General Surgery Flashcards
1: What is an abscess?
An abscess is a collection of pus (dead/dying neutrophils plus proteinacious material) walled off by a zone of acute inflammation.
1a) What can cause an abscess?
Acute abscess formation particularly occurs in response to pyogenic organisms that attract neutrophils but are resistant to phagocytosis and lysosomal destruction.
Main pyogenic organisms of surgical relevance are staph aureus, strep pyogenes, e.coli, coliforms and bacteroides.
Abscesses can also form in response to localised tissue necrosis and organic foreign bodies like wood splints and linen sutures.
1b) What are the symptoms and signs of an abscess?
localised inflammation- redness, heat, swelling and pain.
swinging fever- usually due to bacteraemia
fluctuant mass
lyphadenopathy
1c) If investigations show leukocytosis with more than 80% neutrophils what does this indicate?
pyogenic cause
1d) How do you treat an abscess?
Incision and drainage. If it is superficial a scalpel is used, if it is deep then US or CT guided percutaneous aspiration is conducted.
The abscess will be left open but covered with a wound dressing, so if any more pus is produced it can drain away easily. If the abscess is deep, an antiseptic dressing (gauze wick) may be placed inside the wound to keep it open and let it heal via secondary intention.
Surgery may be required if an internal abscess is too large and can’t be safely accessed.
Antibiotics is not indicated if abscess is fully formed.
If the abscess perforates then treat with IV vancomycin.
- What is cancer staging?
Cancer staging is the process of determining the anatomical location, size and extent of spread of the tumor or its malignant process.
The purpose is to:
- provide a description of the anatomic extent of a cancer that can be communicated to others
- assist in treatment decisions
- serve as an indicator of prognosis
Most widely used staging system is TNM. T= depth of tumor invasion (1-4) N= extent of nodal involvement (0-3) M= presence of metastatic disease (0-1) Once the TNM value is determined an overall stage is assigned.
Specific staging exists for some cancers e.g. Duke stage for colorectal cancer.
2a) What is the difference between grading and staging?
Grading is the pathological assessment of a tumor to estimate the level of malignancy based on cytological differentiation and the mitotic activity of the tumor.
It is an indicator of how quickly a tumor is likely to grow and spread. Whereas, staging refers to the actual size and spread of a tumor.
- What modalities are used to stage cancer?
A range of investigations are used. This includes clinical exam, imaging. biochemistry and histopathology.
History and exam can be used to assess signs and symptoms of cancer and its progression. This includes the constitution symptoms like weight loss, fever, malaise, night sweats.
Furthermore, Hx and Ex can reveal evidence of organ dysfn- e.g. jaundice, SOB, changes in bowel, presence of mass.
Structural imaging can help detect the presence of tumors and extent of spread. This can include Xray (bone,lung), CT (tumor vasculature), US (breat,pelvic), MRI.
Functional imaging can detect the presence of metastatic disease in bone and soft tissue. E.g. PET Scan- only useful in metabolically active cancers.
Biochemical Ix such as tumor markers and physiological changes e.g. LFT change in liver cancer.
Histopathology allows for grading to assess the level of cellular differentiation. This includes biopsy and endoscopy.
- What is the purpose of “staging” a patient’s cancer?
Staging can guide management. It can help determine appropriate treatment option and approach. It can assist in identifying surgical candidate, whether there is a need for adjuvant therapy or palliative therapy is better recommended for the patient. Furthermore, it can prevent unnecessary treatment that would provide little benefit to the patient and their family. E.g. Stage IV is inoperable.
Staging can provide prognostic information via comparison to historical data to provide a 5 year relative survival rate.
Staging is used to better describe a cancer when communicating within a multidisciplinary team.
And finally, staging assists in cancer research as it proivdes information on the pattern of the cancer and can help determine eligibility for clinical trials.
- What is a neoplase? Give examples of benign and malignant neoplasms.
Neoplasia is any new and abnormal growth of tissue.
It is a result of unchecked cell proliferation due to a combination of genetic susceptibility and environmental exposures, that results in overactive growth pathways and underactive growth suppression pathways.
The division of neoplasms as benign or malignant is based on a judgement of histological pattern and the tumors clinical behavior.
Benign neoplasia are usually slow growing, well demarcated and encapsulated. They are histologically similar to the tissue of origin and remains localised at site of origin. Examples include fibroma (fibrous tissue), lipoma, adenoma (glandular tissue).
Malignant neoplasms are fast growing, poorly differentiated with an irregular outline and non-encapsulated. Histologically they range from well differentiated to anaplastic. They can present with pleomorphic nuclei and some tumors may have stromal hyperplasia. They are locally invasive and can metastasise.
Examples include; carcinomas (tumor of epithelial tissue), sarcoma (mesenchymal tissue), melanoma (melanocytes) and teratoma (cells from more than one germ layer).
- What is a fistula? Give some examples.
A fistula is an abnormal communication between 2 epithelial surfaces, such as two hollow organs or between a hollow organ and the exterior. The formation of a fistula generally requires inflammation and pressure.
Examples include:
- anal fistula- may be due to abscess rupture
- rectovaginal- due to trauma of childbirth of pelvic cancer treatment
- colovesical- between colon and bladder due to diverticulitis or chrons
- gastrocolic fistula- stomach and colon
6a) what are some causes of fistulas?
- inflammation
- infection
- congenital
- iatrogenic- surgery/ radiation
- neoplastic
- trauma
6b) what are some causes of a non-healing fistula?
F- foreign body R- radiation I- inflammation/infection E- epithelialisation N- neoplasia D- distal obstruction
How do you treat a fistula?
- treat any sepsis, fluid imbalance and poor nutrition
- analgesia
- relevant Abx
- good drainage to prevent fistula extension (seton stitch- material looped through the fistula which keeps it open and allows pus to drain out)
- biopsy fistula if indicated
Definitive treatment requires:
- excision of organ of origin or closure of site of origin
- removal of chronic fistula track and surrounding inflammaed tissue
- closure of organ if internal
- drainage of external site if skin
- What is a stoma?
A stoma is an artifical opening of an internal tube that has been brought to the surface.
They can be temporary or permanent.
Permanent stomas are necessary when there is no distal bowel segment remaining.
Temporary stomas are necessary for:
- emergency procedures (e.g. complete bowel obstruction that is about to perforate)
- defunctioning (e.g. to protect a distal anastamosis that is at risk of leakage or breakdown)
- bowel rest (e.g. to allow a distal segment of bowel/perineum to rest from inflammatory process).
7a) What are some types of stomas?
- loop stoma- both proximal and distal segments of bowel drain to skin surface. Mainly used for temporary defunctioning.
- split or ‘spectacle’ stoma- defunctioning stoma but has been superceeded by loop stoma. Proximal and distal ends are brought to surface separately.
- end stoma- permanent stoma with the resite of the anus to the abdominal wall.
- Hartmann’s procedure- when primary anastomosis is inadvisable due to obstruction, inflammation, fecal contamination or surgical inexperience. Proximal end is end colostomy and distal end is stapled/sutured and rejoined later.
- What are the potential complications of a surgery?
- complications due to predisposing medical conditions
- anaesthetic complications
- general complications of operating- haemorrage, wound infection, unavoidable tissue damage, inadvertant tissue damage during surgery, impaired wound healing and dehiscence, incisional hernia.
- complications of any surgical conditions- resp complications e.g. pneumonia, atelectasis, ARDS.
Venous thromboembolism- DVT/PE,
renal impairment, ABx complications, pressure sores, fluid or electrolyte disturbances. - complications can also be specific to a particular disorder or surgery.
- What are the risk factors for a superficial wound infection?
A superficial wound infection is one that occurs in 30 days of the surgery and involves only the skin and subcutaneous tissue ad at least one of:
- purulent discharge from surgical site
- purulent discharge from wound or drain placed in wound
- an organism isolated from aseptically obtained wound culture
- at least one sign of infection (redness, heat, pain ,swelling).
Risk factors can be classified into those relating to patients preoperative morbiditiy, intraoperative factors and post operative factors.
Preoperative include age, immunosuppression status, malnutrition, smoking, obesity, PVD
Intra-Op- contamination, poor aseptic technique, open procedures, duration of procedure, ABx prophylaxis adequacy, insertion of devices and blood transfusions.
Post Op- dressing and cleaning of wound, prolonged hospitalisation, glycemic control.
- How do you treat a superficial wound infection?
Inital step- perform primary survey to assess evidence for sepsis or heamodynamic compromise. If so refer to sepsis pathway.
If not, swab wound for microscopy,culture,screen and send bloods for FBC and culture before any ABx therapy.
Then open wound, irrigate and drain pus with 0.9%NaCl, apply a clean dressing and avoid topical ABx.
Relevant ABx can be provided if evidence of systemic involvement such as spreading cellulitis or sepsis.
- What are the principles of antibiotic prophylaxis for surgical patients?
The aim of appropriate antibiotic prophylaxis is to reduce post-operative infections without increasing antimicrobrial resistance.
It is based on three principles: indications, antibiotic selection and timeframe of administration.
Antibiotic prophylaxis should only be used if there is a significant risk of infection or if the post operative infection would have serious consequences.
Indications include:
- insertion of prosthesis or an artifical device like in hip replacements or heart valve replacement.
- clean-contaminated surgery site procedure (when an operative procedure enters into a colonized viscus or cavity of the body, but under elective and controlled circumstances) such as an appendiectomy or cholecystectomy.
- contaminated procedure such as a large bowel resection.
Antibiotic selection should be directed against most likely pathogen and should have a narrower range. The selection may need to be modified according to the patients risk factors (such as pre-exisitng infections, recent antimicrobial use, known colonisatin with multi-drug resistant organisms, prolonged hospitalisation or presence of prosthesis.)
The optimal time for preoperative IV antibiotic administration is within 60minutes before surgical incision. Vancomycin is an exception and needs to be given earlier as it can take an hour to infuse.
A repeat intraoperative dose is only required if the procedure is prolonged and the drug has a short half life.
Postoperative doses of IV ABx are only required in defined circumstances such as some cardiac and vascular surgeries and lower limb amputation.
Prophylaxis should not extend beyond 24 hours regardless of the procedure as extended prophylaxis is associated with an increased risk of adverse effects.
*First line is cephazolin 2g IV
- Why do surgical wounds fail?
Wound healing is achieved through four precisely and highly programmed phases: hemostasis, inflammation, proliferation, and remodeling. For a wound to heal successfully, all four phases must occur in the proper sequence and time frame. Many factors can interfere with one or more phases of this process, thus causing improper or impaired wound healing.
Surgical wound failure, or wound dehiscence, occurs when a wound fails to heal through the progressive stages of healing and possibly reopens after surgery.
Local factors that can affect wound healing include; poor oxygenation, infection, foreign body contamination, arterial or venous insufficiency, patient interference, unsuitable wound sutturing or dressing.
Systemic factors include; age, diabetes, ischemia, malnutrition, vit C or zinc deficiency, anaemia, immunosuppressive drugs or disease, lifestyle factors (like alcohol, smoking, IV drug use, neglect), autoimmune disorders like rheumatoid and collagen disorders like Marfans and cancer.
- How do you categorise abdominal pain?
I categorise abdominal pain based on anatomical location.
If it is right hypochondrium I am thinking of hepatobiliar causes like hepatitis, cholecystitis, cholangitis.
For epigastric, i’m thinking of GIT causes like gastritis, GORD, pancreatitis and cardiovascular conditions like atypical MI and AAA.
In the left hypochondrium I’d be thinking splenic complications like infarcts, abscess or rupture.
In the Right and left lumbar regions I’d be thinking of radiating spinal nerve pain, ureteric colic or pyelonephritis.
In the periumbilical region, I’d be thinking of small bowel obstruction, IBS, IBS, mesenteric ischemia and AAA.
In the right iliac fossa- appendicitis, chrons disease, caecal volvolus, ectopic pregnancy, pelvic inflammatory disease.
suprapubic- cystitis, urinary retention, gynaecological causes in females.
left iliac fossa- diverticulitis, sigmoid volvolus, colorectal cancer, impaction.
- Where is the appendix found?
The appendix is a vestigial structure located in the RIF, more specifically at McBurnys point which is 1/3 the distance from ASIS to the umbilicus.
Internally, it arises from the posteromedial aspect of the caecum and is approximately 2.5 cm below the ileocecal valve and the Tineae coli converge at base of appendix .
The base of the appendix is attached to the caecum but the tip is free to migrate allowing for variation in people- retrocecal, subcecal,other.
- When should you commence antibiotics in a patient who has symptoms and signs of appendicitis?
Surgical drainage and appendicectomy are the mainstays of treatment for appendicitis and antibiotic therapy remains only a bridge to surgery.
Therefore, antibiotics should be given only when the decision to operate has been made.
Empirical IV antibiotic is triple therapy which is the same as peritonitis due to perforated viscus. This includes Gentamicin, Amoxycillin and Metronidazole.
If it is uncomplicated appendicitis in surgery, then the antibiotics should be discontinued after the operation.
If the appendicitis is complicated by perforation or an abscess, then a total treatment duration of 7 days (IV + oral) is recommended.
Once susceptibility results are obtained, antibiotics should be modified appropriately.
- What are the important differential diagnoses to consider when managing a 17 year old woman who has the symptoms and signs of appendicitis?
The differential diagnoses to consider when managing this patient can be categorised into gyneacological and non gynaecological causes.
Gynaecological causes could include: - pelvic inflammatory disease which is usually bilateral but may mimic appendicitis if confined to right fallopian tube - Mittleschmerz from right ovary - ovarian torsion which presents with fever and leucocytosis and RLQ pain - endometriosis - STI - salphingitis AND ruptured ectopic pregnancy
Non gynaecological causes can include urological causes such as UTI, cystitis, pyelonephritis, renal colic and GIT causes such as gastroenteritis, new onset chrons disease.
- You (the candidate) are an Emergency Department resident.
How would you proceed to manage a 22 year-old female patient who presents to you with a 24 hour history of right iliac fossa pain?
If the patient is stable I would take a history to assess the pain and associated symptoms, past medical history including medications and a focussed gynaecological history with appropriate questions about the patient’s menstrual cycle, sexual history and pregnancy.
On examination I’d assess the patient’s vitals, conduct a focussed abdominal exam looking for any signs of peritonism and other abnormalities and a pelvic examination to look for any vaginal bleeding, adnexal tenderness or masses and cervical motion tenderness on bimanual palpation.
To investigate further I’d order a FBC (leukocytosis), CRP, UEC, LFTs, Lipase (exclude pancreatitis), VBG (assess for sepsis), lipase, beta HCG and Group and Save if proceeding to surgery.
I’d also consider a urine dipstick and urine MCS and stool culture if necessary.
I’d consider a chest/abdo Xray if obstruction is suspected,
Abdo Ultrasound for a dilated appendix or pelvic US for ectopics and other gynaecological suspicions
AND CT abdoment if the pt is not pregnant and if it is indicated.
In terms of management, IV access would be important for fluids, analgesia, nil by mouth, IV antibiotics if appendicitis is diagnosed and an appropriate surgical, gynaecological or gastro consult as indicated.
- What is the indication for imaging in suspected appendicitis?
Acute appendicitis is a clinical diagnosis, almost entirely made off history and examination. Imaging should only be used to exclude differential diagnoses and/ or confirm the diagnosis in atypical presentations.
The Alvorado Score (MANTRELS) can be used to help guide clinical decisions.
Plain Xray films are not indicated unless there is a concern for other pathologies such as an intestinal obstruction, renal calculi or perforated viscus.
USS is indicated if there is a suspicion of gynaecological causes or if investigating an atypical presentation especially in pregnant women and young people where exposure to ionising radiation is to be avoided.
CT is indicated if there is an atypical presentation of appendicitis in a pt, especially in the elderly and obese, that needs to be confirmed OR in determining alternative diagnoses.
- Why does the pain and discomfort of appendicitis classically ‘migrate’ from generalised abdominal pain to become localised in the RIF?
The mechanoreceptor and chemoreceptors located within the visceral peritoneum detect distention and inflammation due to appendicitis and this stimulus is carried along Type C nerve fibres within the paleospinothalamic tract to the CNS to produce poorly localised, central, dull, generalised pain.
The pain presents with these features due to low nociceptor density, bilateral symmetric innervation of the visceral organs , C fibres being unmyelinated and the fact that pain is perceived at the spinal level at which the afferent fibers enter (T10-periumbilical.).
As inflammation of the appendix extends to involve the parietal peritoneum there is stimulation of somatic nociceptor and the stimulus of pain is now carried along type A fibres via the neospinothalamic tract to the CNS. As the parietal peritoneum has higher nociceptor density, unilateral innervation and involvement of myelinated type A fibres the pain is now felt localised to the RIF and felt a lot sharper.
- What are the indications for a laparoscopic approach to appendicectomy?
Indications for a laparascopic approach to appendicectomy include:
- uncomplicated appendicitis
- uncertain diagnosis as it provides more visualisation
- obese patients as open requires larger incision
- elderly patients, children and patients with comorobities as it is less invasive and there is a faster recovery with a lower incidence of surgical site infection
Contraindications include:
- haemodynamic instability
- lack of surgical expertise
- generalised peritonitis
- pregnancy
- Severe abdominal distention that causes operative view obstruction or complicates abdominal entry and bowel manipulation
- if there is known extensive adhesions due to multiple surgeries.
