Surgery Questions for Medical Students
Q21. Relative contraindication of MRI is (Question directly from Bailey)
a) Aneurysm clips in head
b) Cochlear implant due to deafness
c) Metallic Ocular foreign body in eye
d) Early pregnancy at 18 weeks
Absolute contraindications of MRI Are:
2. Cochlear implants
3. Metallic ocular foreign body
4. Aneurysm clips
- 1st trimester pregnancy
Ref: Bailey page 135
Q22. True statement about keloid? (Again copied from Bailey an love)
a) More common in females
b) Does not extend beyond margin of scar
c) Histologically there are small number of fibroblasts with increased vascularity
d) Surgical treatment gives the best results
Keloids extend beyond the incision or scar (differentiating point from hypertrophic scar)
Male and female have equal incidence. Africans are more prone for keloids.
They have increased levels of collagen and hyaluronic acid
Surgery alone has a high risk of recurrence. Surgery with intralesional steroid therapy and radiotherapy has less chances of recurrence. Intralesional excision has also shown good results.
Ref: Bailey page 598
Q23) True about HLA molecules (from Text book of surgery)
a) HLA II is expressed in all nucleated cells
b) HLA A, B, DR are most important subtype
c) HLA 1 is present in macrophages/APC
d) HLA matching is compulsary in liver transplant
HLA molecules are encoded by Major Histocompatibility complex (MHC)
HLA class I genes have HLA A, HLA B and HLA C
HLA class II genes have HLA DR, DP and DQ
HLA cross matching is usually done for kidney transplant between the donor and recipient to match as many HLA antigens as possible. Normally one individual can have between 6-12 antigens.
In organ transplant HLA A, B and DR are the most important antigens to match between donor and recipient.
This HLA cross match is not required in liver transplant because graft vs host disease is not common in it.
HLA I molecules are seen on all nucleate cells and HLA II on antigen presenting cells such as T cells, dendritic cells , macrophages etc.
Q24) Post exposure (needle stick injury) prophylaxis for HIV is
a) Effective only when taken within 24 hours
b) ART (Anti retroviral therapy) to be taken for 28 days
c) ART for 14 days
d) Solid needle injuries carries the greatest rick of HIV transmission
After HIV exposure, HAART can start within 72 hours but sooner the start, better it is
ART is to be taken for 28 days and not 14 days
Hollow needle injury carries more risk than solid needle injury.
Q25) Renal stone is seen with which Anti retro viral group of drugs?
a) Protease inhibitors (PI)
b) Non nucleoside Reverse transcriptase inhibitors (NNRTIS)
c) Nucleoside reverse transcriptase inhibitors (NRTI)
d) Entry Inhibitors
Indinavir and Other protease inhibitors cause renal solute precipitation and stone formation.
Mechanism is intra tubular crystal formation which leads to renal lithasis.