Inflammatory disorders (Table 42.2)

Viral

Mumps

The mumps virus is a paramyxovirus and is the most common cause of acute painful parotid swelling affecting children. The disease starts with a prodromal period of 1 or 2 days during which the child experiences feverishness, chills, nausea, anorexia and headache. This is typically followed by pain and swelling of one or both parotid glands. The parotid pain can be very severe and is exacerbated by eating or drinking. Symptoms resolve spontaneously after 5—10 days.

In a classical case of mumps the diagnosis is based on the history and clinical examination. However, the presentation may be atypical or sporadic or have predominantly unilateral or even submandibular involvement. In this situation, paired blood specimens taken approximately 10 days apart are used to confirm the diagnosis. One episode of infection confers lifelong immunity.

A number of other viral agents Coxsackie A and B, parainfluenza 1 and 3, enteric cytopathogenic human orphan viruses (ECHO) and lymphocytic choriomeningitis can all cause identical signs and symptoms.

Bacterial

Acute ascending bacterial sialadenitis affects mostly the parotid glands. Historically it was described in dehydrated, cachectic patients often following major abdominal surgery when the patient was on a ‘nil by mouth’ regime. The reduced salivary flow and oral sepsis resulted in bacteria colonising the parotid duct and subsequently involving the parotid parenchyma. With current medical practice and improved oral hygiene patients are rarely allowed to become dehydrated and this clinical pattern is uncommon. The typical patient presenting with an acute ascending bacterial parotitis now is an otherwise fit young adult with no obvious predisposing factors (Fig. 42.1). The clinical presentation is of the onset of tender, red, painful parotid swelling over a few hours. There is associated malaise, pyrexia and often regional lymphadenopathy. Pain is exacerbated on attempting to eat or drink. The parotid swelling may be diffuse but often it is localised to the lower pole of the gland presumably because the infection tends to localise under the effect of gravity.

If the gland is gently ‘milked’ by massaging the cheek, cloudy turbid saliva can be expressed from the parotid duct and this should be cultured. The infecting organism is usually Staphylococcus aureus or Streptococcus viridans. Sialography must never be undertaken during the acute phase of infection as the retrograde injection of infected material into the duct system will result in bacteraemia. Ultrasound imaging shows the characteristic dilatation of the acinae (Fig. 42.2).

If the patient presents at an early stage before abscess for­mation, the infection can usually be controlled with antibiotics. In a patient not allergic to penicillin a combination of a broad-spectrum penicillin and a penicillinase-resis­tant agent is usually effective. If the gland becomes fluctuant indicating abscess formation, the pus must be drained. Occasionally it is possible to drain the abscess by aspirating the pus through a large-bore hypodermic needle but usually it is necessary to undertake formal surgical drainage under general anaesthesia (Table 42.3).

Chronic bacterial sialadenitis is far more common in the submandibular salivary gland and it usually occurs secondary to chronic obstruction. Unfortunately the submandibular gland has a poor capacity for recovery following infection and, in most cases following control of any acute symptoms with antibiotics, the gland itself must be removed. During the operation great care must be taken not to damage the mandibular branch of the facial nerve when making the incision, the lingual nerve when mobilising the gland and clamping the duct and the hypoglossal nerve when separating the gland from the floor of the submandibular triangle.

Recurrent sialadenitis of childhood

Recurrent sialadenitis of childhood exists as a distinct clinical entity but little is known regarding its aetiology and prognosis. It is characterised by the rapid swelling of usually one parotid gland accompanied by pain and difficulty in chewing as well as systemic symptoms such as fever and malaise. Although each episode of parotid swelling is normally unilateral the opposite side may be involved in subsequent episodes. Each episode of pain and swelling lasts for 3—7 days and is followed by a quiescent period of a few weeks to several months. Occasionally episodes are so frequent that the child loses a considerable amount of schooling. The onset is usually between 3 and 6 years although it has been reported in infants as young as 4 months. The diagnosis is based on the characteristic history and is confirmed by sialography which shows a very characteristic punctate sialectasis often likened to a snow storm against a dark night sky (Fig. 42.3).

Traditionally the episodes of parotitis have been treated with antibiotic and symptoms settle within 3—5 days on such a regime. Occasionally recurrent episodes are so frequent that prophylactic antibiotics are required for a period of months or years. Spontaneous resolution of symptoms seems to occur at puberty.

Specific ‘infections’ (granulomatous sialadenitis)

Mycobacterial infections

Tuberculosis and nontuberculous parotitis typically presents as a tumour-like swelling of the gland. Symptoms are usually minimal with little pain and no pyrexia. Often the diagnosis is not suspected and the mass is excised by formal parotidectomy.

Cat-scratch disease

Cat-scratch disease is caused by Bartonella henselae. It is a common disease in the USA but is not often seen in the UK. Children are usually affected. Symptoms follow a scratch by a cat when a small pustule forms at the site of the scratch. There is an associated lymphadenitis usually affecting the cervical nodes and mild pyrexia and encephalopathy with occasional transient cranial nerve palsies. The parotid glands are swollen in 3 per cent of cases. The condition is self-limiting and resolves without treatment.

Syphilis

Syphilis parotitis is now rare in the UK as the disease itself is uncommon. The glands can be involved in the acute early stages but are more often involved in tertiary syphilis with gumma formation, gland destruction and dense fibrosis.

Toxoplasmosis

Toxoplasmosis is due to the protozoan organism Toxoplasma gondii. In most cases infection is not recognised and is asymptomatic. When symptoms do occur the patient usually presents with lymphadenopathy and malaise sometimes accompanied by a headache and sore throat. The enlarged lymph nodes are rubbery and are not tender. On occasion the patient presents with isolated unilateral parotid swelling some weeks before the lymphadenopathy develops. In this situation a parotidectomy is often performed which leads to the diagnosis. Diagnosis is further confirmed by the detection of a positive Sabin—Feldman dye test on the serum. The disease follows a self-limiting course and resolves sponta­neously after weeks or months. If symptoms are severe the patient is treated with a 3- or 4-week course of pyrimethamine and sulphadiazine.

Deep mycoses

Fungal infections of the salivary glands occur only in immu­nocompromised patients and are most commonly seen in human immunodeficiency virus (HIV)-positive patients. Salivary gland involvement is usually just one manifestation of a more generalised infection. The patient presents with a tumour-like swelling of the affected gland. Often there is extensive central necrosis. Fresh material is needed for culture and identification of the organism. Treatment is by appropriate systemic antifungal chemotherapy.

Sarcoid

Sarcoidosis has a predeliction for salivary tissue, hut only rarely is salivary swelling the presenting feature. Parotid gland involvement occurs in 10 per cent of cases classically as part of Heerfordt’s syndrome which comprises parotid swelling, anterior uveitis, facial palsy and fever. Xerostomia may be a prominent feature. A less usual presentation is with bilateral parotid and submandibular swelling which is one of the causes of Mikulicz’ syndrome. In each of these presentations salivary involvement is widespread and representative histology can be obtained from a minor salivary gland biopsy. Rarely the patient will present with a localised tumour-like swelling in one parotid gland the so-called sarcoid pseudotumour. In the absence of other signs or symptoms the diagnosis is only likely to be made following parotid surgery for a presumed neoplasm.

Wegener’s granulomatosis

Although the typical presentation is chronic granulomatous ulceration and destruction in the nasopharynx or sometimes the oral cavity, Wegener’s granulomatosis can involve the major salivary glands. Diagnosis is based on the histological finding of necrotising arteritis often associated with numerous giant cells and granulomas. Pulmonary and renal involvement is very common. Treatment is by cytotoxic chemotherapy such as cyclophosphamide or azathioprine. The prognosis is poor.

Granulomatous disease of minor salivary glands

Granulomatous cheilitis, Melkersson—Rosenthal syndrome (recurrent facial palsy/facial swelling/fissured tongue) and Crohn’s disease all affect the minor salivary glands of the lips. Cheilitis glandularis is a rare disorder mainly of adult males in whom the lower lip becomes swollen and hard. The labial salivary glands become nodular and their orifices are inflamed and swollen.

Allergic sialadenitis

A variety of potential allergens causing acute parotid swelling has been identified. Some foods, drugs (most frequently chloramphenicol and tetracycline), metals such as nickel and pollens have been incriminated.

Radiation sialadenitis

Following the start of therapeutic irradiation when the parotid glands are within the radiation field the patient develops an acute parotitis usually after 24 hours. The glands are swollen and tender and there is a marked rise in salivary amylase and the salivary flow rate is reduced. The reaction is self-limiting and resolves after 2 or 3 days even though the radiotherapy continues. This reaction is quite distinct from the permanent radiation atrophy that occurs with therapeutic doses above 50 Gy, which develops progressively some weeks after the radiation has been completed.

Human immunodeficiency virus-associated sialadenitis

Chronic parotitis in children is almost pathognomonic of HIV infection. In adults a sicca syndrome and lymphocytic infiltration of the salivary glands are more usual. The presen­tation of HIV-associated sialadenitis is very similar to classic­al Sjogren’s syndrome. Dry mouth, dry eyes and swelling of the salivary glands together with lymphadenopathy suggest the diagnosis. Histologically the condition closely resembles Sjogren’s syndrome and differentiation may be difficult. However, autoantibodies including antinuclear, rheumatoid factor, SS-A and SS-B are absent unless the patient coincidentally has a connective tissue disorder. Acquired immunode­ficiency syndrome (AIDS)-associated lymphoma presenting as salivary gland swelling has also been described.

Another presentation of salivary gland disease in HIV-positive patients is multiple parotid cysts causing gross parotid swelling and significant facial disfigurement. On imaging with computerised tomography (CT) or magnetic resonance imaging (MRI) the parotids have the appearance of Swiss cheese with multiple large cystic lesions. The glands are not painful and there is no reduction in salivary flow rates. Surgery may be indicated to improve the appearance (Fig. 42.4).

Sialadenitis of minor salivary glands

Acute necrotising sialometaplasia is an unusual condition which was first described in 1973. It occurs only on the hard palate in the molar region in the vault of the palate midway between the midline and the gingival margin. It is only seen in heavy smokers. It has a characteristic appearance which resembles a carcinoma with central ulceration and raised erythematous margins. The ulcer may be as much as 3 cm in diameter. As it so closely resembles a carcinoma the diagnosis is often made on the basis of a surgical biopsy. The lesions are self-healing but often take 10—12 weeks to resolve (Fig. 42.5).