HY lecture notes:
On the USMLE, new onset murmur + fever = endocarditis until proven otherwise.
Empiric treatment means that which is given before the culture results are known. It is based on educated guessing. The word empiric comes from the Greek word empeiria, which in direct translation means experience.
Empiric treatment for endocarditis
- Vancomycin or ampicillin/sulbactam, PLUS an aminoglycoside (e.g., gentamicin)
- Add rifampin in patients with prosthetic valves
This means in most patients treatment is vancomycin + gentamicin, OR Ampicillin/sulbactam + gentamicin. In patients with prosthetic valves, rifampin must be added.
Treatment for tinea capitis = oral griseofulvin for patient only (one of the IM forms asks for patient only vs also give to close contacts; answer was patient only); Trichophyton tonsurans is fungal cause. Black under Woods lamp. Griseofulvin inhibits microtubules (Step 1).
Tinea corporis (ring worm) Tx is topical clotrimazole or miconazole.
Tinea pedis = topical terbinafine; but have also seen a Q where it was topical -azoles. In this latter Q, it was the only antifungal listed, but topical terbinafine should be known as the main way to Tx.
Onychomycosis = fungal infection of nails. First-line Tx is oral terbinafine (6 weeks for fingernails; 12 weeks for toenails; USMLE won’t ask duration, but I write that hear as interesting side-context). Second-line is griseofulvin.
Tinea versicolor (Malassezia furfur) = Tx with topical selenium.
Tx of scabies = topical permethrin.
Tx of lice (pediculosis) = also is topical permethrin.
Supraventricular tachycardia (SVT) Tx with carotid massage (vagal maneuvers), followed by adenosine. SVT is NARROW complex QRS complexes (needle-shape).
VT use anti-arrhythmics, e.g., amiodarone. VT is wide-complex. Rarely SVT with BBB can be wide-complex, but you won’t see that on the USMLE. You need to know wide is VT, full-stop.
If pt has tachy arrhythmia and is unconscious, do direct cardioversion as Tx.
A random wide complex beat on an ECG strip = premature ventricular complex (PVC) = ventricular ectopic beat. No Tx necessary if asymptomatic. HY.
Pacemaker for third-degree heart block and Mobitz type II.
Third degree is super slow HR (e.g., 30-40) + no relation between p-waves and QRS complexes.
Mobitz II is when you have a random drop of the QRS complex, where the PR-interval does not gradually increase before the dropped complex. Can become a third-degree HB, which is why pacemaker is used for this.
Mobitz I (Wenckebach) is gradually prolonging PR-interval followed by dropped QRS. Don’t need pacemaker.\
Vaccines:
At birth: Hep B (+ vitamin K)
2, 4, 6 months: Pneumococcal PCV13, rotavirus (live oral), H. influenzae type B, TdP, Polio Salk (killed, IM), Hep B.
New guidelines might not require Hep B at 4 months.
Give MMR first dose at 12-15 months; second dose 4-6 years.
Varicella give 12-18 months.
HPV give age 9-45 years.
Influenza give starting at 6 months (killed IM); can give to pregnant women; give every year in fall/winter; can give live nasal spray vaccine to non-pregnant, non-immunocompromised persons age 2-49.
Alpha-1-antitrypsin deficiency –> codominant inheritance –> enzyme normally produced in liver but goes to the lungs; disease causes hepatic cirrhosis + emphysema young-ish non-smoker; family Hx of someone who’s had emphysema or liver disease. One question says dad died of alcoholic liver disease at age 55 –> probably implying increased susceptibility to severe liver disease bc of the alpha1aT deficiency. Alpha-1 antitrypsin normally breaks down elastase, so increased elastase can cause pan-acinar emphysema; smoking causes centri-acinar. Bullous changes or increased lucency on CXR means emphysema.
More anemia of chronic disease (in hematology #5 lecture):
Renal failure –> increased Cr, Hb low, Hct low, MCV normal, ferritin normal, iron low, transferrin saturation normal –> anemia of chronic disease (AoCD)
Can be due any type of chronic disease, e.g., RA, SLE, IBD; can also be due to chronic infections like HepC.
Can treat with EPO is renal failure is etiology; if not renal failure, CANNOT give EPO and you treat underlying condition.
AoCD is usually normal MCV (80-100), but some 2CK Qs are presenting with low MCV; but if this is the case, you’d easily be able to eliminate the other answer choices in the Q.
For instance, if Q is presentation with a kid who has obvious JRA (Still disease) – salmon rash (about half the time), high ESR, recurrent joint pain – and MCV is, e.g., 72, answer is still AoCD if anemia is present.
Transferrin saturation = Fe / TIBC (total iron binding capacity)
Anemia of chronic disease: iron is low; ferritin is normal or even elevated; transferrin low; transferrin saturation low or normal (bc TIBC is low, bc transferrin low)
Iron deficiency: iron low; ferritin low; transferrin high; transferrin saturation super low (bc TIBC very high, since transferrin high)
