Pseudoachalasia of the cardia-Ba Swallow and CT

66 year old male patient presents with history of dysphagia for solids and liquids since 3 months and chest radiograph was normal. Barium esophagogram showing long segment smooth narrowing in the distal esophagus with significant dilatation and hold up of contrast in the proximal esophagus. On noticing carefully there is mild irregularities in the GE junction and cardiac end of stomach. We kept the possibility of achalasia and pseudoachalasia. Advised further workup of CT scan and endoscopy.

Contrast enhanced CT scan with on table oral contrast showing concenteric wall thicekning (arrow) obliterating the lumen in the distal esophagus involving GE junction and having less than 90 degrees of contact with the descending thoracic aorta and abutting left atrium. Endoscopic biopsy revealed adenocarcinoma. These findings are consistent with pseudoachalasia.

Achalasia cardia is due to loss of myenteric ganglion cells in the gastroesophageal junction and the etiology is idiopathic. But a similar clinical picture can be produced by other diseases, a condition termed as secondary or pseudoachalasia. A very high index of suspicion is required for the diagnosis of this condition because this is most commonly produced by a malignancy involving the gastroesophageal junction which is likely to be missed. In true or primary achalasia, there is loss of myenteric ganglion cells with loss of peristalsis in esophageal body and failure of lower esophageal sphincter to relax when swallowing. Barium swallow shows a typical bird's beak appearance.

The causes for pseudoachalasia include primary malignancy of esophagus or gastroesophageal junction, 53.9%, secondary malignancies such as metastasis from lung or breast, 14.9%, benign disorders like mesenchymal tumors, secondary amyloidosis and peripheral neuropathy, 12.6%, and as a postoperative complication following antireflux surgery, 11.9%. Other rare causes are neurological disorders like meningomyelocele, brain metastasis, infiltration by lymphoma and paraneoplastic syndromes associated with small cell carcinoma lung, bronchial carcinoids and pleural mesothelioma.

It is very important to differentiate pseudoachalasia from true achalasia. The patients with pseudoachalasia tend to be older in age ( more than 60 years), have shorter duration of dysphagia (less than 6 months) and have more substantial weight loss. Barium swallow may reveal a nodular of shouldered segment of distal esophageal narrowing. The length of the narrowed esophageal segment was found to be longer than 3.5 cm in 80% of the patients with pseudoachalsia which is the most important feature in radiological differentiation. A CT scan may show asymmetric thickening of the esophageal wall or cardia, mediastinal lymphadenopathy or may identify primary malignancy in secondary achalasia.

Methylmalonic acidaemia (MMA)

3 year old female child came with developmental delay, lethargy, seizures and hypoglycemia, MRI brain T2 weighted image at the level of basal ganglia showing bilateral symmetrical hyperintensities in globi pallidi.

MMA encompasses a heterogeneous group of disorders characterized by accumulation of methylmalonic acid and its by-products in biological fluids. These disorders are due to a deficiency of the adenosylcobalamin-dependent enzyme methylmalonyl-CoA mutase (apoenzyme deficiency), a defect in intracellular cobalamin metabolism (coenzyme deficiency), transcobalamin II deficiency, intrinsic factor deficiency, or dietary cobalamin deficiency, which is found in vegetarians. The incidence, as derived form a neonatal screening program, is one in 48,000 live births (6). The actual occurrence, however, is estimated to be one in 25,000 live births.

CT and MR imaging of the brain typically reveal atrophy, delay in myelination, and abnormalities in the basal ganglia, predominantly in the globi pallidi. The globi pallidi are particularly sensitive to mitochondrial dysfunction, and are thus prime targets for injury. MR Spectroscopy may show elevated lactate levels either in CSF or in brain parenchyma i.e regions of infarcts. Differential diagnosis for bilateral globi pallidi lesions are HIE (hypoxic ischemic encephalopathy), kernicterus, mitochondrial encephalopathy etc.

MOYAMOYA DISEASE

Two year old male boy presented with recurrent episodes of transient ischemic attacks since the age of 6 months following which he has delayed milestones. The boy also has seizures since one year. He was referred to MRI brain for further evaluation.

Figure a) T1weighted image at the level of basal ganglia show multiple tiny low intensity rounded areas seen in bilateral basal ganglia (arrows) which appear hyperintense on T2 weighted images suggestive of collateral vessels. c) Fluid attenuation inversion recovery (FLAIR) sequence showing atrophy involving bilateral frontal and left parietal cortical areas with chronic ischemic changes. d) Volume rendered 3D time of flight frontal projection cerebral angiography showing significant stenosis in the supraclinoid internal carotid arteries on both the sides with absent flow in the anterior and middle cerebral arteries and multiple collaterals in bilateral basal ganglia appearing as “puff of smoke” (moyamoya). Cause is unknown in this boy.

Discussion:

The term ‘moyamoya’ means ‘wavering puff of smoke’, described by Takaku, Suzuki and others in Japan in the sixties1. Moyamoya disease is a cerebrovascular disease that features narrowing or stenosis, starting at the distal internal carotid and proximal portions of the anterior and middle cerebral arteries of unknown etiology. Moyamoya syndrome is a phenomenon caused by an oligemic state similar in presentation but caused by various disease entities. Some of the conditions associated with Moyamoya syndrome are chromosomal disorders (Neurofibromatosis, Down’s syndrome), hemolytic anemias, infectious diseases (leptospirosis, tuberculous meningitis), neoplasms (Craniopharyngioma, Wilms tumor), drug abuse (phenobarbitol) and others. Etiology of Moyamoya disease is still unknown. There have been recent reports of increased familial incidence of the disease with markers on chromosome 6 and 17, located at 3p24.2-26 and a possible linkage of the marker D6S441 to the disease on chromosome 6. Moyamoya is commonly seen during first decade of life. Frequently the children present with transient ischemic attacks or ischemic strokes. Cerebral ischemia may also present as reversible ischemic neurological deficit, sensory attacks or acute infantile hemiplegia. Headaches, involuntary choreiform movements, seizures and other motor disturbances have been described2.

Majority of children (50-60%) show atrophy of anterior brain more than posterior brain on CT scan, where as adults show hemorrhage especially in intraventricular region. Contrast enhanced CT shows enhancing dots in basal ganglia and ‘net like’ vessels at the base of brain. MRI and MR angiography are diagnostic imaging modality of choice. MRI show multiple dot-like flow voids in basal ganglia on T1 weighted image (WI). Flow voids in the multiple collateral vessels in the cisterns appearing as ‘net like’ cisternal filling defects, associated with hyperintense small vessel cortical and white matter infarcts are seen on T2 WI. Slow flowing engorged pial vessels with thickened arachnoid membranes appear as bright sulci called leptomeningeal “ivy sign”. MR angiography show narrowed distal ICA and proximal Circle of Willis vessels with multiple lenticulostriate and thalamoperforator collaterals giving appearance of a “puff of smoke”. MR spectroscopy will show lactate peak in acutely infracted tissue. Treatment is mainly Encephalo-duro-arterio-synangiosis (EDAS) which is a method of indirect bypass2.

Teaching point:

Moyamoya disease or syndrome should be suspected in a child with recurrent ischemic attacks. MRI with MR angiography is the investigation of choice in this condition. MRI shows multiple dot-like flow voids in basal ganglia on T1 WI and flow voids in the multiple collateral vessels in the cisterns appear as ‘net like’ cisternal filing defects on T2WI. MR angiography show narrowed distal ICA and proximal Circle of Willis vessels with multiple lenticulostriate and thalamoperforator collaterals giving appearance of a “puff of smoke” which is typical appearance of moyamoya.

References:

1. Hoffman HJ. Moyamoya disease and syndrome. Clin Neurol Neurosurg1997; 99 Suppl 2 : S39-44
2. Gosalakkal JA. Moyamoya disease: a review. Neurol India. 2002 Mar;50(1):6-10.
3. Fujisawa I, Asato R, Nishimura K, Togashi K, Itoh K, Noma S, et al. Moyamoya disease: MR imaging. Radiology. 1987 Jul;164(1):103-5.