Edema 1 - Muntz Flashcards
State whether each of the Starling forces would be increased or decreased in order to cause edema:
- capillary hydrostatic pressure
- interstitial hydrostatic pressure
- plasma oncotic pressure
- interstitial oncotic pressure
- capillary hydrostatic pressure = increased
- interstitial hydrostatic pressure = decreased
- plasma oncotic pressure = decreased
- interstitial oncotic pressure = increased
Draw out the Starling Forces Diagram (which of the forces push outwards, which are inwards)
For extra credit, indicate an easy way to tell in equation form which ones are out/in and how they change in order to cause edema
State whether the following diagnoses would be likely to cause bilateral or unilateral edema:
- R-sided heart failure
- DVT
- secondary lymphatic obstruction secondary to neoplasm
- Direct vasodilators (eg Hydralazine, Mioxidil)
- Nephrotic syndrome
- Baker’s Cyst
- cellulitis
- burns
- R-sided heart failure = bilateral
- DVT = unilateral
- secondary lymphatic obstruction secondary to neoplasm = unilateral
- Direct vasodilators (eg Hydralazine, Mioxidil) = bilateral
- Nephrotic syndrome = bilateral
- Baker’s Cyst = unilateral
* Reminder: Baker’s cyst is a popliteal cyst that is inflamed, and once ruptured leaks its contents, causing local edema* - cellulitis = unilateral
- burns = unilateral
Right sided heart failure review:
- Other than bilateral leg edema, what is one of the most specific findings that you would see on a patient?
- Some other symptoms of right sided HF?
- # 1 cause of right sided HF?
- other major causes of right sided HF? (3 major)
- elevated JVD
- hepatomegaly (also ascites, sometimes tricuspid regurg, right sided S3)
- left-sided heart failure
- cor-pulmonale (eg COPD or sleep apnea), pulmonary HTN, or constrictive pericarditis
Advanced renal disease of any kind is likely to lead to ________ overload which will cause:
A. unilateral edema
B. bilateral edema
volume overload, causing bilateral edema
What 3 medications are very common in causing bilateral leg edema, and what are their mechanisms?
Extra credit: can you think of any other medications that may cause bilateral edema? (three major)
Amlodipine: Dihydropyridine Ca2+ channel blocker
Hydralazine, Minoxidil = Direct Vasodilators
Note: other meds that cause bilateral edema can include corticosteroids, hormones like estrogens, NSAIDs
Venous insufficiency:
- What are some clinical features?
- What can it progress to (disease process)? Where is this located on the body typically?
- Does it typically cause unilateral or bilateral edema?
- thickened skin, eventually stasis dermatitis w/ thickened eschar (chronically)
- Can progress to venous stasis ulcers on the anterior and medial aspect of lower leg near the ankle
- unilateral
- What is ‘pitting edema’
- what is the range of scores for pitting edema?
- What types of diseases cause pitting edema
- when is non-pitting edema classicaly seen?
- observable edema to an area that can be demonstrated by pushing in (like with a fingertip) and having the indentation stay
- Scores for pitting edema range from 0(none)-2+(extreme indentation that stays and goes away extremely slowly)
- Majority of diseases that cause edema will cause pitting edema
- Non-pitting edema is most commonly seen in lymphedema + cellulitis
Cellulitis:
- What are 4 major risk factors?
- What are the only two diagnostic tests that are typically done for cellulitis? in what circumstances are these done?
- chronic edema, obesity, immunosuppression, and a ‘portal of entry’ (i.e. tinea pedis (eg athletes foot), injection drug us, IV site, scratch, etc)
- CBC, basic chems: ONLY done if pt admitted to hospital
Culture of fluid: ONLY if there is a true abscess that can be drained and cultured
Note: don’t get blood cultures pretty much EVER! these are only + in about 2-5% of cases, so not helpful AT ALL
1. What are the 2 most common causative organisms of cellulitis and what are they? (G+? G-? Rods? cocci? etc)
- What clinical symptoms are associated with each of these organisms?
- beta-hemolytic strep (i.e. Strep pyogenes): G+ cocci, Catalase-
Staph aureus: G+ cocci, catalase + and coagulase +
- beta-hemolytic strep: no edudate or drainage (i.e. dry cellulitis)
staph aureus: exudate, drainage, +/- abscess
- What causative organism is associated with dry cellulitis? (i.e. no exudate or drainage)
- what causative oragnism is associated with wet cellulitis (exudate or drainage present) / abscess cellulitis?
- beta hemolytic strep (i.e. strep pyogenes)
- staph aureus
A 32 yo male patient, with history of obesity, comes in complaining of ‘spider bites’ to his left lower leg. It is ‘itchy’ and bothers him, not allowing him to sleep at night. Of note, he was recently scratched on his left lower calf in the woods during a hike.
Examination shows marked points of erythema on his left lower extremity, appearing to be small abscesses.
- What is the likely diagnosis?
- What is the likely causative organism? (be careful here)
- Cellulitis (hints were that he is obese and had a recent portal of entry, two major risk factors for cellulitis, along with the actual redness and itching to the leg itself)
- MRSA (methicillin resistant staph aureus) - not just regular staph aureus! One of the major hints that its MRSA caused cellulitis is that it forms ‘small abscesses’, that appear as though ‘spider bites’ on the legs, and pts often complain of itchiness
In each of the following situations, state what organism is known to cause cellulitis, and what it is (G+? G-? rod? cocci? etc.)
- Hot tube exposure
- salt water exposure
- fresh water exposure
- diabetic foot ulcer
- peri-anal
- Hot tube exposure = pseudomonas aeruginosa (G- rod)
- salt water exposure = vibrio vulnificus (G- rod)
- fresh water exposure = aeromonas hydrophilia (G- rod) Note: this is not covered in FA
- diabetic foot ulcer = multiple, including GPC (G+ cocci), GNR (G- rods), and anaerobes
- peri-anal = Group A strep or GNRs
- What are the 3 major antibiotics of choice when treating cellulitis (at least, according to Dr. Muntz)?
- State their ‘classification’ (targeting peptidoglycan synthesis, protein sytnehsis, anti-folates, etc.)
- Why are we choosing these?
Doxycycline: tetracycline, inhibits protein synthesis
Bactrim (i.e. TMP-SMX): sulfonamides-trimethoprim, these are anti-folates
Clindamycin: inhibits protein synthesis
These are all used because they generally cover regular staph aureus, as well as MRSA (instead of a regular beta-lactam like penicillin). Doxycyclin is particularly good because it is bacteriostatic and covers both G+ and G- bacteria
Note: you can also use IV vanco for MRSA infections
Beta-lactams:
- Include what medications?
- Bactericidal or static? G+ or G- target?
- activity is maximal on what kind of bacteria?
- mechanism of action
- side effects
- penicillins, cephalosporins, carbopenems and monobactams
- bactericidal most of the time, G+ and G-
- activity is maximal on actively growing bacteria
- structure mimics PBPs (penicillin binding proteins) –> they covalently bind to PBPs, inhibiting the transpeptidase activity that catalyzes cell wall cross-links (weakning the cell wall and causing osmotic lysis)
- Hypersensitivity, rapid bacterial lysis can cause sx d/t release of bacterial components, including: chills, fever, aching
Glycopeptides:
- Include what medications?
- Bactericidal or static? G+ or G- target?
- mechanism of action
- clinical use?
- Vancomycin
- bactericidal (but slower than beta-lactams): G+
- inhibits cell wall synthesis: it binds to the free carboxyl end (D-ala-D-ala) of the pentapeptide, blocking PBP from transglycosylation –> interfering with crosslinking and elongation of the peptidoglycan chain
- IV vancomycin is useful for MRSA infections
Tetracyclines:
- Include what medications?
- Bactericidal or static? G+ or G- target?
- mechanism of action
- Most common mechanism of resistance?
- Doxycyclin, Minocycline
- Bacteriostatic, G+ and G-
- transported into the cells by a protein-carrier system, prevents attachment of aminoacyl-tRNA binding to 30S ribosomal subunits
- drug efflux pump (decreases concentration of the drug)
Resistance to one tetracycline often implies what?
resistance to all of the tetracyclines!
i.e. if resistant to doxycycline, can assume the person is also resistant to minocycline