Yellow zone Nefroloji / Kronik Hastalık Yönetimi

Diabetic Kidney Disease — Not Every Kidney Disorder in a Diabetic is Due to Diabetes

Diabetic kidney disease is THE MOST COMMON CAUSE OF END-STAGE KIDNEY FAILURE IN THE WORLD and is DETECTED THROUGH SCREENING because IN THE EARLY STAGE IT CAUSES NO SYMPTOMS. Screening is done with TWO TESTS:

URINARY ALBUMIN-TO-CREATININE RATIO and CALCULATED GLOMERULAR FILTRATION RATE; BOTH SHOULD BE REQUESTED together because in SOME PATIENTS, GFR DECREASES WITHOUT ANY DEVELOPMENT OF ALBUMINURIA, and MONITORING ONLY BASED ON ALBUMIN WILL MISS THESE PATIENTS. THE MOST IMPORTANT DISTINGUISHING QUESTION IS:

IS THIS KIDNEY DISORDER REALLY DUE TO DIABETES? NOT EVERY KIDNEY DISORDER IN A DIABETIC IS DUE TO DIABETES, and THERE ARE CLUES SUGGESTING ANOTHER CAUSE:

ABSENCE OF DIABETIC CHANGES IN THE EYE FUNDUS, SUDDEN ONSET, RAPID DETERIORATION, PRESENCE OF BLOOD AND CASTS IN URINE, or VERY SHORT DURATION OF DIABETES. If THESE CLUES ARE PRESENT, THE PATIENT SHOULD BE REFERRED TO NEPHROLOGY AND A BIOPSY SHOULD BE CONSIDERED because a TREATABLE DISEASE may be MISSED.

AS KIDNEY FUNCTION DECLINES, INSULIN AND SOME DIABETIC MEDICATIONS ARE CLEARED MORE SLOWLY FROM THE BODY; THEREFORE, DOSES THAT WERE PREVIOUSLY APPROPRIATE BEGIN TO CAUSE HYPOGLYCEMIA, and DOSES SHOULD BE REDUCED. TWO DIFFERENT RENIN-ANGIOTENSIN BLOCKERS SHOULD NOT BE USED TOGETHER.

ALL DOSES and TARGETS MUST BE VERIFIED FROM THE INSTITUTIONAL PROTOCOL.

Rapid management

SCREENING IS DONE WITH TWO TESTS AND BOTH ARE ORDERED TOGETHER:
THE RATIO OF ALBUMIN-CREATINE IN URINE AND THE CALCULATED FILTRATION FUNCTION.
IT IS NOT ENOUGH TO LOOK ONLY AT ALBUMIN BECAUSE IN SOME PATIENTS, THE FILTERING FUNCTION DECREASES BEFORE ALBUMINURIA DEVELOPS AT ALL; THESE PATIENTS ARE THOUGHT TO BE HEALTHY BECAUSE THEIR ALBUMIN IS CLEAN.
WHEN SCREENING BEGINS VARIES ACCORDING TO THE TYPE OF DIABETES AND SHOULD BE CONFIRMED FROM THE INSTITUTIONAL PROTOCOL.
DIAGNOSIS IS NOT MADE WITH A SINGLE MEASUREMENT; FEVER, EXERCISE, URINARY TRACT INFECTION and HIGH BLOOD SUGAR CAUSE TEMPORARY ALBUMINURIA → MEASUREMENT IS REPEATED.
THE MOST IMPORTANT DISTINGUISHING QUESTION:
IS THIS DISORDER REALLY DUE TO SUGAR?
CLUES SUGGESTING ANOTHER CAUSE:
ABSENCE OF DIABETIC CHANGES IN THE FUNDUS OF THE EYE (especially in type 1 patients), SUDDEN ONSET OF KIDNEY DISORDER, RAPID DETERIORATION OF FILTERING FUNCTION, PRESENCE OF BLOOD AND ERYTHROCYTE DELETION IN THE URINE, VERY SHORT DURATION OF DIABETES, SUDDEN SEVERE PROTEIN LOSS and OTHER SIGNS OF SYSTEMIC DISEASE → IF THESE CLUES ARE PRESENT, NEPHROLOGY REFERRAL and BIOPSY EVALUATION are required because A TREATABLE DISEASE MAY BE MISSED.
HYPOGLYCEMIA TRAP:
AS KIDNEY FUNCTION DECREASES, INSULIN AND SOME DIABETES DRUGS SLOWLY MOVE AWAY FROM THE BODY → PREVIOUSLY APPROPRIATE DOSES BEGIN TO CAUSE HYPOGLYCEMIA; IN A PATIENT WHOSE SUGAR IMPROVES, IT IS NOT SAID THAT "THE DISEASE HAS IMPROVED", KIDNEY FUNCTION IS CHECKED AND DOSES ARE WITHDRAWN.
TWO DIFFERENT RENIN-ANGIOTENSIN BLOCKERS ARE NOT USED TOGETHER; IT DOES NOT PROVIDE BENEFIT and INCREASES THE RISK OF KIDNEY DAMAGE with HIGH POTASSIUM.
AFTER TREATMENT IS STARTED OR THE DOSE IS INCREASED, CREATININE AND POTASSIUM ARE CONTROLLED; A LIMITED ELEVATION IN CREATININE IS EXPECTED and DOES NOT DEDUCE MEDICATION ALONE, BUT A SIGNIFICANT ELEVATION SUGGESTS VASCULAR STENOSIS.
NEPHROTOXIC EXPOSURE AND DISEASE PERIOD DRUG RULE is applied (related protocol).
EYE, FOOT AND CARDIOVASCULAR MONITORING is carried out SIMULTANEOUSLY.
ALL DOSES AND TARGETS SHOULD BE VALIDATED FROM THE INSTITUTIONAL PROTOCOL.

Drug	Adult	Pediatric	Route	Duration
SCREENING WITH TWO TESTS — albumin and filtration together Requesting both tests together is due to the fact that a portion of patients remain undetected with a single test. The classic course of diabetic kidney disease is described as first a small amount of albumin leakage into the urine, then an increase in this amount, and finally a decrease in filtering capacity. This sequence is valid for many patients but not for all. In some patients, the albumin in urine does not increase significantly; on the other hand, the filtration function silently decreases over the years. In these patients, monitoring that looks only at albumin continuously gives normal results and the patient is thought to be protected. The decline in kidney function is only detected at an advanced stage. Therefore, both tests should be requested together and both should be monitored over time.	RATIO OF ALBUMIN-CREATINE IN URINE and CALCULATED FILTRATION FUNCTION SHOULD BE REQUESTED TOGETHER. IT IS NOT ENOUGH TO JUST LOOK AT ALBUMIN: IN SOME PATIENTS, THE FILTERING FUNCTION DECREASES BEFORE ALBUMINURIA DEVELOPS AT ALL, AND THESE PATIENTS ARE THOUGHT TO BE HEALTHY BECAUSE THEIR ALBUMIN IS CLEAR. DIAGNOSIS IS NOT MADE WITH A SINGLE MEASUREMENT; FEVER, HEAVY EXERCISE, URINARY TRACT INFECTION, HIGH BLOOD SUGAR and HEART FAILURE CAUSE TEMPORARY ALBUMINURIA → MEASUREMENT IS REPEATED. Screening start and frequency SHOULD BE VERIFIED FROM THE INSTITUTIONAL PROTOCOL	The timing of screening in children is determined by specialist decision	—	Regular screening
NOT EVERY KIDNEY DISORDER IS CAUSED BY DIABETES Attributing every kidney disorder in a diabetic patient to diabetes is the main way treatable diseases are missed. In a patient who has been diabetic for many years, when kidney function deteriorates, an explanation seems ready; the diagnosis is not questioned, further tests are not performed, and the patient is assumed to be condemned to a progressive course. However, these patients, like anyone else, can develop an independent kidney disease. One of the strongest distinguishing clues is the fundus findings; the damage of diabetes in the kidney and in the eye are the two faces of the same small vessel disease and usually progress together. In a patient with a completely normal eye, significant kidney disease suggests that the condition might be due to another cause.	CLUES SUGGESTING ANOTHER CAUSE: ABSENCE OF DIABETIC CHANGES IN THE EYE FUNDUS, SUDDEN ONSET OF KIDNEY DAMAGE, RAPID DETERIORATION OF FILTRATION FUNCTION, BLOOD IN THE URINE and RED BLOOD CELL CASTS, VERY SHORT DURATION OF DIABETES, SUDDEN SEVERE PROTEIN LOSS, FINDINGS OF OTHER SYSTEMIC DISEASES, and RESISTANT HIGH BLOOD PRESSURE. IF THESE CLUES ARE PRESENT, REFERRAL TO NEPHROLOGY and CONSIDERATION OF BIOPSY are required. In a patient with diabetes, GLOMERULAR DISEASES, DRUG-RELATED DAMAGE, OBSTRUCTION, and VASCULAR NARROWING may also be present	Differential diagnosis in children requires specialist assessment	—	At each assessment
HYPOGLYCEMIA TRAP — as the kidney deteriorates, insulin accumulates As kidney function decreases, the increased risk of hypoglycemia is a common occurrence in clinical practice, though its cause is often recognized late. Insulin and some antidiabetic drugs are largely eliminated from the body through the kidneys. When kidney function declines, this elimination slows and the drug remains in the blood for a longer time; as a result, a dose that has been used without problems for years may start to be excessive. Because this change is slow, it may be interpreted by the patient and physician as an improvement in the disease; blood sugar levels appear improved, and it may even seem appropriate to reduce the medication. However, the underlying issue is the decline in kidney function. If this distinction is not made, the patient may experience severe and recurrent hypoglycemia; in older age, this can lead to falls, cardiac events, and loss of consciousness.	AS KIDNEY FUNCTION DECREASES, INSULIN and SOME ANTIDIABETIC DRUGS LEAVE THE BODY MORE SLOWLY → DOSES THAT WERE PREVIOUSLY SUITABLE START TO CAUSE HYPOGLYCEMIA. IN A PATIENT WHOSE BLOOD SUGAR LEVELS IMPROVE UNEXPECTEDLY or WHO BEGINS TO EXPERIENCE HYPOGLYCEMIA, IT IS NOT SAID THAT 'THE DISEASE HAS IMPROVED'; KIDNEY FUNCTION IS CHECKED, and DOSES ARE REDUCED. SOME DRUGS ARE NOT USED BELOW A CERTAIN FILTRATION LEVEL. Drug selection and dose adjustments SHOULD BE VERIFIED FROM THE INSTITUTIONAL PROTOCOL.	Dose adjustment in children requires a specialist.	—	At each assessment
TWO RENIN-ANGIOTENSIN BLOCKERS ARE NOT USED TOGETHER. The avoidance of using two different renin-angiotensin blockers together is an example that shows the intuition that more suppression would bring more benefit is wrong. This drug group reduces protein loss and slows disease progression by lowering the internal pressure of the kidney’s filtration unit. Based on this, it was thought that administering the two drugs together would increase the effect. However, this approach did not provide the expected additional benefit, while it significantly increased serious side effects such as high potassium and acute kidney injury. Therefore, the two drugs are not used together. Another important detail in the same group is that a limited increase in creatinine at the start of treatment is an expected response and that the drug should not be stopped solely for this reason.	In a patient with ALBUMINURIA and HIGH BLOOD PRESSURE, treatment that blocks the RENIN-ANGIOTENSIN SYSTEM slows the progression of the disease. HOWEVER, USING TWO DIFFERENT DRUGS FROM THIS GROUP TOGETHER PROVIDES NO ADDITIONAL BENEFIT and INCREASES THE RISK OF HIGH POTASSIUM AND ACUTE KIDNEY INJURY. AFTER STARTING TREATMENT or INCREASING THE DOSE, CREATININE and POTASSIUM SHOULD BE MONITORED. Drug selection, doses, and monitoring schedules SHOULD BE VERIFIED FROM THE INSTITUTIONAL PROTOCOL.	Use in children is based on a specialist's decision.	—	Continuous
Blood pressure, sugar, and cardiovascular risk Individualizing goals according to the patient shows that the same target in the same disease is not correct for everyone. The kidney-protective effect of sugar control is most evident in the early stage of the disease; during this period, strict control delays the development and progression of albuminuria. After kidney function has significantly decreased, the benefit of the same strict target diminishes, while the harm increases. The reason is both the increased risk of hypoglycemia and the fact that these patients are generally elderly and have many comorbidities. Severe hypoglycemia can cause harm far sooner than the benefits that would be achieved over many years. Therefore, the target should be determined according to the stage of the disease and the fragility of the patient.	FACTORS THAT SLOW PROGRESSION ARE BLOOD PRESSURE CONTROL, SUGAR CONTROL, REDUCTION OF ALBUMINURIA, SMOKING CESSATION, and WEIGHT MANAGEMENT. The benefit of sugar control is particularly evident in the early stage. Goals should be individualized according to the patient: if there is advanced age, a history of hypoglycemia, and comorbidities, a very strict goal can be harmful. CARDIOVASCULAR RISK IS VERY HIGH IN THESE PATIENTS and must be managed SIMULTANEOUSLY (relevant protocol). Target values and drug choices should be verified from the INSTITUTIONAL PROTOCOL.	In children, targets are determined according to age.	—	Continuous
Rule of nephrotoxic exposure and disease period The fact that the disease period plan in diabetics has two separate components is a point that is easily confused in these patients. On the one hand, in cases that cause fluid loss, some drugs that protect the kidney should be temporarily discontinued. On the other hand, in the same period, diabetes has its own rules and it is dangerous for a patient using insulin to stop insulin completely because he cannot eat; During illness, the body's insulin requirement usually increases, and stopping insulin can lead to a severe metabolic picture. These two rules can be confused and the patient can stop taking all of his medications at once. For this reason, the plan should specify which drug will be discontinued and which will be continued, separately and in writing.	NEPHROTOXIC EXPOSURE SHOULD BE QUESTIONED AND DISCONTINUED: OVER-THE-COUNTER PAINKILLERS, CONTRAST MEDIA (relevant protocol), CERTAIN ANTIBIOTICS AND HERBAL PRODUCTS. THE RULE OF THE PERIOD OF ILLNESS SHOULD BE GIVEN IN WRITING: SOME DRUGS SHOULD BE TEMPORARILY DISCONTINUED IN CASE OF VOMITING, DIARRHEA AND FEBRILE ILLNESS (related protocol). IN THE DIABETIC PATIENT, BLOOD SUGAR AND KETONE MONITORING SHOULD ALSO BE PLANNED ON SICK DAYS AND IT SHOULD BE EXPLAINED THAT INSULIN SHOULD NOT BE DISCONTINUED ON ITS OWN. Rules SHOULD BE VERIFIED FROM THE INSTITUTIONAL PROTOCOL	A written plan should be given to the family in children	—	During periods of illness
Concomitant organ follow-up and referral The simultaneous monitoring of the eye, foot, and heart in these patients is due to the fact that the damage is not limited to a single organ. Changes caused by diabetes in small vessels progress similarly in the kidney, the fundus of the eye, and nerves; therefore, if damage is detected in one organ, the others should also be evaluated. This association is valuable not only for screening but also for diagnosis because the presence or absence of a fundus finding provides clues about the source of kidney disease. Additionally, in patients with nerve damage, foot ulcers develop silently and can only be found during examination. For this reason, monitoring should not be based on a single laboratory value but should follow a plan that encompasses the organs together.	FUNDUS EXAMINATION, FOOT EXAMINATION and CARDIOVASCULAR EVALUATION should be done REGULARLY because THE SAME SMALL VESSEL DISEASE ALSO AFFECTS THESE ORGANS (relevant protocols). NEPHROLOGY REFERRAL SHOULD NOT BE DELAYED: RAPID PROGRESSION, VERY HIGH ALBUMINURIA, SUSPICION OF NON-DIABETIC CAUSE, REFRACTORY HIGH BLOOD PRESSURE, REFRACTORY HIGH POTASSIUM, AND ADVANCED RENAL FAILURE REQUIRE REFERRAL. ARM VEINS SHOULD BE PROTECTED IN ADVANCED STAGE (related protocol)	Follow-up in children is conducted at a specialized center.	—	Throughout follow-up

Alternative

Glomerular diseases can also be present in diabetic patients and may require a biopsy.
Drug-induced kidney damage is revealed through the medication history.
Urinary tract obstruction should be excluded, and bladder dysfunction is common in diabetic patients.
Kidney artery stenosis is considered in cases of resistant hypertension and creatinine increase after medication.
Contrast-induced damage is associated with a history of interventions (relevant protocol).
Kidney dysfunction due to heart failure is a separate entity.
Transient albuminuria due to infection is excluded by repeating the measurement.
Amyloidosis and plasma cell disorders should be considered in older age (relevant protocol).
Kidney disease due to hypertension is evaluated separately.
Recurrent acute kidney injury attacks can lead to permanent loss of function (relevant protocol).

Red flags

ONLY LOOKING AT ALBUMINURIA → IN SOME PATIENTS, ALBUMINURIA DOES NOT INCREASE SIGNIFICANTLY, BUT GLOMERULAR FILTRATION FUNCTION QUIETLY DECREASES OVER THE YEARS; in these patients, monitoring provides CONSISTENTLY CLEAN RESULTS and DECLINE IS ONLY DETECTED AT AN ADVANCED STAGE.
DIAGNOSIS WITH A SINGLE MEASUREMENT → FEVER, EXERCISE, URINARY TRACT INFECTION, HIGH BLOOD SUGAR, and HEART FAILURE CAN CAUSE TRANSIENT ALBUMINURIA.
ATTRIBUTING EVERY KIDNEY IMPAIRMENT IN A DIABETIC PATIENT TO DIABETES → THE EXPLANATION APPEARS READY, THE DIAGNOSIS IS NOT QUESTIONED, and THE PATIENT IS CONSIDERED SUBJECT TO A PROGRESSIVE COURSE; however, THESE PATIENTS CAN ALSO DEVELOP AN INDEPENDENT KIDNEY DISEASE.
Not evaluating the finding at the bottom of the eye → THE DAMAGE IN THE KIDNEY AND EYE ARE TWO SIDES OF THE SAME SMALL VESSEL DISEASE and USUALLY PROGRESS TOGETHER; in a patient whose eye is entirely clean, SIGNIFICANT KIDNEY DISEASE suggests ANOTHER CAUSE.
Overlooking signs such as SUDDEN ONSET, RAPID WORSENING, BLOOD AND CASTS IN URINE, SHORT DISEASE DURATION, and SUDDEN SEVERE PROTEIN LOSS → NEPHROLOGY REFERRAL and BIOPSY EVALUATION are required.
Telling a patient whose blood sugar levels have improved that the 'disease has resolved' → AS KIDNEY FUNCTION DECREASES, INSULIN and SOME MEDICATIONS slowly WEAN OFF, and the DOSE used for YEARS WITHOUT PROBLEMS may now be EXCESSIVE; THE MAIN ISSUE IS THE DECLINE IN KIDNEY FUNCTION.
Not considering the RISK OF HYPOGLYCEMIA → SEVERE AND REPETITIVE HYPOGLYCEMIA in advanced age may lead to FALLS, HEART EVENTS, and LOSS OF CONSCIOUSNESS.
Using TWO DIFFERENT RENIN-ANGIOTENSIN BLOCKERS together → PROVIDES NO ADDITIONAL BENEFIT but SIGNIFICANTLY INCREASES THE RISK OF HIGH POTASSIUM AND ACUTE KIDNEY INJURY.
Not monitoring CREATININE and POTASSIUM at the start of treatment.
Unnecessarily stopping medication due to LIMITED INCREASE IN CREATININE → THIS IS AN EXPECTED RESPONSE; however, A SIGNIFICANT INCREASE SUGGESTS VASCULAR NARROWING.
Applying the same strict blood sugar target to everyone → its benefit is CLEAR IN THE EARLY STAGE; in LATE STAGE, BENEFIT DECREASES and HARM INCREASES. SEVERE HYPOGLYCEMIA can cause harm much sooner than the benefit achieved over many years.
Stopping INSULIN on its own DURING ILLNESS → during illness, INSULIN REQUIREMENT GENERALY INCREASES and stopping it leads to A SEVERE METABOLIC STATE. The plan must specify SEPARATELY and IN WRITING WHICH MEDICATION TO STOP and WHICH TO CONTINUE.
Not asking about USE OF OVER-THE-COUNTER PAINKILLERS AND HERBAL PRODUCTS.
Neglecting EYE and FOOT EXAMINATIONS → in a patient with NERVE DAMAGE, FOOT INJURIES DEVELOP SILENTLY and CAN ONLY BE FOUND BY EXAMINATION.
Delaying NEPHROLOGY REFERRAL and NOT PROTECTING ARM VESSELS IN ADVANCED STAGE.

Disposition and follow-up

Green zone: Patient whose albuminuria and filtration function are stable, blood pressure and blood sugar are on target, no nephrotoxic exposure, and disease period plan is provided: regular follow-up in primary care with planned reevaluation at set intervals.
Yellow zone: Rapid progression, very high albuminuria, suspicion of non-diabetic cause, resistant hypertension, resistant hyperkalemia, recurrent hypoglycemia, and advanced stage kidney failure: referral to nephrology and advanced tests.
Red zone: Severe hypoglycemia and altered consciousness: emergency treatment and review of medication doses. Electrocardiographic changes or muscle weakness due to high potassium: urgent evaluation (relevant protocol). Marked decrease in urine output and rapid rise in creatinine: urgent assessment for acute kidney injury and imaging for obstruction (relevant protocol). Shortness of breath due to fluid overload: urgent evaluation. Fever, foot ulcer, and general deterioration: urgent assessment for infection (relevant protocol). Nausea, vomiting, and high blood sugar with deep breathing: urgent metabolic assessment (relevant protocol).

Key clinical points

READ FIRST — two tests and the question of 'is it really due to sugar?'

SCREENING IS DONE WITH TWO TESTS: URINE ALBUMIN-TO-CREATININE RATIO + ESTIMATED GLOMERULAR FILTRATION RATE | THE CLASSIC COURSE is described as follows: FIRST, A SMALL AMOUNT OF ALBUMIN LEAKS INTO THE URINE → THIS AMOUNT INCREASES → FINALLY, FILTRATION CAPACITY DECREASES | THIS SEQUENCE IS TRUE FOR MANY PATIENTS BUT NOT ALL | In a group of patients, ALBUMIN IN THE URINE DOES NOT INCREASE SIGNIFICANTLY; however, FILTRATION FUNCTION SILENTLY DECREASES OVER YEARS → monitoring only albumin gives CONSISTENTLY NORMAL RESULTS, and IT IS ASSUMED THAT THE PATIENT IS PROTECTED | DECLINE IS ONLY NOTICED AT AN ADVANCED STAGE → BOTH TESTS ARE REQUESTED TOGETHER AND MONITORED OVER TIME | DIAGNOSIS CANNOT BE MADE WITH A SINGLE MEASUREMENT: FEVER | HEAVY EXERCISE | URINARY TRACT INFECTION | HIGH BLOOD SUGAR | HEART FAILURE → TRANSIENT ALBUMINURIA | THE MOST IMPORTANT QUESTION: IS THIS DYSFUNCTION REALLY DUE TO SUGAR? — THE MAIN WAY TO MISS TREATABLE DISEASES | When a long-time diabetic patient develops kidney dysfunction, THE EXPLANATION SEEMS READY → THE DIAGNOSIS IS NOT QUESTIONED | ADVANCED TESTS ARE NOT DONE | THE PATIENT IS ASSUMED TO BE IN A PROGRESSIVE COURSE | HOWEVER, THESE PATIENTS CAN ALSO DEVELOP AN INDEPENDENT KIDNEY DISEASE LIKE ANYONE ELSE | THE STRONGEST CLUE IS THE BACK OF THE EYE: DAMAGE IN THE KIDNEY AND DAMAGE IN THE EYE ARE TWO SIDES OF THE SAME SMALL VESSEL DISEASE OF DIABETES and USUALLY PROGRESS TOGETHER → IN A PATIENT WHOSE EYES ARE COMPLETELY CLEAN, SIGNIFICANT KIDNEY DISEASE SUGGESTS THAT THE CONDITION MAY BE DUE TO ANOTHER CAUSE | OTHER CLUES: SUDDEN ONSET | RAPID WORSENING | BLOOD IN URINE AND ERYTHROCYTE CASTS | VERY SHORT DURATION OF DIABETES | SUDDEN ONSET OF HEAVY PROTEIN LOSS | FINDINGS OF ANOTHER SYSTEMIC DISEASE | RESISTANT HIGH BLOOD PRESSURE → REFER TO NEPHROLOGY + CONSIDER BIOPSY

Screening is done with two tests because the classic sequence does not apply to every patient; in some patients, albumin does not increase significantly, but filtration function silently decreases over the years, and monitoring that only looks at albumin always gives normal results. The most important question is whether the dysfunction is truly due to diabetes because the explanation seems ready and the diagnosis is not questioned, whereas these patients can also develop an independent kidney disease. The strongest clue is the back of the eye: damage in the kidney and eye are two sides of the same small vessel disease and usually progress together, so significant kidney disease in a patient with clean eyes suggests another cause.

Hypoglycemia trap and the two-blocker rule

AS THE KIDNEYS DETERIORATE, HYPOGLYCEMIA INCREASES — a common but LATELY UNDERSTOOD development | INSULIN and SOME SUGAR-LOWERING MEDICATIONS are largely eliminated from the body THROUGH THE KIDNEYS | When kidney function declines, THIS ELIMINATION SLOWS and THE DRUG STAYS LONGER IN THE BLOOD → A DOSE THAT HAS BEEN USED WITHOUT PROBLEMS FOR YEARS now starts to be TOO MUCH | BECAUSE THIS CHANGE IS SLOW, it can be interpreted by both patient and doctor as an IMPROVEMENT IN THE DISEASE: blood sugar levels have IMPROVED, and it may even seem possible to REDUCE THE MEDICATION | HOWEVER, THE MAIN ISSUE IS THE DECLINE IN KIDNEY FUNCTION | IF THIS DISTINCTION IS NOT MADE, the patient experiences SEVERE AND RECURRENT HYPOGLYCEMIA → FALLS IN OLD AGE | HEART EVENTS | LOSS OF CONSCIOUSNESS | RULE: in a patient whose blood sugar unexpectedly improves, one does NOT SAY 'THE DISEASE HAS IMPROVED' → KIDNEY FUNCTION IS CHECKED and DOSES ARE REDUCED | TWO RENIN-ANGIOTENSIN BLOCKERS ARE NOT USED TOGETHER — an example where the intuition 'MORE SUPPRESSION BRINGS MORE BENEFIT' PROVED WRONG | This group reduces protein loss and slows progression by LOWERING THE INTRAGLOMERULAR PRESSURE OF THE KIDNEY → based on this, it was thought that USING TWO DRUGS TOGETHER WOULD INCREASE THE EFFECT | HOWEVER, this approach DID NOT PROVIDE THE EXPECTED ADDITIONAL BENEFIT and on the contrary, SERIOUS SIDE EFFECTS such as HIGH POTASSIUM and ACUTE KIDNEY INJURY INCREASED SIGNIFICANTLY | ADDITIONALLY: a LIMITED INCREASE IN CREATININE at the start of treatment is an EXPECTED RESPONSE and ALONE DOES NOT WARRANT STOPPING THE MEDICATION → but A SIGNIFICANT INCREASE SUGGESTS VASCULAR NARROWING | AFTER TREATMENT STARTS or DOSE INCREASED, CREATININE + POTASSIUM ARE MONITORED

As the kidney deteriorates, hypoglycemia increases because insulin and some sugar-lowering drugs are largely eliminated through the kidneys, and due to the deterioration, the drug stays longer in the blood; since the change is slow, it can be interpreted as an improvement in the disease, whereas the main issue is the decline in kidney function. Using two renin-angiotensin blockers together did not provide the expected additional benefit, on the contrary, it significantly increased the risk of high potassium and acute kidney injury. A limited increase in creatinine at the start of treatment is an expected response and does not alone warrant stopping the drug.

Individualization of targets, disease day plan, and organ monitoring

GOALS ARE INDIVIDUALIZED — the SAME GOAL in the same disease is NOT CORRECT FOR EVERYONE | The kidney-protective effect of blood sugar control appears MOST PROMINENTLY in the EARLY STAGE: during this period, tight control DELAYS THE DEVELOPMENT AND PROGRESSION OF ALBUMINURIA | AFTER KIDNEY FUNCTION HAS SIGNIFICANTLY DECLINED, the benefit of the same tight goal DECREASES, and the harm INCREASES | REASON: INCREASED RISK OF HYPOGLYCEMIA + patients are generally ELDERLY and have MULTIPLE COMORBIDITIES | SEVERE HYPOGLYCEMIA CAN CAUSE HARM IN A MUCH SHORTER TIME THAN THE BENEFIT ACHIEVABLE OVER MANY YEARS → the goal is determined according to the STAGE OF THE DISEASE and the PATIENT'S FRAILTY | THE SICK DAY PLAN HAS TWO COMPONENTS — EASILY CONFUSED | (1) IN SITUATIONS THAT CAUSE FLUID LOSS, SOME KIDNEY-PROTECTIVE DRUGS ARE TEMPORARILY STOPPED | (2) DURING THE SAME PERIOD, THE RULES OF DIABETES APPLY: it is DANGEROUS for a patient using insulin to STOP ALL OF THEIR INSULIN BECAUSE THEY ARE UNABLE TO EAT → during illness, the body's INSULIN NEED USUALLY INCREASES, and stopping it may lead to A SEVERE METABOLIC CONDITION | THESE TWO RULES CAN BE CONFUSED, and THE PATIENT MAY STOP ALL MEDICATION → the plan specifies separately and IN WRITING WHICH DRUG SHOULD BE STOPPED and WHICH SHOULD BE CONTINUED | ORGAN MONITORING IS CONCURRENT: damage IS NOT LIMITED TO A SINGLE ORGAN — changes in small vessels progress SIMILARLY IN THE KIDNEY, THE RETINA, AND THE NERVES | This association is VALUABLE NOT ONLY FOR SCREENING BUT ALSO FOR DIAGNOSIS because the PRESENCE OR ABSENCE OF RETINAL FINDINGS provides a clue about THE ORIGIN OF KIDNEY DISEASE | IN A PATIENT WITH NERVE DAMAGE, FOOT LESIONS DEVELOP SILENTLY AND CAN ONLY BE DETECTED BY EXAMINATION → monitoring is carried out not based on A SINGLE LAB VALUE, but THROUGH A PLAN THAT COVERS THE ORGANS TOGETHER

Goals should be individualized because the kidney-protective effect of blood sugar control appears MOST PROMINENTLY in the early stage; in the advanced stage, the benefit of the same tight goal decreases and the harm increases, and severe hypoglycemia can cause harm in a much shorter time than the benefit achievable over many years. The sick day plan has two components and can be confused: while some medications are temporarily stopped, stopping all insulin is dangerous; therefore, the plan is provided separately and in writing. Organ monitoring is conducted concurrently because damage progresses similarly in the kidney, eye, and nerves, and foot lesions can only be detected through examination.

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Detailed assessment

Diagnostic and decision reasoning

Clinical framework

Overview

Diabetic kidney disease is the most common cause of end-stage kidney failure and, since it does not cause any complaints in the early stage, it is found only through screening. Screening should be done with urine albumin-to-creatinine ratio and estimated filtration function, and both should be requested together because in some patients filtration function decreases before albuminuria develops.

The most important distinguishing question is whether the disorder is really due to diabetes; the absence of changes in the fundus, sudden onset, rapid worsening, blood and casts in the urine, and a short disease duration suggest another cause. As kidney function decreases, insulin and some drugs accumulate and hypoglycemia increases.

Two renin-angiotensin blockers should not be used together.

Differential diagnosis and assessment

Key considerations

Glomerular diseases also occur in diabetic patients and require biopsy.
Drug-induced kidney damage appears with a history of medication.
Urinary tract obstruction should be excluded.
Kidney artery stenosis is considered in resistant hypertension.
Contrast-induced damage is associated with a history of interventions (relevant protocol).
Kidney dysfunction due to heart failure is a separate entity.
Transient albuminuria due to infection is excluded by repeating the measurement.
Amyloidosis and plasma cell disorders should be considered in older age (relevant protocol).
Kidney disease due to hypertension is evaluated separately.
Recurrent acute kidney injury attacks lead to permanent loss (relevant protocol).

Clinical decision reasoning

Why it matters

The points that determine the clinical outcome in this disease are related to how the screening is done and whether the diagnosis is questioned. The first point is that both tests are requested together; the group that regresses without albuminuria is seen only this way.

The second and most overlooked point is that not every kidney disorder is attributed to diabetes; fundus findings are a strong clue. The third point is the hypoglycemia trap; as the kidney deteriorates, insulin accumulates and what is perceived as improvement is actually regression.

The fourth point is that the two blockers should not be used together. The fifth point is the individualization of targets.

The sixth point is that the disease day plan should have two components. The last point is that organ monitoring should be conducted simultaneously.

Safety and monitoring

Complications and safety

Critical complications

End-stage kidney failure and the need for dialysis may develop (relevant protocol).
Cardiovascular disease is the most common cause of death.
Severe and recurrent hypoglycemias cause falls and loss of consciousness.
High potassium can cause life-threatening arrhythmia.
Anemia and bone-mineral disorder develop.
Fluid overload and pulmonary edema may be observed.
Side effects due to drug accumulation increase.
Eye and nerve involvement progress simultaneously.
Foot wounds and infections develop silently (relevant protocol).
Bladder dysfunction may lead to urinary obstruction.

Special patient populations

Special considerations

In type 1 diabetes, the association between eye findings and kidney involvement is stronger.
In older age, targets should be relaxed due to the risk of hypoglycemia and frailty.
Drug choices change during pregnancy and require specialist monitoring.
Some diabetes medications are not used in advanced stage kidney failure.
In patients with heart failure, fluid and medication management should be planned together.
Drug selection changes in patients with liver disease.
Screening and treatment in children and adolescents are carried out in specialized centers.
In dialysis patients, the need for diabetes medications and insulin should be readjusted (relevant protocol).
In post-transplant patients, drug interactions should also be monitored (relevant protocol).

Follow-up and reassessment

Follow-up plan

Monitoring of diabetic kidney disease should be based on re-measuring the albumin-to-creatinine ratio and glomerular filtration function together at planned intervals. Blood pressure should be measured at every visit, the medication list should be reviewed completely, and the use of over-the-counter painkillers should be explicitly asked.

A history of hypoglycemia should be investigated at each visit because patients might not report it, considering it unimportant; in case of increasing frequency of hypoglycemia, kidney function should be checked, and doses should be reviewed. In patients who start or have an increased dose of renin-angiotensin blockers, creatinine and potassium should be monitored.

Fundus examination, foot examination, and cardiovascular evaluation should be performed at regular intervals. A written plan for illness periods should be provided, clearly specifying which medication should be stopped and which should be continued.

In advanced stages, treatment options and vascular protection should be discussed in advance. Warning signs should be explained to the patient; severe hypoglycemia, significant reduction in urine output, rapid weight gain, shortness of breath, muscle weakness, new wounds on the feet, and sudden visual changes require immediate presentation.