ch.32.DzesGIT Flashcards
1
Q
Motor function to the following structures is under the control of which cranial nerve:
sublingual and mandibular salivary glands, lacrimal glands, facial & labial muscles
A
facial nerve
2
Q
The lingual muscles receive their motor and sensory innervation from which cranial nerve (s)?
A
motor: hypoglossal nerve ( CN XII)
sensory: lingual & glossopharyngeal nerves (CN IX)
3
Q
When do the hemimandibles fuse in horses?
A
Mandibular symphysis at approximately 2 to 3 months of age
4
Q
Sinusitis can result from disease of which molars?
A
3rd, 4th, 5th and 6th upper cheek teeth
5
Q
Where do the maxillary sinuses drain?
A
into the back of the nasal cavity via a slitlike aperture– the nasomaxillary openining
6
Q
The medial compartment of the rostral maxillary sinus is called?
A
the ventral conchal sinus
7
Q
The muscles of mastication are innervated by:
A
the motor branch of the mandibular nerve, originates from the trigeminal nerve (CN V)
8
Q
Innervation of the dental structures is supplied by which cranial nerve?
A
trigeminal nerve (CN V)
9
Q
parrot mouth in medical terminology is
A
brachygnathism
10
Q
sow mouth in medical terminology is
A
prognathism
11
Q
define polydontia or hyperdentition
A
supernumery teeth or teath in excess of normal expected number in any of the dental arcades
12
Q
Supernumerary teeth can be loosely categorized morphologically into 2 categories:
A
- supplemental teeth that resemble teeth of the normal series in crown and root structure but not always in size
- rudimentary or dysmorphic teeth that are banormally shaped and smalle rins ize than normal teeth
13
Q
Clinical signs associated with supernummery teeth are d/t
A
dental overgrowth and diastemata, which often lead to secondary periodontal disease
14
Q
define oligodontia
A
the congenital absence of a tooth germ or retention and inclusion of a tooth wihtin the jaw
15
Q
acquired dental disease can be grouped into 6 basic categories:
A
- dental malocclusions and abnormal occlusal wear
- periodontal disease
- caries of the infundibulum or peripheral cementum
- endodontic disease
- tooth resorption and hypercementosis
- traumatic dental injuries
16
Q
How much tooth crown can be removed prior to pulp exposure?
A
recommend 3 to 4mm max, because some pulpe horns are exposed at 2 to 4 mm
17
Q
periodontium involves which structures?
A
gingiva
alveolar bone
periodontal ligament
cementum
18
Q
what pH is required for enamel, dentin and cementum to demineralize?
A
enamel: pH 5.5
dentine: pH 6.2
cementum: pH 6.7
19
Q
endodontic disease referrs to
A
disease of the dental pulp
** occurs in horses age 4 to 10 years
20
Q
pulp horn decay can lead to what?
A
weakening and predispose to crown fracture
21
Q
Functions of saliva
A
hydrates and lubricates the oral cavity
facilitates swallowing
prevents tooth demineralization
regulates oral flora
22
Q
How does the parotid salivary gland communicate with the oral cavity?
A
a pappilla opposite the upper third and fourth cheek tooth
23
Q
How does the mandibular salivary duct communicate with the oral cavity?
A
lateral aspect of teh sublingual caruncle
24
Q
Where are the sublingual salivary ducts located?
A
approximately 30 small pores located in teh sublingual recess
25
Causes of pytalism
heavy metal toxicity
parasympathomimetic poisoning
cholinesterase inhibiting insecticides (organophosphates & carbamates)
neurologic disease
stomatitis
slaframine
26
What is the cause of "slobbers" in horses?
slaframine-- cholineric agonist
on clover contaminated with fungus Rhizoctonia leguminicola
27
Sialoadenitiis results from
salivary duct obruciton caused by accumulation of exudate or mucus, by ingested foreign body or by a sialolith
28
What is a salivary mucocele?
an accumulation of salivary secretions in a single or multiloculated cavity adjacent to a ruptured salivary duct
29
what is a ranula?
a type of mucocele that is secondary to obstruction of the sublingual salivary duct
30
Tumors of the salivary glands:
melanomas- more common in gray horses
other tumors:
benign mixed tumors
adenocarcinomas
acinar cell tumors
31
Equine oral tumors are rare, but are divided into what 3 types?
odontogenic
osteogenic
secondary
32
What are odontogenic tumors?
derived from remnants of dental epithelium
33
Secondary tumours of the head include:
extensions of oropharyngeal squamous cell carcinoma
lymphosarcoma
papilloma
melinoma
34
good dental health is important to equine digestive system. Proper emchanical digestion of feed allows for what?
better carbohydrate absorption in the small intestine & improved fiber fermentation in cecum and large colon
35
Define simple intestinal obstruction
physical obstruction of the lumen without obstruction of mesenteric vascular flow (ie., nonstrangulating obstruction)
36
At what age do ascarid impactions (parascaris equorum) typically occur?
weanling foals (median age: 5 months) that are dewormed with a heavy parasite burden
37
what are products that cause sudden ascarid paralysis or death
piperazine
organophosphates
pyrantel pamoate
38
clinical signs of colic due to ascarid impaction after deworming, usually occurs how many days after deworming?
within 1 to 5 days
39
What is the mortality rate reported in ascarid impactions?
high (range 60 and up to 92% in one study)
40
ileal impactions occur most commonly in horses fed what hays?
coastal Bermuda hay
**SE US
* failure to deworm against tapeworms
41
what is ileal hypertrophy?
disorder in which the muscular layers (both circular and longitudinal) of ileum enlarge for unknown reasons
42
Treatment of ileal hypertrophy?
usually entails an ileocecal or jejunocecal anastomosis to bypass the hypertrophies ileum
**risk w/o removal is rupture of the thickened ileum
43
Where is the meckel diverticulum?
arises from the vitelloumbilical duct which fails to atrophy completely and becomes a blind pouch projecting from the antimesenteric border of the ileum
+/- an associated mesodiverticular band extended from diverticulum to umbilical remnant & serves as a point for SI to become strangulated
44
Where can mesodiverticular bands originate?
meckel diverticulum to umbilical remnant
OR
originate from embryonic ventral mesentary & attach to anti-mesenteric surface of bowel
45
Clinical signs of a meckel diverticulum or mesodiverticular bands?
chronic colic to acute severe colic
46
Idiopathic focal eosinophilic enteritis: which age group is at increased risk?
horses younger than 5 years of age
47
Histo of idiopathic focal eosinophilic enteritis:
severe transmural eosinophilic enteritis
48
A report from NW England revealed what kind of pattern in idiopathic focal eosinophilic enteritis?
seasonal pattern: risk highest between July and November
49
Strangulating obstruction definition
simultaneous occlusion of intestinal lumen and its blood supply
50
Where is the epiploic foramen located?
opening to the omental bursa located within the right cranial quadrant of the abdomen
boundaries:
dorsal: liver & caudal vena cava
ventrally: pancreas, hepatoduodenal ligament & portal vein
51
What is the seasonal pattern associated with epipoloic foramen entrapment lesions?
more cases seen in fall and winter months
52
Besides the seasonal pattern to epiploic foramen entrapments, what other predisposing factor exists?
Cribbing
53
In surgical treatment of epiploic foramen, what fatal complication can occur?
fatal hemorrhage due to laceration of vena cava or portal vein
54
Surgical small intestinal resection due to lipoma reported success rates:
60 to 78% of horses discharged from the hospital after surgical treatment
55
What is a small intestinal volvulus?
twisting of a segment of SI more than 180 degrees along the axis of the mesentery
56
Inguinal hernias are common in what breeds?
Standardbred and Tennessee walking horses
**congenitally large inguinal canals
57
Differentiate between a direct and indirect inguinal hernia:
Direct: bowel ruptures through parietal vaginal tunic & occupies a subcu location
Indirect: remains with the peritoneal cavity
58
in congential hernias, when is surgery recommended
direct hernias
-- for repair of vaginal tunic
59
What is a Richter hernia?
When a hernia involves only part fo the intestinal wall
-- can develop a enterocutaneous fistula
60
Congenital diaphragmatic hernias occur from
incomplete fusion of any embryonic components of the diaphragm: pleuroperitoneal membranes, transverse septum, esophageal mesentery
61
define intussusception
a segment of bowel (intussusceptum) that invaginates into an adjacent aboral segment of bowel (intususscipiens)
62
Reasons for intusussceptions of bowel:
small passes, foreign bodies or parasites (tapeworms Anoplocephala perfoliata)
63
What is the most common location of an intusussception?
ileocecal intusussception
64
Cause of nonstrangulating infarcation to teh SI
secondary to cranial msenteric arteritis caused by igration of S. vulgaris
65
Most common segments involves in a nonstrangulating infarction of cranial mesenteric artery
any segment of intestine it supplies
**particularly distal small intestine and large colon
66
The diagnosis of cecal impaction is based upon?
rectal palpation: firm, impacted cecum or a grossly distended fluid-filled cecum
67
What is the prognosis for a cecal impaction, treated medically and treated surgically?
medical management: 61%
surgical management: 82%
-- mild variation between a jejunnocolostomy and typhlotomy
68
What role do equine feeding programs play a role in the development of large colon impactions?
Twice daily feeding concentrates are associated with secretion of large volumes of fluid into the small intestine-- transient hypovolemia (15% loss of plasma volume)
--> leads to activation of renin-angiotensin- aldosterone system
-aldosterone stimulates absorption of fluid from colon & may dehydrate contents
large concentrate meals may decrease small intestine transit time
69
Prognosis for large colon impaction, medical management vs surgical intervention?
medical management: 95% long term survival in one study
surgical intervention: 58% long term survival in same study
70
What are enteroliths?
mineralized masses typically composed of ammonium magnesium phosphate (struvite)
71
What is usually involved in the formation of enteroliths?
almost always form around a nucleus--> ie: silicon dioxide, stone, nail or peice of rope
72
Where in the United States has the highest incidence of enterolith formation?
California
-- diet composed of alfalfa were at risk for development of enterolithiasis
- horses on pasture was protective against the disease
73
Where are enteroliths most commonly located (which segments of colon)?
right dorsal portion of the colon
transverse colon
small colon
74
Difference between solitary vs multiple enteroliths?
Solitary enteroliths: round
multiple enteroliths: flat sides
75
How often does colon rupture occur when removing an enterolith?
in 15% of 900 cases
76
Prognosis for sand impactions
good: more than 94% of horses survived to discharge, regardless of medical vs surgical management
77
A colon volvulus of what degree does not result in strangulation of blood supply?
less than 270 degrees
78
What is the dose of phenylephrine to be administered prior to exercise or rolling to decrease the size of the spleen, in the treatment of nephrosplenic entrapment?
3 to 6 microg/kg/min over 15 minutes
79
What is the reported rate of recurrence in LDD/nephrosplenic entrapments?
may affect up to 23% of horses
80
atresia coli inheritance in horses?
unknown and can occur in any segment of colon
81
In experimental conditions, the colon is irreversibly damaged within what time period?
within 3 to 4 hours of 360 degree volvulus of the entire colon
82
Postoperative complications reported in large colon volvulus's
-hypovolemic and endotoxemic shock
-extensive loss of circulating protein
-disseminated intravascular coagulation
-laminitis
83
What is the reported prognosis for survival for large colonic volvulus, to hospital discharge?
58 to 88%
84
What is the reported prognosis for long term survival for large colon volvulus?
34 to 66% after 2 years
85
What is the most common intussusception of the large intestine?
cecocolic intussusception
86
At what age tends to have cecocolic intussusceptions?
young horses: 2 to 3 years of age
-- may be assoc. with intestinal parasites (tapeworms & heavy larval cyathostome burden)
87
Prognosis for recovery from cecocolic intussusception?
poor- d/t severe compromise ot cecum, risk of cecal rupture or severe contamination during sx
88
Which populations have increased risk for small colon conditions?
*Arabian horses and ponies (miniature)
*horses > 15 years of age--> strangulating lipoma, injury from foaling, submucosal hematoma
*mares-- hormonal fluctuations, injury during foaling, small colon entrapped by an ovary
89
atresia coli vs myenteric aganglionosis/overo lethal white syndrome
-overo lethal white syndrome/ myenteric aganglionosis of distal intestinal tract result of a mutation the endothelin receptor type B gene
-
90
Loss of the neurons in the myenteric plexus of the small colon can be seen in what 2 diseases?
overo lethal white syndrome
equine dysautonomia (grass sickness)
91
Diagnosis of atresia coli
- retrograde contrast study (lg volume may be required if lesion proximal to transverse colon, up to 20 ml/kg)
-colonoscopy-- not recommended d/t fragility of small colon
92
What is the composition of mecnonium?
substances that are present in the intestinal tract at birth, such as glandular secretions, sloughed cells and swallowed amniotic fluid
93
Which sex has a higher incidence of meconium impactions in foals?
Higher incidence of meconium retention in colts than in fillies
94
Why is acetylcysteine effective in meconium impactions?
it is a mucolytic-- acts by breaking disulfide bonds to make meconium less viscous
95
Proposed cause of mesocolic tears?
trauma and straining during parturition
96
intraluminal objects commonly cause obstruction in what areas of the esophagus?
- cranial part of the cervical portion of the esophagus
-thoracic inlet
-base of the heart
97
What are possible causes of cervical cellulitis?
-perivascular injection of irritating substances
-abscesses
- reaction to hypoerma lineatum larvae
98
Systemic diseases that may lead to esophageal dysfunction:
-rabies
-botulism
tetanus
-poisonous plants: sneezeweed, larkspur, milkweed, red clover infected with fungus R. leguminicola (slaframine)
-pharyngeal trauma
99
What are common clinical pathology features of long-standing choke?
dehydration
metabolic acidosis-- d/t continued loss of sodium bicarbonate & sodium phosphate in saliva
**as sodium depletion develops, composition of saliva shifts to include more potassium under the influence of alodsterone
100
Megaesophagus rarely occurs in ruminants, been has been reported to be associated with or caused by:
1. pharyngeal trauma or resultant inflammatory involvement of vagus
2. hiatal hernia or diaphragmatic hernia
3. sarcocystis arieticanis megaesophagus in a ram
4. eosinophilic submucosal infiltration reported in 18m old heifer
101
Causes of colic signs in ruminants,
Examples of extraintestinal causes of visceral pain
urolithiasis
acute pyelonephritis
ruptured bladder
cystitis/urinary tract diseases
uterine torsion or rupture
acute liver diseases
cholelithiasis
fat necrosis
inguinal hernia
102
Causes of colic signs, Example of extraintestinal parietal pain
peritonitis
103
Causes of colic signs, examples of extraabdominal causes of parietal pain
pleuropneumonia
rib fracture
diaphragmatic hernia
laminitis
myopathy
spinal cord diseases (osteomyelitis, fracture, luxation)
104
Abdominal causes of colic signs, that are gastrointestinal source of visceral pain
torsion of mesentary root
cecal dilation/volvulus
intesitnal volvulus
intussusception
abomasal volvulus
intesitnal foreign body or osruction
intesitnal incarceration, adhesions
atresia coli (neonates)
hemorrhagic bowel syndrome
aboamsal bloat (neonates)
paralytic ileus
enteritis, enterotoxemia
105
Abdominal causes of colic signs, that are gastrointestinal source of parietal pain
acute traumatic reticulitis
reticulopericarditis
abomasal ulcer
