is confirmed by either blood cultures or aspiration of pus from tissue. Early medical treatment is crucial. Treatment often includes intravenous penicillin, vancomycin and clindamycin. If necrotizing fasciitis is suspected, surgical exploration is always necessary, often resulting in aggressive debridement (removal of infected tissue). Amputation of the affected organ(s) may be necessary. Initial treatment consists of antibiotics. Surgical procedures include extensive debridement as soon as possible, secondary closure. The mortality of this disease has not been altered by antimicrobials. Only early recognition and surgical treatment will improve the prognosis.

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Urea cycle

The urea cycle, also known as the ornithine cycle, is a cycle of biochemical reactions occurring in many animal organisms that produces urea from ammonia (NH4+). This cycle was the first metabolic cycle discovered (Krebs and Kurt Henseleit, 1932).

Function

Organisms that cannot easily and quickly remove ammonia usually have to convert it to some other substance, like urea or uric acid, which are much less toxic. Insufficiency of the urea cycle occurs in some genetic disorders (inborn errors of metabolism), and in liver failure. The result of liver failure is accumulation of nitrogenous waste, mainly ammonia, which leads to hepatic encephalopathy.

[edit] Reactions

The urea cycle consists of five reactions - two mitochondrial and three cytosolic. The cycle converts two amino groups, one from NH4+ and one from Asp, and a carbon atom from HCO3-, to relatively nontoxic excretion product, urea, at the cost of four "high-energy" phosphate bonds (3 ATP hydrolyzed to 2 ADP and one AMP). Orn is the carrier of these carbon and nitrogen atoms.

Reactions of cycle:

Step Reactant Product Catalyzed by Location
1 2ATP + HCO3- + NH4+ carbamoyl phosphate + 2ADP + Pi CPS1 mitochondrial
2 carbamoyl phosphate + ornithine citrulline + Pi OTC mitochondrial
3 citrulline + aspartate + ATP argininosuccinate + AMP + PPi ASS cytosolic
4 argininosuccinate Arg + fumarate ASL cytosolic
5 Arg + H2O ornithine + urea ARG1 cytosolic

Summary reaction:

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