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).
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
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
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).