HY lecture notes:
Alcoholic + pancreatitis –> do contrast CT to Dx –> may be negative depending on stage, but still performed to visualize degree of necrosis + fluid collections.
Drain pancreatic fluid collections percutaneously (through the skin).
Frank necrotic pancreas visualized on CT requires either necrosectomy (excision of necrotic pancreas) or aggressive percutaneous drainage (the latter is becoming increasingly favored due to high mortality rate associated with necrosectomy).
Pancreatic abscess is rare (about 3% of patients) and requires the visualization of thick, enhancing walls on CT.
Pancreatic pseudocysts have thin walls visualized on CT and occur in 2-18% of patients ~4 weeks after the acute pancreatitis. <40% will spontaneously resolve. The majority will remain stable in size. A small fraction will grow in size. For those with persistent pseudocyst, internal drainage is the answer on the USMLE. I have seen ERCP as the answer on one of the surgery NBME forms (as I’ve mentioned in this lecture’s audio). That is, the pseudocyst is drained internally via some form of endoscopic procedure. The literature also says endoscopic ultrasound with cystgastrostomy can be performed, which is draining the cyst internally via making a hole through the stomach to the cyst.
(I used this article in regard to the above information.)
45F with diffuse abdo pain + tachy + high leukocytes + hasn’t passed bowel movement in several days –> order AXR –> toxic megacolon –> looking for gas –> if pt stable, give IV steroids. If free air under the diaphragm, shock, peritonitis, or hemorrhage –> laparotomy.
Venous disease:
Dx of lower limb venous disease = duplex venous ultrasound
Venous ulcer = ulcer at medial malleolus + large, irregular, sloughed appearance
Surgery forms like you knowing when to give low-dose prophylaxis heparin dose vs higher-dose therapeutic heparin dose.
Higher-dose therapeutic heparin dose: when there is an active clot (DVT or superficial thrombophlebitis) –> if a leg is painful and swollen, think DVT; if the vignette says there is a painful, palpable, 1-cm cord at the ankle, that’s superficial thrombophlebitis; the vignette might also say there’s a thick, visible, painful vein that runs from the ankle to the knee –> answer = subcutaneous thrombophlebitis. Once again, in DVT or ST, give therapeutic heparin dose.
Low-dose prophylaxis dose: prior to surgery in patients with venous disease – i.e., duplex USS of lower limb shows occlusive disease but there is not an active DVT or ST.
Patients with varicose veins don’t necessarily have venous occlusive disease. Varicose veins is often familial from incompetent venous valves, but the patient doesn’t actually have any occlusion visualized on duplex USS. Treatment of varicose veins on the USMLE = compression stockings.
Now this is where it gets tricky: the first-line treatment for venous occlusive disease (in the absence of DVT or ST) is still compression stockings. So if you get a vignette of a guy with a venous ulcer (medial malleolus) +/- “brawny edema” +/- status dermatitis (pigmentation of lower limbs from hemosiderin deposition secondary to chronic venous leakage), the first-line Tx is compression stockings, HOWEVER, in this same patient, if they say there’s an ST (painful palpable cord at the ankle), and you see both compression stockings and subcutaneous enoxaparin as answers, the subcutaneous enoxaparin is correct.
In other words:
Varicose veins –> answer = compression stockings
55M + medial malleolus ulcer +/- “brawny edema” +/- status dermatitis –> answer = compression stockings
55M + medial malleolus ulcer +/- “brawny edema” +/- status dermatitis + has painful, palpable cord at ankle or tracking up to the knee –> answer = therapeutic dose subcutaneous enoxaparin, not compression stockings.
55M + active DVT or SV = therapeutic dose heparin
55M + medial malleolus ulcer +/- “brawny edema” +/- status dermatitis + prior to surgery –> answer = low-dose heparin prophylaxis
55M + varicose veins + duplex venous USS of legs shows occlusive disease + prior to surgery –> low-dose heparin prophylaxis
55M + varicose veins + duplex venous USS of legs shows nothing + prior to surgery –> answer = compression stockings
Arterial / peripheral vascular disease:
Arterial ulcer = punched-out appearance, generally smaller and more distal on the feet/toes.
Presentation is in patient with severe atherosclerotic disease (i.e., diabetes, hypertension, Hx of coronary artery bypass grafting, pain in the buttocks/thighs with ambulation [intermittent claudication], renal artery stenosis, etc.).
Dx of lower limb arterial disease = ankle-brachial index (ABI) –> always the answer first. Then do arteriography to Dx. Doppler ultrasound is a non-invasive (but less specific and sensitive) alternative to arteriography that is sometimes the answer. So for Dx of arterial disease, do ABI first, then either arteriography or Doppler ultrasound (the Q won’t list both; it will only list one or the other; but if they ask about which is more effective, do arteriography).
Tx of arterial disease always = exercise therapy first BEFORE cilostazol (phosphodiesterase inhibitor used as vasodilator therapy). Students will often jump on cilostazol, but it’s exceedingly HY to know the answer is exercise therapy first.
But then it gets even more annoying: before doing the exercise therapy, you must do a stress test to ascertain the patient’s exercise tolerance first. In other words, you can’t recommend the patient attempt to walk 30 minutes per day if he or she is going to get ST-segment depressions due to ischemia after seven minutes on a treadmill.
So for arterial disease: ABI for initial Dx –> then do confirmatory arteriography or Doppler ultrasound –> then do stress testing to determine patient’s exercise tolerance –> then Tx with exercise therapy/regimen –> next best Tx is cilostazol (vasodilator therapy).
Empyema vs abscess:
(From Surgery #2 lecture):
Empyema = pus in a previously existing space (i.e., pleural space or peritoneal space).
Abscess = pus in a place where there wasn’t a pre-existing cavity (e.g., your forearm).
USMLE wants you to know for empyema that it doesn’t just happen randomly. It happens as a result of worsening pneumonia:
Pneumonia –> progresses to parapneumonic effusion –> empyema.
Parapneumonic effusion is an exudative pleural effusion (increased LDH, protein, WBCs; low glucose in the setting of infective exudates). Low pH of the fluid (<7.1) is the most important indicator of a potential progression to empyema. This is really HY.
For empyema and abscess, always, always, always drain the fluid/pus before giving Abx. Even if you’re like, “Well yeah we’d drain, but wouldn’t we at least start the patient on Abx first?” No. We always drain first.
If skin abscess, the collection will need to be kept open to the air by stuffing it with sterile gauze, which will gradually be pulled out a little each day, until the space has closed. If you’re learning this for the first time, that might sound really weird, but it’s not and is HY. If you drain an abscess and then the area is sealed over or sutured shut via primary intention, bacterial proliferation may not cease.
Primary closure means sutured closed; secondary closure means kept open and allowed to close on its own, leading to worse scar formation, but as we said, the latter has its utility.
