Intestinal causes of weight loss Flashcards
What is weight loss determined by the balance of (nutrient wise)
- intake
- absorption
- utilisation
- loss
What does any alteration in balance of nutrient intake/absorption/utilisation/loss affect?
- the ability to maintain weight
Pathophysiological mechanisms of weight loss
▪Decreased dietary intake
▪Increased rate of utilization
▪Loss of nutrients (malabsorption/maldigestion (but maldigestion is less important in herbivores))
▪Inadequate delivery to tissues
▪Conditions that cause muscle wasting
Small intestinal causes of weight loss
- Chronic inflammatory bowel disease (CIBD):
– Granulomatous enteritis (GE)
– Eosinophilic Entercolitis (EE)
– Lymphocytic-Plasmacytic Enterocolitis (LPE) - Proliferative enteropathy
- Alimentary tract neoplasias
Granulomatous enteritis (GE) (what is it, cause?, signalment)
▪Rare in past years
▪Lymphoid and macrophage infiltration (lamina propria)
▪Ileal villous atrophy
▪Unknown cause
– Hypothetical inflammatory reaction to intestinal bacteria
▪Any age, sex breed
Eosinophilic enterocolitis (EE) - different types
▪Eosinophil infiltration (intestinal mucosa)
▪Multisystemic eosinophilic epitheliotropic disease (MEED)
– Other organs involved
▪Diffuse eosinophilic enterocolitis (DEE)
– Affects all small and large intestine
▪Idiopathic focal eosinophilic enteritis/colitis (IFEE or IFEC)
– Segmental small or large intestinal lesions present
Eosinophilic enterocolitis (EE) - cause, signalment
▪Unknown cause
– Speculated to be related to nematode infestation
– Parasites can induce hypersensivity reaction
– Parasites contain endogenous factors that attract eosinophils
▪Any age, sex, breed
– Most common in young Thoroughbreds & Standardbreds
Lymphocytic-Plasmacytic Enterocolitis (LPE) - description, cause, signalment
▪Incidence increased in last years
▪Lymphocyte and plasma cells infiltration (lamina propria)
▪Unknown cause
– Speculated to precede development of intestinal lymphoma
▪Any age, sex breed
Proliferative enteropathy
▪Disease caused by Lawsonia intracellularis
– Obligate intracellular bacterium
▪ Affects:
– Cytoplasm of proliferative crypt epithelial cells
– Of the jejunum & ileum
Proliferative enteropathy - signalment, epidemiology
▪Weanling foals between 3 to 8 months age
▪Individuals or outbreaks
▪Uncommonly in yearlings and adult horses
▪Close proximity to swine
Proliferative enteropathy: risk factors
▪Overcrowding
▪Feed changes
▪ATB usage
▪Mixing & transportation
▪Weaning
Large intestinal causes of weight loss
▪Parasite infestation ▪Right dorsal colitis (RDC) ▪Sand enteropathy
▪EEs
Parasite infestation
- More common to be involved in cases of colic and diarrhoea
- Heavy infestations can cause weight loss
- More commonly seen in horses with poor husbandry or negletced horses.
Parasite infestation - large strongyles species
▪Strongylus vulgaris
–> important & pathogenic
▪Strongylus edentatus ▪Strongylus equinus
Parasite infestation - large strongyles - disease pathogenesis
▪Migration of larvae through intestinal wall
– 4th stage larvae migrates
– Lumen → mucosa & submucosa
– Affects myoelectrical activity
– Infiltration with inflammatory cells
– Edema & haemorrhage
–Increased secretion through the intestinal mucosa + decreased absorption through the intestinal lumen
Small strongyles - pathogenesis
▪Migration of L4 through mucosa of LI
▪Include a period of hypobiosis
▪Larvae emerge in response to unknown stimulus
▪Sudden emergence causes:
– Mucosal injury
– Ulceration
– Inflammatory reaction
▪Affects motility patterns ▪Seasonality associated to the emergence of the larvae
▪Diarrhoea:
– ⇈ secretion 2ry to granulomatous inflammation
– Disruption of interstitium
▪Protein loss is often significant
Right dorsal colitis (RDC) aetiology
▪PGE2 and PGI2
– Mucosal blood flow
– ⇈ secretion of mucus, H2O & HCO3-
– ⇈ mucosal cell turnover & migration
▪NSAIDs inhibit PG production (specially non-selective NSAIDs)
▪PHBZ (phenylbutazone) is common cause
▪Particularly those receiving inappropriately large doses
▪Some have underlying disorders
▪Causes ulceration and severe inflammation of the right dorsal colon
▪Causes intermittent colic, diarrohea, weight loss
Sand enteropathy
- Occurs in horses that live in handy areas and eat in paddocks with sand in the soil - ingest sand over a period of time.
- Intestinal contents and water continue to flow in the lumen but the sand due to its weight accumulates in the sacculations of the ventral colon, this leads to damage of the colonic mucosa -> diarrhoea and weight loss.
- In severe cases sand impaction can occur -> colic.
Granulomatous enteritis (CS, albumin, blood work, glucose absorption test, biopsies)
CS:
- Weight loss- Anorexia
- Skin lesion on coronet (+/-)
Albumin:
- Low
Blood work:
- Anaemia
Glucose absorption test:
- Abnormal
Biopsies:
- Good correlation with rectal biopsy
Lymphocytic enterocolitis (CS, albumin, blood work, glucose absorption test, biopsies)
CS:
- Weight loss
Albumin:
- ± low
Blood work:
- Normal
Glucose absorption test:
- Abnormal
Biopsies:
- Unreliable
Focal eosinophilic enteritis (CS, albumin, blood work, glucose absorption test, biopsies)
CS:
- Colic
- Weight loss rare
Albumin:
- Normal
Blood work:
- Normal
Glucose absorption test:
±
Biopsies:
- Focal full thickness
- Not rectal biopsy
MEED (CS, albumin, blood work, glucose absorption test, biopsies)
CS:
- Weight loss
- Skin lesions
- Liver dz
Albumin:
- Normal initially
- Low in advanced cases
Blood work:
- Normal (± eosinophilia)
- Anaemia
- High GGT
Glucose absorption test:
- Normal (LI»_space; SI)
Biopsies:
- 50% with rectal biopsy
Intestinal lymphoma (CS, albumin, blood work, glucose absorption test, biopsies)
CS:
- Weight loss
- Mild colic
- Diarrhoea
Albumin:
- Low
Blood work:
- Anaemia
Glucose absorption test:
- Generally abnormal
Biopsies:
- Full thickness
- Rectal or duodenal if diffuse
