The onset of the disease is insidious and most patients have difficulty in stating a definite time of onset. The clinical manifestations are diverse. The severity of the disease varies greatly.
1.Local manifestations
(1) Dry mouth: due to salivary gland lesions, the lack of salivary mucin causes the following common symptoms.
(1) 70~80% of patients complain of dry mouth, but it is not always the first symptom or the main complaint. In serious cases, the oral mucosa, teeth and tongue are sticky, so that it is necessary to drink water frequently when speaking, and it is necessary to send down with water or liquid food when eating solid food, and sometimes it is necessary to get up to drink water at night.
Rampant dental caries is one of the characteristics of this disease. About 50% of the patients have multiple caries which is difficult to control the development, and it shows that the teeth gradually become black, then small pieces fall off, and finally only the residual roots remain.
(iii) In adult mumps, 50% of patients present with intermittent alternating parotid swelling and pain, involving unilateral or bilateral. Most of them resolve on their own in about 10 days, but sometimes the enlargement persists. A few have submandibular gland enlargement and less frequently sublingual gland enlargement. Some of them are accompanied by fever. Some of them have persistent enlargement of the parotid gland and should be alerted to the possibility of malignant lymphoma.
④The tongue shows painful tongue, dry and cracked tongue, and atrophied and smooth tongue papillae.
(5) The oral mucosa appears to be ulcerated or secondary to infection.
(2) Dry keratoconjunctivitis This is due to the decrease of mucin secretion from the lacrimal gland and the symptoms of dry eyes, foreign body sensation, few tears, and in severe cases, painful crying without tears. Some patients have recurrent purulent infections of the eyelid margin, conjunctivitis, and keratitis.
(3) Other superficial areas such as nose, hard palate, trachea and its branches, digestive tract mucosa, and exocrine glands of vaginal mucosa can be involved, resulting in less secretion and corresponding symptoms.
2.Systemic manifestations
In addition to dry mouth and eyes, patients may also have systemic symptoms such as weakness and low fever. About 2/3 of patients have systemic damage.
(1) The pathological basis of skin lesions is local vasculitis. The following manifestations are present.
(1) Allergic purpura-like rash: mostly seen in the lower extremities, it is a rice-grain-sized red papule with clear borders, does not fade when pressed, and appears in batches. Each batch lasts for about 10 days and can fade on its own with brown pigmentation.
Erythema nodosum is less common.
(3) Raynaud’s phenomenon is not serious and does not cause ulceration of the finger end or atrophy of the corresponding tissue.
(2) Skeletal muscle Joint pain is more common. Only a small percentage of joints are swollen, but most of them are not serious and transient. Destruction of joint structures is not a characteristic feature of the disease. Myositis is seen in about 5% of patients.
(3) Kidney About 30-50% of patients in China have kidney damage, mainly involving the distal tubules, manifested as hypokalemic muscle paralysis due to type I renal tubular acidosis. Nephrogenic dysuria, which manifests as polyhydramnios and polyuria, is also frequently seen in patients with renal tubular acidosis. A subclinical form of renal tubular acidosis can be seen in about 50% of patients by ammonium chloride loading test. Proximal renal tubular damage is less common. A small percentage of patients present with more pronounced glomerular damage, with clinical manifestations of massive proteinuria, hypoalbuminemia, and even renal insufficiency.
(4) Lung Most patients have no respiratory symptoms. Those with mild involvement present with a dry cough and those with severe involvement present with shortness of breath. The main pathology of the lungs is interstitial lesions, with some developing diffuse interstitial lung fibrosis, which may result in respiratory failure and death in a minority of cases. Early interstitial lung lesions are not apparent on lung X-rays and can only be detected by high-resolution lung CT. A small percentage of patients develop pulmonary hypertension. The prognosis is poor in patients with pulmonary fibrosis and severe pulmonary hypertension.
(5) Digestive system The gastrointestinal tract can have non-specific symptoms such as atrophic gastritis, decreased gastric acid, and dyspepsia due to lesions of the exocrine glands in its mucosal layer. Approximately 20% of patients have liver damage, with a clinical spectrum ranging from jaundice to no clinical symptoms but liver function impairment. The liver pathology is diverse, with changes such as infiltration of small intrahepatic bile duct walls and their surrounding lymphocytes and destruction of the border plate being prominent. Chronic pancreatitis is also not uncommon.
(6) Nerve The incidence of involvement of the nervous system is about 5%. Peripheral nerve damage is the most common, whether it is central or peripheral nerve damage is associated with vasculitis.
(7) Hematologic The disease may present with leukopenia or/and thrombocytopenia, and bleeding may occur in severe cases of low platelets. The incidence of lymphoma in this disease is about 44 times that of normal population. In China, there are reports of angioimmunoblastoma lymphadenopathy (with macroglobulinemia), non-Hodgkin’s lymphoma and multiple myeloma in patients with primary dry syndrome.