Macintosh and Miller Laryngoscope Blades Mnemonic

There are two main types of laryngoscope blades used for intubation. These are named the Macintosh (or Mac) and Miller blades. The main difference between these two blades is that the Macintosh blade is curved, while the Miller blade is straight. It can be easy to confuse which blade is which, so here is the way I remember it.

  

Macintosh is also the name of a computer made by Apple, and apples are curved.

Miller is also the name of a beer which comes in a tall, straight bottle.

  

Next time you see these blades, bring the apple and beer bottle to mind and it will be easy to recall which blade is shaped like which object.

Causes of Hyperglycemia Mnemonic: The “Eight I’s”

Hyperglycemia is a common finding encountered in the emergency department and on the hospital floor. The two main conditions associated with hyperglycemia are diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). Aside from treating the symptoms of these conditions and lowering the glucose, it is important to determine the etiology so that the underlying problem may be addressed.

An article published in Clinical Diabetes in March 2011 defined their “Five I’s” for the main causes of hyperglycemia. I won’t list them all here because I think that their list can be improved. I modified and added to their list (along with consulting my ER preceptor and UpToDate) to come up with “Eight I’s” for the causes of hyperglycemia.

The “Eight I’s” mnemonic for the main causes of hyperglycemia is:

·        Infection (think pancreatitis, pneumonia, and UTI)

·        Infarction (think MI)

·        Infraction (think patient noncompliant with therapy)

·        Infant (think pregnancy)

·        Ischemic (think CVA)

·        Illegal (think cocaine abuse)

·        Iatrogenic (think prescription drug interactions)

·        Idiopathic (think new onset type 1 diabetes or other cause)

Now you can remember the “Eight I’s” that cause HyperglYcemia!

The next time you are confronted with a patient with very high glucose, use this list to quickly go over the main causes. If one of them fits, you can start the additional workup to help the patient as best as possible!

Sources:

Kitabchi, AE, and BD Rose. Clinical features and diagnosis of diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

McNaughton, Candace D., Wesley H. Self, and Corey Slovis. "Diabetes in the Emergency Department: Acute Care of Diabetes Patients." Clinical Diabetes 29.2 (2011): 51-59. DiabetesJournals.org. American Diabetes Association. Web. 20 Dec. 2011. <http://clinical.diabetesjournals.org/content/29/2/51.full>

Bury the Buzzword: Bull’s-Eye Rash

The buzzword “bull’s-eye rash” is used to describe the appearance of a rash located on the skin. The rash has either a cleared area or red area in the center, with red rings circling it. It can also be known as a “target-rash.”

I came across four main conditions that cause a bull’s-eye rash. They are Lyme disease, Southern Tick Associated Rash Illness (STARI), erythema multiforme, and erythema annulare centrifugum (EAC).

Lyme disease is the most well-known condition that causes a bull’s-eye rash. The rash is also known as erythema chronicum migrans (ECM or EM). It appears early in the infection, and is formed around the area where the tick bit the skin. This is the first condition you should think about ruling out when you see this rash. You should ask about any history of exposure to the woods, such as hiking or camping, and if the patient has noticed any ticks on them. The rash is most commonly found in the groin, armpit, and thigh.

Southern Tick Associated Rash Illness (STARI) can cause a rash that looks identical to that of Lyme disease, but is not caused by Borrelia burgdorferi. This condition is also known as Masters disease. It is postulated that the bacteria Borrelia lonestari from the bite of the lone star tick, Amblyomma americanum may cause the disease. This tick is only present in the south and northeast. Patients may present similar to those with Lyme disease, except that their rash might be of lesser size.

Erythema multiforme can cause a bull’s-eye rash because of a hypersensitivity reaction or infection. The most common causes are herpes simplex virus or mycoplasma bacteria. The hypersensitivity reaction can be caused by certain drugs such as antibiotics or seizure mediations. It can even progress to Stevens-Johnson syndrome.

Erythema annulare centrifugum (EAC) can also cause a bull’s-eye rash because of a hypersensitivity reaction. The hypersensitivity reaction can be caused by infection, drugs, chemical exposure, autoimmune diseases, or cancer. It can be considered a chronic form of erythema multiforme that is most commonly located on the legs.

The “bull’s-eye rash” could easily be another image question that shows up on the boards. You will most commonly be tested over Lyme disease, but you should add these other three conditions to your differential if you are able. Even if you are not tested over these on the boards, it is good to have more than one thing come to mind when you see an actual patient present with a bull’s-eye rash.

Sources:

"Erythema Annulare Centrifugum." The Free Dictionary Medical Dictionary. Farlex. Web. 19 Dec. 2011. <http://medical-dictionary.thefreedictionary.com/erythema+annulare+centrifugum>.

Fauci, Anthony S., and Tinsley Randolph Harrison. "Lyme Borreliosis." Harrison's Principles of Internal Medicine. 17th ed. New York: McGraw-Hill Medical, 2008. Print.

Goljan, Edward F. "Musculoskeletal and Soft Tissue Disorders." Rapid Review Pathology. Ed. Edward F. Goljan. 3rd ed. Philadelphia, PA: Mosby/Elsevier, 2010. 531. Print.

"Southern Tick Associated Rash Illness (STARI)." ALDF.com. American Lyme Disease Foundation, 28 Apr. 2011. Web. 19 Dec. 2011. <http://www.aldf.com/stari.shtml>.

Vorvick, Linda J., Kevin Berman, and David Zieve. "Erythema Multiforme." NIH.gov. PubMed Health, 10 Oct. 2010. Web. 19 Dec. 2011. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001854/>.

Willard, Robert J. "Erythema Annulare Centrifugum." Emedicine.medscape.com. Ed. Dirk M. Elston. WebMD, 12 July 2010. Web. 19 Dec. 2011. <http://emedicine.medscape.com/article/1122701-overview>.

Bury the Buzzword: Envelope Crystals

This buzzword refers to the appearance of calcium oxalate dihydrate crystals that can be found in the urine of patients with ethylene glycol toxicity, or kidney stones (nephrolithiasis). They look like squares with an “X” in the center, which appear similar to a mail envelope.

The “envelope” appearance is specific to the calcium oxalate dihydrate crystals only. Another type of calcium oxalate crystals exist, termed calcium oxalate monohydrate crystals. These crystals have a needle-shaped appearance, and can also be found in the two above conditions.

It is important to take the clinical presentation into context when the presence of these crystals are encountered, especially in the case of possible ethylene glycol ingestion. Unless there is a plausible history of poisoning, use caution in making this diagnosis because these patients could also very well have a kidney stone!

A picture of these crystals might show up on the USMLE or COMLEX. If they do, you will now be able to make the diagnosis using the question stem to put them in the correct clinical scenario.

Sources:

Preminger, GM, and GC Curhan. The first kidney stone and asymptomatic nephrolithiasis in adults. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

Sivilotti, ML, and JF Winchester. Methanol and ethylene glycol poisoning. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

Bury the Buzzword: Kanavel Signs

This buzzword deals with the diagnosis of septic flexor tenosynovitis, which can occur in a finger when the flexor tendon becomes infected. The most common cause of this infection is from an injury. The term is an eponym, named after the surgeon Allen Kanavel.

There are four different Kanavel signs. If all are exhibited in a patient, then the diagnosis of septic flexor tenosynovitis can be made.

The four Kanavel signs are as follows:

·        Swelling of the entire finger

·        Pain with passive extension

·        Pain with palpation of the flexor surface

·        Finger held in slight flexion at rest

When this diagnosis is made, an orthopedic surgeon must be consulted immediately because it is considered an emergency. Left untreated, the patient may lose the finger.

I had never heard of these signs before until my ER rotation. These signs are important to remember not just in the ER setting, but also in the office setting where a patient may come to you after they have suffered an injury to their finger. It is imperative to recognize these signs because surgical intervention is needed along with antibiotics to minimize complications.

Sources:

Likes, Randle L. "Infectious and Inflammatory Flexor Tenosynovitis." Emedicine.medscape.com. Ed. Harris Gellman. WebMD, 8 Sept. 2009. Web. 16 Dec. 2011. <http://emedicine.medscape.com/article/1239040-overview>.

Phemister, Dallas B. "ALLEN B. KANAVEL 1874–1938." Annals Of Surgery 108.2 (1938): 161-62. NIH.gov. PubMed Central. Web. 16 Dec. 2011. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1386889/>.

Sexton, DJ. Infectious tenosynovitis. In: UpToDate, Basow, DS (Ed), UpToDate, Waltham, MA, 2011.

Bury the Buzzword: Mittelschmerz

The medical term mittelschmerz (pronounced mittelschmerts) is one of those classic buzzwords, in that knowing the word tells you nothing about its meaning. However, if you know German you could get a clue as to what the word means, because it literally translates to “middle pain.”

Interestingly, the “middle” part of the translation does not refer to an anatomical location, but to the middle part of a woman’s menstrual cycle when ovulation takes place. The “pain” part of the translation refers to unilateral, lower abdominal pain that accompanies ovulation.

The pain may be due to tension on the ovaries or inflammation of the abdominal wall caused by ovulation. Some women feel cramping pain, while others may have sharp pain in one of the lower abdominal quadrants. The pain does not always have to be located on the same side, and can also alternate sides throughout the day. The pain is usually mild and subsides after a few minutes or hours, but can last up to 1-2 days.

Mittelschmerz is not considered worrisome, and can be treated with pain medicine or oral contraceptive pills. A physician should be notified if any bleeding occurs, if the pain begins to bother the patient, or if the pain starts to occur outside of the couple days surrounding day 14 of the menstrual cycle.

Mittelschmerz is an important term to understand the meaning of. You will run into it on your OB/GYN rotations, and may encounter it on the boards as well. Now you will have a great understanding of this interesting German word and how we apply it to medicine.

Sources:

Mayo Clinic Staff. "Mittelschmerz." MayoClinic.com. Mayo Foundation for Medical Education and Research, 11 June 2011. Web. 15 Dec. 2011. <http://www.mayoclinic.com/health/mittelschmerz/DS00507>.

Vorvick, Linda J., Susan Storck, and David Zieve. "Mittelschmerz." NIH.gov. PubMed Health, 2 June 2011. Web. 15 Dec. 2011. <http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002472/>.

Bury the Buzzword: B Symptoms

“B symptoms” is a buzzword used to describe the systemic (constitutional) symptoms of:

·        Fever (unexplained, > 38⁰C or > 100.4⁰F)

·        Night sweats (soaking)

·        Weight loss (> 10% over past 6 months)

These symptoms are used in the Ann Arbor Staging Classification for Hodgkin’s disease and non-Hodgkin’s lymphoma, published in Cancer Research in 1971. The letter is used following the numerical numbering to complete the classification. However, that was not the first time the letter “B” was used in the staging system.

The Ann Arbor committee that met in 1971 revised the original Rye Classification for Hodgkin’s disease, published in Cancer in 1966. The Rye system was the first to come up with the sub-classifications for stages I-IV. The letter “A” was used if systemic symptoms were absent, and the letter “B” was used if systemic symptoms were present. The “B symptoms” in this classification were different and included fever (unexplained), night sweats, and pruritus. The Ann Arbor committee decided to remove pruritus and add weight loss to the “B symptoms” definition.

I think that the above history of how the term “B symptoms” came to be is very interesting. Knowing some additional background information can help in memorization, because now the term can be put into context.

A mnemonic to help remember the difference between the “A” and “B” symptoms is the following:

The letter “A” is used when the symptoms are Absent

The letter “B” is used when the symptoms are Bothersome

A mnemonic to help remember the three components of the “B symptoms” is with the saying “These Bothersome symptoms give the patient Wednesday Night Fever!”

Congratulations, you have just buried another buzzword!

Sources:

Carbone, Paul P., Henry S. Kaplan, Karl Musshoff, David W. Smithers, and Maurice Tubiana. "Report of the Committee on Hodgkin's Disease Staging Classification." Cancer Research 31 (1971): 1860-861. Cancer Research. American Association for Cancer Research. Web. 13 Dec. 2011. <http://cancerres.aacrjournals.org/content/31/11/1860.long>.

Lukes, Robert J., James J. Butler, and Ethel B. Hicks. "Natural History of Hodgkin's Disease as Related to Its Pathologic Picture." Cancer 19.3 (1966): 317-44. Wiley Online Library. 23 June 2006. Web. <http://onlinelibrary.wiley.com/doi/10.1002/1097-0142%28196603%2919:3%3C317::AID-CNCR2820190304%3E3.0.CO;2-O/abstract>.

Newton, K. A., D. H. Mackenzie, Margaret F. Spittle, and Anna Mikolajczuk. "Hodgkin's Disease A Clinico-Pathological Study of 250 Cases with a 5-Year Follow-up." British Journal of Cancer 27.1 (1973): 80-91. PubMed. Web. 13 Dec. 2011. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2008821/?tool=pubmed>.

Weinkove, Robert. "Ann Arbor Staging." BloodRef.com. Web. 13 Dec. 2011. <http://www.bloodref.com/lymphoma/ann-arbor-staging>.

Internalize Info of the Week: Lichen Planus Buzzwords

Lichen planus is an autoimmune disease that can cause a rash on the skin, mucous membranes of the mouth and genital area, nails, and head. The exact cause of this condition is not known.

There are several key buzzwords associated with lichen planus which will be defined in this post. The entire pathogenesis will not be discussed here. The definitions of these buzzwords are important to know because they can help clinically by making the diagnosis and help academically by making the correct answer choice on board exams.

Wickham’s Striae: This term is an eponym, named after Louis Frédéric Wickham. It describes the appearance of the material located on the surface of the papular rash or located in the mucous membranes of the mouth. The material is lacy, white or grey in color, and made up of thin lines or dots. The exact cause for the striae to appear is not known, but is thought to possibly be due to activation of the epidermis to produce more cells and/or a loss of blood supply to the dermis.

Koebner Phenomenon: This term is also an eponym, named after Heinrich Koebner, and is likewise known as the isomorphic response. It describes the occurrence of new lesions that appear around a wound or site of irritation. It is seen not only in lichen planus, but also in other conditions such as psoriasis, warts, and molluscum contagiosum.

Saw-Tooth Appearance: This term refers to how a biopsy specimen of the skin appears when looked at under the microscope. When viewing the area where the epidermis and dermis come together, it looks more irregular and bumpy giving the impression of the teeth on a saw.

Civatte Bodies: This term is another eponym, named after Achille Civatte. They are also known as colloid bodies. They describe the appearance of cells located in the epidermis or dermis that have a dark-staining circular appearance with no nucleus. They are created from dying skin cells.

These are the main medical buzzwords associated with lichen planus. Knowing these terms will help differentiate lichen planus from other diseases in your differential.

Sources:

Ismail, Sumairi B., Satish K. S. Kumar, and Rosnah B. Zain. "Oral Lichen Planus and Lichenoid Reactions: Etiopathogenesis, Diagnosis, Management and Malignant Transformation." Journal of Oral Science 49.2 (2007): 89-106. Nihon University School of Dentistry. Web. 12 Dec. 2011. <http://www.jstage.jst.go.jp/article/josnusd/49/2/49_89/_article>.

Katta, Rajani. "Lichen Planus." American Family Physician 61.11 (2000): 3319-324. AAFP.org. American Academy of Family Physicians. Web. 12 Dec. 2011. <http://www.aafp.org/afp/2000/0601/p3319.html>.

"Koebner Phenomenon." The Free Dictionary Medical Dictionary. Farlex. Web. 12 Dec. 2011. <http://medical-dictionary.thefreedictionary.com/Koebner+phenomenon>.

Sachdeva, Silonie, Pranav Kapoor, and Shabina Sachdeva. "Wickham Striae: Etiopathogenensis and Clinical Significance." Indian Journal of Dermatology 56.4 (2011): 442. PubMed. Web. 12 Dec. 2011. <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3179016/?tool=pubmed>.

"Sawtooth Pattern." The Free Dictionary Medical Dictionary. Farlex. Web. 12 Dec. 2011. <http://medical-dictionary.thefreedictionary.com/Sawtooth+Pattern>.

Stone, M. S., and T. L. Ray. "DermPathTutor-Civatte." University of Iowa Carver College of Medicine. Sept. 1995. Web. 12 Dec. 2011. <http://www.healthcare.uiowa.edu/dermatology/DPT/Civatte.htm>.

"Whonamedit - Civatte's Bodies." Whonamedit - Dictionary of Medical Eponyms. Web. 12 Dec. 2011. <http://www.whonamedit.com/synd.cfm/3422.html>.

"Whonamedit - Wickham's Striae." Whonamedit - Dictionary of Medical Eponyms. Web. 12 Dec. 2011. <http://www.whonamedit.com/synd.cfm/2520.html>.

Williams, Gary, and Murray Karcher. "Skin Lesions: Koebner Phenomenon." Department of Pediatrics. University of Wisconsin Madison. Web. 12 Dec. 2011. <http://www.pediatrics.wisc.edu/education/derm/tutc/koebner.html>.

Medical Buzzwords are Convenient, but it is Important to Remember the Underlying Meaning

This week I started a new series of posts called “Bury the Buzzword.” I already explained what this series will entail in its first post, but I think the subject of medical buzzwords deserves further thought.

Buzzwords are not exclusive to the medical profession, but I would venture to say that they are not as widely used in other fields as they are in the medical world. For those of us in the medical profession, buzzwords are a part of our daily vernacular. They are taught in our medical classes, reviewed in the medical textbooks, and tested on the boards. They include a lot of information packed into a single word or phrase so that knowledge can be communicated faster, effectively, and more efficiently.

The sheer volume of medical buzzwords can seem overwhelming at first, as each specialty in medicine has their own. These buzzwords are used to describe diseases, physical exam findings, imaging results, and just about any other kind of pathology. Because of their widespread use, they become intricately associated with their target. By nature they are only useful to the members of the profession, because the buzzword itself does not have enough information contained within it to completely describe its recipient. Herein lies a potential problem.

It can become too convenient to simply play the match game with each buzzword, and merely associate the word with the disease and forget the underlying meaning behind it. This is easy to do because of the large number of buzzwords as stated above, and also how board questions are set up. If a board question includes a buzzword, it only takes word association to come up with the correct diagnosis among the answer choices. However, medical board exams are starting to lean away from using buzzwords in the question stems. Even though it may make the question a bit harder, the board examiners are realizing the importance of comprehending the definition of the buzzwords.

When you look at a cell under the microscope there’s not going to be a neon sign that says “clue cell”, or when you look into someone’s eye with the ophthalmoscope the blood vessels are not going to spell out “cherry-red macula.” Consequently, it takes a complete understanding of the pathophysiology behind the buzzword before you are able to recognize it. In our real world clinical experience we are confronted with the explanations and definitions of disease and it is our responsibility to provide the diagnosis. When the findings of a buzzword are present, it becomes helpful in making that diagnosis.

Therefore, buzzwords do not become completely useful until they can be defined and recognized. Only then should they be used in communication with other healthcare professionals where a mutual understanding of the vocabulary exists.

Sudden Sensorineural Hearing Loss

Don’t miss this diagnosis in a patient who presents with unilateral hearing loss occurring within 72 hours and has a normal ear examination. These patients frequently get misdiagnosed as having fluid in the middle-ear or having an infection. It is important to recognize this diagnosis, initiate treatment early, and refer to a specialist so that permanent hearing loss can be minimized.   

Sudden sensorineural hearing loss has been reported in up to 5-20 cases per 100,000 per year. Only in roughly 10-15% of these cases is a cause able to be determined. It arises proportionately in men and women, and most commonly in the fourth and fifth decades of life. The hearing loss usually occurs only in one ear, but can occur in both ears as well. Associated symptoms include tinnitus, vertigo, and aural (ear) fullness.

Causes of sudden sensorineural hearing loss are thought to be viral (including cytomegalovirus [CMV], enterovirus, Epstein-Barr [EBV], herpes simplex I and II [HSV-1 and -2], HIV, influenza, mumps, rubella, and varicella zoster [VZV] viruses), bacterial (including Lyme disease, meningitis, and syphilis), fungal (from meningitis), thromboembolic (including stroke), autoimmune (including systemic lupus erythematosus [SLE], multiple sclerosis [MS], Sjogren’s syndrome [SS], and Behcet’s disease), neoplastic (including acoustic neuroma [schwannoma], meningioma, and paraneoplastic), traumatic (including diving, flying, and motor vehicle accidents), surgical (including stapedectomy, lumbar puncture, and general anesthesia), drug induced (including aminoglycosides, and chemo drugs), psychiatric, and from Meniere’s disease.

When a patient presents with the above symptoms, it is imperative to determine if they have true sensorineural hearing loss. It is vital to look into the patient’s ear to rule out fluid in the middle-ear, acute otitis media or externa, cerumen impaction, perforated tympanic membrane (including from cotton swab use), and mass. It is also important to evaluate for temporomandibular joint (TMJ) dysfunction because this can cause the feeling of fullness. A neurologic exam assessing the cranial nerves, gait, and cerebellum should be performed.

Essential diagnostic testing to perform is the Weber and Rinne tuning fork tests to evaluate sensorineural vs. conductive hearing loss. The patient should receive an audiogram performed by an audiologist to document the hearing loss and an MRI with contrast to rule out neoplasm.

Treatment consists of steroids (60 mg prednisone taper over 10-14 days) started as quickly as possible. Steroids given intratympanically can also be used alone or in combination with the oral, if oral therapy fails to recover hearing, or if there is a contraindication to giving systemic steroids. Antiviral treatment can be initiated empirically but has not been proven to show improvement in hearing recovery. Prompt referral to an ENT specialist is required for optimal evaluation.

The prognosis for this condition is good, as most patients’ hearing returns completely within two weeks. The degree of initial hearing loss corresponds to the final degree of recovery, as patients who have minimal hearing loss usually recover in full, whereas those with severe hearing loss may only regain part of their hearing.

There is still a lot to learn about this condition, as the cause for most presentations are not known and universal treatment protocols have not been established. It is important for physicians and clinicians to have a high index of suspicion for this diagnosis, and to not pass it off as just fluid in the middle-ear. The results of misdiagnosing or putting off treatment could mean permanent hearing loss.  

Sources:

Rauch, Steven D. "Idiopathic Sudden Sensorineural Hearing Loss." New England Journal of Medicine 359.8 (2008): 833-40. NEJM.org. Web. 8 Dec. 2011. <http://www.nejm.org/doi/full/10.1056/NEJMcp0802129>.

Schreiber, Benjamin E., Charlotte Agrup, Dorian O. Haskard, and Linda M. Luxon. "Sudden Sensorineural Hearing Loss." The Lancet 375.9721 (2010): 1203-211. TheLancet.com. Web. 8 Dec. 2011. <http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2809%2962071-7/fulltext>.

Bury the Buzzword: Thumb Sign

The buzzword Thumb sign can refer to two very different clinical scenarios.

The first and most common use of the thumb sign refers to a radiographic finding seen in epiglottitis. It is seen on a lateral x-ray and refers to the shape the epiglottis takes when it becomes immense and swollen, because it looks like a big thumbprint. The board question may not specifically use the term “thumb sign,” but it may show the lateral x-ray and ask you to make the diagnosis of epiglottitis.

Another use of the thumb sign refers to a physical exam finding seen in Marfan syndrome. It is seen when the patient with Marfan syndrome makes a closed fist over the top of the thumb. When looking at the closed fist, the thumb will extend beyond the fifth digit (pinky finger) and will be able to be seen poking out. A way this question could be tested is to show a picture of closed fists with long thumbs extending out though the ulnar side and asking you to make the diagnosis of Marfan syndrome.

The thumb sign referring to epiglottitis is well known to medical students, but this second clinical scenario is a good tidbit to know to completely bury this buzzword. If you suspect Marfan syndrome, the thumb sign is another physical exam finding that can be helpful.

Sources:

Eagle, Kim, and Rodney H. Falk. "The “Thumb Sign” in Marfan's Syndrome." New England Journal of Medicine 333.7 (1995): 430. NEJM.org. Web. 6 Dec. 2011. <http://www.nejm.org/doi/full/10.1056/NEJM199508173330706>.

Grover, Casey. "“Thumb Sign” of Epiglottitis." New England Journal of Medicine 365.5 (2011): 447. NEJM.org. Web. 6 Dec. 2011. <http://www.nejm.org/doi/full/10.1056/NEJMicm1009990>.

Bury the Buzzword: Cherry-red Coloration

This post addresses the large differential diagnosis of the buzzword Cherry-red coloration. The cherry-red coloration most often refers to the macula located on the retina of the eye, but it can also refer to the coloration of the skin, esophagus, and epiglottis.

The cherry-red spot on the macula is seen on funduscopic examination. It is observed in the middle of the macula and has a pale-yellow or white area around it. This buzzword could be considered a misnomer, because the cherry-red spot is theoretically a normal finding. It becomes visually enhanced by the pathological discoloration of the retina surrounding it.

The macula is the area located a few millimeters lateral to the optic disc. There is a circular area in the middle of the macula termed the fovea, and a circular area in the middle of the fovea termed the foveola. These anatomical terms are important to understand the pathophysiology.

The cherry-red spot on the macula is most commonly caused by the metabolic diseases listed below. These metabolic diseases are characterized by buildup of storage material in the retina, which causes it to have a pale-yellow or white discoloration. However, the foveola does not collect these deposits so the blood vessels are still able to be seen through it, allowing it to remain a cherry-red color.

Select metabolic diseases causing a cherry-red spot on the macula:

·        Tay-Sachs disease

·        Sandhoff disease

·        Sialidosis

·        Niemann-Pick disease

·        GM1 Gangliosidosis

·        Galactosialidosis

·        Metachromatic leukodystrophy

·        Farber’s disease

·        Goldberg’s disease

·        Gaucher’s disease

·        Hurler’s syndrome

There are also other metabolic diseases that have been associated with a cherry-red spot on the macula, but the ones listed above are the most board relevant.

After the metabolic diseases, the next most board relevant condition causing a cherry-red spot on the macula is central retinal artery occlusion. Since the retinal artery is blocked, the loss of blood supply causes a white discoloration of the retina. The fovea remains a cherry-red color because it receives its blood supply from the choroid (the vascular layer of the eye), and not the retinal artery.

Additional conditions causing a cherry-red spot on the macula include orbital ischemia and orbital contusion due to constriction of the arteries. Quinine, dapsone, methanol, and carbon monoxide poisoning are substance-induced causes.

Cherry-red discoloration of the skin can also be found in carbon monoxide poisoning, as well as cyanide poisoning. Furthermore, cherry-red discoloration of the esophagus can be due to esophageal varices and cherry-red discoloration of the epiglottis can be due to epiglottitis.

In conclusion, cherry-red coloration can be due to a variety of different pathology. It is important to not jump too quickly to a diagnosis because the answer may not always involve the macula. It is imperative to take the entire clinical scenario into context when dealing with this buzzword.

Sources:

Fauci, Anthony S., and Tinsley Randolph Harrison. Harrison's Principles of Internal Medicine. 17th ed. New York: McGraw-Hill Medical, 2008. Print.

Goljan, Edward F. Rapid Review Pathology. 3rd ed. Philadelphia, PA: Mosby/Elsevier, 2010. 4, 86, 601. Print.

Le, Tao, and Vikas Bhushan. First Aid for the USMLE Step 1. 2010 ed. New York: McGraw-Hill Medical, 2010. 111, 183, 417, 516. Print.

Suvarna JC, Hajela SA. Cherry-red spot. J Postgrad Med [serial online] 2008 [cited 2011 Dec 5];54:54-7. Available from: http://www.jpgmonline.com/text.asp?2008/54/1/54/39196

Bury the Buzzword: Clue Cells

This is the first post in a new series where I take medical buzzwords, define them, and explain them so that you can bury them! Buzzwords are helpful in answering questions on the boards, but the USMLE and COMLEX will not always use them. It is important to know the definitions of what the buzzwords mean, and not just memorize which words go with which pathology. This series will allow you to bury the buzzword with the knowledge of what lies behind it!

This first post will define the buzzword Clue Cells.

Clue cells are included as a part of the Amsel criteria for diagnosing bacterial vaginosis. They refer to the appearance of epithelial cells from the vagina when looked at under the microscope. When infected with bacterial vaginosis, the epithelial cells get covered with the bacteria. It is all these bacteria that make the cells take on a grainy appearance. Additionally, the edges of the cells and the spaces between them become harder to define because of all the attached bacteria.

A mnemonic to remember this is with the saying “I don’t have a clue where one cell ends and another begins because of all these bacteria!”

Source:

Fauci, Anthony S., and Tinsley Randolph Harrison. "Sexually Transmitted Infections: Overview and Clinical Approach." Harrison's Principles of Internal Medicine. 17th ed. New York: McGraw-Hill Medical, 2008. Print.

Internalize Info of the Week: Lipitor (atorvastatin) Goes Generic But Not Without Controversy

This week there was not very much interesting material from my clinical experience to write about, so I decided to post on a noteworthy and attention-grabbing topic in the news this week.

Pfizer’s patent on Lipitor expired this week on Wednesday, November 30, but not without some questionable and unparalleled tactics from Pfizer itself. Lipitor is the world’s best-selling drug and Pfizer, the world’s biggest drug company, is not ready to give up its market share yet. The drug made $106 billion in sales over the past ten years, $7.2 billion of that in 2010. It was the first drug to make more than $10 billion in one year. Up until Wednesday, only Pfizer was able to make money off of it.

The FDA approved India’s biggest drug company, Ranbaxy, to be able to produce generic atorvastatin. Interestingly, this decision by the FDA was made after a compromise by Ranbaxy to share its profits with the world’s biggest generic drug producer, Teva. The compromise may have been necessary because the FDA was concerned about suspected violations in drug manufacturing that occurred at Ranbaxy’s plants. It is unknown what share Teva will receive, but is speculated to be about one third of the profits. In addition, Pfizer approved Watson Pharmaceuticals to sell the generic as well, but in return Watson will have to turn over approximately 70% of the profits back to them. Ranbaxy will be the only FDA approved company to sell the generic for the first six months. These two companies are the only ones allowed to sell it during this period. It is noteworthy that both of these drug manufacturers had to use profit-sharing to gain the exclusive rights to sell the generic version. After the first six months, the restriction ends.

Pfizer has been working for at least a year on strategies for how to keep Lipitor’s market share. One of the tactics includes a coupon for a lowered co-pay of just $4, which is cheaper than the generic. I have already heard Pfizer’s advertisements on the radio and seen them on television for this discount card. The main restriction of this program is that only patients with private insurance are eligible.

Pfizer has also made agreements with pharmacy benefit managers, which are third-party companies that coordinate between the drug companies, insurance companies, and pharmacies. The agreement gives substantial price decreases for the pharmacy benefit managers who are able to convince pharmacies to not sell the generic, and fill prescriptions written for atorvastatin with Lipitor instead. This deal would last for the first six months that the generic is available, and would even apply to some Medicare Part D plans. It gives Pfizer more money and disadvantages patients who have to pay more for the brand name. A way patients could get around it would be to use the coupon.

Another tactic Pfizer is using is preventing the generic drug from being filled in mail-orders. This is significant because anywhere from 30-40% of prescriptions written for Lipitor are filled in this way. Pfizer was able to preserve about 90% of this business through matching the generic price and promising to not let the market run out of the drug.

Combining these tactics, Pfizer could keep up to 40% of the market share for Lipitor for up to the first six months it is generic. However, Pfizer’s tactics did not completely pay off. WellPoint, the health insurance company with the biggest number of members, decided to sell the generic cheaper than Lipitor. Additionally, not all pharmacy benefit managers are supporting Pfizer’s strategies and are advocating that the generic be used because it is cheaper. Others are suggesting that the brand name drug be purchased for a reduced price with the discount card for just the first six months, then switching to the cheaper generic afterwards.

It is interesting to note that Pfizer’s behaviors provoked further interest by three senators, who wanted to investigate the potential effects on Medicare and patients. The senators are concerned that Pfizer’s tactics may end up costing patients more.

I think Pfizer is trying to do as much as it can to squeeze the remaining amount of money out of Lipitor. Pfizer knows Lipitor’s days are numbered and eventually will be too cheap to promote, but it seems they are not going down without a fight. From a strictly business perspective these tactics seem smart and savvy, but from a doctor’s and patient’s perspective they seem a bit sneaky. In my opinion, costing patients more money for the brand name because they are not able to get the generic even after the patent has expired is not right. However, whether patients will have to pay more is not fully clear yet. Hopefully the discount card will allow cheaper access to the drug for the next six months.

Check out the sources below for more information.

 

Sources:

Edney, Anna, Adi Narayan, and Drew Armstrong. "Pfizer Lipitor Sales Are Threatened by Ranbaxy Generic Copy." Bloomberg - Business & Financial News, Breaking News Headlines. Bloomberg.com, 1 Dec. 2011. Web. 02 Dec. 2011. <http://www.bloomberg.com/news/2011-12-01/ranbaxy-s-lipitor-copy-threatens-pfizer-sales.html>.

Grey, Jamie. "World's Top-selling Drug Goes Generic." Dallas - Fort Worth News | Wfaa.com. KTVB, 2 Dec. 2011. Web. 02 Dec. 2011. <http://www.wfaa.com/news/health/134923188.html>.

MacDonald, Elizabeth. "Generic Lipitor About to Hit the Market." Fox Business | Business News & Stock Quotes - Saving & Investing. FoxBusiness.com, 2 Dec. 2011. Web. 02 Dec. 2011. <http://www.foxbusiness.com/markets/2011/12/02/generic-lipitor-about-to-hit-market/>.

Wilson, Duff. "Facing Generic Lipitor Rivals, Pfizer Battles to Protect Its Cash Cow." NYTimes.com. The New York Times, 29 Nov. 2011. Web. 2 Dec. 2011. <http://www.nytimes.com/2011/11/30/health/generic-lipitor-sets-off-an-aggressive-push-by-pfizer.html?pagewanted=all#>.

Wilson, Duff. "Plan Would Delay Sales of Generic for Lipitor." NYTimes.com. The New York Times, 11 Nov. 2011. Web. 2 Dec. 2011. <http://www.nytimes.com/2011/11/12/health/plan-would-delay-sales-of-generic-for-lipitor.html>.

Wilson, Duff. "Senators Question Deals to Block Generic Lipitor." NYTimes.com. The New York Times, 1 Dec. 2011. Web. 2 Dec. 2011. <http://www.nytimes.com/2011/12/01/health/senators-question-plan-to-stall-generic-lipitor.html?_r=1>.

Deciphering the Weber and Rinne Tuning Fork Tests

The Weber and Rinne tests have been known to show up on boards, and are notoriously confusing and hard to remember. This post addresses what the tests are and how to perform them, interpret them, and remember them.

The Weber and Rinne tests are more than just a way to evaluate the Vestibulocochlear nerve (cranial nerve VIII). They are screening tests to determine the presence of hearing loss. They are performed using tuning forks at the frequencies of 512- and 1024-Hz. Tuning forks with these different frequencies are utilized so that both low (512-Hz) and high (1024-Hz) frequency hearing loss may be revealed. The Weber test is able to test for and distinguish between conductive hearing loss (CHL) and sensorineural hearing loss (SNHL), while the Rinne test assesses for the presence of CHL only.

The Weber test is executed by hitting the tuning fork and then holding it in the middle of the patient’s forehead. If the patient is unable to hear the tuning fork in this position, it can also be placed on the nasal bone or in the middle of the front two teeth. The patient is then asked to determine where the sound is heard the best. A normal result is when the sound is the same in both ears. If the sound is louder in one ear, it is indicative of conductive hearing loss (CHL) in that ear or sensorineural hearing loss (SNHL) in the opposite ear. The reverse is also true. If the sound is quieter in one ear, it is indicative of SNHL in that ear or CHL in the opposite ear.

At first glance, the results of the Weber test seem opposite to what you would normally think. However, the key to understanding it is realizing that the tuning fork is measuring how well the sound conducts through the bone (termed bone conduction), and the patient reports how well this sound is heard. Additionally, outside sound is still being conducted through the air (termed air conduction) to the patient’s ear (if no CHL is present). The bone conduction is a measure of SNHL, while the air conduction is a measure of CHL.

If bone conduction is intact on both sides (therefore no SNHL), the patient will report a louder sound in the ear with CHL. This is because the ear with the CHL is only receiving input from the bone conduction and no air conduction, and the sound is perceived as louder in that ear.

If air conduction is intact on both sides (therefore no CHL), the patient will report a quieter sound in the ear with the SNHL. This is because the ear with the SNHL is not receiving input from the bone conduction, and the sound is perceived as louder in the normal ear.

The Rinne test (pronounced like the name Renée) is executed by hitting the tuning fork and then holding it on the patient’s mastoid process. After the patient states the sound can no longer be heard, the tuning fork is then moved to just outside the external auditory meatus. If the sound is able to be heard again, it is a normal result. This is termed a positive test because the air conduction (AC) is greater than the bone conduction (BC). A negative test is when the sound cannot be heard again, and the BC > AC. If there is no air conduction, then CHL must be present.

A mnemonic you can use to help you to not mix up the tests is to think of Rinne as a woman screaming right into your ear, and Weber as a level-headed man who doesn’t sway from the center. For the Rinne test, the normal result is a good “positive” result and is also in alphabetical order (AC > BC).

Source:

Beasley, Donald J., and Ronald G. Amedee. "Hearing Loss." Expert Guide to Otolaryngology. By Karen H. Calhoun, Mark K. Wax, and David E. Eibling. Philadelphia, PA: American College of Physicians-American Society of Internal Medicine, 2001. 59. Print. ACP Expert Guide Series.