Illness and disease are different

Imagine this typical scenario. A new patient visits an audiologist’s office, reporting that hearing is getting harder. She’s mentally exhausted after small gatherings with friends over dinner. She’s started declining invitations to restaurants because conversations in noisy restaurants are too much work. She doesn’t enjoy concerts anymore, and she’s embarrassed asking her husband to repeat himself.

The audiologist conducts hearing examinations. The patient leaves the office with hearing aids and a follow-up appointment. The encounter is considered a measurable success for audiology. And yet something is missing. The patient herself identified hearing loss as the root cause of her mental fatigue, withdrawal from people she loves, and embarrassment, broadly defined as quality of life. The driving force of the appointment was the unspoken mutual expectation by the patient and the audiologist that hearing aids fix those problems.

There is a useful distinction between illness and disease that gets at what is going on here, drawn from rheumatology, which deals with autoimmune diseases that also compromise quality of life and are often difficult to diagnose. Rheumatologist Nortin Hadler made the case decades ago that medicine muddles the two, urging medicine to improve patient care by understanding the difference.

Hadler argued that disease is what medicine can point to. It’s measurable, recorded in the medical chart. Disease is the lab results, the imaging study, the audiogram. Illness is what patients live with. Mental exhaustion, social withdrawal, embarrassment. Measurable data and quality of life are not the same. The person is not the disease.

When medicine organizes itself around the disease dimension, as it largely has for the last seventy or eighty years, it can dismiss or miss illness entirely. Not by indifference. By design. The chart asks a set of questions. The clinician, working responsibly inside the institution, records the answers. Illness is not on the chart. Data is its surrogate.

Hadler made his argument about fibromyalgia, which sits at one end of a useful spectrum for audiology. With fibromyalgia, the illness is clearly in front – pain, fatigue, misery, disrupted life, but no clear disease to point to. No discrete pathology, no measurable target. Hadler’s insight was that labeling something a disease when you cannot show its pathology was doing more harm than good.

Hearing loss sits at the opposite end of that spectrum, the inverse case. Sensorineural hearing loss has a target. The underlying mechanism is not mysterious. The pathophysiology has been studied for decades, much of it with federal funding. The biology is well characterized by oxidative stress accumulating in the cochlea, hair cells and ribbon synapses becoming metabolically embattled, mitochondrial function declining over years.

We know what is going on inside the inner ear, in considerable detail. And yet audiology, and medicine more broadly, are organized around hearing loss as if there were no target to address, as if hearing loss is an illness without a disease.

It’s worth pausing to reflect on that inversion. Fibromyalgia is an illness in search of its disease. Hearing loss is a disease the field has been treating like an illness, a characterization that has led to amplification after the fact as the singular response.

Which leaves a question. What would it look like if we stopped treating hearing loss as if it had no metabolic target, and started acting on what we know?

That is the next post.