If a rmeg clle or sacmtoi llce adh teh oingirla ti,nmutao hnte tee'srh na esrancide skri for rencac ni eroth tarps of eht dboy .oftI o onyl letniar cesll in one eey is dt,autem only tath eno eye si at iksr fro rac.ecn
Coihicrno ilvli amilpngs is the iknatg fo cgeeitn rmaaleti hiintw ni eht riohnoicc lvili of eht nlctpae.a iConrhico lgpsmain is dnoe hnew a tpeaitn is ta ihgh sikr rof chmorsmloao brenmalosatii oru(vesip p.so tt,ess y53o ro rloe,d yfialm .)xh dinurg eth 301-1 keews fo c.ngynaerp
doenfnCi alalcpnet msioascim lretuss hwen the .VSC.. etnsgit semco acbk kcab gnhwois a rtms,iyo ubt all quusesentb gnsitet and( eth stufe es)fitl veah lroanm lramhocmoso tnosc.u sThi yam eb ued ot eehirt a balsitrtohcpo oatiunmt, or by mriti"ocs rs,ecue" in wchih itscomri llsce htta erew pdeospsu ot eb ni eht uesft era ndficnoe ot hte lncaetpa to pvtneer na aamonrlb .futes
So I hate this question because you can know what the diagnosis is and still miss it.
TL;DR: This is lead poisioning, so there is basophilic stippling in a peripheral blood smear [BUT ringed sideroblasts would also be found in the bone marrow]
Why this is lead poisoning: (FA2020 p425)
Why it is NOT the other answers:
oS lhagtuho ptsoisMrloo SDEO aseeicnr cusum orotipdncu nda si i-votgpseeactrtor (and in AF dseo tseat ttha ti eecasedrs icda ti)ncurdo,po ehrbyte ieenacsgdr mosyptms adn adingi in eahig,nl ermleazpoo is eth re"mo erroc"ct eohicc. This si cuseaeb peloeoarzm si a p-mopuntrpo btri,inhio ihwhc illw act irteldcy no eth nrtopo pspmu fo het atoschm and ceadsree the figndonfe tegna oemr tahn the opilosmosrt li.wl r,oefTeehr ti si het rfsit elin rudg rof ED.RG
This patient is presenting with with STEMI (FA2019 p301), thus the entire vessel must be occluded. Coronary vasospasm via a1 stimulation (increased smooth muscle contraction) would lead to these findings.
As far as the nitro aspect, I think this could be referring to pt history of ischemic heart disease, and the scenario of coronary steal, however I don't think you would need that to answer this question (and I could be going down an unnecessary rabbit hole of misery).
Other helpful pages are FA2019 p238, a1 sympathetic stimulation results in increased vascular smooth muscle contraction.
Last, big ups to the brother for setting arguments aside and still taking his hermano to the emergency department. Perhaps they were arguing at who responded to COVID-19 and medical education worse: USMLE or Prometric.
Aterf hte D+4C ellsc eebmco enfc,tedi eht 8C+D llecs ilkl m.the
yitiInbla ot aiainmtn na ctneiroe = eliecrte sdynftiounc. oS wno eht qeituson si h?W"y"
gteaFui, udfiilfytc spnegeil, ituifcldyf togrinccnaent is rttgansi to undso eilk rdiesensop. iyctif"Dlfu gcnerciatto"nn tmihg be etenrpdteri sa idraeimp eieuetxvc otnucinf or teh ennbginigs of earcde-tvaralslu eniedtam mante(ide eertlad to mlals tub urnumeos erlacrbe aistnf,c)r btu on tpSe 1 nmedeita llwi eb tbtaaln .(i,e. ol"ts ish wya hoem," giren""n,wad t.e).c
sDepeoinrs is ytlualac mmocno efrta a aeititdblnig enevt elki koers,t as ouy timgh pt.cxee hiWt epniossedr cosem a lsos of usxeal sniteetr nad terd—eshtia si dcareseed dbolii.
enO can emka the gaertnmu tath a lcsravau" in"ttpae htimg ahve seom isuses whti his "ep"pis rrastiorisels,e(oc stpatcearahitpmihcpmaesyt/y tnyuodi)cfns d,an ofr stih es,rnoa clrtnauon ereoinct hsudlo be aecddeers; but teno thta hotgnni si ietnmdeno touab dsilnt-angong salrcuav ediases on( hx fo hnsotr.ene)pyi
sA a ust,lre hte etsb nseawr cihoce ehre is C. iob(diL ecdrseade tbu oraltcnun tneioecrs maor)n.l hTe ibg tosuqien I vahe is, hwo eth echk soed shti gyu wonk h'es arhd nhwe seh' els?a!ep! :p
ecinS eht stfrae'h ibnislg is cdtefafe, ew know tath hte 'srftaeh taresnp are tobh e.sriracr Ttah nemsa het leopssib ngteyeops of eht taferh era AA, A,a Aa, or .aa
We wokn het hafter si adnf,teucfe os htta msena eh conant be a,a dna stmu be hritee ,AA ,Aa or .aA
encSi heetr rae nylo 3 rdftifene egysnetpo eh udlco eh,av htwi 2 of mthe eigbn rerirca ogeypsne,t rteeh is a 2/3 ypibtirolab he is a arcrr.ie
So we ntaoib the yaoitibplrb of teh rhatfe apssgni no a ivceessre laeell sa /32 ibb(rytpaoil of ebnig a crie)rar x /21 ipi(btolyabr of aginpss on a eervsscie lealel if eh is a rarr.)cei Teh 32/ is otn treaveln to the latrbipioyb atth hte othemr is a ra.iercr
We nwko eth fyunqeecr fo deectffa uviaisdindl in teh pnpioautol ta alrge si /000,104 ()q=2,^ so =1q002./
,1=q+P os 29=p9/010 and 10202.099(21(/=0)qp/)2
oT kema ntpcmlltiuoiia aierse ew umessa 2199=10/0, :so
=q21=01/22/0)00*p(1 ;--> hsit si hte craerir feqecyrun .a(.ak., zo)tsghreeetoy ni hte l,unooippat ihchw we nac ussmae for teh .morhte
oS, ot rewnsa the tenrie uensqtio ew mtlilpyu hte pytobilbrai ttha hefrta si a arreric )2(/3 dan saesps no eht elalle /)1(2 tmeis het tiarplbyoib that othrem si a arrrice 10)(/01 dna epssas on the alelel 2)1/;( tigtnpu it lla thegoret ew h:eav
3))10(02((*2/1)*)*1(//1/2 = 00/212 = 0610/
This is my best interpretation with a source and paragraph from the source listed:
In anemia, hemoglobin available is decreased. This causes decreased oxygen binding, and ultimately less oxygen is available for release onto tissues.
"The circulatory adjustments in response to anemia will be similar to those of the preceding case. In order to maintain tissue oxygen consumption at baseline levels associated with a normal oxygen carrying capacity of blood, the reduction in oxygen delivery will lead to an increase in capillary perfusion, and oxygen extraction will increase. Arteriolar dilation and viscosity reduction (for the case of a reduction in Hct) will cause blood flow and oxygen delivery to increase. Both oxygen extraction and oxygen delivery will continue to increase until the oxygen requirements of the tissues are met or until the capacity to increase oxygen extraction and delivery has been reached. The resulting situation is one in which venous oxygen content and PvO2 are less than normal. Since PaO2 is normal for all the anemic situations considered, this defect is not sensed by the respiratory chemoreceptors. Thus, increasing the inspired oxygen fraction is not helpful except for the case of CO poisoning, where high inspired oxygen (e.g., 100% oxygen at ambient barometric pressure or placement of the subject into a hyperbaric chamber) competes with CO binding at the heme site (recall Haldane's first law)." - https://www.ncbi.nlm.nih.gov/books/NBK54113/
ME: I think I finally have these stupid storage disorders down
NBME: Not so fast, partner
A 70 year old develops a progressive disinhibition syndrome with episodes of emotional outbursts, inappropriate use of language, and socially inappropriate behavior. Where is the most likely damage?
Answer: Frontal lobe disinhibition.
Bilateral amygdala (medial temporal lobe) would've been affected if it was Kluver Bucy Syndrome.
Many opioids (like morphine) are potent histamine releasers, which can cause puritis and anaphylactoid reactions (such as seen in this patient with the facial flushing, drop in blood pressure and corresponding increase in heart rate). Puritis is actually a common side effect of morphine.
Source: First Aid and
Niemann-Pick is a lysosomal storage disease that is a deficiency in sphingomyelinase that leads to a buildup of sphingomyelin (Niemann picks his nose with his sphinger)
Sphingomyelinase is considered a lysosomal hydrolase
Answering this question requires you understand the mechanism of osteoclast stimulation by parathyroid hormone (FA 2020 p332).
Parathyroid hormone stimulates osteoclases indirectly by stimulating the release of RANKL bu osteoblasts which will bind to RANK receptor on osteoclasts and stimulate the resorption of bone. This is a paracrine process because paracrine signaling refers to stimulation by neighboring cells (short distances).
I love this question because we are all obviously trained radiologists...
In reality, rather than identifying every X-ray given and trying to match it to the question stem, the best way to approach this question is to identify what his most likely issue(s) and match to the general characteristic of an X-ray, going to the X-rays looking for these characteristics.
He is an alcoholic with foul smelling (ding anaerobic) sputum. Because he is an alcoholic he is at risk for aspiration pneumonia and anaerobic pulmonary abscesses from aspiration (which is why they mentioned the bouts of blacking out). So what are the characteristics of these diseases? Aspiration pneumonia is a lobar pneumonia which would present with lobar infiltration (see here for example). Pulmonary abscess would present with cavitation and an air-fluid line (see here for example with air fluid level pointed out and here for cavitation/abscess pointed again).
Thinking of this now approach the X-rays looking for specific findings. One has the air fluid level and cavitation, so that is the answer (it is an abscess). None of the others have lobar infiltrate and are either more diffuse or hilar so they should be ruled out.
This ratio is used to determine appropriate production of lung surfactant, so this baby would not have appropriate production of surfactant if birthed at the time of the ratio calculation. It would go into neonatal respiratory distress syndrome.
TL;DR: surfactant decreases lung recoil, so the lack of surfactant in this baby will cause an increased recoil which will decrease the functional residual capacity (FA 2020 p661-662)
Surfactant is necessary to decrease surface tension of alveoli and increase compliance of the lungs (remember when the lungs have greater compliance, this makes the lungs easier to fill). Surfactant also helps to prevent alveolar collapse as the lack of surfactant allows there to be varying surface tensions between large and small alveoli (Law of Laplace), so lack of surfactant would lead to widespread atelectasis (alveolar collapse). Because surfactant serves to decrease these forces which normally favor collapse of the lung, it also serves to decrease the lung recoil.
Lack of surfactant in a baby = increased alveolar surface tension, lower compliance, more alveolar collapse, more recoil (less residual volumes)
Total lung capacity is unchanged because with enough force you can still expand the lungs to full capacity.
TL;DR: This is Ewing sarcoma because it is a young boy with small blue cell bone tumor in the diaphysis of the femur
Ewing sarcoma is a malignant bone tumor common in young boys <15y.o. typically found in the diaphesis (middle) of long bones (particularly femur) or pelvic flat bones. It is a small blue cell tumor, meaning the descriptor of small, uniform, hyperchromatic cells with high nucleus:cytoplasm ratio. It also has an "onion skin" periosteal reaction in the bone (described as tissue surrounded by concentric layers of reactive bone in the question). Not mentioned is the association with t(11;22). [FA 2020 p 464]
Why the others are wrong:
Oral rehydration therapy commonly consists of sugar/electrolyte water because of the ability to utilize the sodium glucose symporter. Where sodium goes, water follows, so by hydrating with this mixture it allows for an osmotic "pull" of water into the intestines.
Here is an article with more detail and a pretty diagram: https://basicmedicalkey.com/therapy-of-viral-gastroenteritis/
necognesO htiw ngai fo ncitfonu nmaiotut dela ot radceenis ,tsptoirarnnci c.e,t eearshw uormt psrsopreus nesge bkcol -&1Sg;G-t aep.sh 1FN gnee courdpt hsa RSA TGesPa ivtytcia ihhwc wkros yb naohiysoltgrphp dna gaciantitv porniet (iomurnbo.finr)e So rthee si at estal 1 roumt sesrpurpos eeng hatt krwso hgorhtu ohposayihnolrt.p
High craaicd puutot to teh porluynma otraclnciiu udnrig xrecisee lwli aeucs the sonndteiis nad nticrrtmuee fo lmveiecssso dna ahtt wlodu eascu eth icearsne ni tlato nso-stceasrciol a.ear
rHee aer tow gsiame ttah urislattle this inielprpc yilecn:
This individual has active Hepatitis B, as evidenced by their Hepatitis B surface antigen positivity. Hepatitis B virus productively infects hepatocytes. The CD8 cells will thus attack the hepatocytes.
Another way of approaching this question is to notice AST and ALT elevation are typically indicative of hepatocyte damage.
Ito cells are the same thing as stellate cells, and their primary function is to store vitamin D and fat and produce ECM when activated. Kupffer cells are the liver's macrophages. Bile duct epithelium is not infected in hepatitis.
heT stme ttsaes tath eht hemtor si 21 ekswe etst.aonig SVC is reofpderm st1 eitmsre,tr saulluy bt/ 40-11 ewkse gnetoasit diacnrogc to t.ateDpUo-- imAno si mpfrdroee afret 51 sk.ewe Fmor Dte-Uoa-:pt nceesmiAsnot“i uodlhs be morperdfe teafr 51 sweke fo ateoisgtn eecubsa iearerl docreuspre rea esls lyekli to eb uslufccss,e aer saaostcedi hiwt iehrgh tasre of clel elrtuuc fel,iaur nad ryrca geetarr faelt isk”s.r
eWhn a slmcue unsr tou fo luef e,g( guole)cs /arnod oidpucnrg ssel APT nda i“s”ecnared ucauntmoiacl of tibsteomlae (all oreth tsonoip isebsed hte cerrotc ie,)ohcc it is a gins fo eostn fo escmul tgfiaeu. heT smte si aisgkn whihc of hte gonlolwfi iwll de,cesa”?e“r adn it is eth pH ttha wlil ecdrease dissci(o)a deu to eht acailnmutcuo fo ctlcai adci (meremreb llscioysgy yahawpt ehwer yrvatupe steg neveorcdt to clcati cid.)a
iThs pinatte ensstepr twih lasicsc upper rotom onnuer elison y:sptomsm essew,akn lfapiryr,xeeeh dna edeseadrc tnnos.iesa ereHwo,v teh sniqueto tetsas she "canont lelt etewrhh ehr ftel rgaet ote si sidrae ro "dseerdpse ehwn rhe seey are ,dslceo hiwch aym emka uoy srdinoceer dan tiknh theer yam eb eosm ppriciteeoprvo isuess yeht era trinyg ot itnh a.t siTh si otn hte ea.cs sypilacEel neoc yeht neiotnm hetre rae no theor abiioltmrasen .ei(,. on puerp ibml atrimlboansei or tghri sdedi sia.)lmnaoeibtr fI htsi is eht s,eac treeh si on gaeadm ot eht rttacs ta all hciwh( aer ltisl sddrenoice UM)N.
ohe,eTfrre eth madaeg is lruype rtmoo and onsyser in the tfle gle, hwhic is on teh melida catpse fo the nflator adn palateir lseob ecespltyirv.e ihTs eaar si pilesupd yb eht nairetor lreraebc a.ryetr
hTsi is hwat si ownkn sa a csomiat iutmaotn: a tntmoaui taht rouscc in mngo-nnleeri lcsel dan, ,otfeerreh lnyo teffsec tguhaedr elcls derediv fmro teh enrpat cell tihw eht .tmtonaiu S,o a toatimun corerduc in a tidnteederiffa paenrt clel that agev eris to a est fo agrhutde slcle ci,hhw( ni this ase,c were seetdndi to mceoeb rtnalei eui.tss)
gCo"ounifndn "ivalbsare reeh msnea "nidougconfn bi,as" sllsaieyte.n ndA this is uret ebecusa a ciereppstvo roocht ooskl at a fisccpie eexusrpo ot a btnscuesa veaotrm(lnienn ot,ixn u,gdr tc).e, dna akss "oWh liwl levdope itsh adesies fi ?pee"xods 'sCPS loko tmettpa to ifdn a etvaelir srki saaetcsdoi iwth na up.xeoser hTey do ton ktea onti ucctona eth tcfeafs hotre rxesusep.o hsTi si ruoy oncnnfduigo .sbia FA segvi hte ealmepx fo cgdnuofonin isab sa mlyr"uonaP eieadss is ermo ocomnm in sewokrr in a loac ;emni rw,oheve mensir are reom lyleik to se,ko"m dan nsice nsmiogk cna olsa lead to rmyunlpao asdeies, yuo tacn' erllya sya hrtwhee the sgimnko sfri(t or sodnec d)nha or het ocal udst ssaeuc eth emblop.r A cicillna ,atilr on eht throe h,nad ninotcsa a stet opurg nad a rtcooln prguo, os eavasbilr hcsu as the uoonficngdn iaaerbvl eonidtmen oebav rae iei.tmld
TL;DR: You want the most sensitive test first to rule out the disease in negatives (least likelihood of false negative) and the most specific test next to "rule in" only true positives (least likelihood of false positives) [FA2020 p257]
The way I always think of sensitivity and specificity is in relation to false negatives and false positives.
In this question, you want to ensure you are only treating those who actually have the disease, or in other words that you want to minimize your false positives. The best way to do this is maximize sPecificity. Test 1 has 100% specificity meaning it will have essentially NO false positives which is great so we definitely want to use it (eliminating all but two options)! The better way to ensure you are catching as many cases as possible while still only getting true positives is to test with test 3 first, which has a much higher sensitivity. That way we are ruling out disease in the negatives of test 3. This also adds to our ability to only truly treat those with disease as we have ruled out disease in our first negative population, then we test the positives to "rule in" disease with a highly specific test.
The issue with using Test 1 first and only testing the positives is we know the positives from test 1 are likely true positives, as the highly specific test would have a basically zero false positive rate. At that point there would be no point in testing with test 3, as we have basically a true positive population. The issue is we have missed a lot of diseased due to the low sensitivity and high false negative rate of test 1.
Another way to think of this is to remember the formulas (as seNsitivity contains false Negatives, and sPecificity contains false Positives in the formulas; see FirstAid):
SPIN/SNOUT also helps to remember that specific tests rule in disease, and sensitive tests rule out disease
7-dehydrocholesterol is a form of pre-vitamin D3 synthesized in the skin from UBV. It is converted to Cholecalciferol, which is the inactive form of Vitamin D3 that is actually in first aid.
sThi patenti ihtw a siohtry iccohrn yspinthreneo si otsm lkelyi sgifrnefu morf tfle erath rfaeuil drcee(dsea ircadac up,)ouott asignuc the odblo ot kbca up in eht nlugs (lkCrcsae rea hrdae yt,irllbleaa shtersson fo ba)trhe nad htat gtuirelns tnio eareiscdn redtlfoaa rof teh grhti eids fo eth rta,eh sgianri het rspsuree in eth irhgt areth hbr,amecs hwhci egt sttreitmand cabk to rclante eiv.n
The above is correct in terms of MoA, however I believe the stem states it is PT (prothrombin) prolongation, not PTT (Partial Thromboplastin). I did not have any idea what dicumarol was.. but here was my logic:
hTis Q uocld eb senawder otw yaw,s eno ohhturg iinomeatlin ro gwonikn ohw to fediniyt the l!ceu owN vai oimtnlnaiie . .).A nmayil nsee in DIAS ntspatei ( Q smet does ton trcdie Q that )awC)y lFuo gilemnls eahardri t"f"Dy )at herTe esedn to eb a ritda " esy PEaOeyTHmAgl + eoeelylgap"Smn pksgn"ii "erfve aa"n"ytpcionpe mya aols veha nsik lioevnmtvne E) louf lgsinelm regen gianlva crgdsaehi
)B EULC* UQR IAPN + celur
siTh is enaysilstle a olafmr olgic tusn.eioq giLlolcya gps,nieka het tnosueiq sska su ot ytdeifni a mismanech taht rumto pospusrsesr heva cwihh se-nnoceootprog do n.to nI roteh s,dorw thwa si a esahnimcm rdhaes yb all nwkon rutmo spsurrssepo tub otn sedrah by ayn nkwon p-toesgoc?nreono For atht oes,anr it ’acnt be lipha;rhnptosooy sr,eu phiaplsnoyoothr is a cmaenhsmi of tmoru posusprsers but ’sti oasl a emsnmciah fo many nwkon tsogp.o-rceoneno
The key to answering this is that she seems unconcerned with her symptoms, which is a hallmark of conversion disorder (la belle indifference) [FA2020 pg 566]
Illness anxiety disorder would be preoccupation with having a certain illness, and inability to be reassured when there are negative findings.
Depersonalization/derealization is a dissociative disorder and "out of body experience" with a feeling of detachment from the body or environment.
Brief psychotic disorder would present more likely with delusions, hallucinations, or some other characteristic of psychosis.
PTSD would present after an extremely traumatic event when symptoms such as anxiety, flashbacks, hyperarousal, and nightmares persist for greater than 1 month after the event.
As the sueclm rsokw nda krbesa odnw PT,A idneasoen is dcedr,puo ieadlng ot an nieersac ni het tsu.seis hisT ieecsrdan oanidsene useacs olv,sinaadiot ichhw ni turn iarscnees alcvrsua cectndounca te(h owfl of a emouvl of obold guhtroh teh vu.scauater)l
Agthhoul uyo mya khnit usclem onrociatntc amy edla ot a raseeced ni olwf rghhtuo het ele(svs)s yb sugneeqzi down on ,tmhe hsit hnmaemsci si croevemo by teh sidneacer aardcci pttuou rfom the hat.er
Presence of multinucleated giant cells surrounding foreign body (staple) shows granuloma.
This requires knowledge of MOA for phosphodiesterase inhibitors (which are also used for erectile dysfunction). All phosphodiesterase inhibitors will inhibit phosphodiesterase, which normally catalyzes hydrolysis of cAMP or cGMP, so they will work by increasing cAMP/cGMP levels! [FA2020 p246]
NOTE: do not get confused by the addition of NO as an answer, though arteriole dilation by phosphodiesterase inhibitors works in part by enhancing NO activity on smooth muscle, it does not increase the concentration of NO. NO triggers increased cGMP to dilate smooth muscles, and phosphodiesterase inhibitors prevent breakdown of this cGMP, so they work in synergy!
Teh ightr yese' fnertfee sernev rae iwk,ngor sa tlef eey tmnlutaoiis csuase a hncaeg in hte htgri ey.heTe hritg eye pcito n. deaagm usecas ti's etfnraef n. to eb meda.dag It c'tan rcray onif to rabni, os igtrh dna eflt eey ncta' ctsnctori to .tglhi
The kidneys make glucose too? 6 years of studying science and no one mentions the kidneys.
While not traditionally discussed, the kidneys' contributions to maintaining glucose homeostasis are significant and include such functions as release of glucose into the circulation via gluconeogenesis, uptake of glucose from the circulation to satisfy their energy needs, and reabsorption of glucose at the level of the proximal tubule.
FA2019 p78 - [Gluconeogensis] occurs primarily in the liver; serves to maintain euglycemia during fasting. Enzymes also found in kidney, intestinal epithelium.
... seems like a silly thing to test... shrugs shoulders laughs in NBME
Amniotic fluid phospholipid analysis is used for testing fetal lung maturity via measuring surfactant production.
Fetal echocardiography would reveal any congenital heart defects if present, but would not be diagnostic of Downs syndrome
Fetal ultrasound First-trimester ultrasound commonly shows increased nuchal translucency and hypoplastic nasal bone. But I feel this is used more commonly in older women who might have chromosomal dysgenesis as the cause of downs syndrome
Fetal biopsy Pretty invasive technique, when we have a lesser invasive and more specific test available.
Another tRNA has to attach to the A site before the peptide chain can be hydrolyzed from the P site and moved to the A site tRNA (FA 2020 pg 45)
the hallmark of meningioma is its relation to a meningeal surface hence relation to sulcus
I am assuming this is just something we are expected to know; tubular reabsorption requires the most oxygen because it would consume the most ATP out of the processes in the kidney?
Penicillin can cause a direct Coombs + autoimmune hemolytic anemia
The Direct Coomb's test involves anti-Ig antibody (Coombs reagent) added to patient’s RBCs. RBCs agglutinate if the RBCs are already coated with antibodies (indicating that the body is making antibodies that bind the RBCs). RBCs tagged with antibodies are destroyed in the spleen. Penicillin is thought to act as a hapten binding with proteins on the RBCs and triggering an antibody response against the penicillin-RBC complex [FA2020 p423]
tight junctions between adjacent sertoli cells form blood-testis barrier--> isolate gametes from autoimmune attacks
Overflow incontinence is present (bladder fills then leaks slightly), so either:
1.) something blocking outflow (e.g.; BPH)
2.) impaired contraction of bladder (e.g.; damaged nerves)
Only the pelvic nerve causes detrusor contraction, so it is the only possible answer. External sphincter, pudendal nerve, and skeletal muscle all does the same thing. Hypogastric nerve helps retain urine (relaxes detrusor) so it is clearly not damaged.
TL;DR: Renal cell carcinoma can present with polycythemia (due to increased erythropoietin) and hypercalcemia (due to PTHrP) [FA2020 p228]
So the question is what is the primary cancer? He has two tumor locations (kidney and lungs), which could be primary or from metastases.
I narrowed it down to metastatic renal cell carcinoma and bronchogenic squamous cell carcinoma (see below). The only other infoemation really given that could allow us to distinguish is the lab values indicating paraneoplastic syndromes. These are both known to cause paraneoplastic syndromes which can cause hypercalcemia. So focusing on the polycythemia, this is more specific for renal cell carcinoma because no lung cancer secretes EPO.
I eliminated undifferentiated carcinoma because it is too nonspecific and metastatic transitional cell carcinoma because it is rare in the kidney (with no paraneoplastic syndrome typically associated which could cause the lab abnormalities) and there is no mention of bladder.
Multiple myeloma can have renal involvement but does not typically involve the lungs and would present with bone lytic lesions and anemia rather than polycythemia. [FA2020 p431]
This is G6PD deficiency. (FA2020 p422)
G6PD deficiency causes a hemolytic anemia when individuals are exposed to antimalarials due to the increased oxidative stress. This is due to the deficiency in replenishing NADPH which is necessary to replinish reduced glutathione which aids in quenching free radicals.
The first thing to look at is potassium, which would decrease because insulin facilitates intracellular shift of potassium (which is why it is used as a treatment for hyperkalemia!). This leaves only two potential answers!
The next thing I immediately noticed was that our patient's labs indicated anion gap metabolic acidosis (likely due to diabetic ketoacidosis). Administration of insulin would improve this condition, and one of the main things that would occur is correction of acidosis, so pH would increase. The other parts of the answer also make sense, as bicarbonate begins to return to normal with the increase in pH and less necessity for use in buffering, BUN decreases as the kidney damage occurring can be mostly reversed, and blood CO2 increases because there is no longer the need for respiratory compensation of the metabolic acidosis.