Block 24 Flashcards
scaphoid fractures can lead to
- avascualr necrosis owing to retrograde blood supply
- its the most commonly fractured bone in wrist
- it should be suspected in any patient with persistant wrist pain and tenderness in the anatomical snuffbox.(between extensor pollicis longus and extensor pollices bravis tendons)
Patients with interstitial lung disease have increased expiratory flow rates, why?
-patients with progressive pulmonary fibrosis with thickining and stiffening of the pulmonary interstitium. This cause increased lung elastic recoil as well as airway widening due to increased pulling (radial traction) by the surrounding fibrotic tissue.
CGD
Pathogenesis : inactivation mutation affecting NADPH oxidase
- impaired respiratory burst inhibits phagocytic intracellular killing
Clinical:
- recurrent infections with catalase positive bacteria and fungi
- Lung, skin, lymph nodes and liver most commonly involved
- diffuse granuloma formation
Diagnosis:
- measurment of neutrophil superoxide production
- DHR flow cytometry (asses the production of superoxide radical by measiring the conversion of DHR to rhodamine, which is floruscent green compound that can be detected by flow cytometry, cells deficient in NADPH oxidase have decreased fluorescence)
- NBT testing.
High arginine in CSF with spastic paresis and failure to thrive
Arginase deficiency, its the enzyme involve in conversion of arginine to urea.
- unlike other urea cycle disorders patients have mild or no hyperammonemia..
- treatment consists of low protein diet.
Hawkins test
Involves abduction of the arm by 90˙ angle , while thumb is facing downward and flexion 30˙.
- then a pressure is elicited on the arm, if pain is present its positive
- positive test means there is impingement on the supraspinatus tendon, between the head of the humerous and acromion during abduction/
If a patient with active TB gets treated with isoniazid monotherapy —>
- rapid emergence of resistance will occur
- it occurs via two selective gene mutations, the first is decrease in bacterial expression of catalase peroxidase enzyme that is required for isoniazid activation once the drug enters the cell, and the other occur through modification of the protien target binding site for isoniazid.
- treatment of active TB is acomplished by combining multiple antibiotics to avoid selecting for resistant strains.
- however isoniazid monotherapy is used for patients with positive PPD but no evidence of clinical disease (latent Tb)
Protein kinase A is a pathway used by
Increased cAMP(by adenelate cyclase) —> activates protein kinase A —> phosphorylation effect. -used by glucoagon, epinephrine ,...etc
Patent foramen ovale is failure of
Septum primum and secondum to fuse
Can lead to paradoxical emboli (from DVT usually)
Measles effect on vitamins
-VITAMIN A supplementation is recommended in acute measles. Acute measles infection depletes vitamin A stores resulting in a risk of keratitis and corneal ulceration. It helps prevent and treat these ocularcomplications in addition it reduces risk of other comorbidities, recovery time and length of hospital stay.
Soft systolic ejection murmur at right intercostal space radiating to neck ?
-most likely to by aortic stenosis, usually due to bicuspid aortic valve in young asymptomatic patients.
Features of rheumatoid arthritis
Clinical:
-pain, swelling and morning stiffeness in multiple joint
-small joints (PIP,MCP,MTP) and spares DIP joints
-systemic symptoms (fever,weight loss and anemia)
-cervical spine involvment, subluxation and cord compression.
LAB:
- positive RF, and anti CCP antibodies
-CRP and ESR correlate with disease activity
- x-ray:soft tissue swelling, joint space narrowing and bony erosions.
Anticentromere antibodies are found in
CREST syndrome
Acidosis effect on kidney
- acidosis stimulates renal ammoniagenesis, a process by which renal epethelium metabolize glutamine, generating ammonium and bicarbonate.
- ammonium ion are transported into the tubular fluid and excerted in the urine while peritubular capillaries absorb bicarbonate which functions to buffer acids in the blood.
- under normal physiologic conditions, about half of the total amount of acid secreted in the urine is in the form of ammonium and the remainder is excerted primarily as titratable acids, particulary inorganic phosphate, however increased ammonium production is almost entierly responsible for the increase in renal acid excertion seen in chronic acidosis.
Pleotropy
The occurance of multiple ssmingly unrelated phenotypic manifestation often in different organ system as a result of single genetic defect.
Direct effect of å-adrenergic agonist
å1 = -vascular smooth muscle contraction -mydriasis -increase urethral sphincter tone and prostate contraction å2= -CNS mediated decrease in BP - decrease intraocular pressure -decrease lipolysis -decrease presynaptic NE release - increase platelet aggregation.
