Complex Case Study: Chronic Fatigue in a Multisystem Presentation

Fatigue is one of the most common symptoms in practice and one of the least specific. Sometimes it has a single, clear cause. Often, particularly in people with several conditions, it has many contributors, none sufficient alone. This case, an illustrative composite, shows how systematic assessment and sequential treatment peeled back the layers of a multisystem presentation.

Presentation

A 47 year old warehouse supervisor reports 2 years of fatigue so severe that he falls asleep in his car at lunch, has stopped playing with his children and has taken sick leave. He has type 2 diabetes treated with metformin for 8 years, hypertension, chronic back pain treated with a low dose opioid for 3 years and a BMI of 36. He drinks 4 or 5 beers most evenings “to unwind”. His mood is low. Previous blood tests, including a blood count and thyroid function, were normal, and he was told his fatigue was due to his weight.

Red flags and safety

Falling asleep while driving is an immediate safety concern. He is advised not to drive until his sleepiness is assessed and treated, and to check the reporting requirements where he lives. No weight loss, fever, night sweats or other red flags are present.

A systematic differential

Findings

• Epworth score 17, indicating severe daytime sleepiness; sleep study shows severe obstructive sleep apnoea.
• Morning testosterone low on 2 occasions, with low normal LH and FSH, consistent with secondary hypogonadism related to obesity and opioid use.
• PHQ 9 in the moderately severe range; no thoughts of self harm.
• B12 low, with raised methylmalonic acid.
• AUDIT score indicating hazardous drinking; GGT and MCV raised.
• HbA1c 60 mmol/mol.
• Vitamin D low; ferritin, kidney function and coeliac serology normal.

Sequencing treatment

With 5 significant contributors, the team, his doctor, a sleep physician, the practitioner and later a psychologist, agreed to prioritise by safety and likely impact, and to reassess after each step.

Step 1: sleep apnoea

CPAP therapy begins. Within 4 weeks his Epworth score falls to 9, he no longer falls asleep during the day and he is cleared to drive after meeting the requirements. His energy improves noticeably, but he still feels flat and tired in the evenings.

Step 2: B12 and vitamin D

His doctor starts B12 replacement and vitamin D. Metformin continues, with plans for periodic B12 monitoring.

Step 3: alcohol

Using motivational interviewing, the practitioner explores his drinking. He notices that it worsens his sleep, and he agrees to reduce to weekends only. His sleep quality with CPAP improves further, and his GGT falls.

Step 4: mood

His depression persists despite better sleep. He starts cognitive behavioural therapy and, after discussion with his doctor, an antidepressant. Behavioural activation includes a weekly walk with his children.

Step 5: pain and opioids

His doctor and a pain physiotherapist review his back pain. A graded activity programme is introduced, and the opioid is tapered slowly over several months.

Step 6: metabolic health and testosterone

A nutrition plan addresses refined carbohydrates and late evening eating. His doctor adds a glucose lowering medicine that also supports weight loss. Testosterone is rechecked after 6 months, rather than treated immediately, because sleep apnoea treatment, weight loss, reduced alcohol and opioid tapering can all raise it.

Reassessment at 12 months

He has returned to work full time and plays football with his children at weekends.

Reasoning notes

• “It’s your weight” was incomplete. Weight contributed, but 5 specific, treatable factors were operating.
• Safety came first: driving advice was given immediately.
• Sequencing and reassessment showed how much each factor contributed and prevented premature conclusions, such as starting testosterone treatment that might not have been needed.
• Mediators interacted: alcohol worsened sleep apnoea; sleep apnoea worsened mood and glucose; opioids lowered testosterone and affected breathing during sleep.
• A team of doctor, sleep physician, practitioner, psychologist and physiotherapist each addressed a layer.

Layers, not labels

Multisystem fatigue rarely has a single answer. A systematic differential, safety first, sequential treatment and regular reassessment allow each layer to be identified and addressed, and allow practitioners to know when the picture is complete.