Anus, Rectum & Prostate Flashcards
What forms the terminal portions of the GI tract?
rectum and anus
How long is the anal canal?
2.5 to 4 cm and opens onto the perineum
What is the characteristic of the tissue visible at the external margin of the anus?
moist and hairless mucosa
What is the characteristic of the juncture with the perianal skin?
increased pigmentation and in the adult, presence of hair
What normally keeps the anal canal closed?
concentric rings of muscle- the internal and external sphincters
Which concentric ring is under involuntary autonomic control?
the internal ring
What causes the URGE to defecate?
when the rectum fills with feces and causes reflective stimulation that relaxes the internal sphincter
What controls defecation?
controlled by the striated external sphincter which is under voluntary control
What supplies the lower half of the canal making it sensitive to painful stimuli?
somatic sensory nerves
What supplies the upper half of the canal, making it relatively insensitive to pain?
autonomic control
What lines the anal canal that fuse to form the anorectal junction?
lined by columns of mucosal tissue (columns of Morgagni) that fuse to form the anorectal junction
What are the spaces between the columns of Margagni called that anal glands empty into?
crypts
What can be the result of inflammation of the crypts?
fistula or fissure formation
What is it called when anastomosing veins cross the columns forming a ring?
zona hemorrhoidalis
Dilation of the zonal hemorrhoidalis veins causes what?
internal hemorrhoids
The lower segment of the anal canal contains a venous plexus that drains into the ___ ____ ____.
inferior rectal veins
Dilation of the inferior rectal veins results in what?
external hemorrhoids
How long is the rectum?
12 cm long
The proximal end of the rectum is continuous with the ______.
sigmoid colon
Is the distal end of the rectum at the anorectal junction, is the sawtooth- like edge palpable?
NO just visual on proctoscopic exam
Above the anorectal junction, the rectum ____ and turns ___ into the hallow of the coccyx and sacrum, forming the ____ ____.
dilates, posteriorly, rectal ampulla
What is stored in the rectal ampulla?
flats and feces
What are the 3 semilunar traverse folds of the rectal wall?
Houston valves
The prostate is ____ and divided by a shallow median sulcus into ______.
convex; right and left lateral lobes
Is the third or median lobe palpable on examination?
No
What composes the median lobe of the prostate and where is it located?
glandular tissue and lies between the ejaculatory duct and urethra.
What extends outward from the prostate?
seminal vesicles
How does the prostate contribute to ejaculatory fluid?
it contains active secretory alveoli
What causes retention of stool in older adults?
degeneration of afferent neurons in the rectal wall interferes with relaxation of the internal sphincter in response to dissension of the rectum.Higher pressure threshold.
What can cause fecal incontinence in older adults?
the autonomically controlled internal sphincter loses tone, the external by itself cannot control the bowels
What replaces the muscular component of the prostate?
collagen
What often obscures the atrophy of aging of the prostate?
benign hyperplasia of the glandular tissue
What are the risk factors of prostate cancer?
age
more common in African Americans
common in north america and northwestern Europe, Australia and Caribbean
family history
inherited BRCA or hereditary non polyposis colorectal cancer
gonadectomy in transgender women does not decrease the risk
What are the risk factors of anal cancer?
HPV multiple sex partners receptive anal intercourse ciggs immunosuppression of HIV more common in women
What might indicate that a pt is in pain during the exam?
with acute rectal problem the pt will shift uncomfortably from side to side sitting
How should transgender pts be examined for rectal exam?
in the position of their identified gender
What type of infection at the dscrococcygeal and perianal areas are more common in adults? children?
adults: fungal infections in pts with DM
children: pinworms
IF tenderness and inflammation are found at the sacrococcygeal and perianal areas would should you consider?
perianal abscess, anorectal fistula/fissure, pilondial cysts or pruritus ani
What might be an indication with a lax sphincter?
neurologic deficit or sexual abuse
An extremely tight sphincter might be the result of what?
scarring, spasticity caused by a fissure or other lesion, inflammation or anxiety about the exam
Rectal pain is almost always indicative of ______.
local disease.
When are internal hemorrhoids felt?
NOT ordinarily felt unless they are thrombosed
How far can an examining finger palpate into the rectum?
6 to 10 cm
what technique is useful for detecting a perianal abscess?
bidigital palpation
What may produce such extremes tenderness the you are unable to complete the exam without local anesthesia?
anal fistula or fissure
Asking the pt to bear down when palpating the anterior rectal wall does what?
allows you to reach a few centimeters farther into the rectum, you may be able to detect tenderness of peritoneal inflammation and nodularity of peritoneal mets
What are the hard nodules called that are palpable in the peritoneal cup de sac?
shelf lesions
How should the prostate feel on examination?
like a pencil eraser- firm, smooth, slightly moveable and non tender
A healthy prostate has a diameter of ____cm, with less than ____cm protrusion into the rectum.
4
1
What does greater protrusion into the rectum indicate?
prostatic enlargement
What might be obliterated when the prostate lobes are hypertrophied or neoplastic?
median sulcus
A rubbery or boggy consistency of the prostate might indicate what?
benign hypertrophy
A tender fluctuant softness of the prostate suggests what?
carcinoma, prostatic calculi or chronic fibrosis
A tender fluctuant softness of the prostate suggests what?
prostatic abscess
Are the seminal vesicles palpable?
NO unless inflamed
What is a grade I of prostate enlargement?
1 to 2 cm protrusion into the rectum
What is a grade II of prostate enlargement?
2 to 3 cm
What is a grade III of prostate enlargement?
3 to 4cm
What is a grade IV of prostate enlargement?
more than 4 cm
What needs to be done if palpation of the prostate forces secretions through the urethral orifice?
cultured and examined microscopically
Which trial showed that the rate of death from prostate cancer was very low and did not differ significantly between the screening and the control group?
The US trial
Which trial suggested that PSA based screening reduced the relative risk of death from prostate ca by 21% in the screening group but was associated with over diagnosis?
The European trial
What was the difference between the US and European trial that resulted in unsettled controversy?
the trials had different designs
tested different populations
different screening intervals
conflicting results
What are the associated harms associated with prostate ca screening?
false positive tests
unnecessary biopsies
over diagnosis
What is the The US Preventative Services task force (USPSTF) view on PSA testing?
they recommend against it but recognizes the common use of PSA screening in practice and understand that some will request it and some providers will offer it
What might very light tan or grey stool indicate?
obstructive jaundice
What might black tarry stool indicate?
upper GI bleed
What does intermittent, pencil like stool suggest?
spasmodic contraction in the rectal area
What does persistent pencil like stool indicate?
permanent stenosis from scarring or from pressure of a malignancy
What does decreased caliber (pencil thin stools) indicate?
lower rectal stricture
what does a large amount of mucus in the fecal matter characteristic of?
intestinal inflammation and mucous colitis
Small flecks of bloodstained mucus in liquid feces is indicative of what?
amebiasis
When are fatty tools often seen?
pts with pancreatic disorders and malabsorption syndromes such as cystic fibrosis
What causes the stool to be the color of aluminum?
mixture of melena and fat. Occur in tropical sprue, carcinoma of the hepataopancreatic ampulla, and children treated with sulfonamides for diarrhea
What are the common causes of rectal bleeding?
anal fissures anaphylactoid purpura asa medications bleeding disorders colitis dysentery esophageal varices familial telangiectasia foreign body trauma hemorrhoids hiatal hernia hookworm intussusception iron poisoning Meckel diverticulum neoplasms oral steroids peptic ulcers polyps regional enteritis strangulated hernia swallowed blood thrombocytopenia volvulus
How might an older pts prostate feel on palpation?
more enlarged, which will be felt as smooth, rubbery and symmetric
the median sulcus MAY be obliterated
Why is the rectal exam so important in older adults?
they are more likely to have polyps increasing the risk of carcinoma
What are common STIs that affect the anus?
HSV infection of the skin and mucosa causing reoccurring sores and pain
gonorrheal infection of the mucosa causing infectious discharge
HPV- anal warts
parasites that affect the GI tract
Syphilis- early infection causing painless lesion
What are 2 STIs whose symptoms do not appear on the anus but can be transmitted through sex?
Hepatitis and HIV
What are other ways that STIs can be acquired without penetration?
oral-anal contact, oral contact with fingers that have contacted the anus, use of sex toys
What is a cyst or sinus near the cleft of the buttocks?
pilondial cyst
What is the result of loose hairs penetrating the skin in the sacrococcygeal area?
pilondial cyst
What predisposes the development of a pilondial cyst?
excessive pressure or repetitive trauma to the sacrococcygeal
When are pilondial cysts first diagnosed?
most in young adults although they are usually a congenital anomaly
What are the symptoms of a pilondial cyst?
usually asymptomatic but may have pain with sitting and inflammation from secondary infection
What is the appearance of a pilondial cyst?
cyst or sinus seen as a dimple with a sinus tract opening located in the midline, superficial to the coccyx and lower sacrum
What is an infection of the mucus-secreting anal glands, which drain into the anal crypts; abscess formation occurs in the deeper tissues?
perirectal abscess
What are the manifestations of a perirectal or perianal abscess?
painful and tender anal area
fever
pain on defecation, sitting or walking
What are risk factors for a perianal or perirectal abscess?
crohns disease
immunosuprresion
What is an infection of the soft tissues surrounding the anal canal with formation of a discrete abscess cavity
perianal abscess
What is the presentation of a perianal abscess?
tender swollen fluctuant mass in the superficial subcutaneous tissue just adjacent to the anus
What is the presentation of a perirectal abscess?
tender mass that may be indurated, fluctuant or draining
What is a tear usually caused by tramatic passage of large, hard stools?
anorectal fissure
What is the manifestations of an anorectal fissure?
h/o hard stools
bleeding in toilet or on TP
rectal pain, itching or bleeding
Where is a fissure most likely seen?
most often in the posterior midline although it can also occur in the anterior midline
What may be seen at the lower edge of an anorectal fissure?
sentinel skin tag
What is significant about the internal sphincter with an anorectal fissure?
there may be ulceration through the internal sphincter
it is spastic
What is caused by inflammation of a perianal or perirectal abscess; the abscess degrades the tissue until a tract and an opening in the skin is created?
anal fistula
What is the clinical complaints of an anal fistula?
may report child, fever, N&V, malaise
What is the presentation on exam on an anal fistula?
external opening of a fistula appears as a pink or red, elevated red granular tissue on the skin near the anus
palpable indurated tract may be present on digital rectal exam
What might appear with compression at the area of an anal fistula?
serosanguineous or purulent drainage
What is itching of the anal area commonly caused by fungal infection in adults and by parasites in children?
pruritis ani
What is seen on examination of pruiritis ani?
excoriation, thickening and pigmentation of anal and perianal tissue
What are varicosed veins that original below the anorectal line and are covered by anal skin?
external hemorrhoids
What are varicose veins that originate above the anorectal junction and are covered by rectal mucosa?
internal hemorrhoids
What causes hemorrhoids?
pressure on the veins in the pelvis and rectal area from straining, diarrhea, constipation, prolonged sitting or pregnancy
Are internal hemorrhoids symptomatic?
NO unless they are thromboses, prolapsed or infected
How do thromboses hemorrhoids appear?
blue, shiny masses at the anus
Are internal hemorrhoids palpable on rectal exam?
No and they are not visible unless they prolapse through the anus
Proctoscopy usually required for dx
What can appear at the site of resolved hemorrhoids?
hemorrhoidal skin tags which are fibrotic or flaccid and painless
What are most anal cancers?
squamous cell origin associated with HPV infection
What % of anal cancers are adenocarcinomas?
15%
Where do adenocarcinomas of the anus originate?
glands near the anus
What are the other rare types of anal cancer? (2)
basal cell ca and melanoma
What is significant about melanoma anal ca?
it is difficult to see and often diagnosed late stage
What are the objective findings in anal ca?
raised erythematous mucosa white scaling mucosa pigmented mucosa mucosal ulceration verrucous lesion
What makes up the majority of colorectal cancers?
adenocarcinomas
What is defective in more than 80% of adenomatous polyps and colon cancers?
the APC tumor supressor gene is defective
How might rectal cancer present on exam?
may be felt as a sessile polypoid mass with nodular raised edges and areas of ulceration; the consistency is often stony and the contour is irregular
higher in the colon not palpable
What organism causes acute prostatitis?
e-coli
klebsiella
proteus
How might prostatitis be acquired?
STD
infection of an adjacent organ
complication of prostate biopsy
What is significant about chronic prostatitis?
may be bacterial or non bacterial (chronic pelvic pain syndrome)
Why is gentle examination imperative in acute prostatitis?
massage of the prostate can cause bacteremia
The search for an unexplained fever should always include what?
a rectal examination- abscess or prostatitis may be the cause
