Case Presentation
An 87-year-old Japanese man, who had atrial fibrillation and left internal carotid artery stenosis, presented at the emergency department. He had hiccups persisting for two days. About three weeks earlier, doctors had treated him for bleeding in the left occipital lobe due to amyloid angiopathy. During treatment, he stopped taking apixaban and aspirin, experiencing acute right back pain, that went untreated. The exact onset of this pain is unclear. Five days before the hiccup episode, doctors discharged him from the hospital, resuming apixaban and aspirin.
He had never experienced prolonged hiccups and had no history of renal issues. For over 60 years, he had a history of drinking a glass of beer daily. He quit smoking about 30 years ago, after smoking two packs a day.
At the emergency room, his vital signs were stable. However, his serum lactate dehydrogenase (LDH) and C-reactive protein (CRP) levels were elevated. Urine tests revealed hidden blood and protein. He complained only of tenderness in his right costovertebral angle.
Further examination with contrast-enhanced computed tomography (CT) showed poorly enhanced areas and a cortical rim sign in his right kidney. This indicated a renal infarction. The medical team referred him to the internal medicine department for further evaluation and management.
Investigations
The CT findings revealed fat stranding extending from the kidney to the diaphragm, leading to the hypothesis that inflammation from the right kidney infarction stimulated the diaphragm, potentially causing prolonged hiccups, as suggested by previous research. No other findings provided a plausible explanation for the hiccups. Doctors continued the patient’s regular doses of apixaban (5 mg/day) and aspirin (20.25 mg/day), supplemented with Hangeshashinto for symptomatic relief. Additionally, they administered ceftriaxone (2 g every 24 hours) due to a suspected urinary tract infection. By the second hospital day, there was an improvement in the patient’s LDH levels (922 U/l). Although the hiccups persisted, albeit with reduced frequency. By the fourth hospital day, doctors noticed further improvements in LDH (579 U/l) and CRP (5.91 mg/dl) levels. Negative urine and blood cultures led to the discontinuation of ceftriaxone. Following a gradual decrease in hiccup frequency, complete resolution occurred by the eighth hospital day. Subsequent upper gastrointestinal endoscopy revealed ulcerative scarring, while brain MRI detected an old infarction in the left parietal lobe. Discharge on the eleventh hospital day included continuation of apixaban (5 mg/day) and aspirin (20.25 mg/day). Post-discharge follow-up with the family physician showed no reported consequences or recurrence of hiccups.
Hiccups
Hiccups can be triggered by various medical conditions, including issues with the central nervous system, irritation of the diaphragm or vagus nerve, medications, and metabolic disorders. These conditions affect different parts of the nervous system, including the vagus nerve, phrenic nerve, upper spinal cord, brainstem in the medulla oblongata, reticular formation, and hypothalamus. The vagus nerve has branches that extend into the thoracic, pharyngeal, and abdominal regions, with diseases affecting the abdominal branches potentially leading to hiccups. Patients with renal conditions like renal abscess, giant hydronephrosis, acute tubular injury, or renal cell carcinoma have reported experiencing hiccups. Additionally, diseases that irritate the diaphragm, such as liver abscesses, can also cause hiccups.
In this case, it was theorized that inflammation resulting from a right kidney infarction stimulated the diaphragm, leading to prolonged hiccups, as indicated by CT images. The presence of a cortical rim sign, indicating zonal enhancement of the renal cortex, is typically observed in cases of renal infarction. This sign reflects the outer renal margin, which receives collateral circulation from the gonadal and phrenic arteries. Symptoms such as blood in the urine, elevated serum LDH levels, and increased serum creatinine levels are important indicators of renal infarction. Previous research has shown that 80% of patients with renal infarction exhibit a triad of persistent flank pain, elevated serum LDH levels, and proteinuria. Atrial fibrillation or the discontinuation of antithrombotic therapy, which increases the risk of thrombotic events, is also associated with renal infarction.
Discussion
In this particular patient, the temporary discontinuation of antithrombotic therapy was due to subcortical bleeding in the left occipital lobe. Given the patient’s history of atrial fibrillation, a high-risk factor for thromboembolism, the symptoms of right back pain, elevated serum LDH levels, hematuria, and proteinuria are consistent with renal infarction. Although renal infarction typically presents with these symptoms, hiccups as a result of renal infarction have not been previously reported. However, the CT findings align with the diagnosis of renal infarction.
While upper gastrointestinal and central nervous system issues were ruled out, the CT scan did show fat stranding from the right kidney to the diaphragm. Doctors found no other findings that could cause hiccups on the CT scan. The discontinuation of anticoagulation therapy could not have directly stimulated the nerve pathway of hiccups, and there was a time gap between its discontinuation and the onset of hiccups. It’s plausible that inflammation from the kidney infarction affected the diaphragm, especially considering the proximity between the kidney and the diaphragm. Additionally, the presence of right back pain observed in another hospital may have contributed to the spread of inflammation. While hiccups due to renal diseases have been reported previously, this is the first documented case of hiccups resulting from renal infarction. Thus, renal conditions should be considered in patients with persistent hiccups. Since this is a case report, further research is necessary to explore the neurological mechanism linking hiccups to internal organ diseases, particularly renal infarction. Investigating the connection between renal infarction and hiccups presents an intriguing avenue for future research.
Conclusion
Hiccups refer to irregular and rapid contractions of the diaphragm. Typically lasting under 48 hours, most instances resolve within minutes. However, prolonged hiccups lasting over 48 hours can significantly disrupt daily life. Various medical conditions, including central nervous system disorders, irritation of the diaphragm, and metabolic issues, can trigger hiccups. While some studies have documented hiccups associated with renal diseases, none have explored hiccups stemming from renal infarction. This report introduces the first case of a patient experiencing renal infarction alongside prolonged hiccups. Acute renal infarction typically manifests with symptoms like abdominal or flank pain, nausea, vomiting, and hematuria, though some patients may be asymptomatic. Hiccups caused by renal infarction are rare occurrences.
