Melena

Question 1

what is melena?

Answer 1

Melena (dark, tarry faeces) is caused by (presence of) blood in the lumen of the stomach or proximal intestinal tract, resulting in black (digested) blood appearing in the faeces

Question 2

what are the Gastrointestinal differentials for melena?

Answer 2

• PROXIMAL:
  ◦ Oral/pharyngeal/oesophageal bleeding; trauma/infection/neoplasia
  ◦ Ingestion of blood; i.e. after parturition or coughed up (see later on)
• MIDDLE:
  ◦ Rumen/reticular ulcers
  ◦ Abomasal ulceration; adult cattle & calves
  ‣ Multiple potential causes ……. not well understood
  ‣ BVDV
  ‣ BLV; lymphosarcoma
  ‣ MCF
  ◦ Duodenal ulcers
  ◦ Abomasal torsion/displacement
  ◦ Haemorrhagic bowel syndrome
  ◦ Intussusception
  ◦ Gastro-enteritis + bleeding
  ‣ Enteritis; Winter dysentery (?coronavirus), coccidiosis

Question 3

what are the respiratory, toxicity and other differentials for melena?

Answer 3

Respiratory
* Vena caval thrombosis +/- hepatic abscess; coughed up blood

Toxicity
* NSAID use
* Warfarin poisoning
* (Sulphur toxicity)
* Arsenic toxicity
* Oak toxicity
* (Snake bite)….

Other
* Coagulopathy (i.e. factor VIII deficiency, DIC)
* Bacillary haemoglobinuria (Clostridia haemolyticum)

Question 4

when are abomasal ulcers more commonly seen?
what are the risk factors?

Answer 4

• Abomasal ulcers are more commonly seen in intensively managed herds, fed high energy, acidic diets (think concentrates)
• Maize silage as a major part of the diet seems to be a risk factor
• High yielding dairy cows are seemingly predisposed; particularly in the first 4-6 weeks of lactation and in the dry period
• Long term NSAIDs are also a risk factor

Question 5

How are abomasal ulcers classified?

Answer 5

Question 6

abomasal ulcers are diagnosed on clinical signs? what are the signs of each type?

Answer 6

• Type 1 (no haemorrhage)- no signs/ waxing and waning
• Type 2 (varying haemorrhage)
  ◦ SLIGHT BLEEDING: small/tarry faeces
  ◦ MODERATE BLEEDING: abdominal pain/intermittent anorexia/ ++ tarry faeces/occult blood in faeces
  ◦ MAJOR BLEEDING: obvious melena/complete anorexia/pale-chalk mucous membranes/weak pulse/ HR 100-140 bpm/cool extremities+
  ◦ LDA/RDA presence?
• Type 3 (acute local peritonitis)- MILD-MODERATELY SICK- intermittent anorexia/pyrexia/rumen stasis/local abdominal pain
• Type 4 (acute diffuse peritonitis)- MUCH SICKER -complex anorexia/ ++pyrexia (>40 degC)/complete GI stasis/cold periphery/dehydrated/expiratory grunt/depressed/HR 100-140 bpm
• Type 5 (peritonitis in omental bursa)- similar to Type 3- often MILDER

Question 7

what is the treatment and management for the differnt types of abomasal ulcers

Answer 7

• Type 1: ?
• Type 2: depends on degree of haemorrhage
  ◦ SLIGHT BLEEDING: high quality hay (no silage/concentrate feed for 5-14d), oral antacid?
  ◦ MOD-MAJOR BLEEDING: diet as above + ….
  ‣ If white mucous membranes/ HR >100 bpm/ RR+/ PCV <14% if not peracute or chronic bleed : whole blood transfusion (4-6L)
  ‣ If bleeding as LDA/RDA: PCV >14% –> surgery to correct DA, PCV <14% –> transfuse then DA surgery
• Type 3: dietary change + broad-spectrum antibiotics (amoxycillin) for 7-14 days/until normal temperature for 48h.
  ◦ (Ranitidine IV – NOT FOR USE IN FOOD PRODUCING ANIMALS (FPA))
  ◦ Omeprazole orally? Valuable animals ONLY + ?evidence
• Type 4: often unsuccessful, massive septic peritonitis
  ◦ IV broad spectrum antibiotics
  ◦ IV fluid therapy- address acid-base/electrolyte status
  ◦ Peritoneal lavage?
  ◦ Surgery to oversew/resect ulcer? VERY DIFFICULT TO ACHIEVE, +++ ADHESIONS

Question 8

what is the prognosis of abomasal ulcers?

Answer 8

• Type 1: ?
• Type 2: good prognosis if before severe anaemia
  ◦ Recovery in 7-14 days, even if need blood transfusion
  ◦ If bleed + perforate –> very poor prognosis (often chronic/involve DA)
• Type 3/5: good prognosis with dietary and medical management
  ◦ Recovery in 7-14 days, little recurrence documented?
• Type 4: grave prognosis –> death 24-48h despite therapy

BEWARE - repeated melena after treatment for suspected Type 2 ulcer = ?abomasal neoplasia (lymphosarcoma most common)

Question 9

what are the risk factors for abomasal ulcers in calves?

Answer 9

UNCLEAR!!
**Large volume milk feeding **(in only twice daily feeding)
Trichobezoars? (hair balls)
Bedding/shavings?
Prolonged NSAID use

Question 10

what is different in the clinical signs of abomasal ulcers in calves?

Answer 10

• Perforating ulcers more common in calves
• Calves with perforating ulcers:
  ◦ Develop diffuse peritonitis
  ◦ Abdominal distension + found down
  ◦ Death within 12-36 hrs
  ◦ Or found dead …..
  • U/S very useful in calves to dx diffuse peritonitis

Question 11

what is the treatment of abomasal ulcers in calves?

Answer 11

same as for adults, plus:
Diet: small amounts of milk frequently (mixed with antacid or alternated with alkalinising electrolyte solution)

Oral omeprazole to increase abomasal pH (? evidence)