Investigation of Surgical patients

M K ALAM MS; FRCS Edited by Dr Shaher Abbarah

ILOs

• Aims- Why investigate?
• Spectrum of investigations.
• Justify (indication) use of relevant investigations
• Complications.

Management of a clinical problem

Clinical presentation

• History
• Clinical examination
• Provisional/ working diagnosis/ DD
• Investigations
• Final diagnosis
• Treatment

What is Triple Assessment ?

Aims of investigation

• Support clinical suspicion
• Refute clinical suspicion
• Assess physiological impairment- risk to surgical treatment
• Detect asymptomatic disorders
• Screen - carcinoma breast, carcinoma colon etc.

“Always keep in consideration- risk & cost”

Hematological investigations

• FBC or CBC: low Hb (anemia), MCV, MCHC (normocytic, microcytic), leukocytosis (infection)

• Platelet count: Thrombocytopenia ( drug- heparin, ITP, autoimmune), Thrombocytosis ( post-splenectomy)

• Coagulation profile: PT, INR, APTT Disordered in: chronic liver disease, jaundice, bleeding, medications

  • PT assess the Extrinsic & common pathway
  • PTT assess the Intrinsic & common pathway

CBC: complete blood count , FBC: Full blood count Warfarin follow up by INR Heparin follow up by PTT

Biochemical Investigations

• Na: 135-146 mmol/L- ↓ -water overload, SIADH ↑- fasting, vomiting, burn, Conn’s syndrome
• K: 3.5- 5.5 mmol/L- changes- vulnerable to arrhythmias ↑ met. acido, blood trans, crush injury, ↓ vom/diarrh, ileus, met alkalo, diuretics
• Urea: 2.6- 6.7 mmol/L- dehydration, renal insufficiency
• Creatinine: 60-120 mmol/L- marker of renal disease
• Glucose: 3.9-5.6 mmol/L- diabetes
• Total protein: 62-80 G/L
• Albumin: 35-50G/L- nutritional assessmentZ

Low Albumin indicate post op morbidity and increase in complication Pre-albumin is acute indicator of nutritional status

• Bilirubin <17 mmol/L- direct/ indirect type (jaundice)

• ALP: 25-120 U/L- liver, bone, placenta & intestine Indicator of bile ducts obstruction, primary biliary cirrhosis, sclerosing cholangitis

• AST: 10-40 U/L- liver, cardiac muscle, skeletal muscles, kidneys, brain, pancreas

• ALT: 5-30U/L- liver, skeletal muscle,

• GGT - (M-10-55, F 5-35 u/L) - ↑- bile duct injury

What are liver function test? ALT: more specific of Liver injury GGT: Gamma-Glutamyl Transferase, ALP: Alkaline phosphatase AST: Aspartate Aminotransferase (SGOT) ALT: Alanine Transaminase (SGPT)

• LDH: 49-195U/L- found in most body tissues, ↑- liver disease, heart attack, anemia, muscle trauma, bone fractures, cancers, meningitis, encephalitis, HIV

• Creatinine phosphokinase (CPK/ CK)- 24-195 U/L: Found in heart, skeletal muscles, brain CPK indicative of muscular damage. CK-MB - specific of myocardial muscle damage, CK-MM- specific of skeletal muscle damage

• Amylase <100 u/L mild rise- non-specific- sialadenitis, perf. PU, cholecystitis, intestinal obstruction

• Lipase: 0-160 U/L – specific for pancreatic disease

LDH: Lactate Dehydrogenase CK: Creatinine Kinase

Tumour markers

• PSA- Prostate (Screening + Followup)

• CEA- Colorectal (Followup) - (colonoscopy for screening)

• α- fetoprotein (AFP)- Hepatocellular (Follow up) + (US/AFP screening)

• β-hCG- Testicular (Non-seminoma no screening), gestational

• CA 19-9- pancreas (monitor treatment), Colorectal

• CA 125 - Ovarian (screening + Follow up)

• CA 15-3 & CA 27.29- Breast (not very helpful, monitor treatment) (No screen/follow)

CEA: carcinoembryonic antigen CA: Cancer Antigen

lady 25 years old - one his friends has breast cancer, she came to screen for breast - give mammogram (less than 40 dont screen)

lady 40 years is done for screening for breast cancer - orr 10 years family hx age diagnosis

mamogram used for screening not gene study

Microbiological, serology, immunological investigations

• Urine
• Sputum
• Stool
• Hepatitis screening
• Antibiotic sensitivity
• Serology- antibodies against infection
• Immunology- autoantibodies- TSI-thyroid stimulating immunoglobulin, Anti-thyroglobulin antibody, anti-TPO- thyroid peroxidase

Imaging studies

Plain x-ray- CXR, AXR, tomograms

OSPEZ Modality: plain x-ray Findings: air under diaphram / multiple air fluid levels Differentials: perforation / obstruction

Side effects of radiation:

• Induction of malignancy
• Genetic mutation

Modality: Findings: Differentials:

Modality: plain x-ray Findings: radiopaque Differentials: gallbladder

Contrast Imaging

• Gastrograffin swallow, Barium meal / enema

  • Visualize GI tract
  • Single/ double contrast
  • Inferior to endoscopy

  Modality: Gastrography swallow / Barium Enema Findings: apple core / out pouching lesions Differentials: colon cancer / diverticulum

40 yrs old man presents to ER w/ acute adominal pain - hx of gallbladder stone - which of the following

• initial test = ERECT CHEST X-RAY - to exclude perforation
• FIRST CHOICE = U/S

Imaging studies- Ultrasound

• Safe
• Low cost
• Operator dependent

Investigation of first choice: biliary dis. & gynaecology.

Imaging studies- CT scan

• Oral, IV contrast
• Used for: Abdomen, chest , brain, vascular and urinary tract.
• Side effects: Anaphylactic reaction, renal injury, radiation

What is the relation of Metformin and the IV contrast ?

Before CT

• Wear hospital gown
• Take off jewelry/metal objects
• NPO ?
• If IV contrast needed, Renal profile needed
• Consent

Imagi˚ng studies - MRI

• Good images: Soft tissue (better than CT) Blood vessel (MRI angiogram)
• No known deleterious effect
• No radiation
• Slow and expensive.
• Contraindications

Absolute: ferromagnetic implants

MRI use electromagnetic fields and radio waves rather than ionizing radiation

Ionizing radiation is radiation that contains enough energy to liberate electrons from atomic orbit, which ionizes them. , which can create damaging free radicals (x-ray)

Imaging studies – Isotope scan

• Isotope scan: More information about function than structure. I131,Tc99, I123, Ga67, Th201- incorporated into other molecule to localize target organ.
  • Detected by gamma camera.
  • Bone metastasis, renal function, foci of infection, GI bleeding, infarction of myocardium, sentinel node detection
• PET scan: Expensive. Use: Brain physiology, tumour detection , cardiac physiology

Technetium-99 Tagged RBC scan can detect bleeding rate of 0.1 ml/hr

PET: positron emission tomography

Endoscopy

• Precise diagnosis: GI, pancreatic, biliary, bronchus, urinary tract
• Cytology/ biopsy.
• Minimally invasive therapy: laparoscopy, arthroscopy, ERCP.
• Disadvantages: Unpleasant, uncomfortable (sedation/ anesthesia)
• Complications: Infection, perforation, aspiration, bleeding, cardiac arrhythmias, respiratory arrest

ERCP: Endoscopic retrograde cholangiopancreatography

Tissue sampling

• Body fluids- pleura, peritoneum, sputum , urine.
• Smears, brush cytology
• FNACZ (Shows abnormality only without margin)
• Core biopsyZ (basement membrane differentiation)
• Open biopsy (incision/ excision)
• Frozen section biopsy: Biopsy material frozen in liquid nitrogen, sliced, stained & reported in minutes

Z Fine Needle Aspiration: A thin, hollow needle is used to collect a sample of cells from a mass or lesion for analysis. (Less invasive procedure). Commonly used in thyroid nodule

Core Needle Biopsy: A hollow needle is used to collect a sample of tissue for evaluation of its histopathological features. Commonly used to assess suspicious breast lesion

Open Biopsy: Incisional or Excisional

Function tests

• Cardiac evaluation: ECG, Thallium scan, Echocardiography
• Respiratory function: ABG (risk pCO2 > 45 mmHg) FVC & FEV1 ( risk- < 70% of predicted)
• Renal function: Lab, Scintigraphic renography- DMSA, MAG3, DTPA
• Endocrine function- lab, isotope scan DMSA: Dimercaptosuccinic acid scintigraphy DTPA: Diethylene-triamine-penta-acetic acid MAG: Mercaptoacetyle triglycine

Screening

• Screening for malignant disease ((((FOB))), FIT replacing FOB, mammography, PSA, endoscopy)
• Screening for surgical disease (one-t aneurysm AAA - ultrasonography in men ages 65 to 75 years who have ever smoked.

FOBT: Fecal Occult Blood Test False positive in? “Ever smoker”: who smoke 100 cigarettes during his/her lifetime

FIT: Fecal Immunohistochemical test

Colonoscopy for colon cancer starting age at recommended at general 45 on recent suggestion - 40 family hx or 10 years earlier Mammogram for breast cancer starting age at 40