Mother of All Inducers

Barbiturates, as a class, are the most prolific inducers known, affecting almost all P450 enzymes. Inducers generally do not create drug-toxicity interactions when an inducer is added, however, on withdrawing an enzyme inducer, the resultant decrease level of enzyme will result in increased levels of drugs metabolized by these enzymes and could result in severe toxicity.

DDx of Positional Headaches

Two conditions that cause positional headaches are:

1. Colloid Cysts in the third ventricle which block the Foramen of Monro when a person changes position.

2. Post-spinal tap headache. Make sure the patient lies flat after the procedure.

Vomiting in Peds

Pyloric Stenosis vs Viral Gastroenteritis

PS: voracious appetite
Viral GE: no appetite

Internship

Hi everyone. Recently, I haven't posted as often because I started my internship last week. I'll pick up the posting in a week or so.

The ABCD's of drugs that slow down the AV node.

Four drugs can slow down the AV node and thus lead to heart block and probably should not be used in WPW.

A=Adenosine
B=Beta Blocker
C=Calcium Channel Blockers
D=Digoxin

What goes through my head when I get a calcium question...

#1: Is calcium too high or too low?
#2: What is the phospate level?

The question stem might not give calcium levels so I might have to look for the S/S of hyper or hypocalcemia. Hypercalcemia is classically summarized by the mnemonic "stones, bones, abdominal groans and psychic moans". Hypocalcemia is best remembered by the 2 signs associated with it, Chovstek's sign and Trousseau's sign. The tricky part is that hypocalcemia causes tetany, not hypercalcemia. Most people get this backwards.

The phosphate level tells me who is causing the problem, vitamin D or PTH. The "job" of PTH is to increase free calcium and to decrease phosphate. This leads to a high calcium and a low phosphate. The "job" of vitamin D is to increase both calcium and phosphate, increasing bone mineralization.

So if calcium is high and phosphate is low, PTH did its job. If calcium is low and phosphate is high, PTH is sleeping and should be fired.

If both calcium and phosphate are high, vitamin D did its job. If both are low, vitamin D is slacking.

Next post: what to do with your newfound information on PTH and vitamin D activity.

Answer to the Endocrine Question

This question really boils down to a calcium question and the choices should be broken down into what causes hypocalcemia and what causes hypercalcemia.

WRONG ANSWERS:
Choice (A) lung cancer was put there because of the distractor in the stem, the possibility of squamous cell lung cancer and the paraneoplastic syndrome associated with hypercalcemia and PTHrp (PTHrp is not measured when you get a PTH level. PTH should be suppressed due to the high calcium levels).

Choice (B) primary hyperparathyroidism is another distractor because the patient has a high PTH level. But when does primary hyperparathyroidism ever cause hypocalcemia? Never!

Choice (D) thyroidectomy done by a sloppy surgeon can sometimes cause hypocalcemia due to the inadvertant removal of the parathyroid glands. This would indeed cause hypocalcemia, but, PTH would NEVER be elevated.

Choice (E) plasma cell infiltration of the bone marrow referred to multiple myeloma, which is in the differential diagnosis of HYPERcalcemia. PTH would be suppressed.


ANSWER:
Choice (C) renal failure is the answer because it is the only choice that can cause hyperphosphatemia, hypocalcemia and elevated PTH. The history of diabetes is subltly included but it is not necessary to answer this question. I used to get confused with renal disease until I boiled it down to, "don't give chronic renal failure patients Coca Cola." The main problem with calcium in renal failure is due to the high phosphate levels that the kidneys can't get rid of. The phosphate and the calcium combine in the blood. This lowers the calcium. The parathyroids go into panic mode and try to raise calcium by destroying the bones (osteitis fibrosa cystica).

What's in a name... Baclofen

If you want a clue on the MOA of baclofen, add "GA" to the front of the name to make GAbaclofen. Baclofen is a GABA B agonist used for its muscle relaxing properties.

Find the Gold Standard... Endocrine question

A 65 y/o male is admitted to the hospital for a lower lobe pneumonia. His past medical history includes diabetes mellitus, COPD, and hypertension. He is a chronic smoker, with a 50 pack year smoking history. Upon admission to the hosptital, his lab report shows decreased serum calcium levels, elevated phosphate levels, and and elevated intact serum PTH levels. What is the most likely cause of abnormal lab values?

A. Lung cancer
B. Primary hyperparathyroidism
C. Renal failure
D. Thyroidectomy
E. Plasma cell infiltration in the bone marrow

Please leave you answer in the comments section along with what you think is the "gold standard" of this question. I will post my reponse tomorrow.

Find the Gold Standard!

A 35-year-old diabetic woman presents to her gynecologist with complaints of burning on urination for the past 2 days. Dipstick test of her urine demonstrates markedly positivity for leukocyte esterase, but no reactivity for nitrite. Urine culture later grows out large numbers of organisms. Which of the following bacteria are most likely to be responsible for this patient's infection?

A. Enterobacter sp.
B. Enterococcus faecalis
C. Escherichia coli
D. Klebsiella pneumoniae
E. Pesudomonas aeruginosa



The gold standard in this question is not the culture, because all five of these bugs will grow on agar. Here the gold standard is the "no reactivity for nitrite." Production of nitrites is typically found in gram negatives when the converted nitrate to nitrite (via reductase). So this question boils down to which one of the bugs is the gram positive? Enterococcus (B) is the answer to the question, but I wanted to bring the trickiness of the name Enterococcus to everyones attention. It sounds too similar to the gram negatives sp. Enterobacter. I have confused these two since I opened my first micro book. Nowadays, I consciously slow down my reading whenever I see the word "entero." Enterotoxin and endotoxin are often confused as well. So be careful!

2 for 1 Deal... Hemolytic Diseases with Gallstones.

There are two hemolytic diseases with bilirubin stones as complications. One is sickle cell anemia, and the other is hereditary spherocytosis. One quick and dirty way to tell them apart is by looking at the spleen size. Sickle cell patients will have a spleen the size of a walnut buy the age of 2. Hereditary spherocytosis is the only hemolytic anemia with an enlarged spleen.

What's in a Name: HUS and TTP

Hemolytic uremic syndrome often follows an infection from E. coli O157:H7. HUS should really be called H.U.T.S (hemolysis, uremia, thrombocytopenia syndrome). Questions with syndromes are tricky becuase most people miss them because instead of saying directly hemolysis, uremia, and thrombocytopenia, the stem will usually say that the patient has increased LDH and decreased haptoglobin, elevated BUN and creatinine, and petechiae.

If you add altered mental status and fever to HUTS, you get TTP.

The way that I see the "big picture" and avoid getting lost in the details of a question, I read through the stem pretty quickly, painting a picture of whats going on in the patient. If the AST/ALT is elevated, the liver is likely involved. If there is hemoptysis, the lungs are invovled.

I then do some very basic math in my head... Liver + Lung = could be alpha 1 antitrypsin deficiency in a young, non-drinker with cirrhosis and hemoptysis.

Question Dissection

Question:

A mailman gets a severe bite wound from a pit bull guarding a junkyard. The wound is cleansed and he receives a booster injection of tetanus toxoid and an injection of penicillin G. Several days later, the wound is inflamed and purulent. The exudate is cultured on blood agar and yields gram-negative rods. Antibiotic sensitivity tests are pending. The most likely agent to be isolated is

A. Actinomyces israelii

B. Leptospira interrogans

C. Clostridium tetani

D. Pasteurella multocida

E. Capnocytophagia canimorsus





Answer: (D) Pasteurella multicida

It is important to know the infections you get from a cat/dog bite, scratch, and urine.

Bite: Pasteurella multicida
Scratch: Bartonella henselae
Urine: Leptospira interrogans

Of the above choices, only two are gram negative rods, Pasteurella and Capnocytophagia. Actinomyces is "actin like a myces" so it is a gram positive filamentous rod. Leptospira is a spirochete. Clostridium is a gram positive rod. The tricky one is (E) Capnocytophagia canimorsus. If you look at the name, Capnocytophagia, you can see the "capno" and the "cytophagia." "Capno" refers to carbon dioxide and "cytophaga" means "cell eater." Capnocytophagia is a fastidious grower which requires a microaerophilic environment to grow so it probably wouldn't grow on the above blood agar.

One of the most my important resources is my Stedman's medical dictionary. I have it on my Blackberry, computer, and Palm. Stedman's is nice because it gives you the Latin and Greek roots of the words. How can you answer a question if you don't know the difference between sclerosis and stenosis? In the question above, knowing that "capno" meant carbon dioxide, gave me enough information to get a similar question right on my USMLE Step 1.

What's in a Mnemonic: encapsulated organisms

One of the most high yield mnemonics in microbiology is the one for encapulated organisms:

"Some Nasty Killers Have Some Capsule Protection":

Streptococcus pneumoniae
Neisseria meningitidis
Klebsiella pnemoniae
Haemophilus influenzae
Salmonella typhi
Cryptococcus neoformans
Pseudomanas aeruginosa

Most people know this mnemonic. However, many people don't realize how many questions they can answer just by memorizing just one sentence.

The following are uses for the above mnemonic:

1. If the question presents a patient missing anything needed to kill encapsulated organisms (eg spleen, IgG, C3b, macrophages, etc.), they are at increased risk for infections from the above bugs.
2. Diseases that are infamously susceptible to encapsulated organisms:
   
1. anyone who doesn't have a functional spleen (eg: sickle cell)
2. Bruton's agammaglobulinemia
3. If an organism has a capsule, some vaccines are made against the capsule
   
1. Pneumococci
2. Meningococci
3. H. influenzae type b
4. Usually, the capsule is a major virulence factor for the above organisms.
5. If the question mentions a positive Quellung reaction, look for one of the above bugs for an answer.
6. Big mucoid colonies on blood agar is Klebsiella (from a big mucoid capsule)
   

How to find the gold standard in each USMLE question.

A 68 year old male presents with 5 days of fever, non-productive cough, confusion, and a chest x-ray showing non-specific pneumonia. He works in a community hospital with a desk underneath an air-conditioning vent. A sputum culture is taken and it grows a large number of organisms on blood agar. What is the most likely cause of his pneumonia?

The answer to this question could be a number of things, but the one thing I'm certain about, is that the answer is NOT Legionella pneumophilia. True, he has exposure to air-conditioning and presents with the typical symptoms of Legionella pneumonia, but when did Legionella ever grow on normal blood agar? It is a fastidious organism that grows on charcoal yeast extract (CYE) agar. Most of the people I ask know the culture requirements of Legionella, but those same people still answer Legionella for the preceding stem. Why does this happen? And how do you prevent yourself from making the same mistake again?

The way I avoid making this mistake on a multiple choice test is by finding the "gold standard" information in each question. Usually the gold standard information is found in the pathology or microbiology report, followed by blood tests, radiology reports, physical exam, patient history, and finally by risk factors, in that order. A good example of this is found in the treatment of cancer. Would you be willing to give a patient months of chemotherapy based on a just a history of smoking and a cough? How about a single calcified nodule in the lungs? How about a pathology report showing small cell lung carcinoma? I think most of us would rely on the later for our treatment decisions.

The same logic can be applied to answering our original scenario. Would you give this patient the drug of choice for Legionella, a macrolide, based on the history of exposure to air conditioners? If that is how medicine was practiced, I would be on erythromycin right now. The differential diagnosis of diseases in people who were exposed to air conditioners includes just about ALL diseases.

Here is my "gold standard" list from most reliable to least reliable.

1. Pathology/histology reports
2. Microbiology cultures/stains
3. Blood tests including CBC, electrolytes, tumor markers, hormone levels
4. Radiology reports
5. Vitals and physical exam
6. Symptoms
7. Patient's past medical history
8. Patient's age
   
9. Patients risk factors
   
10. Family history

Is it jaundice... or too many carrots?

• TOO MUCH BILIRUBIN BEING PRODUCED ("hemolytic jaundice")
• Ineffective hematopoiesis", i.e., normoblasts dying in the bone marrow
• Thalassemias (even mild ones like beta-thal minor)
• Megaloblastic anemias (folate or B12 deficiencies)
• Intravascular hemolysis (many causes)
  
• Extravascular hemolysis
• Big hematomas
• GI bleeding

• LIVER FAILS TO TAKE UP AND/OR CONJUGATE BILIRUBIN ("hepatocellular jaundice")
• Newborns (don’t give opiates (except meperidine), sulfonamides)
• Hypoperfusion (CHF)
• Bad alcoholism
• Hepatitis (many causes)
• Cirrhosis (many causes)
• Glucuronyl transferase (solubilizes bilirubin)
• Gilbert’s non-disease [worse w/ fasting)
• Crigler-Najjar

• LIVER DOESN'T SEND BILIRUBIN TO THE RIGHT PLACE ("cholestatic jaundice" water soluble so urine can be darker)
• Problems with the liver cells
• Drugs (estrogen, anabolic steroids)
• Dubin-Johnson (pigmented) non-disease
• These people lack a pump
• Rotor (non-pigmented) non-disease.
• Problems with the bile ducts in the liver
• Biliary cirrhosis
• Biliary atresia
• Problems with the bile ducts beyond the liver (surgical)
• Gallstone in the common duct (the only time a gallstone in the gallbladder will cause jaundice is in Mirizzi Syndrome)Cancer (i.e., biliary, pancreatic, ampullary)
• Iatrogenic (i.e., the surgeon nicked the common bile duct)
  

BTW: the eye sclera should never be yellow if the "jaundice" from carrots.

Gram Positive Cocci MindMap

2 for 1 Deal... Ramsay Hunt Syndrome and Bullous Myringitis

The differential of vesicles/bullae in the external ear are Ramsay Hunt Syndrome and bullous myringitis. Ramsay Hunt Syndrome is an extremely painful manifestation of varicella zoster virus and is one of the indications for IV acyclovir. It can also include hyperacusis and loss of taste to the anterior 2/3 of the tongue. Bullous myringitis (image on right) is seen atypical (non-productive cough) pneumonia from mycoplasma.

2 for 1 Deal... Salmonella typhi and Ceftriaxone

Two unusual things "live" in the gallbladder. One is S. typhi, which is a motile gram negative rod who "swims" upstream from the colon to the gallbladder and lives there chronically (see Typhoid Mary). It also famous for causing rose spots on the abdomen and relative bradycardia.

Ceftriaxone is a lipid soluble third generation cephalosporin which is famous for treating a wide variety of diseases including gram negative and gram positives. Since it is lipid soluble it can cross the blood-brain barrier and is useful for the empiric treatment of meningitis. Like most lipid soluble drugs, it is metabolized by the liver and is excreted in the bile. It reaches very high concentrations in the gall bladder where is causes gallbladder sludge.

2 for 1 Deal... Botulinum and Eaton Lambert Syndrome

2 diseases inhibit the release of ACh from the presynaptic terminal. The obvious one is the botulinum toxin. The other disease is Eaton Lambert syndrome which is an autoimmune process in which antibodies develop to the voltage-gated calcium channels and impair the release of ACh from the presynaptic terminal. Eaton Lambert syndrome is often a paraneoplastic syndrome associated with small cell lung cancer.

Myasthenia gravis and Eaton Lambert often appear in the same question. The key difference to look for in the question stem is whether or not the weakness gets better or worse throughout the day. Myasthenia gravis gets worse as the day progresses. Eaton Lambert gets better.

2 for 1 Deal... Idiopathic Thrombocytopenic Purpura and Abciximab

Idiopathic thrombocytopenic purpura and the drug abciximab both target platelet membrane glycoprotein IIb-IIIa. ITP is an immune destruction of platelets. Besides being impossible to pronounce, abciximab is used in patients undergoing percutaneous coronary intervention, and is an antiplatelet agent.

Gluteus maximus, medius, minimus

It is easy to mix up the actions and innervations of the gluteus maximus, gluteus medius, and gluteus minimus. The easiest way to approach questions on the gluteal muscles is to group the gluteus medius and minimus together. The medius and minimus both abduct the hip or more importantly, they allow our hips to stay level when we stand on one leg (Trendelenburg Test). The gluteus maximus helps us get out of a chair. The trick to these muscles is their innervation. The maximus goes with the inferior gluteal nerve. The medius and minimus are both innervated by the superior gluteal nerve. Be aware of this because it would seem logical that the maximus would go with the superior, but it doesn't!

2 for 1 deal... Achalasia and Hirschsprung's Disease

Achalasia is the Hirschsprung's of the esophagus. Both are missing the Auerbach's plexus (or myenteric plexus). Both have problems relaxing. Achalasia causes a megaesophagus and Hischsprung's causes a mega colon.

Note that Chagas disease = achalasia + Hirschsprung's. Chagas disease can cause both a megaesophagus and a megacolon.

Opposites: SIADH vs DI drugs

SIADH Drugs:

Acetaminophen
Barbiturates
Carbamazepine
Chlorpropamide
Clofibrate
Cyclophosphamide
Indomethacin
Isoproterenol
PGE1
Meperidine
Nicotine
Tolbutamide
Vincristine

Diabetes Insipidus Drugs:

Ethanol
Phenytoin
Chlorpromazine
Lithium
Demeclocycline
Glyburide
Amphoterocin B
Colchicine
Vinblastine

Bicycles in my urine!

There are two important "cycle" drugs that cause problems in the GU system. Picture a bunch of bicycles riding around in the renal tubules and bladder. The first drug is a"cyclo"vir which crystalizes in the renal tubules. The other drug is "cyclo"phosphamide which causes the infamous hemorrhagic cystitis which is prevented with mesna.

My approach to diuretic questions

DDx of diuretics

1. Loops
2. Thiazides
3. K+ sparing
4. Acetazolamide
   

My first rule: all diuretics cause hypokalemia except for 3 drugs (potassium sparing diuretics)

1. Spironolactone (competitive aldosterone antagonist, also interferes with testosterone synthesis causing incr estradiol in treating hirsutism in PCOS. Spironolactone has been shown to improve mortality in patients with CHF by blocking the toxicity of aldosterone as it hits the heart. (Weird MOA)
2. Amiloride (inhibits directly, the Na/K pump in the DCT)
3. Triamterene (same MOA amiloride)

To separate all of the diuretics that cause hypokalemia, look at the [Ca++] to separate loops and thiazides.

1. Loops lose everything including Ca++, so if the patient is hypokalemic and hypocalcemic, they are probably on a loop (furosemide, torsemide, ethacrynic Acid, bumetanide) be careful of ethacrynic acid, it's name doesn’t look like a loop at all!
2. Thiazides cause increased Ca++ reabsorption from renal tubules so they cause hypercalcemia, but they are used to treat calcium renal stones because they decrease Ca++ in the tubules, where it is causing the problem.
   

To separate acetazolamide from loops and thiazides, look at the acid-base status.

1. Acetazolamide is one of the few things that causes a metabolic acidosis with hypokalemia. Acetazolamide is a carbonic anhydrase inhibitor producing an alkaline diuresis. (you pee bicarb, and with the bicarb, Na follows). Usually, acidosis goes with hyperkalemia. Acetazolamide is also used to decr aqueous humor production and to treat acute mountain sickness.

Be aware that licorice acts like aldosterone, so it can cause hypokalemia.

ACE-I and Digoxin causes hyperkalemia so watch these drugs with spironolactone.

If you get a question w/ Bartter’s Syndrome (mutation of the Na+/K+/2Cl- cotransporter in TAL, just look for the lab values that match a loop diuretic (remember loops LOSE everything). You must rule out diuretic abuse in a patient you suspect has Bartter’s Sydrome.

Highly protein bound drugs

Warfarin, phenytoin, valproic acid, diazepam

o Generally have low volumes of distribution

o Can be displaced and are usually lipid soluble

PGE1 agonists

Misoprostol: used for prophylaxis of GI ulcers when on NSAIDS. Think of drinking "miso" soup to help your stomach pain. Look at the "prost" to remind yourself of its MOA, prostaglandin E1 agonist.

Alprostadil (prostaglandin E1): maintains patency of ductus arteriosus (opposite of what indomethacin or any NSAID does). Look at the "prost" to remind yourself of the MOA, PGE1 agonist and look at the "dil" to remind yourself that it DILates the PDA.

DDx Diarrhea in AIDS patients

Diarrhea in HIV/AIDS

---

DDx

Viral: CMV colitis, also causes CMV esophagitis Bacterial: Campylobacter, Salmonella, Shigella, Clostridium difficile, Mycobacterium avium complex (MAC), tuberculosis Protozoal: Cryptosporidium (no real treatment available) Entamoeba histolytica (amoebic dysentery, look for liver abscess as well) Giardia (watery diarrhea, often prolonged, with bloating, gas and malabsorption; upper GI symptoms w/ lower GI symptoms; risk factors: anal sex and drinking "pure" mountain water) Isospora, microsporidia HIV-associated malabsorption

What's in a name... Amiodarone

• Amiodarone
• Iodine: think iodine in the lungs (pulmonary fibrosis, iodine in the liver (hepatic necrosis), iodine in the eyes (corneal deposits), iodine in the skin (smurf skin, phototoxicity), iodine is also in thyroid hormone (thyroid dysfunction).

What's in a number?

If you didn't notice, I reformatted the goljan lectures to 1.618 times speed. I will send my biochem on crack usmle lectures the first person who leaves a comment correctly identifying the significance of the ratio 1.618.

Chemotactic Factors

• Chemotactic Factors for Neutrophils
• Bacterial Products (i.e. teichoic acid)
  
• Components of the complement system, particularly C5a
• Products of the arachidonic acid metabolism, particularly
• Leukotriene B4
• Chemotactic Factors for Monoctyes
• Bacterial Products
• C5a components of complement
• Fibrinopeptides
• Leukotriene B4
• Lymphokines
• Growth factors (PDGF, TGFB)
• Fragments of collagen and/or fibronectin
• Chemotactic factors for Eosinophils
• Leukotriene B4
• Prostaglandin D2
• Histamine
• Eosinophil chemotactic factor of anaphylaxis

My Antibiotics Lecture

Nitroprusside

Nitroprusside has an important indication for the treatment of hypertensive emergencies. However, it is more famous for its side-effect, i.e. cyanide poisoning. How do we associate nitroprusside with cyanide poisoning?

o We already associate Prussian with blue (i.e. “Prussian Blue”)

o Cyanide (cyan is a bluish color)

o So we know that nitroprusside has blue in it from cyanide

o If you use nitroprusside for too long, you can cause cyanide poisoning.

Coombs vs Indirect Coombs

What's in a name?

A very famous question on the boards is what clotting factor enoxaprin works on. The answer is in its name; enoXaprin works on factor Xa!

Is the ampicillin rash the new MonoSpot for EBV?

the sensitivity of the monospot for EBV is 85%. if you give ampicillin to a patient with EBV, >90% will get a maculopapular rash. this means that if a person has infectious mono, they are more likely to break out into a rash after receiving ampicillin than having a positive monospot test.

fyi: up to 80% of patients with CLL also break out into a rash after receiving ampicillin.

Adenosine vs. Theophylline

These drugs have opposite actions on same receptors: adenosine treats arrhythmias but causes asthma, theophylline causes arrhythmias but treats asthma

Abnormal Cell Counts in various fluids

Should culture fluids with these abnormal cell counts

• CSF>5
• Urine>10
• Ascites>250 pmn's or >500 wbc's
• Joint>2,000 for inflammation or >20,000 for infection

So in other words, your brain should have the least wbc's followed by your pee, belly and joints.

Skin findings in conditions with GI bleeding

• Pigmented macules on lips, palms and soles: Peutz-Jegers
• Cafe au lait spots: Neurofibromatosis
• Spider angiomata: liver cirrhosis
• Acanthosis nigricans: neoplasm
• Fragile skin and keloids: Ehlers Danlos
• Webbed neck, purpura and skin nodules: Turner's syndrome
  

Cardiac drugs that induce pulmonary symptoms/disease.

• Amiodarone - pneumonitis and pulmonary fibrosis
• Beta blockers - bronchoconstriction (especially with BB's N-Z)
  
• ACE-I - dry cough (take patient off of ACE-I and put on ARB)
  
• Drug induced SLE (hydralazine, INH, procainamide, etc) - pleurisy (anti-histone antibodies)
• Aspirin - Sampter's triad (rhinitis, nasal polyps, bronchospasm/asthma; if i see nasal polyps in a question I am immediately looking for aspirin or asthma in the answer)

Why are patients with SIADH normovolemic?

Increased ADH with H2O intake causes increased ECF. This volume expansion activates the volume receptors in the heart and causes the release of ANP. ANP causes naturesis w/ some kaliuresis and diuresis. The loss of Na keeps enables the body to have a normal volume.

DDx of exophthalmos

DDx

Graves’ ophthalmopathy (B/L) Tumor (usually unilateral) Hand-Schuller-Christian disease (eosinophilic granuloma)

DDx of Pulseless electrical activity (PEA)

’CHEAPMD’ (mnemonic) Cardiac Tamponade Hypoxia, Hypovolemia, Hypothermia, Hyperkalemia Embolism (massive pulmonary embolism) Acidosis Pneumothorax (tension pneumothorax) Myocardial Infarction Drug overdose, eg, tricyclic antidepressant, digoxin, beta blocker, calcium channel blocker

Paraneoplastic Syndromes

Etiology

(++ = strong association; + = reported association) Endocrine Cushing's syndrome Small-cell lung cancer: ++ Non-small-cell lung cancer: + Gonadotropin excess Small-cell lung cancer: ++ Non-small-cell lung cancer: + Gastrointestinal cancers: + Gestational trophoblastic disease: + Renal cell cancer: + Carcinoid: + Hypercalcemia Small-cell lung cancer: ++ Non-small-cell lung cancer: + Breast cancer: + Multiple myeloma: + Lymphoma: + Prostate cancer: + Hyperthyroidism Gestational trophoblastic disease: + Hypoglycemia Gastrointestinal cancers: + Hepatocellular cancer: + SIADH Small-cell lung cancer: ++ Non-small-cell lung cancer: + Neuromuscular Dermatomyositis/polymyositis Small-cell lung cancer: ++ Non-small-cell lung cancer: + Breast cancer: + Gastrointestinal cancers: ++ Ovarian cancer: + Myeloproliferative disease: + Lambert-Eaton syndrome Small-cell lung cancer: ++ Breast cancer: + Gastrointestinal cancers: + Ovarian cancer: + Sensorimotor peripheral neuropathy Small-cell lung cancer: ++ Non-small-cell lung cancer: + Stiff man syndrome Breast cancer: + Ovarian cancer: + Subacute cerebellar degeneration Small-cell lung cancer: ++ Non-small-cell lung cancer: + Gastrointestinal cancers: + Lymphoma: + Ovarian cancer: + Skin Acanthosis nigricans Non-small-cell lung cancer: + Breast cancer: + Gastrointestinal cancers: + Carcinoid: + Prostate cancer: + Myeloproliferative disease: + Dermatomyositis Small-cell lung cancer: ++ Non-small-cell lung cancer: + Breast cancer: + Gastrointestinal cancers: ++ Ovarian cancer: + Myeloproliferative disease: + Sweet's syndrome Non-small-cell lung cancer: + Breast cancer: + Gastrointestinal cancers: + Lymphoma: ++ Renal cell cancer: + Ovarian cancer: + Prostate cancer: + Myeloproliferative disease: ++ Hematologic Coagulopathy Breast cancer: + Lymphoma: + Renal cell cancer: + Carcinoid: + Prostate cancer: + Myeloproliferative disease: + Eosinophilia Lymphoma: ++ Erythrocytosis Hepatocellular cancer: + Renal cell cancer: + Ovarian cancer: + Adrenocortical tumors: + Cerebellar hemangioblastomas: + Pure red cell aplasia Non-small-cell lung cancer: + Breast cancer: + Gastrointestinal cancers: + Lymphoma: + Thymoma: ++ Thrombocytosis Small-cell lung cancer: + Non-small-cell lung cancer: + Breast cancer: + Multiple myeloma: + Gastrointestinal cancers: + Hepatocellular cancer: + Gestational trophoblastic disease: + Lymphoma: + Renal cell cancer: + Carcinoid: + Thymoma: + Ovarian cancer: + Prostate cancer: + Myeloproliferative disease: + Adrenocortical tumors: + Cerebellar hemangioblastomas: + Fever Small-cell lung cancer: + Non-small-cell lung cancer: + Breast cancer: + Multiple myeloma: + Gastrointestinal cancers: + Hepatocellular cancer: + Gestational trophoblastic disease: + Lymphoma: + Renal cell cancer: + Carcinoid: + Thymoma: + Ovarian cancer: + Prostate cancer: + Myeloproliferative disease: + Adrenocortical tumors: + Cerebellar hemangioblastomas: + Amyloidosis Multiple myeloma: + Lymphoma: + Renal cell cancer: +

Pearl of the Day: DDx of Relative Bradycardia

Salmonella typhi, leptospirosis, brucelliosis, facticious, beta blocker

Cool infectious disease site!

Check out Persiflagers Annotated Compendium of Infectious Disease (PACID). This site is filled with great practical advice and excellent pearls for infectious diseases.

Best Programs for your Blackberry, Palm, Pocket PC

1. Pepid Clinical Rotation Companion - best program by far. Has an excellent disease database, drug list and medical calculator. Major drawback is it's price, but you get 1 free month trial. (pepid.com Blackberry, Palm, Pocket PC)
   
2. iSilo - allows you to carry Harrisons, Washington Manual, Robbins, Netter's, etc in your palm. There is now a beta release of iSilo for the blackberry. Best feature is the ability search entire document. (isilo.com Blackberry, Palm, Pocket PC)
3. Epocrates (free version) - The minimum any student should have on their palm for drug references. (epocrates.com Blackberry, Palm, Pocket PC)
   

Female pathology by age

Where in the brain?

Bile Acid Secretion

Acid secretion in stomach

Sinusitis and Wegener's Granulomatosis

Granulomatous diseases of the lung

Sulfonamides

Quinolones

Drugs to use in pregnancy

Neonatal Infections

High Yield Zoonotic Infections

Bacteria stains

Gram negative rods

Bacteria flow sheet

Hypersensitivity Reactions

Primary Bone tumors by age

• 1st or 2nd decade: Ewing's Sarcoma
  
• Location: diaphysis of long bones
  
• t(11;22)(q24;q12)
• characteristic "onion skin" periosteal reaction on plain XR.
• 10-25 yrs: Oseosarcoma/Osteogenic Sarcoma
  
• "fir-tree" or "sun-burst" appearance on X-ray examination
• Codman's triangle - periosteum lifted into a triangle as the tumour emerges through the cortex
• the American Cancer Society states: "Probably in no other cancer is it as important to perform this procedure properly. An improperly performed biopsy may make it difficult to save the affected limb from amputation"
• Location: metaphysis
• "far from the elbow, close to the knee"
• proximal humerous, the distal radius, the distal femur and the tibia
  
• >30 yrs: Chondrosarcoma
• >50 yrs: Multiple Myeloma

How to keep the locations of Ewing's vs Osteosarcoma straight...
"E" is closer to "D" (Ewing's-Diaphysis)
"O" is closer to "M" (Osteosarcoma-Metaphysis)

Familial syndromes causing sarcomas include:

• neurofibromatosis
• familial retinoblastoma
• Li-Fraumeni syndrome
• Beckwith-Wiedemann syndrome
• basal cell nevus
• Gardner syndrome

Vasculitides

Monoclonal Antibodies... what's up with the name abciximab?

The following guidelines have been developed for monoclonal antibodies:

1. The suffix -mab is used for monoclonal antibodies and fragments.

2. Identification of the animal source of the product is an important safety factor based on the number of products that may cause source-specific antibodies to develop in patients.

The following letters were approved as product source identifiers:

u = human
o = mouse
a = rat
zu = humanized
e = hamster
i = primate
xi = chimera
axo = rat/mouse
xizu = combination of humanized and chimeric chains

These identifiers are used as infixes preceding the -mab suffix stem, eg:

-umab (human)
-omab (mouse)
-ximab (chimera)
-zumab (humanized)

Subclasses
The general disease state subclass must be incorporated into the name by use of a code syllable. The following disease state subclasses were approved based on products currently before the Council. Additional subclasses will be added as necessary.

Disease or Target Class:

Viral	-vir-
Bacterial	-bac-
Immune	-lim-
Infectious Lesions	-les-
Cardiovascular	-cir-
Antifungal	-fung-
Neurologic	-ner-
Interleukins	-kin-
Musculoskeletal	-mul-
Bone	-os-
Toxin as target	-toxa-

Tumors

Adalimumab

infliximab

colon	-col-
melanoma	-mel-
mammary	-mar-
testis	-got-
ovary	-gov-
prostate	-pr(o)-
miscellaneous	-tum-

• In order to create a unique name, a distinct, compatible syllable should be selected as the starting prefix.
• Sequence of stems: The order for combining the key elements is as follows: Infix representing the target disease state, the source of the product, and the monoclonal root -mab used as a suffix (eg, biciromab, satumomab, nebacumab, sevirumab, tuvirumab). When combining a target or disease infix stem with the source stem for chimeric monoclonal antibody, the last consonant of the target/disease syllable is dropped, eg:

TARGET	SOURCE	-MAB STEM	USAN
-cir-	-xi	-mab	abciximab
-lim-	-zu	-mab	daclizumab