Having Cushing’s disease can increase a person’s risk of infectious disease complications like tuberculous meningitis — when the bacteria responsible for tuberculosis affects the central nervous system — a case report suggests.
The study, “Tuberculous Meningitis in a Patient with Cushing’s Disease: Glucocorticoid-mediated Immunosuppression: Case Report, and Review of the Literature,” was published in the journal Neurology India.
Excessive production of cortisol in the body, like that observed in people with Cushing’s disease, can inhibit the immune response and increase the risk of opportunistic infections, such as tuberculosis.
Researchers now reported the case of a man who developed tuberculous meningitis probably related to Cushing’s disease.
The patient had latent tuberculosis — infection with Mycobacterium tuberculosis that does not result in disease symptoms — when he was 12 years old. At that time, he was treated with a mixture of antibiotics. However, he was lost to follow up after that.
At the age of 20, the man, now a college student, went to the emergency room with severe headaches, nausea, intolerance to light, and high blood pressure. He received treatment for elevated blood pressure and was discharged, but the following day had reduced awareness and consciousness.
A computed tomography (CT) scan showed excessive accumulation of liquid in the brain, known as cerebral edema.
The doctors took a sample of the man’s cerebrospinal fluid — the liquid surrounding the brain and spinal cord — and discovered elevated proteins and white blood cells, and decreased glucose. The fluid also tested positive for Mycobacterium tuberculosis.
A magnetic resonance image (MRI) showed tuberculomas (nodules caused by the bacteria) in the patient’s brain, which confirmed the diagnosis of tuberculous meningitis.
The man was treated with a combination of antibiotics and dexamethasone, a corticosteroid. which cleared the bacteria from the cerebrospinal fluid. However, his other symptoms showed little improvement.
During the subsequent eight months, the doctors reduced the dose of corticosteroids, but the patient continued to have symptoms like cognitive impairment, loss of hearing, impaired vision, and high blood pressure. He also gained 42 kg (92 lbs).
Lab tests showed that the man’s body produced excessive amounts of adrenocorticotropic hormone (ACTH) — a hormone made in the pituitary gland — and cortisol.
A second MRI revealed a tumor in the left pituitary gland that, along with further tests examining hormone production, confirmed the diagnosis of Cushing’s disease.
The patient underwent surgery to remove the tumor, and a biopsy confirmed that it produced ACTH. A year and a half after the surgery, an MRI showed that the meningitis nodules were disappearing. The production of ACTH and cortisol had recovered progressively, and the man reported having better cognitive ability and less fatigue.
“The predisposition to opportunistic infections in states of hypercortisolemia [excessive cortisol production] results from the effects of glucocorticoids on cellular and humoral immunity,” the researchers said. In this case, they said, that led to the reactivation of Mycobacterium tuberculosis, and tuberculous meningitis.
The researchers also noted that the treatment with corticosteroids and antibiotics might have introduced confounding factors, delaying the Cushing’s disease diagnosis.
“Although tuberculous meningitis has not been previously described in the setting of [Cushing’s disease] and that it may be a possible coincidental finding with an ACTH-secreting adenoma, our report suggests that hypercortisolemia causes immunosuppression that may lead to the reactivation of latent [tuberculosis] and dissemination,” the investigators concluded.
“We emphasize the need to consider hypercortisolemia in a patient presenting with unexplained immunological compromise and symptoms consistent with cortisol excess.”