Pulmonary Conditions PDF

MEHLMANMEDICAL.COM HY Alveolar fluid conditions - Due to left heart failure on USMLE. - There is such thing as “non-cardiac pulmonary edema” (i.e., ARDS, TRALI [discussed...

MEHLMANMEDICAL.COM HY Alveolar fluid conditions - Due to left heart failure on USMLE. - There is such thing as “non-cardiac pulmonary edema” (i.e., ARDS, TRALI [discussed below in this table]), but for USMLE purposes, if you see “pulmonary edema” as an isolated phrase, it refers to transudation of fluid into the alveolar spaces due to ­ pulmonary capillary hydrostatic pressure from left heart pathology. - PCWP and LAP are both elevated. Pulmonary edema - USMLE can give you vignette of, e.g., MI with dyspnea, and they ask for the mechanism of the dyspnea in the patient à answer = “increased alveolar- arteriolar oxygen gradient” – i.e., the patient can breathe just fine so alveolar O2 is normal, but fluid impairs the gas exchange, so we have low arterial/arteriolar oxygen. - “Cephalization of pulmonary vessels” is buzzy and synonymous with pulmonary edema on USMLE. Shows up in some NBME vignettes. - The answer on USMLE for bilateral exudative chest infiltrates and ¯ O2 sats in patient following: pancreatitis; aspiration of vomitus; near-drowning episodes (aspiration of fresh/sea water); improper insertion of NG tube into the lungs with feeding initiated; toxic shock syndrome; or general trauma / sepsis. - 2CK NBME Q gives vignette of toxic shock syndrome and then asks most likely cause of death in this patient à answer = ARDS. - Pulmonary decompensation associated with pancreatitis is very buzzy. - Another 2CK Q gives patient who is brought to hospital following near- drowning episode + they ask what the patient needs to be monitored for à Acute respiratory distress answer = ARDS. syndrome (ARDS) - ARDS is technically defined as a PaO2/FiO2 10mm (+): Health care worker or prisoner/prison worker; immigrant from endemic area; TB laboratory personnel, children 15mm (+): everyone else. - If a PPD test is (+), never repeat it. If it is negative, it must be repeated in 1-2 weeks (i.e., sometimes false-negatives). - Answer on a 2CK form for a guy who moves into a new apartment building Hot tub lung with a hot tub and gets bilateral chest infection à inhalation of fumes with Mycobacterium avium complex (MAC). MEHLMANMEDICAL.COM 66  MEHLMANMEDICAL.COM - Exceedingly HY on USMLE. - USMLE wants “aspiration of oropharyngeal normal flora,” or “aspiration of oropharyngeal anaerobes” as the cause. - Q will give aspiration risk factor, such as alcoholism, dementia (can cause loss of gag reflex), Hx of stroke (leading to dysphagia), or epilepsy. - Q can also mention broken or missing teeth (hypodontia) as risk factor. - Often described on NBME as pulmonary lesion with an air-fluid level. This is buzzy, but not a mandatory descriptor. This refers to the top half of the circle being air, and the bottom being pus, the latter settling due to gravity. Pulmonary abscess - The stem can say the patient has “foul-smelling sputum.” This descriptor is exceedingly HY and is synonymous with anaerobes on USMLE. - Oropharyngeal normal flora = Bacteroides (strictly anaerobic gram-negative rods); as well as Peptostreptococcus and Mobiluncus. The latter two are not HY, but Bacteroides is. I mention all three, however, because the Q can say sputum sample shows “gram-negative rods, gram-positive cocci, and gram- positive rods,” which refers to all three. But the bigger picture concept is, this = mixed normal flora. - Tx = clindamycin. USMLE loves this. - If Q tells you patient was treated for pulmonary abscess + a year later there’s still a lesion seen on CXR à answer = “failure of maintenance of basement membranes.” Acute bronchopulmonary - Presents as asthma-like presentation in patient with ­ sensitivity to aspergillosis (ABPA) aspergillus skin antigen. - Answer on USMLE for bilateral lung condition + fever in farmer who has exposure to hay (on new NBME). Hypersensitivity - They will tell you the fever self-resolves after 2 days and he now is afebrile. pneumonitis - Byssinosis (pneumoconiosis from hemp) is wrong answer, since this won’t present with fever + classically presents in textile workers. - Idiopathic restrictive lung disease where patient has pneumonia-like presentation that fails to improve with antibiotics. Not actual pneumonia. Cryptogenic organizing - Formerly known as bronchiolitis obliterans organizing pneumonia (BOOP). pneumonia (COP) - Nonexistent yieldness on USMLE, but I mention it because you will sometimes see this as a wrong answer choice, particularly on hard 2CK Qs, and I’ve seen enough students erroneously pick it. - Infection of portion of ear just deep to tympanic membrane. Otitis media (OM) - Most commonly Strep pnuemo. MEHLMANMEDICAL.COM 67  MEHLMANMEDICAL.COM - Will present as red, immobile tympanic membrane. Immobility of the tympanic membrane is highly sensitive for OM, meaning that if the Q says mobility is normal, we can rule out. - “Ear tugging” can be a sign in children of either otitis media or externa. - Tx is amoxicillin or penicillin. - Augmentin (amoxicillin/clavulanate) is classically given for recurrent OM. So if you are forced to choose between amoxicillin/penicillin alone or Augmentin, go with the former. - For 2CK Peds, a tympanostomy tube (aka grommet) is used if the kid has >3 OM occurrences in 6 months, or >4 in a year. - Aka otitis media with effusion. - Presents as fluid behind the tympanic membrane in a kid weeks after Serous otitis media resolution of 1 or 2 otitis media infections. - Almost always benign and self-resolves in 4-8 weeks. Answer is observation. - “Tympanic membrane perforation” is the answer on new 2CK NBME for 2- year-old who had 3-day Hx of viral infection followed by awakening with severe ear pain + has dried blood on ear lobe and pillow + otoscopy cannot Tympanic membrane visualize tympanic membrane because of seropurulent fluid draining from the perforation ear canal. - Can occur due to otitis media, although vignette on NBME doesn’t sound like classic OM and is as described above. - Inflammation of mastoid bone caused by untreated otitis media. - The mastoid process is the posterior part of the temporal bone that is felt just behind the ear. - Can present as a painful ear pinna that is displaced (e.g., upward and Mastoiditis outward). - Diagnosis is made by CT or MRI. X-ray is wrong answer. - 2CK IM Q gives a 2-year-old with mastoiditis where the answer is “CT of the temporal bone.” Sounds wrong, since this is ­ radiation for a kid, but it’s what they want. - Isolated inflammation of the tympanic membrane. Myringitis - Can be bullous (i.e., bullous myringitis). - Caused by Strep pneumo or Mycoplasma. - Infection of ear superficial to tympanic membrane. - Classically caused by Pseudomonas. - Increased risk in swimmers and diabetics. - An NBME form has “necrotizing otitis externa” as answer for black skin Otitis externa (OE) within the ear canal in a patient. This is aka “malignant otitis externa.” - USMLE wants “acetic acid-alcohol drops” as prophylaxis in college student who does crew + continues to have water exposure. - Tx (not prophylaxis) = “topical ciprofloxacin-hydrocortisone” drops. - The answer if they tell you a school-age kid has a lingering fever after an upper respiratory tract infection (URTI) for 10-14+ days. - Whenever a URTI lingers for more than ~10ish days, you want to think about sinusitis as a differential. - A 2CK vignette gives nocturnal cough (reflects aspiration; in this case, from the sinuses) and grey membranes in the oropharynx. - The grey oropharyngeal membranes detail sounds weird, since that is Sinusitis normally buzzy for Diphtheria, but it shows up on an NBME Q where the answer is sinusitis and Diphtheria isn’t listed. - IgA deficiency Qs, which presents as recurrent sinopulmonary infections, can say patient has Hx of pneumonias + presents today with sore left cheek à reflects sinusitis. - For 2CK, CT scan is done if chronic sinusitis >12 weeks. After CT is performed for chronic sinusitis, nasal endoscopy can be performed. MEHLMANMEDICAL.COM 68  MEHLMANMEDICAL.COM - Tx is amoxicillin/clavulanate (Augmentin). This is in contrast to OM and Strep pharyngitis, which are treated with just amoxicillin or penicillin alone, without the clavulanate (unless recurrent). - Causes respiratory distress, fever, and myalgias (muscle pain). For USMLE purposes, the myalgias are exceedingly HY as a vignette finding that usually suggests the flu over other diagnoses. - Has 8 segments, two of which are hemagglutinin and neuraminidase. - Hemagglutinin mediates viral attachment to the cell by enabling its binding at sialic acid receptors. - If a question asks about the molecule most flu vaccines are targeted against, the answer is hemagglutinin. - Neuraminidase allows for newly synthesized viral particles to leave the host cell. This enzyme cleaves sialic acid residues, which normally bind the new viral particles within the cell. Once these residues are cleaved, the viral particles can leave the cell. - Drugs such as oseltamivir and zanamivir are sialic acid analogues that function as neuraminidase competitive inhibitors. In other words, they prevent the virus from leaving the cell. If the USMLE asks which drug prevents viral spread within a community, or they tell you a drug is given and now host cells are "packed with virions" (because they can't leave the cell), the answer Influenza is one of the -mivirs. - Antigenic drift is point mutations in hemagglutinin and/or neuraminidase, where the virus has changed slightly. It leads to seasonal epidemics. Antigenic shift is due to two influenza viruses entering a cell, one of human origin, the other of animal origin (such as bird or swine), where they engage in reassortment of viral segments, leading to a completely novel influenza virus. It leads to generational pandemics. - If a patient gets a bacterial lobar pneumonia following recent convalescence from influenza infection, USMLE likes S. aureus as a HY cause. The USMLE will not play trivia where they list S. aureus alongside S. pneumo and you're forced to choose. What they'll do is say something about how a guy recently recovered from a viral illness in which he had high fever and myalgias, and now he has a pneumonia caused by a gram-positive coccus in clusters --> answer = S. aureus. In contrast, S. pneumo is gram-positive diplococci. - IM killed vaccine: start age 6 months, then give yearly in the fall or winter throughout life; safe to give during pregnancy. - Intranasal live-attenuated vaccine: ages 2-45; immunocompetent, non- pregnant persons only. - The virus specifically known as SARS-CoV-2, or COVID-19, caused the 2019 global pandemic. - SARS stands for Severe Acute Respiratory Syndrome. - The pandemic is believed to have started following a laboratory leak in Wuhan, China, although this has been a source of political debate, where initial explanations asserted that there was a natural, zoonotic origin for the virus (i.e., originating from animals, e.g., bats). - Has characteristic spike proteins that create a crown-like appearance on electron microscopy. Coronavirus - The spike proteins bind to ACE2 receptor, allowing for viral fusion with host respiratory epithelium. - Presentation can range from mild respiratory symptoms similar to the common cold (rhinovirus) all the way to severe respiratory disease with multi- organ failure. - Many different vaccine types exist - i.e., mRNA (Moderna; delivers mRNA coding for the spike protein), viral vector (AstraZeneca; delivers mRNA in a harmless viral capsid), and killed (Sinovac; delivers inactivated, killed virus). - Both live viral infection as well as vaccination are known to cause rare adverse effects, such as Bell's palsy and myocarditis, although these effects MEHLMANMEDICAL.COM 69  MEHLMANMEDICAL.COM are not unique to coronavirus and can rarely happen with many viral infections and vaccines. - Vaccination mandates and their political implications were (and still are) a source of contentious debate. - Prior to the 2019 pandemic, coronavirus was known to cause SARS in China in 2002 and Middle Eastern Respiratory Syndrome (MERS) in Saudi Arabia in 2012. - Vaccination schedule for children now recommends IM vaccine starting at 6 months; 2-3-doses. Vaccine stuff - PCV15 at 2, 4, 6 months, then again 12-15 months. - Age ³65: PCV20 once; OR, PCV15 then PPSV23 a year later. S. pneumo - For asplenia/surgical splenectomy, sickle cell, cochlear implant, CSF leak, chronic renal failure/nephrotic syndrome, HIV, and immunosuppressed patients: extra dose of PCV15, followed by PPSV23 8+ weeks later. - IM killed vaccine: start age 6 months, then give yearly through life; safe to give during pregnancy. Influenza - Intranasal live-attenuated: ages 2-45; immunocompetent, non-pregnant persons. Coronavirus - IM vaccine starting at 6 months; 2-3-doses. HY Pediatric-related respiratory stuff - HY pediatric condition in which the proximal esophagus ends in a blind pouch + the distal esophagus connects to the trachea. Tracheoesophageal fistula (TEF) - Will present as a neonate who coughs up milk with initial feeding. - Highest yield point about TEF is that diagnosis is made via insertion of nasogastric tube (which cannot be inserted fully because it hits the blind pouch of the esophagus). - An NBME Q wants “endoderm” as the abnormal embryology for TEF (makes sense, since esophagus is epithelial lining of the gut à endoderm). - Weird condition in which the nasal passages don’t develop patency, so Choanal atresia the neonate is an obligate mouth-breather. MEHLMANMEDICAL.COM 70