Block 43 Flashcards
Tetralogy of fallot embryological defect
Deviation of the infundibular septum
What is the most useful measure for assessing the degree of mitral stenosis
A2 to opening snap(high frequency) interval
What is the major protective factor against giardia
Secretory IgA production.
What is the predisposing factor for sickling in sickle cell anemia.
Sickling is promoted by conditions associated with low oxygen levels, increased acidity, or low blood (dehydration).
-organs with particularly high metabolic demands such as the (brain, muscle, placenta) promote sickling by extracting more oxygen from the blood (oxygen unloading).
Serum leukocyte alkaline phosphatase
Can be normal or increased in leukemoid reaction, but its usually low in CML.
-the peripheral smear in leukemoid reaction can show dohle bodies which are light blue (basophillic) peripheral granules in neutrophils.
DNA polymerase I in prokaryotics
- DNA polymerase I is unique as its the only prokaryotic polymerase that also has 5’ to 3’ exonuclease activity.
- the activity functions to remove the RNA primer created by RNA primase and repair damaged DNA sequences.
- DNA polymerase III has 5’ to 3’ polymerase and 3’ to 5’ exonuclease activity however doesnt posses 5’ to 3’ exonuclease activity.
Side effects of inhaled corticosteroids
Poor inhalation technique can cause much of the medication to be deposited on the oral mucous membranes, where its ineffective and can lead to oropharyngeal candidiasis.
- patients can avoid this complication by using a spacer and rinsing the mouth after inhalation.
- dysphonia unrelated to oral candidiasis can also occur due to myopathy of laryngeal muscles and mucosal irritation.
Tibial nerve injury
- injury to the nerve at the popliteal fossa can cause weakness on foot plantarflexion because the nerve innervates the gastocnimius, soleus and plantaris muscles.
- weakness may also be evident on foot inversion and toe flexion.
- consequently, patients often present with the foot held in calceneovalgus position.
- in contrast injury to the tibial nerve at the tarsal tunnel may cause sensory loss over the sole with intrinsic foot muscle weakness. However plantarflexion and inversion remain intact as fibers innervating these muscles branch off more proximally.
Hemoglobin A2 and HbA1c
- in general conditions that alter RBC survival alters the HbA1c levels. (Hemolytic anemia, thalasemia …)
- elevated Hemoglobin A2 precentage is suggestive of coexisting beta thalssemia. HbA2 becomes elevated in beta thalassemia to compensate for beta globin chain underproduction, but the resulting microcytic Red cells are prone to hemolysis . The increase in red cell turnover causes falsely low HbA1c levels.
CN III palsy
Symptoms of CN III palsy relate to the function of CN III
1. Somatic component innervates the inferior, superior and medial rectus, inferior oblique and levator palpebrae muscles.
Ptosis occur due to paralysis of the levator palpebrae and the unopposed action of the lateral rectus and superior oblique muscles leads to a down and out gaze.
2 .parasymphatetic fibers of CN III innervate the iris sphincter and cilliary muscle. Paralysis of these fibers causes a fixed, dilated pupil and loss of accommodation.
Lower extremities lymphatic drainage
In the lower extremities, the superficial lymphatic system is divided into medial and lateral tracks.
The medial tracks runs along the long saphenous vein up to the superficial inguinal lymph nodes, by passing the popliteal nodes.
-consequently lesion on the medial foot causes inguinal lymphadenopathy.
-in contrast lateral lesion which drain via lateral track and communicates with the popliteal and inguinal nodes are more likely to cause lymphadenopathy in both popliteal and inguinal areas.
Anaphylaxis changes in cardiovascular system
Anaphylaxis causes widespread venous and arteriolar dilation along with increased capillary permability and third spacing of fluids. This result in significant drop in venous return.
Tetrodotoxin symptoms
- parasethesia, weakness dizzenes and nausea.
- history of fish consumption is strongle suggestive
- tetrodotoxin binds to voltage gated sodium channels in nerve and cardiac tissue preventing sodium influx and depolarization.
- symptoms occur quickly after ingestion.
- treatment include supportive care and intestinal decontamination with gut lavage and charcoal.
Selective Differential Enrichment Reducing Medias
- Selective : eg include thayer martin selective medium which contains several antibiotics that kill potential contaminants in order to get pure culture of Neisseria
- Differential media help identify cultured organism based on their metabolic and biochemical properties such as macConkey agar and eosin methyline blue (pink on macconkey and black on eosin methyline blue)
- Entichment media contain special growth factors required for some organism. Eg include factor X and V required for H.infleunza
- Reducing media (eg, thioglycolate broth) removes oxygen and are used to culture anaerobic organisms.
Hepatic abscess
- presence of fluid filled cavity, in the liver in conjuction with fevers, chills and RUQ pain is suggestive of abscess.
- in underdevlloped countries hepatic abscess are usually caused by parasitic infections such as E.histolytica, and echinoccal infection.
- in developed areas, abscesses are uncommon and usually caused by bacterial infection in about 80% of cases.
- pyogenic bacteria can gain access to liver through following routes:
- billiary tract infection, portal vein pyemia, hepatic artery , direct invasion from adjacent source or penetrating trauma or injury.
Achondroplasia
- limb shortening with normal torso length.
- craniofacial features such as frontal bossing and midface hypoplasia
- autosomal dominant inheritence.(50% transmission chance)
- point mutation in FGFR3 gene, 90% are denovo and 10% inherited.
- achondroplasia affects endochondral ossification, the process that makes long bones and portion of the skull and face.
- FGFR3 is normally responsible for limiting chondrocyte proliferation during endochondral ossification. In achnondroplasia, FGFR3 becomes constitutively activated causing exaggerated inhibition of chondrocyte proliferation that results in the characteristic bone shortening and craniofacial abnormalities.
In the treatment of radioactive iodine therapy, which drug should be given as a pretreatment to decrease effect of radiotherapy through competitive inhibition of iodine transportation
Potassium iodide (potassium percholrate)
Head pounding accompanied by involuntary head bobbing
Its found in aortic regurgitation.
-head bobbing can be a sign of widened pulse pressure (pulse pressure = peak systolic arterial pressure - end diastolic arterial pressure)
Treatment of acute C.diphtheriae infection
- Diphtheria antitoxin (inactivates all toxin but ineffective against toxins that have gained access to cardiac or neural cells) (this is called passive immunization- preexisting antibodies)
- Penicllin or erythromycin
- DPT vaccine
Adverse effects of succinylcholine
- Malignant hyperthermia (especially with halothane) in gentically susceptible patients.
- Severe hyperkalemia in patients with burns, myopathies and denervation(quaroplegia or guillain-barre syndrome), these pathalogic states causes upregulation of muscle nAChRs and or rhabdomyolysis which can result in release of large amount of potassium. In these patients vecuronium of rocuronium are better choices.
- Bradycardia from parasympathetic stimulation or tachycardia from symphathetic effects.
MVP click
- the click results from sudden tensing of the chordae tendineae as they are pulled taut by the balloning valve leaflets . The murmur is due to malalignment of the valve margins during systole.
- primary MVP is most commonly a sporadic disorder and is charactrized by myxomatour degeneration( deterioration of the connective tissue) affecting the mitral valve leaflets and chordae tendineae.
- secondary MVP is associated with inherited connective tissue disorders including marfan, ehlers danoles and osteogenesis imperfecta.
- the myxomatous lesion are charactrized by proliferation of spongiosa of the valve leaflets, fragmentation of elastin fibers with increase mucopolysaccharide and type III collagen deposits.
Cons adenoma treament
- Surgery
2. Aldosterone antagonist
Lung biopsy shows macrophages containing a golden cytoplasmic granules that turn dark blue with prussian blue staining
- this is caused by LV dysfunction
- rise in pressure in the lung results in extravasation of RBC and alveolar hemorrhage. These RBC are eventually phagocytosed by macrophages and the iron from hemoglobin is converted to hemosiderin.
- prussian blue stain detects intracellular iron.
- thes are called HF macrophages or hemosiderin laden macrophages.
