60-64 IleusandBowelObstruction. Flashcards
What are the types of bowel Obstruction (6)
Mechanical obstruction
Functional obstruction.
Simple obstruction
Strangulation obstruction
Open-loop obstruction
Closed-loop obstructions
Mechanical obstruction definition
Mechanical obstruction.
means that luminal contents cannot pass through the gut tube because the lumen is blocked.
definition of
Functional obstruction.
There are neurogenic or functional obstructions in which luminal contents are prevented from passing because of disturbances in gut motility that prevent coordinated peristalsis from one region of the gut to the next.
simple obstruction definition
the intestinal lumen is partially or completely occluded without compromise of intestinal blood flow.
may be complete, meaning that the lumen is totally occluded
or
incomplete, lumen is narrowed but permitting distal passage of some fluid and air.
Strangulation obstruction.
- def
- ceonsequences
complete/ incomplete obstruction
In strangulation obstruction, blood flow to the obstructed segment is compromised and tissue necrosis and gangrene are imminent.
Strangulation usually implies that the obstruction is complete.
Open-loop obstruction. def
open-loop obstruction occurs when intestinal flow is blocked but proximal decompression is possible through vomiting.
Closed-loop obstructions
- def
- is decompression possible
closed-loop obstruction occurs when inflow to the loop of bowel and outflow from the loop are both blocked. This obstruction permits gas and secretions to accumulate in the loop without a means of decompression, proximally or distally
classification of Intestinal obstruction
Dynamic- Peristalsis against a mechanical obstruction
- intraluminal
- intramural
- Extraluminal
Adynamic – absent or non propulsive peristalsis
Dynamic classification of Bowel Obstruction
Intraluminal
- Foreign bodies, Gallstones,
- Parasites, Enteroliths, Intussuseption
- Swallowed objects
Intramural
- Congenital: Meckels, Atresia, Stenosis,
- Inflammatory: crohns, Diverticulitis, Radiation enteritis
- Traumas: Intramural/Extramural
- Tumors: mg/ benign
Extraluminal
- Adhesions
- Meckels bands
- Hernia
- Volvulus
- External Mass Effect
Adynamic /functional obstruction - absent or non propulsive peristalsis
( func obs has disturbances in gut motility )
- paralytic ileus (neuourigenic)
- Mesenteric Vascular Occlusion
- Pseudo-obstruction
Pathophysiology of Intestinal Obstruction
When a loop of bowel becomes obstructed, intestinal gas and fluid accumulate.
Stasis of luminal content favors bacterial overgrowth!! → alters intestinal fluid transport properties and motility, and causes variations in intestinal perfusion and lymph flow. →
altered flow leads to Changes in hydrostatic and osmotic pressures on the blood and lumen sides of the mucosa. →
pressure changes lead to favor flow of extracellular fluid into the lumen. →
Perfusion is compromised as luminal pressures increase,bacteria invade, and inflammation leads to edema within the bowel wall.
complications of closed-loop obstructions
closed loop obstructinos evolve rapidly compared to open loop
blood supply of the obstructed loop is compromised→ gangrene and perforation → free perforation w/ Peritonitis ( clinically leads to a rigid abdomen)
Toxins from necrotic tissue and bacterial overgrowth are released into the systemic circulation → shock ensures
conplications of open-loop obstructions
dosent evolve as quickly since proximal jeujenum can be decompressed by vomitting
Complications / charaacteristics clinical sx of Proximal obstruction
vomiting →loss of gastric, pancreatic, and biliary secretions, → electrolyte disturbances.
- sx of Elyte disturbance
- dehydration,
- metabolic alkalosis
- hypochloremia -( gastric)
- hypokalemia -(bile)
- hyponatremia -(hypovolemic hyponatremia)
Characteristics Complications of Obstructions of the distal ileum
- speed of progression
- most marked comp
this type of obs leads to slowly progressing distention of the small intestine.
distal jejunal obstruction tend to present with complications resulting from
- Loss of intestinal contents from vomiting, as well as
- distention of Lower abdom seg
- compromise of intestinal wall perfusion.
General sx of intestinal obstruction
Abdominal pain. - first symptom - colicky in the early stages → severe, constant as the process progresses
- Prox obstruction - with an acute onset of pain (less than 1 day)
- Distal - indolent course (a few days)
- strangulated in contact with the inner abdominal wall → well-localised severe pain
Nausea and vomiting.- follows the pain - emphasis must placed on the nature
- bilious emesis - proximal obstruction
- feculant* emesis - *Distal obstruction
Constipation - at ANY LEVEL = absolute constipation for both stool and gas.
Physical findings of Intestinal Obstruction
Inspection
- Distension!! - lower the obstruction in the small bowel, the greater the distension.
- Visible peristalsis may occasionally in a thin patient
Palpation
-
mass - suggests a specific cause for the obstruction,
- irreducible mass - strangulated hernia
- tenderness and guarding - strangulation / perforation
Percussion
-
tympanitic note - presence of gas-filled loops of bowel
- absent - if Slow evolution of complications ( Distal ileal obstruction)
Auscultation
- Early → Increased Frequency of high-pitched, tinkling bowel sounds that resemble water lapping the side of a small boat
- Late → absent bowel sounds → PERITONITIS from PERFORATED LOOP!!
N.B. what does it mean When mechanical obstruction is indicated by other clinical findings but bowel sounds are absent?
advanced condition or there is peritonitis which has resulted from perforation of an involved loop!
What is the Imaging modality of choice for Intestinal obstruction
what is the appearance of inestinal obstruction on this imaging modality ]
Plain abdominal X-rays taken in the erect and/or supine positions are the standard and most reliable means of diagnosis.
Characteristic appearance of small-bowel ob‐struction is a number of distended, gas- and fluid-filled loops of bowel with, in the erect posture,
Wat are the 5 Queations that MUST be answered through clinical dg, labs and Imaging in order to determine whether the Management of Intestinal Obstriction will be CONSERVATIVE or SURGICAL
- Is the pain proportional to the physical findings?
- How rapidly are the symptoms and signs evolving (minutes, hours,or more slowly)?
- Does the patient suffer from dehydration and serum electrolyte and pH imbalances?
- Is the obstruction complete or incomplete?
- Is there a possibility of strangulation?
Indications of
Non-operative management / CONSERVATIVE of Intestinal Obstruction
- firm evidence that there is not a threat to the viability of the bowel and thus no risk of strangulation or perforation)
- incomplete obstruction of the small bowel with features which suggest non-progression;
- adhesive obstruction is the only instance a Complete obstructio is permitted .
what does Conservative management of Intestinal obstruction actually involves
- proximal decompression by a nasogastric tube with aspiration either continuously or on a regular intermittent basis,
- Homeostasis-> water and electrolyte replacement,
- monitoring -> repeated (4-6-hourly) evaluation of the clinical state-abdominal pain, development of tenderness, changes in bowel sounds and in cardiovascular status,
- repeated reassessment -> plain X-rays or contrast studies and haematological and biochemical
Indications for Operative management.of Intestinal Obstruction
irreducible Mass
- established or suspected strangulation;
- causes requiring surgical removal (e.g. tumor)
complete bowel obstruction+ tenderness
- -indicative of closed-loop obstruction with possible perforation,
failure of resolution after a period of non-operative management,
WHat procedures preceede operatvie management of Intestinal Obstruction
- gastric suction,
- water and electrolyte replacement.
what is the only indication of urgent operation (w/o pre op procedures) of Intestinal obstruction
how is it managed in the operative field
only indication for urgent operation is when strangulation or other causes of non-viability of the bowel are likely.
- At operation, the obstruction is relieved
- underlying cause removed. if possible!
- Dead or damaged intestine must be excised.
Occasionally an irremovable obstruction (e.g. a fixed neoplasm) is bypassed.
Paralytic ileus definition
Type of adynamic obstruction with no peristaltic waves d/2 neuromuscular failure of auerbach/ meissner’s plexus
- doesn’t involve a physical blockage.
- Muscle or nerve problems disrupt the normal coordinated muscle contractions of the intestines
Types of paralytic ileus = PIRM paralysis
whichi is self limiting
which leads to adhesions
which fractures can cause ileus
which elecytolyte imbalances causes ileus
- Post operative ileus & pharmacologic- Sefl limiting, prolonged after 24 hrs iif protein is low
- Infective ileus - aka Intra-abdom Sepsis - causes local or general ileus and can lead to adhesions
- Reflex ileus -(neurogenic) - Fractures of the Spine or rip cuasing RP heamorrhage
- Metabolic ileus - uremia or hypokalemia
PP pf paralytic ileus
disorganized electrical activity leads to paralysis of intestinal segments. This lack of coordinated propulsive action leads to the accumulation of gas and fluids within the bowel
post op ( Abdominal or pelvic surgery) paralytic ileus
Normal resumption of bowel activity after abdominal surgery follows a predictable pattern:
- small bowel typically regains function within hours;
- stomach regains activity in 1-2 days; a
- colon regains activity in 3-5 days.
Pharmacological Paralytic Ileus
medications that affect muscles and nerves,
- TCA’s , such as amitriptyline and imipramine (Tofranil), and
- OPIODS such as those containing hydrocodone (Vicodin) and oxycodone (Oxycontin)
Risk factors for Paralytic ileus
- Abdominal or pelvic surgery, which often causes adhesions — a common intestinal obstruction
- Crohn’s disease, which can cause the intestine’s walls to thicken, narrowing the passageway
- Cancer in your abdomen, especially if you’ve had surgery to remove an abdominal tumor or radiation therapy
Clinical picture of Paralytic ileus
Sx
distention, fullness, and bloating. - Abdominal cramping is usually not present.
effortless vomiting, and poor appetite. Patients may or may not continue to pass flatus and stool.
phys exam
tympanic on percussion
absent or hypoactive bowel sounds
imaging
x-ray - air fluid lvls
CT w/ Gastrofinn - gold for postop ileus
RX of ileus
- Most cases of postoperative ileus resolve with watchful waiting and supportive treatment
- Naso -gastric-tube decompression
- food restriction until bowel sounds return
- intravenous hydration
- NSAIDS may improve ileus by reducing local inflammation
- discontinue meds causing Ileus (opiods)
- surgery (laparoscopic) if conservative fails
complicatoins of paralytic ileus
same as other intestinal obsructions
NECROSIS from loss of perfusion
PERITONITIS after perforation
