Oral and pharyngeal problems can be disconcerting from the viewpoint of the cat owner and that of the veterinary surgeon. These conditions of the mouth and throat are a common occurrence and many of them are unresponsive to treatment. For a large proportion of these conditions no rational therapy is available because, at the moment, we do not completely understand their cause.

Although the causes of oropharyngeal disease in the cat are poorly recorded, it is clear that a number of these conditions may be a consequence of underlying generalised disease, particularly chronic kidney failure, leucopenia (depressed white blood cell count), immunosuppression secondary to FeLV or FIV infections and, rarely, diabetes mellitus. In such cases the oral problem cannot be expected to resolve unless the underlying problem is diagnosed and, where amenable to treatment, treated.

There are a number of signs which will suggest that a cat has some disorder of the mouth or pharynx. The cat may show no interest in food, or may come to the food bowl and then be reluctant to eat. It may chew with obvious caution and discomfort, may drop food from its mouth, or may swallow with great difficulty or discomfort. Excessive saliva may overflow from the mouth, there may be a marked unpleasant odour to the breath and, in some cases, bleeding. Clawing at the mouth and head shaking may also occur, particularly with foreign bodies or very painful disorders. The reluctance to eat may lead to weight loss which can become quite marked.

Lips  

A number of conditions may affect the lips and surrounding skin.

Eosinophilic granuloma (rodent ulcer, labial ulcer)

This is a chronic ulcerative area occurring on the lips, usually where the skin joins the lining membrane of the mouth. The affected part is relatively localised but the area gradually becomes larger. It is usually found in the region between the mid-line cleft of the lip (philtrum) and the canine tooth on the upper lip. The problem may occur on one side or both and occasionally may be seen elsewhere. The edges of the ulcer are hard and raised and the broken skin irregular. The base of the ulcer is salmon-pink. In most cases the problem is a cosmetic one rather than presenting any real disability for the cat, but sometimes very deep ulcers may cause pain and reluctance or inability to eat, and the animal may be unable to groom itself. A number of causes have been suggested for this problem, including continual irritation by the rough tongue, infection or food allergy; there is little to support these propositions.

A wide variation of treatments have been applied in cases of eosinophilic granuloma, reflecting the lack of any one uniformly successful treatment, and the unsatisfactory outcome of treatment in many patients. It would seem that the most successful approach is a four to six week course of the steroid prednisolone. This may resolve the lesion, but, if not, it may be followed by cryosurgery - a double cycle of controlled freezing and thawing. Although this inevitably leads to some scarring, recurrence seems less frequent than with other methods of treatment. In some cases Ovarid has also been used successfully. Whatever treatment is used, recurrence is common and the treatment may have to be repeated.

Squamous cell carcinoma (see below)

This cancerous growth can occur on the lips, as may fibratoma. This must be distinguished from eosinophilic granuloma and in cases of doubt, a biopsy may be taken from pathological examination to establish the diagnosis. Cryosurgery is the treatment of choice in those lesions which have not reached an advanced stage. Advanced lesions may require euthanasia.

Mycobacterial granulomata

These are very prolific masses in which mycobacteria may be identified on biopsy. The masses may ulcerate. Surgical removal or cryosurgery are the treatments of choice but fortunately the condition is rare.

Harelip

Harelip is a congenital anatomical defect. It will be apparent when the affected kitten is born, and may occur with a cleft palate. The degree of hare lip varies and a mild deficit may not interfere with normal life too much or may be repairable. However, for a severe deficit, especially if there is also a cleft palate, surgery is impractical and euthanasia is the only humane course since sucking is interfered with.

Wounds  

Wounds are commonly encountered as a result of road traffic accidents and as a consequence of fighting, particularly among entire males. Abscess formation may follow. If possible, wounds should be presented immediately to a veterinary surgeon so that they can be stitched if necessary, since scarring of the lips may hinder feeding. Animals with abscesses which do not burst with one or two days of regular bathing with warm water should be taken to a veterinary surgeon for lancing, as should those which make the cat generally unwell.

Acute inflammation of the mouth (stomatitis) and ulceration of the tongue (glossitis)  

Acute stomatitis

This can be caused by a variety of micro-organisms, but commonly one of the 'flu viruses is responsible. Both feline calcivirus and feline rhinotracheitis virus will produce stomatitis but feline calcivirus does so more commonly.

Feline calcivirus (FCV) is divisible into a number of strains which vary in capacity to produce disease. Some strains will produce mouth ulceration only, the ulcers appearing typically on the upper surface and margin of the tongue, although they may also occur on the gums, palate and nose. Other strains of calcivirus may produce ulceration together with relatively mild signs of upper respiratory tract disease.

Feline viral rhinotracheitis (FVR) is a more severe disease with typical signs of upper respiratory tract disease, often involving inflammation of the pharynx and tonsils. The presence of tongue ulcers is rare.

In both cases the viral infection may predispose to superimposed bacterial infection. Since there are no usable antiviral drugs, treatment must consist of the use of broad spectrum antibiotics to control secondary infection. Palatable antibiotic syrups formulated for children can be of particular value because of their ease of administration and their local action in the mouth and throat.

Attentive nursing of the patient with frequent removal of secretions is important. The cat should be offered liquidised or pureed aromatic foods such as strongly flavoured fish. If the cat refuses to eat for long periods, or becomes collapsed, specialised intensive nursing treatment may be needed.

Irritants

Many household materials, such as cleaners, paint strippers and bleach are irritants, and curiosity may lead cats (and children) to swallow these, causing irritation of the mouth and gut which may be very severe in some cases. Prevention is better than cure, and all such agents should be kept away from curious creatures, be they man or beast. Should such an accident occur, the cat should be taken to the veterinary surgeon (with the container of irritant).

Dental problems and gingivitis  

These problems will be considered together since they may be closely inter-related.

Dental disease

True dental caries, the process of decay to which human teeth are so susceptible, is very rare in the cat, though occasionally, true caries of the tooth table is encountered, particularly involving molar teeth. Affected teeth should be extracted, as should teeth in which injury has led to the tooth shattering, cracking or breaking off so as to expose its central sensitive pulp.

A more common problem than caries is erosion of the junction of the crown and the root which may lead to the crown shearing off from the root, either under normal wear or when an attempt is made to extract the tooth. The root is very likely to be infected and should be extracted.

Abscesses

Abscesses may form at the root tip of any tooth and may produce marked pain. After the diagnosis has been established by radiography, the tooth should be removed to allow the abscess to drain. One of the upper cheek teeth has roots which terminate in the bone just below the eye; occasionally abscessation around these roots may reveal itself as a distinctly fluid-feeling swelling below the eye or as a small hole in the skin from which pus discharges. If there is any doubt, radiography will confirm this diagnosis and extraction of the tooth is necessary.

Dental calculus, periodontitis and gingivitis

Dental calculus, also known as tartar, consists of mineral-impregnated bacterial plaque. Tartar may build up on any tooth, but is commonest on the outer faces of the molars and premolars, and on the inside surface of the incisors. Calculus accumulates with age and is more likely to occur in animals fed soft diets.

Calculus tends to accumulate around the junction of the gum with the tooth and, as this occurs, a niche is produced in which bacteria can flourish. As a consequence of this bacterial infection, the gum becomes inflamed (gingivitis) and retracts from the base of the tooth. It may also become ulcerated and the infection may spread to the gum. The retraction of the gum allows infection to track down the outside of the tooth root (periodontitis) and a discharge of pus (pyorrhoea) from around the teeth results. The tooth root may also become infected and eroded (see above).

In early cases, all that is needed is for the cat to have the tartar removed by 'scaling' under general anaesthesia. In severe, established cases, it will be necessary to take swabs to identify the organisms involved in the infection and to give long-term antibiotic therapy. After antibiotics have been given for three of four days, all the involved teeth should be taken out. This sequence avoids the risk of septicaemia following extraction.

Calculus usually reforms after scaling and, once it has been initiated, dental attention is likely to be required increasingly often. It is suggested that the feeding of dry cat food may help to limit the problem. If dry food is fed, free access to water should be allowed to avoid the risk or urinary tract disease.

Hyperaemia of the gum margin

In kittens a narrow band of reddening of the gum margin just below the teeth is a common finding. This appears to present no problem to the cat and resolves without any treatment. Owners need not be particularly concerned therefore unless other signs of disease are associated with it. A specific and rather more extensive and dramatic gingivitis (gum inflammation) has been reported in kittens three and a half to seven months of age. The cause of this condition is not known and it often fails to respond to treatment. The condition may disappear spontaneously when the cat cuts its permanent adult teeth.

Non-specific inflammation of the mouth and gums  

Inflammation and ulceration

Apart from the conditions mentioned above, there remains a large group of oral inflammatory conditions in the adult cat which are unrelated to dental disease and which are extremely unresponsive to treatment. These conditions present with long-term inflammation of the lining of the mouth, little vesicles and ulcers being present in most cases. The problem most frequently affects the angles where the jaws meet at the back of the mouth although, less commonly, any other part of the mouth can be affected.

The cause of this condition is not fully understood; a number of bacteria have been isolated but their significance remains uncertain. FCV and FVR occasionally cause a short-lived inflammation of the mouth (see above) lasting two to three weeks. It is suspected, however, the feline calcivirus may have a significant causal role in the chronic condition. In a survey undertaken at Bristol , it was found that gingivitis is very much more common in pedigree cats than in cats of mixed breeding. All the cases in pedigree cats were of the non-specific form, whilst most cases in cats of mixed breeding were associated with dental disease. The difference in the incidence of non-specific gingivitis was reflected in the frequency with which FCV could be isolated from the two groups of cats. Furthermore, in both groups there was a strong correlation between the presence of FCV and non-specific gingivitis. there is also a significant association between gingivitis/stomatitis and FIV infection. In fact, oral inflammation is one of the most common clinical signs in FIV-infected cats. It is not clear whether FIV plays a direct role or whether, like FeLV, it may precipitate gingivitis by its deleterious effect on the immune system. However, there is evidence that there is a link between FIV infection, FCV infection and gingivitis, and that cats infected with both viruses will have more severe oral lesions.

Treatment of these cases needs long-term antibiotic therapy and, in carefully selected cases, steroids may be used with caution. Cats infected with FIV are likely to respond favourable to corticosteroid therapy. Careful supportive nursing by the owner is again of great importance. Despite the lack of apparent involvement of dental disease in this condition, unresponsive cases may be improved by the removal of any involved teeth or even all the teeth. Provided they are fed moderately divided soft food, cats do well without their teeth.

Gingival hyperplasia

This is proliferation of the tissues of the gum to produce florid irregular masses. These are very friable and are easily damaged, causing ulceration and haemorrhage. Removal of the teeth may again be helpful since the teeth damage the mass during chewing. Attempts to cut off the masses are usually unsuccessful; bleeding is a problem and the masses recur. Burning them off by electrocautery, or the use of cryosurgery are more successful initially, but may provoke an increased response. The cause of this condition is unknown and its relation to the ulcerative condition is uncertain.

Oral cancers

The proliferating masses of non-specific gingivitis must be distinguished from the several types of cancerous growth which can affect the mouth. In cases of doubt, biopsy may be needed to obtain a diagnosis. Malignant tumours of the mouth, particularly squamous cell carcinomas, are unfortunately relatively common. Occasional benign tumours may be seen.

Tumours are encountered mainly in older cats, they commonly occur under the tongue, but may also be seen on the gums, tonsils and palate. Early in their growth they are firm white or pink nodules or lobed masses. Often, however, they are not noticed until they are advanced in growth and are large ulcerated bleeding masses, difficult to distinguish from gingival hyperplasia. Radiology, as well as biopsy, can then be helpful in diagnosis. Tumours of the mouth rarely spread to other parts of the body but, if removed, they commonly recur locally. The exception to this rule is squamous cell carcinoma of the tonsil, which frequently spreads elsewhere. In all cases of malignant tumours, treatment is palliative and euthanasia will be necessary sooner or later.

Benign fibrous tumours occasionally occur on the lips and cause no problem: they need not be removed unless so large as to be a hindrance to the cat. Polyps arising from the palate and growing up into the back of the nasal cavities and the pharynx can be very successfully removed surgically.

Salivary gland

Salivary gland disease is rare in the cat. Very occasionally, blockage of a salivary duct can give rise to a swelling under the tongue or on the neck; these are amenable to surgical treatment. Very rarely, cats exposed to human cases of mumps may develop a similar disease; there is no specific treatment, but supportive nursing is helpful.

Hard palate - foreign bodies

Not uncommonly, foreign bodies such as small sticks or bones may become wedged across the palate between the teeth, or may impale it. A general anaesthetic may be required for the removal of these.

Cleft palate

Cleft palate occurs in kittens as a developmental abnormality; some, but not all cases are of genetic origin. It may occur alone, or with hare lip. The condition becomes apparent soon after birth when there is difficulty in suckling and regurgitation of milk down the nose, accompanied by sneezing, noisy breathing and distress. The kittens do not thrive and can develop pneumonia due to inhalation of milk. Sometimes a kitten may die suddenly without warning signs. Treatment is not practical and euthanasia is the most appropriate course. Cleft palate also occurs in cats of all ages as a result of trauma, most commonly in road traffic accidents. The practicality of repair will depend on the severity of any other injuries sustained in the accident.

Soft palate

Congenital shortening of the soft palate occurs in kittens and is very similar in its effects to cleft palate. Treatment is not practicable.

The pharynx

Diseases of the throat and tonsils have similar signs to disease of the mouth but retching may also occur.

Pharyngitis

Inflammation of the pharynx commonly occurs as part of upper respiratory tract viral infection and the measures described above are applicable.

Pharyngeal tumours

These are usually malignant and euthanasia is indicated.

Foreign bodies

In any cat with signs of pharyngeal disease, the possibility of the presence of a foreign body must be considered. Foreign bodies, when present, are usually small bones, fish scales, fish hooks or fibrous or filamentous material. Anaesthesia may be required for radiology and is necessary for direct inspection of the pharynx and for the removal of offending items.

Tonsillitis

Tonsillitis is very rare except as a component of 'cat 'flu'.

Tonsillar squamous cell carcinoma

This is discussed above.