What is the best approach to manage a dry cough in a patient with impaired renal function on hemodialysis (HD)?

Managing Dry Cough in Hemodialysis Patients

The best approach is to systematically identify and treat the underlying cause rather than empirically treating the cough itself, with ACE inhibitor-induced cough, fluid overload, and GERD being the three most common etiologies requiring targeted intervention. 1

Algorithmic Approach to Diagnosis

Step 1: Evaluate for ACE Inhibitor-Induced Cough

• Immediately switch from ACE inhibitors to an angiotensin receptor blocker (ARB) if the patient is taking an ACE inhibitor, as this is the most common reversible cause of dry cough in dialysis patients and ARBs provide equivalent renal and cardiovascular protection without the cough side effect. 1
• ACE inhibitor-induced cough is a class effect that occurs in a substantial proportion of patients and resolves within days to weeks of switching to an ARB. 1

Step 2: Assess for Fluid Overload and Pulmonary Edema

• Evaluate for pulmonary congestion even in the absence of peripheral edema, as dialysis patients can have isolated pulmonary edema without ankle swelling due to left ventricular dysfunction or diastolic heart failure. 2
• Look specifically for orthopnea, jugular venous distension, hepatojugular reflux, pulmonary rales, and S3 gallop rather than relying on peripheral edema. 2
• Fluid overload causes both restrictive and obstructive respiratory abnormalities that manifest as cough and dyspnea. 3
• If fluid overload is present, optimize ultrafiltration during dialysis sessions by gradually probing for true dry weight over 4-12 weeks, reducing interdialytic weight gains to less than 4.8% of body weight, and considering high-dose loop diuretics if residual renal function exists. 4, 1

Step 3: Consider GERD (Less Common in HD than PD)

• While GERD is significantly more common in peritoneal dialysis patients (3-fold higher risk), it can still occur in hemodialysis patients. 1, 5
• If heartburn symptoms are present alongside cough, initiate twice-daily proton pump inhibitor therapy. 1

Step 4: Evaluate for Asthma/Bronchospasm

• Avoid beta-blocking medications if bronchospasm is suspected, as 40% of dialysis patients with cough may have wheezing. 1
• Initiate inhaled bronchodilators and corticosteroids as appropriate if wheezing is present on examination. 1

Step 5: Rule Out Infectious Causes

• Dialysis patients have increased susceptibility to tuberculosis and other respiratory infections due to immunosuppression. 1
• Obtain chest imaging and consider tuberculosis screening if cough is persistent and other causes have been excluded. 1

Optimizing Fluid Management to Address Volume-Related Cough

Achieving True Dry Weight

• Gradually probe for dry weight over multiple dialysis sessions (4-12 weeks) by incrementally increasing ultrafiltration while monitoring for hypotension and cramping, as rapid achievement can cause intradialytic complications. 4
• Reduce ultrafiltration rate toward the end of dialysis to allow adequate vascular refilling from tissue spaces, which prevents hypotension while still achieving target weight. 4
• Recognize the "lag phenomenon" where blood pressure continues to decrease for 8 months or longer after extracellular fluid volume normalizes, allowing systematic tapering of antihypertensive medications. 4

Monitoring Fluid Status

• Use clinical assessment including blood pressure trends, presence of edema, and tolerance to ultrafiltration rather than waiting for gross volume overload to become apparent. 4
• Patients can have "silent overhydration" without obvious clinical signs, so systematic probing for dry weight is essential even when overt fluid excess is not evident. 4

Critical Pitfalls to Avoid

• Never use empiric cough suppressants like erdosteine as first-line therapy without identifying the underlying cause, as this delays appropriate treatment of potentially serious conditions like pulmonary edema or tuberculosis. 1
• Never assume all cough in dialysis patients is benign—always evaluate for life-threatening pulmonary edema, which requires optimization of dialysis ultrafiltration rather than symptomatic treatment. 1, 2
• Never continue ACE inhibitors if cough develops—switching to an ARB is mandatory and provides equivalent benefit without the adverse effect. 1
• Never rely on the presence or absence of ankle edema to rule in or rule out pulmonary congestion, as left ventricular failure can cause isolated pulmonary edema without peripheral signs. 2
• Never ignore the possibility of bilateral renal artery stenosis (Pickering syndrome) in patients with recurrent pulmonary edema and poorly controlled hypertension, as this affects 94% of patients presenting with this syndrome and requires specific intervention. 2