Journal of Feline Medicine and Surgery (1999) 1, 199–207

Intestinal obstruction by trichobezoars in five cats

V R Barrs*1, J A Beatty1, P L C Tisdall1, G B Hunt1, M Gunew2, R G Nicoll1, R Malik1

1Department of Veterinary ClinicalSciences, The University ofSydney, New South Wales 2006;2Creek Road Cat Clinic,189 Creek Rd, Mt Gravat,Queensland 4122, Australia

Date accepted: 7 September 1999

Between 1997 and 1999, five domestic crossbred cats (four long haired, oneshort haired) presented with a palpable abdominal mass and were shown tohave small intestinal trichobezoars at laparotomy or necropsy. Hair balls wereassociated with partial or complete intestinal obstruction and were situated inthe proximal jejunum to distal ileum. In four cats obstructions were simple,while the remaining cat had a strangulating obstruction. Three of the cats were10 years or older, and two were less than 4 years. In the three older catsabdominal neoplasia was suspected and investigations were delayed ordeclined in two of these cats because of a perceived poor prognosis.Predisposing factors identified in this series of cats included a long-hair coat,flea allergy dermatitis, inflammatory bowel disease and ingestion ofnon-digestible plant material. This report shows that the ingestion of hair is notalways innocuous and that intestinal trichobezoars should be considered in thedifferential diagnoses of intestinal obstruction and intra-abdominal mass lesions,particularly in long-haired cats. © 1999 European Society for Feline Medicine

Because of their fastidious grooming habitsand barbed tongues, cats commonly ingestlarge quantities of hair. Ingested hair is

either passed undigested in the faeces or accu-mulates in the stomach, from where it is vomitedperiodically as a ‘hair ball’. This is considered anormal physiological process (Wilkinson 1984).Hair may be retained in the stomach followingingestion because cats lack interdigestive migrat-ing myoelectric complexes (IMMC) that clearnon-digestible material from the gastrointestinaltract in other species. IMMC begin in thestomach and result in strong peristaltic contrac-tions that continue along the intestinal tract,moving large particulate material to the colon. Incats, IMMC have only been detected near theileum (Twedt 1994). In some cats, excessiveamounts of hair may accumulate in the gastro-intestinal tract as a result of overgrooming sec-ondary to pruritus or gastrointestinal motilitydisorders (Crystal 1998). Affected cats are usuallylong haired since short hair passes more readilythrough the pylorus and intestines.

To the authors’ knowledge there are no pub-lished case reports of small intestinal obstructionby trichobezoars in cats, although one case isdocumented briefly in a textbook (Green 1993).

*Corresponding author. E-mail vanessabarrs@catstudy.demon.co.uk

1098–612X/99/040199+09 $12.00/0

Case reports

Case 1

A 15-year-old spayed domestic long-haired(DLH) cat presented with a 4-day history ofanorexia and vomiting. Physical findingsincluded dehydration, pale mucous membranesand slow capillary refill. A thickened, solidlydistended segment of intestine (approximately8 cm in length) was palpated in the cranial abdo-men. Haematology demonstrated neutrophiliawith a left shift (segmented neutrophils25.5×109/l; band neutrophils 6.0×106/l) andmonocytosis (1.9×109/l). Abnormal serum bio-chemistry results included hypokalaemia(3.5 mmol/l), azotemia (urea 23 mmol/l), hypo-albuminaemia (20 g/l) and metabolic alkalosis(bicarbonate 31 mmol/l). Intravenous fluids,amoxycillin and trimethoprim–sulfoximazolewere administered parenterally. Intestinal neo-plasia was considered likely and the cat wasreferred to the University Veterinary Centre,Sydney (UVCS) 3 days later for furtherinvestigation.

The cat was moribund and hypothermic (rectaltemperature 36.8°C) at presentation. Mucousmembranes were pale and tacky with prolongedcapillary refill. The cranial abdomen was grossly

© 1999 European Society of Feline Medicine

200 V R Barrs et al

Fig 1. Right lateral abdominal radiograph of Case 1 showsmassive distention of the stomach with gas and fluid.Caudal to the stomach, a greatly distended loop of smallintestine is evident containing material of heterogeneousradio-opacity.

Fig 2. Left lateral thoracic radiograph of Case 1 shows dis-tention of the oesophagus with soft-tissue or fluid opacity.There is a localised area of pulmonary infiltrate super-imposed on the cardiac silhouette in the region of the rightmiddle lung lobe, suggestive of aspiration pneumonia.

Fig 3. Resected length of proximal jejunum from Case 1.Note the trichobezoar obstructing it.

distended with gas and fluid and the intestinalmass was still palpable. A right lateral abdominalradiograph showed massive distension of thestomach with gas and fluid (Fig 1). Thoracicradiographs showed distension of the oesoph-agus, probably with fluid, associated with ven-tral displacement of the trachea. An area ofpoorly defined interstitial-alveolar opacity in theregion of the right middle lung lobe was consist-ent with aspiration pneumonia (Fig 2). Afterpassage of a stomach tube, 640 ml of brownfluid containing digested blood was drained.Laboratory tests demonstrated anaemia (hae-matocrit 0.17 l/l), hypoproteinaemia (45 g/l),

hypokalaemia (2.0 mmol/l), hyponatraemia(135 mmol/l), hypochloraemia (85 mmol/l) andmetabolic alkalosis (bicarbonate 32 mmol/l,base excess 7.5 mmol/l, pH 7.41). The cat wasconsidered to have complete small intestinalobstruction. Diagnostic possibilities includedintestinal neoplasia, a foreign body or intussus-ception. Abdominal ultrasonography demon-strated the mass was a segment of boweldistended with solid material; the intestinal wallwas not thickened and a multi-layered appear-ance characteristic of an intussusception wasabsent. A needle aspirate from the lumen ofthe intestinal segment yielded material with afoetid odour. An intestinal foreign body wasconsidered most likely and an exploratorylaparotomy was performed immediately, as thecat’s condition was rapidly deteriorating. Thecat was given intravenous colloids (15 ml/kg;Haemaccel, Hoechst), amoxycillin/clavulanicacid (20 mg/kg subcutaneously; Clavulox,Pfizer) and enrofloxacin (5 mg/kg subcutane-ously; Baytril, Bayer) pre-operatively. A typedblood transfusion (50 ml type B blood) was givenintra-operatively. At laparotomy, the duodenumwas distended with gas and fluid and a segmentof proximal jejunum (12 cm) was distended withsolid material (3 cm diameter). The intestinalwall was discoloured purple and the mass couldnot be moved within the intestinal lumen. Re-gional lymph nodes were moderately enlarged.The segment of intestine was considered non-viable and was resected. It contained a largetrichobezoar (Fig 3). An end-to-end intestinalanastomosis was performed using single inter-rupted sutures of 4-0 polydiaxanone (PDS). To-wards the end of the procedure the cat suffereda cardiac arrest. It was resuscitated, but hadanother cardiac arrest 1 h later and could not be

Intestinal obstruction by trichobezoars in five cats 201

Fig 4. Lateral (a) and ventrodorsal (b) radiographs of Case 2showing distention of the stomach with gas and fluid,dilated intestinal loops and bunching together of the smallintestines in the mid-ventral abdomen.

Case 2

A 4-year-old castrated DLH cat had a history ofrecurrent ‘miliary dermatitis’ associated withheavy flea infestations. The cat presented toUVCS with a 3 day history of malaise, vomitingand inappetence. A similar episode had occurred5 months previously and had resolved followingintravenous fluid therapy and amoxycillin/clavulanic acid (125 mg every 12 h per os). Onphysical examination the cat was dehydrated,had a moderate flea burden and a matted haircoat. An abdominal mass was palpated andthought to be a thickened loop of small intestine.Haematology showed a mild segmented neutro-philia (10.5×109/l) with granulation and hyper-segmentation of neutrophils and monocytosis(1.29×109/l), consistent with inflammation andstress. The haematocrit (0.45 l/l) and totalplasma protein (95 g/l) were increased, suggest-ive of haemoconcentration. Serum biochemistryshowed azotaemia (urea 22 mmol/l, creatinine185 mmol/l), hyperglycaemia (13.2 mmol/l),elevated ALT activity (145 U/l), hyperkalaemia(5.4 mmol/l), hyponatraemia (141 mmol/l),hypochloraemia (94 mmol/l) and metabolicalkalosis (bicarbonate 30 mmol/l). The urinespecific gravity was >1.050 and there was noglucosuria.

Abdominal radiographs showed distension ofthe stomach with fluid and gas, dilated, fluid-filled loops of small intestine and bunching ofsmall intestinal loops in the mid-ventral abdo-men (Fig 4). The physical findings, radiographicchanges and electrolyte abnormalities were sug-gestive of a proximal small intestinal obstruction.Given the cat’s age and acute onset of clinicalsigns, a foreign body or intussusceptionwas suspected and an exploratory laparotomywas performed. A 10 cm length of jejunum washyperaemic and distended but considered viable(Fig 5). A longitudinal enterotomy incision wasmade distal to this area and a long mattedtrichobezoar was removed with Adson thumbforceps (Fig 6). The enterotomy incision wasclosed with simple interrupted sutures of 4-0PDS. A small tear occurred in the hyperaemic

area of jejunum during enterotomy closure andwas repaired. A bilateral serosal patch wasplaced over the hyperaemic area using adjacentloops of jejunum sutured with 4-0 PDS. The liver

resuscitated. Permission for necropsy was notgiven. Histology of the resected bowel showednecrosis of the mucosa, submucosa and some ofthe muscularis. The outer muscularis and serosawere considered viable, although there was aheavy neutrophilic infiltration and blood vesselswere dilated.

202 V R Barrs et al

Fig 5. The distended loop of proximal jejunum in Case 2.

Fig 6. The intestinal trichobezoar from Case 2 duringremoval from the proximal jejunum.

was normal on gross appearance and on histo-pathology of a liver biopsy there was mildcentral fibrosis in some lobules, considered un-likely to be of clinical significance. Amoxycillin/clavulanic acid (20 mg/kg subcutaneously every12 h) was administered post-operatively. The catrecovered unremarkably and prior to dischargefrom hospital the hair coat was clipped short anda topical insecticidal spray (fipronil; Frontline,Rhone Merieux) was applied. The owners wereadvised to use ongoing, regular flea control andto groom the cat frequently to prevent excessiveingestion of hair.

Case 3

A 10-year old spayed Persian-cross cat presentedto UVCS with a 4-day history of anorexia anda 1-day history of dry-retching. The cat had achronic history of intermittent vomiting and wasfed tinned fish, dry cat food and raw meat. It was

in poor body condition (3.3 kg) and a large masswas palpated in the mid-abdomen. Serologicalscreening tests for feline leukaemia virus antigenand feline immunodeficiency virus antibodywere negative. Serum biochemistries wereunremarkable. An abdominal ultrasonographicexamination demonstrated a region of distendedcolon or ileum adjacent to a region of circumfer-entially thickened intestinal wall and enlarge-ment of several mesenteric lymph nodes. Anintestinal obstruction secondary to neoplasticinfiltration of the gut wall with metastases to themesenteric lymph nodes was suspected; how-ever, cytology of aspirates from the enlargedlymph nodes was consistent with reactivechange (70% small lymphocytes, 20% mediumlymphoid cells and scattered large lymphoblasts,occasional eosinophils, plasma cells, neutrophilsand macrophages). Abdominal radiographstaken subsequently demonstrated a large tubularmass of heterogeneous gas and soft tissueopacity in the cranioventral abdomen in theregion of the ascending and transverse colon.Several loops of small intestine in the leftcraniodorsal abdomen were dilated with gas anddisplaced by the mass (Fig 7).

At exploratory laparotomy, intestinal obstruc-tion was detected at the ileocaecocolic junction.The affected area of bowel appeared abnormallythickened and was resected from the distal endof the ileum to the proximal colon, including theileocaecocolic junction. It contained a large massof matted hair. End-to-end anastomosis of theremaining ileum to the colon was performedusing single interrupted, obliquely angledsutures of 4-0 PDS. Histopathology of the distalileum showed villous atrophy, crypt abscessesand oedema of the submucosa and muscularis.In the submucosa, fibroplasia and a heavyeosinophilic infiltrate was apparent. The proxi-mal colon was normal histologically and themesenteric lymph nodes were reactive.Amoxycillin/clavulanic acid (20 mg/kg every12 h subcutaneously) was administered follow-ing surgery and the cat recovered unremarkably.Since food allergy was considered a possibleaetiology for the eosinophilic enteritis, theowner was advised to feed a restricted diet byavoidance of dry cat food and tinned fish. Thecat was returned for vaccination 1 year laterand was considered to be in good health,having gained 1.8 kg (bodyweight 5.1 kg) sincethe time of surgery. It was fed a diet of rawbeef and chicken and had no recent history ofvomiting.

Intestinal obstruction by trichobezoars in five cats 203

Case 4

An approximately 10-year old spayed domesticshort-haired cat was presented for lethargy and

inappetence. A small abdominal mass was pal-pated on physical examination, which in otherrespects was unremarkable. Diagnostic possi-bilities including lymphosarcoma or intestinaladenocarcinoma were considered likely bythe attending clinician. Further investigationsincluding haematology, biochemistry and ab-dominal ultrasonography were recommended;however the owners requested that the catbe euthanased. A post-mortem examinationrevealed the mass detected on physical examin-ation to be within the lumen of the proximaljejunum. The small intestine oral to the mass wasdilated to three times its normal diameter, whiledistal to the mass the intestine was of normalcalibre. When the intestine was incised longi-tudinally, the mass was found to consist of aspherical ball of hair approximately 1 cm indiameter. Irregular erythemic mucosal erosionsorientated longitudinally were evident immedi-ately oral to the hair ball. No other significantnecrospy findings were recorded.

Fig 7. Lateral (a) and dorsoventral (b) radiographs of Case 3showing a tubular mass of heterogeneous gas and soft tissueopacity in the cranioventral abdomen in the region of theascending and transverse colon. Note also the increasedamounts of gas within numerous loops of small intestine.

Case 5

A 7-month-old castrated Birman presented toCreek Road Cat Clinic with a 4-day history ofinappetence, lethargy and vomiting. Physicalfindings included moderate dehydration anddepression. A small, firm mass was palpated inthe mid-abdomen, while some intestinal loopswere considered to be dilated with fluid and gas.The cat was normothermic (38.6°C). Results ofin-house haematology and serum biochemistrieswere normal. At exploratory laparotomy, a 5 cmlong cylindrical mass (2 cm diameter) waspresent in the ileum approximately 5 cm oral tothe ileocaecal valve. There was marked erythemaof the ileum at the site of obstruction. An enter-otomy was performed and a trichophytobezoarconsisting of hair tangled with ‘Cobbler’s peg’(Bidens pilosa) burrs was removed. The enter-otomy incision was closed using simple inter-rupted sutures of 4-0 PDS. Gentamicin (6 mg/kgintravenously every 24 h) and amoxycillin(15 mg/kg subcutaneously every 12 h) wereadministered following surgery. The catrecovered uneventfully.

DiscussionExcessive accumulation of hair in the alimentarytract of cats may result in oesophageal obstruc-tion, gastric outflow obstruction, small intestinalobstruction, constipation or colitis. Obstructions

204 V R Barrs et al

may be partial or complete. Intraoesophagealhairballs may occur secondary to underlyingoesophageal hypomotility or stricture (Cliffordet al 1970, Van Stee et al 1980, Regnier 1985) andalso in cats with no evidence of oesophagealdysfunction due to incomplete vomition of hairfrom the stomach (Squires 1989, Court et al1994).

Hair, or hair and plant material, if chronicallyretained in the stomach may cause pyloric out-flow obstruction and may form calcified concre-tions (Frye 1972, Twedt 1994). Recurrence aftersurgical removal has been reported in catsdespite regular grooming, flea control andadministration of laxatives (Ryan et al 1978,Worwood & Jones 1979). Although not specifi-cally characterised, gastric motility disturbancesare hypothesised to cause recurrent gastrictrichobezoars/trichophytobezoars and therapywith prokinetic drugs such as metoclopramide orcisapride represent an appropriate component oftherapy (Crystal 1998). Factors which may con-tribute to a decrease in gastric motility andtrichobezoar formation include activation of thesympathetic nervous system secondary to painor stress, hypokalaemia, uraemia, gastritis andanticholinergic drugs (Twedt 1994).

Gastric hair balls in rabbits commonly resultfrom gastrointestinal stasis due to stress, pain orfright combined with a lack of dietary fibre,behavioural-related overgrooming or excessivehair loss, especially when combined with dehy-dration. In addition, rabbits are prone to theformation of hairballs since they are unable tovomit (Gillet et al 1983, Harcourt-Brown 1998,Ramer et al 1999). Gastric rupture in rabbits hasbeen reported secondary to large or calcifiedbezoars (Lee et al 1978). In humans, gastricphytobezoars consisting of undigested cellulosefibres occur more commonly than trichobezoarsand may develop as a complication of diabeticgastroparesis or following vagotomy. In thesepatients phase III interdigestive motor complexactivity is characteristically reduced, providingthe physiological explanation for the develop-ment of phytobezoars (Winkler & Saleh 1983).

Obstruction of the small intestine by hair hasbeen documented incompletely in the cat (Bright& Bauer 1994, Crystal 1998). The entity has beenwell-described in rabbits where it may occurspontaneously or secondary to medical treat-ment of gastric hairballs (Sebesteny 1977,Harcourt-Brown 1998). Likewise, in humanpatients, small intestinal obstruction may occursecondary to spontaneous passage of gastric

phytobezoars or following enzymatic digestionor endoscopic fragmentation (Rumley et al 1983,Nomura et al 1997).

The pertinent details concerning the five catsin this report are summarised in Table 1. It isnoteworthy that in the three older cats abdomi-nal neoplasia was considered likely by theattending clinicians and as a result, investiga-tions were delayed or declined in two of thesecases because of the anticipated poor prognosis.Mesenteric lymphadenomegaly was detected atlaparotomy in Case 1 and during abdominalultrasonography in Case 3. In Case 3, the sono-graphic findings were suggestive of intestinalobstruction; however, thickening of the intestinalwall and enlargement of regional lymph nodeswere considered likely result from a neoplasticprocess. Abdominal radiographs taken subse-quently were more suggestive of an intraluminalforeign body because of the size and hetero-geneous soft-tissue density of the intestinal mass.Ultrasonographic imaging of the gastrointestinaltract is compromised by the presence of intra-luminal gas which causes a highly hyperechoicinterface associated with a distal acousticshadow (Penninck et al 1989). Thus, when ileusor intestinal obstruction are suspected, plainabdominal radiographs should be obtained priorto abdominal ultrasonography.

Causes of intestinal obstruction in cats includetumours (lymphosarcoma, adenocarcinoma,mast cell tumour), foreign bodies, intussuscep-tion, volvulus, intestinal torsion, incarceration ofbowel in a hernia, adhesions or stricture, intra-mural abscess, granuloma or haematoma andcongenital malformations (Sherding 1994). Dueto the fascination of some cats with string-likeobjects, the majority of intestinal foreign bodiesin cats are linear and the ingestion of non-plicating foreign bodies is generally considereduncommon. In the absence of historical evidenceof foreign body ingestion, ingested hair shouldbe considered as a potential cause of intestinalobstruction, particularly in long-haired cats.

Intestinal trichobezoars may cause a spectrumof clinical signs since obstruction may be partialor complete, involve any portion of the smallintestine or colon, and be strangulating or non-strangulating. Case 1 was characterised by anacute, strangulating obstruction of the proximaljejunum. Strangulating obstructions involvesevere vascular compromise of the obstructedbowel segment (Bright & Bauer 1994). In Case 1,the affected segment of intestine probably hadvenous drainage with intact arterial perfusion,

Intestinal obstruction by trichobezoars in five cats 205

Tab

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Cas

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115

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mL

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hair

coat

Unk

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Stra

ngul

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24

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54

MN

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(‘C

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Dom

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csh

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hair

;FN

—Fe

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N—

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206 V R Barrs et al

AcknowledgementsJA Beatty is supported by a Research CareerDevelopment Fellowship awarded by TheWellcome Trust, UK. Richard Malik is supportedby the Valentine Charlton Bequests administeredby the Post Graduate Foundation in VeterinaryScience of The University of Sydney. The authors

resulting in intraluminal sequestration of fluidand blood, hypovolaemia and Gram-negativesepsis secondary to transmural migration oftoxins and bacteria. In contrast, the clinical signsin Case 3 (anorexia and non-productive vomit-ing) and Case 4 (inappetence and lethargy) weremore subtle, consistent with simple obstructionof the small intestine. Constipation is anothersequel of ingesting large quantities of hair be-cause its incorporation into the stool results inhard impactions that are difficult or painful toevacuate from the colon (Sherding 1994). Colitisoccurs through a similar mechanism with physi-cal abrasion of the colonic wall giving rise topainful defaecation and sometimes fresh bloodin the stool (Menrath & Malik, unpublishedobservations).

Electrolyte imbalances observed in cats withintestinal obstructions depend on the level of theobstruction. Metabolic alkalosis is typicallyassociated with pyloric outflow obstruction andmay also occur with proximal intestinal obstruc-tion (such as in Cases 1 and 2) because loss ofgastric acid is prominent. Hypokalaemia, as seenin Case 1, occurs commonly in cats with intes-tinal obstructions and results from loss ofpotassium-rich alimentary secretions proximal tothe obstruction and from renal potassium loss. Itis thought that endotoxins secreted by bacteria inthe obstructed intestinal segment activate cyclic-AMP-driven secretion as intestinal secretiondoes not occur in obstructed germ-free dogs(Guilford & Strombeck 1996). Other factors con-tributing to mucosal secretion of water, sodiumand potassium proximal to the obstruction mayinclude increased portal and lymphatic pressure,and ischaemia (Johnson 1992).

In Case 3, underlying disease of the smallintestine may have predisposed the cat to intes-tinal obstruction by a hair ball. Fibrosis andinflammatory infiltration of the distal ileum mayhave resulted in a localised decrease in intestinalmotility and failure to propel ingested hairthrough the ileocaecocolic junction. Although thehistological changes were somewhat unusual,the cat’s marked weight gain and resolution ofchronic vomiting after surgery and dietarychange are consistent with food hypersensitivity.In retrospect, multiple small intestinal biopsiesfrom this cat at the time of exploratorylaparotomy may have helped to clarify thenature and extent of its enteropathy. Structurallesions of the gastrointestinal tract should beruled out as an underlying cause of intestinalobstruction by trichobezoars particularly if there

is no historical or physical evidence of over-grooming secondary to pruritus or behaviouraldisorders.

In Case 4, the mucosal lesions seen at necropsywere presumably the result of traumatic damageas the hair ball was propelled aborally by intes-tinal peristalsis. Even though partial intralumi-nal obstruction was present, it was consideredthat the administration of a petroleum-basedlaxative by mouth would probably have resultedin the eventual passage of the hair ball into thecolon.

Cases 2 and 5 were both young cats andintestinal obstruction was presumably the resultof excessive ingestion of hair associated with fleaallergy dermatitis (Case 2) or overgrooming toremove non-digestible plant material from thehair coat (Case 5). Plant material entangled in thehair may have impeded passage of the tricho-phytobezoar through the gastrointestinal tract.Any pruritic condition may result in overgroom-ing and should be considered a risk factor forthe development of alimentary trichobezoars,particularly in long-haired cats.

Recommended treatments for hair balls in longhaired cats include regular grooming and admin-istration of semi-solid petroleum-based laxativesto lubricate the material and facilitate its aboralpassage (Crystal 1998). Liquid preparations con-taining mineral oil should be avoided because ofthe risk of lipid pneumonia following aspiration.Access to lawn grass may be helpful since theingestion of non-digestible plant material isassociated anecdotally with the vomiting of hairballs. A commercial diet formulated to assist inthe safe passage of ingested hair has recentlybecome available (Hill’s Science Diet, hairballcontrol formula). Prokinetic drugs such as cis-apride may be of therapeutic value in cats withunderlying motility disorders. Clipping the coatof long-haired cats every 3 to 4 months to mini-mise hair ingestion should be considered also,especially in warmer environments where fleaburdens are likely to be higher. Furthermoreregular grooming and flea control is important inlong haired cats.

Intestinal obstruction by trichobezoars in five cats 207

wish to thank Dr Paul Horsky for referring oneof the cases and contributions from colleagues atthe University Veterinary Centre, Sydney.

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