NBME Medicine Shelf Incorrects Flashcards
Patient with headache, wheezing, itchiness, headache after eating MahiMahi, unwashed fruit, unrefrigerated cream puff, and lettuce. Most likely diagnosis?
Scombroid poisoning results from ingestion of accumulated histamine, produced by bacteria from the high histidine content of dark meat fish often when not stored properly.
Histamine ingestion can cause flushing, urticaria, wheezing, itchiness, blurry vision, abdominal cramping, diarrhea, and headache. In severe cases, it can present similarly to anaphylaxis.
The most common bacterial (and overall) cause of lymphangitis is _______________ with _____________ representing the most common fungal lymphangitis.
Clinically, it presents with ________________________
Streptococcus pyogenes (Group A)
Sporothrix schenckii
-erythema in a linear, longitudinal band appearance, which correlates with the associated lymphatic drainage channel. There is also typically painful lymphadenopathy along the associated lymphatic drainage channel. This can result in pain and swelling with the possibility for high fevers.
-Lymphangitis refers to inflammation or infection of the lymphatic channels, which often occurs secondary to an infectious source at a location distal to the lymphatic channel, in this case correlating with the location of the patient’s burns.
Fever, nuchal rigidity, CSF showing gram neg diplococci, history of prior episodes.
Most likely immune deficiency?
What is pathophys?
Diagnostic test?
**Deficiency of the terminal complement proteins (C5-C9) ** prevents the formation of the MAC, so the transmembrane pore that interferes with the integrity of the cellular membrane leading to cell lysis cannot be formed.
C3 convertase complex subsequently leads to activation of C5, with formation of C5a and C5b, the latter of which complexes with C6, C7, C8, and C9 to form the MAC.
Deficiency predisposes to recurrent infections with Neisseria species.
Screening for terminal complement deficiency usually starts with determination of the CH50, a diagnostic test that measures the ability of the patient’s serum to lyse sheep erythrocytes coated with antibodies directed against erythrocyte membrane proteins. Because this test measures the activity of factors C1–C9, a deficiency at any point will lead to an abnormal result, although in patients with terminal complement deficiency, the CH50 concentration will be very decreased or even zero. In addition to treating infections, further treatment should include vaccination against N. meningitidis, H. influenzae, and S. pneumoniae.
A previously healthy 45-year-old male presenting w/ 3.5-month history of progressively worsening
fatigue and 13-kg (28-lb) weight loss. Vitals wnl. Spleen palpated 8 cm below the left costal margin. Examination shows no other abnormalities.
hematocrit is 40%,
leukocyte count 36,000/mm
platelet count is 70,000/mm
Bone marrow aspirate and biopsy show 100% cellularity with an
increase in all hematopoietic cell lines. The presence of which of the following is most likely to confirm the diagnosis?
A. P-glycoprotein
B. BRCA1 oncogene
C. BCR/ABL fusion protein
D. p53 Suppressor gene E. t (8,16) Translocation
C. BCR/ABL fusion protein (philadelphia chromosome)
Diagnosis: CML
CML is diagnosed by the presence of the Ph chromosome, a translocation between chromosomes 9 and 22, which causes constitutive activation of the ABL kinase —> JAK/STAT & Ras/MAPK/ERK activation—-? increased hematopoietic proliferation, inhibition of normal checkpoint inhibition, and resistance to apoptosis.
Typical laboratory findings in CML include leukocytosis with an increase in nearly all cell lines. Basophilia and eosinophilia are characteristic.
Treatment of CML is primarily with tyrosine kinase inhibitors such as imatinib or dasatinib
Pathophys of anemia of chronic disease
How do you distinguish from IDA?
Inflammatory cytokines lead to increased retention of iron within the reticuloendothelial system and impaired iron exportation for use in erythropoiesis with consequent anemia.
ACD is distinguished from IDA w/ history clues (patients with rheumatologic diseases, renal disease, and those with chronic or frequent infections) and the following labs:
-normal/mild inc ferritin
-decreased serum iron
-decreased TIBC
Treatment must focus on treating the underlying disease to decrease inflammation.
MLD: patient presenting w/ pruritus after hot showers, episodic severe burning pain w/ red-blue discoloration in extremity vessels, & hyperviscosity syndrome (blurry vision, CNS symptoms related to vascular congestion ie headache)
Lab findings: increased production of RBC, WBC, and platelets
Tx?
Polycythemia vera
chronic myeloproliferative disorder resulting in disordered, increased production of red blood cells, white blood cells, and platelets 2/2 JAK2 mutation.
Pruritus after shower–> inc mast cell production
discoloration and pain in extremities–> blood clot formation (erythromelalgia)
Increased RBCs and hct–> hyperviscosity syndrome–> CNS issues–> treat w/ phlebotomy
MLD: mucocutaneous bleeding and low platelet count with increased megakaryocytes concentration on bone marrow biopsy
NBS:
idiopathic thrombocytopenia (ITP). This is thought to be mediated by antibodies to platelets.
An initial first step for treatment is steroid therapy. Splenectomy indicated in severe cases failing medical treatment
Timeline, pathophys, and lab findings for delayed hemolytic transfusion reaction
Delayed hemolytic transfusion reactions typically occur within 1 to 2 weeks following erythrocyte transfusion and are usually the result of pre-formed antibodies against minor erythrocyte antigens. Diagnosis is suggested by the presence of a positive Coombs test, indirect hyperbilirubinemia, and anemia.
single most important modifiable risk factor for cerebral infarction
Hypertension
Uncontrolled hypertension is associated with an approximately two-fold increase in the risk for ischemic stroke. This risk is incompletely eliminated even when hypertension is well-controlled.
