Nephrology · Bardet-Biedl syndrome type 9

Daily Life and Medical Red Flags

At a Glance

For people with BBS9, an individualized sick-day plan can help prevent kidney injury during vomiting or diarrhea. Seek urgent care for very little or no urine, trouble keeping fluids down, breathing problems, unusual severe headaches or vision changes, or signs of a diabetes emergency.

Managing Bardet-Biedl Syndrome type 9 (BBS9) means being a vigilant observer of health. While most days will be defined by routine, certain situations require quick action to protect the kidneys, vision, and breathing. This page outlines specific medical “red flags” and situations where you should seek prompt care.

Protecting the Kidneys: The Sick-Day Plan

A common medical risk for individuals with BBS involves the kidneys ^[1]. Because of underlying kidney differences, a dehydrating illness like gastroenteritis (a stomach bug with vomiting or diarrhea) can quickly become a serious issue called Acute Kidney Injury (AKI) ^[2].

When dehydrated, the kidneys may not receive enough blood flow to function properly ^[3].

The Sick-Day Plan: Work with your nephrologist to get an individualized written sick-day plan. This should define what counts as markedly reduced urine for your specific baseline and when to call the team versus seeking emergency care. Seek urgent help immediately for an inability to keep fluids down, no urine, extreme lethargy, or breathing difficulty ^[4]^[5].
The Medication Trap: Your plan will list which medicines to pause. Avoid giving NSAIDs (like ibuprofen or naproxen) when you or your child is dehydrated, or when specifically contraindicated by your clinician, as these medications can further restrict blood flow to the kidneys during an illness ^[6].

Pressure in the Brain: IIH

An uncommon but important differential diagnosis in BBS is Idiopathic Intracranial Hypertension (IIH), which is increased pressure of the fluid surrounding the brain ^[7]. This is dangerous because the pressure can damage the optic nerve and cause rapid, permanent vision loss ^[8].

Because progressive vision loss is already occurring, IIH can be easily missed or mistaken for “normal” BBS progression ^[7].

Red Flags: Watch for severe, persistent headaches (often worse when lying down or in the morning), frequent nausea or vomiting ^[9], double vision, or a sudden change in vision that feels different from the “usual” retinal dystrophy course ^[10].
Urgent Evaluation: These symptoms require urgent clinical evaluation. While routine exams may check for papilledema (swelling of the optic nerve), you should not wait for a routine visit if these red flags appear ^[11]. If IIH is suspected, imaging (like a brain MRI with venous imaging) and a lumbar puncture (spinal tap) are typically used ^[12].

Sleep Apnea and Anesthesia Planning

Obstructive Sleep Apnea (OSA)—where breathing repeatedly stops and starts during sleep—is common in BBS due to both the syndrome and associated obesity ^[13].

Screening: Your care team will recommend when to have a polysomnogram (sleep study) based on symptoms, weight, and current BBS guidelines ^[14].
Anesthesia Planning: If you or your child needs surgery, it is vital to obtain an individualized preoperative assessment. Tell the anesthesiologist about the BBS diagnosis, sleep study results, kidney function, and any prior airway issues, as obesity and OSA can increase respiratory risks and the chance of the airway collapsing under sedation ^[15]^[16]^[17].

Signs of New-Onset Diabetes

Because of the metabolic changes in BBS, there is an increased risk for diabetes ^[18]. Dysglycemia can be silent, requiring routine, clinician-directed metabolic surveillance. In rare cases, this can lead to a life-threatening emergency called Diabetic Ketoacidosis (DKA) ^[19].

Signs to Watch For: Excessive thirst (polydipsia) and frequent urination (polyuria) can be signs, but remember these can also be caused by kidney concentrating defects. If you see vomiting, deep or rapid breathing, severe abdominal pain, fruity-smelling breath, or confusion alongside these signs, you must seek emergency medical services immediately ^[19]. Do not wait for a home blood sugar check.

Knowing these risks empowers you to act. By keeping a written sick-day plan and understanding when to call the clinic versus when to go to the ER, you can navigate unexpected illnesses safely ^[20].

Common questions in this guide

What should a sick-day plan include for someone with BBS9?

A nephrologist should create a written plan for the individual that explains what reduced urine means for that person, which medicines to pause, and when to call the clinic or go to emergency care. The plan should also include after-hours contact instructions.

When is dehydration an emergency in BBS9?

Seek urgent help if the person cannot keep fluids down, has no or markedly less urine than their usual baseline, is extremely lethargic, or has trouble breathing. Do not give ibuprofen, naproxen, or another NSAID during dehydration unless the treating clinician specifically says it is safe.

What headache or vision symptoms could signal increased pressure around the brain in BBS9?

A severe or persistent headache, especially one worse in the morning or when lying down, repeated nausea or vomiting, double vision, or a sudden vision change that differs from the usual retinal dystrophy should be evaluated urgently. These symptoms can indicate idiopathic intracranial hypertension, and you should not wait for the next routine eye examination.

How should BBS9 affect sleep apnea and surgery planning?

BBS9 and associated obesity can increase the risk of obstructive sleep apnea, in which breathing repeatedly stops and starts during sleep. Before surgery, tell the anesthesiologist about the BBS9 diagnosis, sleep-study results, kidney function, and any previous airway problems so the anesthesia plan can be individualized.

What are the emergency signs of diabetic ketoacidosis in BBS9?

Excessive thirst and frequent urination can occur with diabetes, but vomiting, deep or rapid breathing, severe abdominal pain, fruity-smelling breath, or confusion are emergency warning signs. Call emergency medical services immediately and do not wait for a home blood sugar check.

How is diabetes monitored in people with BBS9?

Diabetes or other blood-sugar problems may be silent, so monitoring should follow a clinician-directed schedule. Your care team may recommend tests such as HbA1c and lipid testing based on the person's health and BBS9 care plan.

What sleep symptoms should be reported in BBS9?

Gasping, choking, or pauses in breathing during sleep should be reported to the care team. A polysomnogram, or sleep study, may be recommended based on symptoms, weight, and current BBS9 guidance.

Get notified when new evidence is published on BBS9-related ciliopathy.

We monitor PubMed for new peer-reviewed studies on this topic and email a short summary when something meaningful changes.

Key takeaways

Every person with BBS9 should have a written, individualized sick-day plan from their nephrologist that defines reduced urine and when to seek emergency care.
Vomiting or diarrhea can lead to acute kidney injury, and NSAIDs such as ibuprofen or naproxen may worsen kidney blood flow during dehydration.
Severe or unusual headaches, morning or positional headache, vomiting, double vision, or sudden visual changes need urgent evaluation for possible idiopathic intracranial hypertension.
Sleep apnea and obesity can increase breathing risks during sleep and anesthesia, so surgical teams need sleep-study and kidney information.
Vomiting, deep or rapid breathing, abdominal pain, fruity breath, or confusion with thirst or frequent urination may signal diabetic ketoacidosis and require emergency services.

References (20)

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This page is for informational purposes only and does not constitute medical advice. It cannot replace an individualized BBS9 sick-day, kidney, vision, sleep, or diabetes plan from your healthcare team; seek emergency help for severe symptoms.