Cysticercosis differential diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Ahmed Younes M.B.B.CH [2]

Overview

Cysticercosis must be differentiated from other diseases that cause brain cystic lesions (as brain abscess and brain tumors) or ocular lesions (as retinal detachment and coats disease).

Differentiating cysticercosis from other diseases

Differentiating neurocysticercosis from other brain cyst lesions

Disease	Prominent clinical features	Lab findings	Radiological findings
Neurocysticercosis	Presenting symptoms differ according to the site of the cysticerci. Parenchymal neurocysticercosis causes all the symptoms and signs of space occupying lesions. Extraparenchymal neurocysticercosis causes manifestations of increased intracranial pressure if cysts are present in the subarachnoid space or in the ventricles, manifestations of spinal cord compression if present in the spinal cord or causes eye disease if cysts are present in the orbit.	CDC's immunoblot is based on detection of antibody to one or more of 7 lentil-lectin purified structural glycoprotein antigens from the larval cysts. It is 100% specific and has a sensitivity superior to that of any other test yet evaluated	Computerized tomography (CT) is superior to magnetic resonance imaging (MRI) for demonstrating small calcifications. However, MRI shows cysts in some locations (cerebral convexity, ventricular ependyma) better than CT, is more sensitive than CT to demonstrate surrounding edema, and may show internal changes indicating the death of cysticerci.
Brain abscess	Headaches are the most common symptom. Usually, headaches occur on the same side of the abscess and tend to be severe (not responding to analgesics). Fever is not a reliable sign.	Lumbar puncture is contraindicated but when done, it was variable between patients. Culture from the CT-guided aspirated lesion helps in identifying the causative agent.	Contrast enhanced CT provides rapid assessment of the size and number of the abscesses. MRI: Diffusion-weighted imaging (DWI) MRI can differentiate brain abscesses from cystic brain lesions with sensitivity and specificity of 96%.
Brain tumors	Most common presenting symptom is dull aching headache. Usually, it's associated with other symptoms of increased intracranial pressure (ICP) as seizures, visual disturbances, nausea, and vomiting.		CT may be used in localizing the tumor and getting a rough estimate on the dimensions. MRI: Gadolinium-enhanced MRI is the preferred imaging modality for assessing the extension of the tumor and its exact location.
Brain tuberculoma	Brain tuberculomas has insidious onset of symptoms as compared to tuberculous meningitis. Presentations are usually due to the pressure effect, not the T.B. bacilli. Presenting symptoms and signs in order of occurrence: Episodes of focal seizures Signs of increased intracranial pressure Focal neurologic deficits.	T.B. should be investigated everywhere else in the body (e.g. peripheral lymphadenopathy, sputum and blood culture)	CT: Contrast-enhanced CT scan shows a ring enhancing lesion surrounded by an area of hypodensity (cerebritis) and the resulting mass effect. MRI: Better than CT scan in assessing the site and size of the tuberculoma. Gadolinium-enhanced MRI shows a ring enhancing lesion between 1-5 cm in size (In NCC, the wall is thicker, calcifications are eccentric and the diameter is less than 2 cm)
Neurosarcoidosis	70% of the patients present with the neurological symptoms rather than the presentation of systemic disease. Common presentations are: Cranial nerve neuropathies: Facial palsy is the most common presentation. Meningeal involvement: diffuse meningeal inflammation can cause diffuse basilar polyneuropathy in 40% of the patients. with neurosarcoidosis. Inflammatory spinal cord disease: Inflammatory span usually more than 3 spinal cord segments which helps to differentiate it from Multiple Sclerosis. Peripheral neuropathy: Asymmetric polyneuropathy or mononeuritis multiplex. It may also manifest as Guillain-Barré syndrome (GBS) like presentation. HPO axis involvement: may present as diabetes insipidus. More than 50% of the cases have no radiological signs.	Noninvasive tests have low sensitivity and specificity. Serum ACE levels are elevated in 25% of the cases Lumbar puncture shows elevated CSF proteins together with mild-moderate pleocytosis. It is usually accompanied by oligoclonal bands.	MRI with contrast shows enhancement of the inflamed areas (i.e. cranial nerves, meninges or HPO axis)

MRI brain showing brain abscess - Case courtesy of A.Prof Frank Gaillard, https://radiopaedia.org/ From the case https://radiopaedia.org/cases/4933"	MRI brain showing Glioblastoma multiforme - Case courtesy of A.Prof Frank Gaillard, <a href="https://radiopaedia.org/">Radiopaedia.org</a>. From the case <a href="https://radiopaedia.org/cases/28272">rID: 28272</a>	MRI brain showing tuberculoma - Case courtesy of Dr G Balachandran, https://radiopaedia.org/ From the case https://radiopaedia.org/cases/5489"	MRI brain showing Neurosarcoidosis - Case courtesy of A.Prof Frank Gaillard, https://radiopaedia.org/ From the case https://radiopaedia.org/cases/4364S

Differentiating ocular cysticercosis from other ocular lesions

Disease	Prominent clinical feature	Radiological findings
Coats disease	Diagnosis made usually between 8-16 years (rarely in adulthood) Wide range of symptoms from being asymptomatic to decreased vision and strabismus. Decreased visual acuity at initial presentation has a poor prognosis.	Fundus examination reveals vascular lesions and exudates. Fluorescein angiography is the best method to visualize the lesions. CT and MRI are reserved for atypical cases.
Retinal detachment	Most common presenting symptoms are photophobia and floaters Visual field defects (described as curtain falling from periphery to the center)	Ophthalmoscope is not reliable in detecting retinal detachment as there might be associated hemorrhage Ultrasound can be used to identify and localize the detachment.
Hyperthyroid Ophthalmopathy	The hallmark is Eye protrusion, photophobia, lacrimation and later in the disease, diminished eye motility.	Ultrasonography: inflamed thickened extraocular muscles. CT: shows inflamed muscle and free tendon from inflammation MRI: shows periorbital fat expansion, increased water content of the muscles as a result of the inflammation.
Retinoblastoma	The most prominent sign is leukocoria, followed by strabismus The patient also may present with buphthalmos, corneal clouding and eye tearing.	Ultrasound: can detect the tumor as a result of the calcifications inside. MRI: assess sellar and parasellar regions .. it can also detect extraocular spread of the tumor.

MRI of the orbit showing Coats disease - Case courtesy of Dr Michael Sargent, https://radiopaedia.org/. From the case https://radiopaedia.org/cases/6089	MRI of the orbit showing retinal detachment - Case courtesy of A.Prof Frank Gaillard, https://radiopaedia.org/. From the case https://radiopaedia.org/cases/3134	MRI of the orbit showing retinoblastoma - Case courtesy of https://radiopaedia.org/. From the case https://radiopaedia.org/cases/11877	CT head showing hyperthyroid-induced orbitopathy - Case courtesy of A.Prof Frank Gaillard, https://radiopaedia.org/. From the case https://radiopaedia.org/cases/4854