Pneumomediastinum secondary to hyperemesis gravidarum during early pregnancy

Abstract

Pneumomediastinum has been well documented under conditions that cause high intra-alveolar or intraesophageal pressures, such as forceful or excessive coughing, persistent emesis with alcohol abuse and labor. Free air subsequently trapped in the mediastinal connective tissue is disseminated from the alveoli along the perivascular fascial planes (1). Pneumomediastinum is a rare complication of pregnancy, in most cases occurring in the second stage of labor (2). To our knowledge, there have been four previous reports in which hyperemesis gravidarum was caused (2-5). In all cases, it was improved by cessation of vomiting. We report here a woman who suffered from severe hyperemesis gravidarum and advanced pneumomediastinum during early pregnancy. A multiparous 29-year-old woman, gravida 6, para 1, presented at 6 weeks’ gestation with nausea and vomiting and at 10 weeks’ gestation (with a three-week history of emesis), she was admitted to another hospital due to the appearance of face swelling (Fig. 1). She also complained about severe toothache. In spite of antiemetics for 4 days, symptoms deteriorated and she was transferred to our hospital. She had no chills, rash, abdominal pain, or hepatitis exposure. Past medical history was unremarkable, but there was marked subcutaneous emphysema over the upper chest extending into the neck and face. Blood pressure was 120/78 mmHg, and pulse was 110 bpm. Body temperature was 38.3°C. The urine was 2+ ketones. Her blood data were WBC 9,200 /mm3, RBC 415X104/mm3, hemoglobin 12.8 g/dl, hematocrit 37.6%, platelet 18.8X104/mm3, C-reactive protein 3.3 mg/dl. The biochemical data were sodium (Na) 128 mEq/l, potassium (K) 2.9 mEq/l, chloride (Cl) 85 mEq/l. Liver enzymes were elevated (GOT 94 IU/l, GPT 295 IU/l, total bilirubin 1.6 mg/dl) (Fig. 2). These data suggested she might be suffering from severe hyperemesis gravidarum. Swelling of the face on admission to our hospital at 10 weeks’ gestation. Blood and biochemical data during pregnancy and after surgery. ○=WBC, ●=CRP, ▵=GOT, ▴=total bilirubin (T. bil), □=Na, █=Cl. On admission to our hospital, the levels of Na, K and Cl were depressed, and liver enzymes (GOT, GPT and total bilirubin) elevated. On 4 day after the operation, her blood data and biochemical data were normalized. Chest X-rays demonstrated subcutaneous emphysema and enhancement of the margins of large vessels without continuous diaphragmatic and extrapleural air signs (common findings of pneumomediastinum) (Fig. 3a). Computed tomography (CT) showed free air present from the mediastinum cavity to the subcutaneous tissues (anterior chest wall, neck and face) (Fig. 4). We thus diagnosed as pneumomediastinum by chest X-ray and CT. Since she had been complaining of toothache for 4 days, we consulted dentists. They suspected her to have stomatosis because of infection of anaerobic microorganisms and requested to administer antibiotics and perform debridement. She and her husband subsequently selected to terminate the pregnancy. We first induced abortion. Although both dentists and surgeons tried debridement of stomatosis, they failed to find necrotic tissues. She was managed in an intensive care unit (ICU) for monitoring respiratory and circulatory function and administration of antibiotics. On chest X-rays 1 day after surgery, subcutaneous emphysema appeared to be weakening. As soon as abortion had been induced, hyperemesis improved and her face swelling was reduced. Her blood data on day 2 were WBC 8,700 /mm3, C-reactive protein 2.0 mg/dl. The biochemical data were Na 131 mEq/l, K 2.8 mEq/l, Cl 95 mEq/l. Liver enzymes were decreased (GOT 55 IU/l, GPT 163 IU/l, total bilirubin 0.9 mg/dl) (Fig. 2) and she could be discharged from ICU. Subcutaneous emphysema and pneumomediastinum had disappeared on chest X-rays on day 4, and CT showed that there was no longer air in the subcutaneous tissue of her face. However, small amounts of free air still existed in both subcutaneous tissue of chest wall and mediastinum cavity. Her blood data, the biochemical data and liver enzymes on day 4 were normalized (Fig. 2). Contrast ruled out esophageal perforation on day 11. a. Chest X-ray on admission to our hospital with highlights of the thoracic aorta with vertical translucent streaks. Subcutaneous air is also visible in the neck area. b. Chest X-ray 1 day after the operation. Subcutaneous emphysema has weakened. c. Chest X-ray 4 days after the operation. Subcutaneous emphysema and pneumomediastinum are no longer evident. CT scan on admission to our hospital. Free air is present from the mediastinum cavity to subcutaneous tissues (anterior chest wall, neck and face). There were no abnormal findings for the esophagus. Aberrant gas in the mediastinum can originate from the esophagus, lung, airways, neck and abdominal cavity, decompressing through a continuum of fascial planes. The two common physical findings of pneumomediastinum are subcutaneous emphysema and ‘Hamman’s sign’ (6). Our patient had the former but not the latter. The most common method to confirm the diagnosis of pneumomediastinum is to take a chest X-ray. Furthermore, CT is useful in the diagnosis of esophageal rupture to detect the presence of extraluminal air and fluid from the esophageal thickness (7). In this case, there were no abnormal findings. Patients with pneumomediastinum secondary to esophageal rupture normally have more signs of toxicity and are more seriously ill. We could find only four cases of spontaneous pneumomediastinum secondary to hyperemesis gravidarum in the literature (2-5). In all cases, the pneumomediastinum disappeared as soon as the vomiting ceased and generally it is not necessary to perform any medical intervention against pneumomediastinum secondary to hyperemesis gravidum. In our case, the subcutaneous emphysema and pneumomediastinum were decreased within less than 48 hours after termination of pregnancy, and this is in good agreement with the literature. Our findings suggest there might be a clearer correlation between vomiting and pneumomediastinum than is commonly assumed. Furthermore, detailed examinations, such as chest X-rays (every day till day 4 after the operation and three times on day 5), chest CT (three times) and contrast esophagography (11 days after operation) allowed the healing process to be well observed.