Sunday, January 13, 2008

8 - surgery mcqs - 41 to 50

41. Ultrasound is the preferred method of investigation of

(a) A breast lump in a women less than 35 years old
(b) Right upper quadrant abdominal pain in a women aged 45 years
(c) Possible bone metastases in man age 70 years old
(d) A possible subphrenic abscess in a postoperative patient
(e) The detection of a deep venous thrombosis in any patient with a painful swollen leg


a , b , d , e are right . Ultrasound is useful in the investigation of breast, abdominal, urological and vascular disease. It take advantage of differences in echogenicity between adjacent structures. It is the preferred method of imaging the breast in young women allowing easy differentiation between solid lesions and cysts. In the investigation of abdominal pain gallstones can usually be easily identified. Ultrasound is useful for guiding interventional procedures such as percutaneous biopsy or aspiration of intrabadominal collection. Duplex ultrasound is gradually replacing venography as the initial radiological investigation of suspected deep venous thrombosis.


42. The following may be seen in iron deficiency anaemia

(a) A reduced mean cell volume
(b) An increased mean cell haemoglobin concentration
(c) A reduced serum ferritin concentration
(d) A reduced serum iron concentration
(e) A reduced total iron-binding capacity


a , c , d are right . Iron deficiency produces a hypochromic microcytic anemia which can be confirmed with a blood film. Other finding can include a reduced mean cell volume (MCV), a reduced mean cell haemoglobin (MCH) and a reduced mean cell haemoglobin concentration (MCHC). Serum ferritin and iron concentrations are reduced. Total iron-binding capacity is increased. Other causes of a microcytic anaemia include anamia of chronic disease, thalassaemia trait and sideroblastic anaemia.


43. Methods used in the sterilisation of surgical equipment include

(a) Ethylene oxide
(b) Gamma irradiation
(c) Autoclave
(d) 2% Gluteraldehyde
(e) Chlorhexidine


a , b , c are right . Sterilisation involves the erradication of all microbiological organisms including spores and viruses. Disinfection is the reduction in number (not to zero) of viable organisms. During disinfection viruses and bacterial spores may not be erradicated. Surgical instruments, sutures, dressings etc are sterilised. Other medical instruments such as endoscopes are usually only disinfected. Sterilisation can be achieved using hot air, steam under pressure (autoclave), ethylene oxide and gamma irradiation. The method used depends on the physical properties of the object needing sterilisation.


44. Spinal anaesthesia

(a) Has a more rapid onset than epidural anaesthesia
(b) Hypotension is a significant risk
(c) Is safe in anticoagulant patients
(d) Does not produce a block of the lower limb motor supply
(e) Has a higher risk of postoperative headache than epidural anaesthesia


a , b , e are right . Lower limb or pelvic regional anaesthesia can be achieved by either a spinal or epidural anaesthetic. Spinal anaesthesia is technically easier and produces a rapid and effective block. Compared with epidural anaesthesia it is, however, associated with a significnt risk of hypotension and produces a dense motor blockade. In order to achieve spinal anaesthesia a dural puncture is inevitably required, occasionally producing a postoperative headache. Both spinal and epidural anaesthesia are contraindicated in bleeding diatheses, neurological disorders and sepsis.


45. A postoperative pulmonary embolus

(a) Is invariably associated with chest pain
(b) A chest x-ray may be normal
(c) Diagnosis can be confirmed by a radioisotope ventilation / perfusion scan
(d) ECG may show an S wave in Lead I, A Q wave in Lead III and a T wave in Lead III
(e) If most commonly seen between 7 and 10 days after operation


b, c , d , e are right . A postoperative pulmonary embolus occurs most commonly between 7 and 10 days postoperatively and may occur in the absence of clinical features of a deep venous thrombosis. Risk factors include immobility, malignancy and prolonged surgery. Patients undergoing particular operations (e.g. hip surgery) are at particular risk. The classical clinical presentation is with breathlessness, pleuritic chest pain, tachycardia and hypotension. A chest x-ray may be normal. The diagnosis can be confirmed by a V/Q can or spiral CT scanning.


46. Regarding postoperative nutritional support

(a) Early enteral feeding is able to maintain the gut mucosal barrier
(b) Enteral feeding should never be considered in the early postoperative period following trauma or gastrointestinal surgery
(c) Parenteral nutrition should always be given through a central line
(d) An enterocutaneous fistula may be an indication for parenteral nutrition
(e) Jaundice is a recognised complication of parenteral nutrition


a , d , e are right . Surgery and trauma result in a significant catabolic state. In patients undergoing major surgery or in those who develop complications, nutritional support is essential. As a general rule if the gastrointestinal tract is available and functioning then enteral nutrition is preferred. Early enteral nutrition maintains the gastrointsetinal mucosal barrier and has fewer complications than parenteral nutrition. There are few absolute indication for parenteral nutrition but an enterocutaneous fistula is one. Parenteral nutrition is often associated with metabolic derangements including hyperglycaemia, hyperkalaemia and abnormal liver function tests.


47. The following metabolic responses occur in response to trauma

(a) Increased growth hormone
(b) Increased anti-diuretic hormone
(c) Increased ACTH
(d) Increased urine osmolality
(e) Increased glucagon


all are right . The metabolic response to trauma is mediated by both endocrine and paracrine factors. In the neurohumoral response the pituitary-adrenal axis and the sympathetic nervous system are important. Local released cytokines (e.g. tumour necrosis factot-alpha, interleukins) are important in modulating the response. Increased growth hormone and glucagon contribute to the hyperglycaemia seen following surgery and trauma. Hypovolaemia results in increased ADH production and an increase in urine osmolality.


48. In the management of major trauma

(a) The peripheral circulation should be evaluated before the airway is assessed
(b) The airway should always be assessed with the cervical spine
(c) CT scanning is a useful investigation for the assessment of unexplained shock
(d) A jaw thrust to maintain the airway is contraindicated in the presence of a suspected cervical spine injury
(e) Venous access should usually be by two large cannulas in the antecubital fossae


b, d are right . The management of major trauma should be by ATLS principles. The first priority is to secure the airway always with consideration for the management of potential cervical spine injuries. A jaw thrust is safe in the presence of suspected cervical spine injury as it avoids hyperextension of the spine. In the absence of upper limb fractures, venous access can best be achieved by two large cannulas in the antecubital fossae. CT is not a useful investigation for the cardiovasculary unstable or shocked patient. These patients usually require an emergency laparotomy.


49. Regarding compartment syndromes

(a) They can occur only in the lower limb
(b) Are usually characterised by pain that is worse on passive movement
(c) Can be diagnosed by the loss of distal peripheral pulses
(d) Compartment pressure monitoring may be a useful diagnostic aid
(e) Require fasciotomies to be performed on the next available elective operating list


b , d are right . Compartment syndromes are characterised by a rise in intracompartmental pressure as a result of trauma or tissue ischaemia. They can occur in both the upper and lower limbs. The charcteristic clinical feature is severe pain that is made worse on passive movement. Examination will show limb swelling and tenderness over the involved compartment. Loss of peripheral pulses is a late feature and therefore the presence of peripheral pulses does not exclude the diagnosis. The diagnosis can often be made on clinical grounds but if there is doubt compartment pressure monitoring may be useful. If diagnosis is suspected then emergency fasciotomies are required.


50. Regarding malignant melanoma

(a) Lentigo maligna melanoma is a superficial lesion with a good prognosis
(b) Acral lentiginous melanomas most commonly occur on the dorsum of then hand
(c) The Breslow thickness is a good prognostic factor
(d) Sentinel lymph node biopsy is a useful means of assessing lymph node status
(e) Isolated limb perfusion with cytotoxic agents palliates recurrent limb disease


except b all are right . The prognosis of melanomas is related to depth of tumour invasion measured by either the Breslow thickness or the Clark Level of invasion. Lesions with a prolonged radial growth phase and a late vertical growth phase (e.g. lentigo maligna) have the best prognsosis. Acral lentiginous and nodular melanomas have an early vertical grwoth phase and have a poor prognosis. Acral lentiginous melanomas usually occur on the soles of the feet. Melanomas spread to the regional lymph nodes and sentinel node biopsy is of proven value in assessing the nodal status of these patients. Isolated limb perfusion is valuable in palliating recurrent limb disease.


No comments:

Subscribe Now: Feed

You are visitor number

Visitors currently online